KOD

SEC source: 0001209191-20-051701 · doc4.xml · nonDerivative · entry 5

EHRLICH JASON · CIK 0001754049 · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 34,003

F1 · kind: The sales reported in this Form 4 were effected pursuant to a 10b5-1 trading plan.

F5 · price: The price reported in Column 4 is a weighted-average price. The shares were sold in multiple transactions ranging from $54.21 to $54.28, inclusive.

SEC source: 0001209191-20-051701 · doc4.xml · nonDerivative · entry 4

EHRLICH JASON · CIK 0001754049 · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 34,548

F1 · kind: The sales reported in this Form 4 were effected pursuant to a 10b5-1 trading plan.

F4 · price: The price reported in Column 4 is a weighted-average price. The shares were sold in multiple transactions ranging from $53.30 to $54.12, inclusive.

SEC source: 0001209191-20-051701 · doc4.xml · nonDerivative · entry 3

EHRLICH JASON · CIK 0001754049 · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 35,645

F1 · kind: The sales reported in this Form 4 were effected pursuant to a 10b5-1 trading plan.

F3 · price: The price reported in Column 4 is a weighted-average price. The shares were sold in multiple transactions ranging from $52.35 to $53.19, inclusive.

SEC source: 0001209191-20-051701 · doc4.xml · nonDerivative · entry 2

EHRLICH JASON · CIK 0001754049 · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 37,620

F1 · kind: The sales reported in this Form 4 were effected pursuant to a 10b5-1 trading plan.

F2 · price: The price reported in Column 4 is a weighted-average price. The shares were sold in multiple transactions ranging from $51.21 to $51.96, inclusive. The Reporting Person undertakes to provide the Issuer, any security holder of the Issuer, or the Staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in these footnotes.

SEC source: 0001209191-20-051701 · doc4.xml · nonDerivative · entry 1

EHRLICH JASON · CIK 0001754049 · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 40,934

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

SEC source: 0001638599-20-000818 · doc4_6873.xml · nonDerivative · entry 24

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 11,090,409

F14 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667 and Life Sciences in multiple transactions at prices ranging from $47.153 to $48.15, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the Staff, upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F3 · ownership.nature: After giving effect to the transaction reported herein and as a result of their ownership interest in (i) Baker Brothers Life Sciences Capital L.P. and (ii) Life Sciences, Felix J. Baker and Julian C. Baker may be deemed to have an indirect pecuniary interest in Common Stock reported in column 5 of Table I beneficially owned by Life Sciences, a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital, L.P., a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital (GP), LLC, due to their interest in Life Sciences and Baker Brothers Life Sciences Capital, L.P.'s right to receive an allocation of a portion of the profits from Life Sciences.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000818 · doc4_6873.xml · nonDerivative · entry 23

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 1,010,594

F14 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667 and Life Sciences in multiple transactions at prices ranging from $47.153 to $48.15, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the Staff, upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F2 · ownership.nature: After giving effect to the transaction and as a result of their ownership interest in (i) Baker Biotech Capital, L.P. and (ii) 667, Julian C. Baker and Felix J. Baker each may be deemed to have an indirect pecuniary interest in common stock ("Common Stock") of the Issuer reported in column 5 of Table I directly held by 667, a limited partnership of which the sole general partner is Baker Biotech Capital, L.P., a limited partnership of which the sole general partner is Baker Biotech Capital (GP), LLC, due to their interest in 667 and Baker Biotech Capital, L.P.'s right to receive an allocation of a portion of the profits from 667.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000818 · doc4_6873.xml · nonDerivative · entry 22

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 11,075,237

F13 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667 and Life Sciences in multiple transactions at prices ranging from $46.96 to $47.57, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the Staff, upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F3 · ownership.nature: After giving effect to the transaction reported herein and as a result of their ownership interest in (i) Baker Brothers Life Sciences Capital L.P. and (ii) Life Sciences, Felix J. Baker and Julian C. Baker may be deemed to have an indirect pecuniary interest in Common Stock reported in column 5 of Table I beneficially owned by Life Sciences, a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital, L.P., a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital (GP), LLC, due to their interest in Life Sciences and Baker Brothers Life Sciences Capital, L.P.'s right to receive an allocation of a portion of the profits from Life Sciences.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000818 · doc4_6873.xml · nonDerivative · entry 21

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 1,009,374

F13 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667 and Life Sciences in multiple transactions at prices ranging from $46.96 to $47.57, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the Staff, upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F2 · ownership.nature: After giving effect to the transaction and as a result of their ownership interest in (i) Baker Biotech Capital, L.P. and (ii) 667, Julian C. Baker and Felix J. Baker each may be deemed to have an indirect pecuniary interest in common stock ("Common Stock") of the Issuer reported in column 5 of Table I directly held by 667, a limited partnership of which the sole general partner is Baker Biotech Capital, L.P., a limited partnership of which the sole general partner is Baker Biotech Capital (GP), LLC, due to their interest in 667 and Baker Biotech Capital, L.P.'s right to receive an allocation of a portion of the profits from 667.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000818 · doc4_6873.xml · nonDerivative · entry 20

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 10,998,764

F12 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667 and Life Sciences in multiple transactions at prices ranging from $46.82 to $47.15, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the Staff, upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F3 · ownership.nature: After giving effect to the transaction reported herein and as a result of their ownership interest in (i) Baker Brothers Life Sciences Capital L.P. and (ii) Life Sciences, Felix J. Baker and Julian C. Baker may be deemed to have an indirect pecuniary interest in Common Stock reported in column 5 of Table I beneficially owned by Life Sciences, a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital, L.P., a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital (GP), LLC, due to their interest in Life Sciences and Baker Brothers Life Sciences Capital, L.P.'s right to receive an allocation of a portion of the profits from Life Sciences.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000818 · doc4_6873.xml · nonDerivative · entry 19

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 1,003,223

F12 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667 and Life Sciences in multiple transactions at prices ranging from $46.82 to $47.15, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the Staff, upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F2 · ownership.nature: After giving effect to the transaction and as a result of their ownership interest in (i) Baker Biotech Capital, L.P. and (ii) 667, Julian C. Baker and Felix J. Baker each may be deemed to have an indirect pecuniary interest in common stock ("Common Stock") of the Issuer reported in column 5 of Table I directly held by 667, a limited partnership of which the sole general partner is Baker Biotech Capital, L.P., a limited partnership of which the sole general partner is Baker Biotech Capital (GP), LLC, due to their interest in 667 and Baker Biotech Capital, L.P.'s right to receive an allocation of a portion of the profits from 667.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000818 · doc4_6873.xml · nonDerivative · entry 18

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 10,982,957

F3 · ownership.nature: After giving effect to the transaction reported herein and as a result of their ownership interest in (i) Baker Brothers Life Sciences Capital L.P. and (ii) Life Sciences, Felix J. Baker and Julian C. Baker may be deemed to have an indirect pecuniary interest in Common Stock reported in column 5 of Table I beneficially owned by Life Sciences, a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital, L.P., a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital (GP), LLC, due to their interest in Life Sciences and Baker Brothers Life Sciences Capital, L.P.'s right to receive an allocation of a portion of the profits from Life Sciences.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000818 · doc4_6873.xml · nonDerivative · entry 17

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 1,001,951

F2 · ownership.nature: After giving effect to the transaction and as a result of their ownership interest in (i) Baker Biotech Capital, L.P. and (ii) 667, Julian C. Baker and Felix J. Baker each may be deemed to have an indirect pecuniary interest in common stock ("Common Stock") of the Issuer reported in column 5 of Table I directly held by 667, a limited partnership of which the sole general partner is Baker Biotech Capital, L.P., a limited partnership of which the sole general partner is Baker Biotech Capital (GP), LLC, due to their interest in 667 and Baker Biotech Capital, L.P.'s right to receive an allocation of a portion of the profits from 667.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000818 · doc4_6873.xml · nonDerivative · entry 16

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 10,982,772

F11 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667 and Life Sciences in multiple transactions at prices ranging from $47.03 to $48.00, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the Staff, upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F3 · ownership.nature: After giving effect to the transaction reported herein and as a result of their ownership interest in (i) Baker Brothers Life Sciences Capital L.P. and (ii) Life Sciences, Felix J. Baker and Julian C. Baker may be deemed to have an indirect pecuniary interest in Common Stock reported in column 5 of Table I beneficially owned by Life Sciences, a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital, L.P., a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital (GP), LLC, due to their interest in Life Sciences and Baker Brothers Life Sciences Capital, L.P.'s right to receive an allocation of a portion of the profits from Life Sciences.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000818 · doc4_6873.xml · nonDerivative · entry 15

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 1,001,936

F11 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667 and Life Sciences in multiple transactions at prices ranging from $47.03 to $48.00, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the Staff, upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F2 · ownership.nature: After giving effect to the transaction and as a result of their ownership interest in (i) Baker Biotech Capital, L.P. and (ii) 667, Julian C. Baker and Felix J. Baker each may be deemed to have an indirect pecuniary interest in common stock ("Common Stock") of the Issuer reported in column 5 of Table I directly held by 667, a limited partnership of which the sole general partner is Baker Biotech Capital, L.P., a limited partnership of which the sole general partner is Baker Biotech Capital (GP), LLC, due to their interest in 667 and Baker Biotech Capital, L.P.'s right to receive an allocation of a portion of the profits from 667.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000818 · doc4_6873.xml · nonDerivative · entry 14

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 10,973,671

F10 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667 and Life Sciences in multiple transactions at prices ranging from $46.63 to $47.50, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the Staff, upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F3 · ownership.nature: After giving effect to the transaction reported herein and as a result of their ownership interest in (i) Baker Brothers Life Sciences Capital L.P. and (ii) Life Sciences, Felix J. Baker and Julian C. Baker may be deemed to have an indirect pecuniary interest in Common Stock reported in column 5 of Table I beneficially owned by Life Sciences, a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital, L.P., a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital (GP), LLC, due to their interest in Life Sciences and Baker Brothers Life Sciences Capital, L.P.'s right to receive an allocation of a portion of the profits from Life Sciences.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000818 · doc4_6873.xml · nonDerivative · entry 13

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 1,001,224

F10 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667 and Life Sciences in multiple transactions at prices ranging from $46.63 to $47.50, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the Staff, upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F2 · ownership.nature: After giving effect to the transaction and as a result of their ownership interest in (i) Baker Biotech Capital, L.P. and (ii) 667, Julian C. Baker and Felix J. Baker each may be deemed to have an indirect pecuniary interest in common stock ("Common Stock") of the Issuer reported in column 5 of Table I directly held by 667, a limited partnership of which the sole general partner is Baker Biotech Capital, L.P., a limited partnership of which the sole general partner is Baker Biotech Capital (GP), LLC, due to their interest in 667 and Baker Biotech Capital, L.P.'s right to receive an allocation of a portion of the profits from 667.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000818 · doc4_6873.xml · nonDerivative · entry 12

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 10,947,433

F9 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667 and Life Sciences in multiple transactions at prices ranging from $46.08 to $47.00, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the Staff, upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F3 · ownership.nature: After giving effect to the transaction reported herein and as a result of their ownership interest in (i) Baker Brothers Life Sciences Capital L.P. and (ii) Life Sciences, Felix J. Baker and Julian C. Baker may be deemed to have an indirect pecuniary interest in Common Stock reported in column 5 of Table I beneficially owned by Life Sciences, a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital, L.P., a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital (GP), LLC, due to their interest in Life Sciences and Baker Brothers Life Sciences Capital, L.P.'s right to receive an allocation of a portion of the profits from Life Sciences.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000818 · doc4_6873.xml · nonDerivative · entry 11

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 999,170

F9 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667 and Life Sciences in multiple transactions at prices ranging from $46.08 to $47.00, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the Staff, upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F2 · ownership.nature: After giving effect to the transaction and as a result of their ownership interest in (i) Baker Biotech Capital, L.P. and (ii) 667, Julian C. Baker and Felix J. Baker each may be deemed to have an indirect pecuniary interest in common stock ("Common Stock") of the Issuer reported in column 5 of Table I directly held by 667, a limited partnership of which the sole general partner is Baker Biotech Capital, L.P., a limited partnership of which the sole general partner is Baker Biotech Capital (GP), LLC, due to their interest in 667 and Baker Biotech Capital, L.P.'s right to receive an allocation of a portion of the profits from 667.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000818 · doc4_6873.xml · nonDerivative · entry 10

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 10,918,114

F8 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667 and Life Sciences in multiple transactions at prices ranging from $45.04 to $45.50, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the Staff, upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F3 · ownership.nature: After giving effect to the transaction reported herein and as a result of their ownership interest in (i) Baker Brothers Life Sciences Capital L.P. and (ii) Life Sciences, Felix J. Baker and Julian C. Baker may be deemed to have an indirect pecuniary interest in Common Stock reported in column 5 of Table I beneficially owned by Life Sciences, a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital, L.P., a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital (GP), LLC, due to their interest in Life Sciences and Baker Brothers Life Sciences Capital, L.P.'s right to receive an allocation of a portion of the profits from Life Sciences.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000818 · doc4_6873.xml · nonDerivative · entry 9

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 996,875

F8 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667 and Life Sciences in multiple transactions at prices ranging from $45.04 to $45.50, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the Staff, upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F2 · ownership.nature: After giving effect to the transaction and as a result of their ownership interest in (i) Baker Biotech Capital, L.P. and (ii) 667, Julian C. Baker and Felix J. Baker each may be deemed to have an indirect pecuniary interest in common stock ("Common Stock") of the Issuer reported in column 5 of Table I directly held by 667, a limited partnership of which the sole general partner is Baker Biotech Capital, L.P., a limited partnership of which the sole general partner is Baker Biotech Capital (GP), LLC, due to their interest in 667 and Baker Biotech Capital, L.P.'s right to receive an allocation of a portion of the profits from 667.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000818 · doc4_6873.xml · nonDerivative · entry 8

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 10,905,982

F3 · ownership.nature: After giving effect to the transaction reported herein and as a result of their ownership interest in (i) Baker Brothers Life Sciences Capital L.P. and (ii) Life Sciences, Felix J. Baker and Julian C. Baker may be deemed to have an indirect pecuniary interest in Common Stock reported in column 5 of Table I beneficially owned by Life Sciences, a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital, L.P., a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital (GP), LLC, due to their interest in Life Sciences and Baker Brothers Life Sciences Capital, L.P.'s right to receive an allocation of a portion of the profits from Life Sciences.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000818 · doc4_6873.xml · nonDerivative · entry 7

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 995,925

F2 · ownership.nature: After giving effect to the transaction and as a result of their ownership interest in (i) Baker Biotech Capital, L.P. and (ii) 667, Julian C. Baker and Felix J. Baker each may be deemed to have an indirect pecuniary interest in common stock ("Common Stock") of the Issuer reported in column 5 of Table I directly held by 667, a limited partnership of which the sole general partner is Baker Biotech Capital, L.P., a limited partnership of which the sole general partner is Baker Biotech Capital (GP), LLC, due to their interest in 667 and Baker Biotech Capital, L.P.'s right to receive an allocation of a portion of the profits from 667.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000818 · doc4_6873.xml · nonDerivative · entry 6

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 10,873,894

F7 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667 and Life Sciences in multiple transactions at prices ranging from $47.00 to $47.995, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the Staff, upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F3 · ownership.nature: After giving effect to the transaction reported herein and as a result of their ownership interest in (i) Baker Brothers Life Sciences Capital L.P. and (ii) Life Sciences, Felix J. Baker and Julian C. Baker may be deemed to have an indirect pecuniary interest in Common Stock reported in column 5 of Table I beneficially owned by Life Sciences, a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital, L.P., a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital (GP), LLC, due to their interest in Life Sciences and Baker Brothers Life Sciences Capital, L.P.'s right to receive an allocation of a portion of the profits from Life Sciences.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000818 · doc4_6873.xml · nonDerivative · entry 5

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 993,413

F7 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667 and Life Sciences in multiple transactions at prices ranging from $47.00 to $47.995, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the Staff, upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F2 · ownership.nature: After giving effect to the transaction and as a result of their ownership interest in (i) Baker Biotech Capital, L.P. and (ii) 667, Julian C. Baker and Felix J. Baker each may be deemed to have an indirect pecuniary interest in common stock ("Common Stock") of the Issuer reported in column 5 of Table I directly held by 667, a limited partnership of which the sole general partner is Baker Biotech Capital, L.P., a limited partnership of which the sole general partner is Baker Biotech Capital (GP), LLC, due to their interest in 667 and Baker Biotech Capital, L.P.'s right to receive an allocation of a portion of the profits from 667.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000818 · doc4_6873.xml · nonDerivative · entry 4

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 10,796,438

F6 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667 and Life Sciences in multiple transactions at prices ranging from $47.33 to $47.60, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the Staff, upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F3 · ownership.nature: After giving effect to the transaction reported herein and as a result of their ownership interest in (i) Baker Brothers Life Sciences Capital L.P. and (ii) Life Sciences, Felix J. Baker and Julian C. Baker may be deemed to have an indirect pecuniary interest in Common Stock reported in column 5 of Table I beneficially owned by Life Sciences, a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital, L.P., a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital (GP), LLC, due to their interest in Life Sciences and Baker Brothers Life Sciences Capital, L.P.'s right to receive an allocation of a portion of the profits from Life Sciences.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000818 · doc4_6873.xml · nonDerivative · entry 3

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 987,351

F6 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667 and Life Sciences in multiple transactions at prices ranging from $47.33 to $47.60, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the Staff, upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F2 · ownership.nature: After giving effect to the transaction and as a result of their ownership interest in (i) Baker Biotech Capital, L.P. and (ii) 667, Julian C. Baker and Felix J. Baker each may be deemed to have an indirect pecuniary interest in common stock ("Common Stock") of the Issuer reported in column 5 of Table I directly held by 667, a limited partnership of which the sole general partner is Baker Biotech Capital, L.P., a limited partnership of which the sole general partner is Baker Biotech Capital (GP), LLC, due to their interest in 667 and Baker Biotech Capital, L.P.'s right to receive an allocation of a portion of the profits from 667.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000818 · doc4_6873.xml · nonDerivative · entry 2

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 10,793,451

F1 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667, L.P. ("667") and Baker Brothers Life Sciences, L.P. ("Life Sciences", and together with 667, the "Funds") in multiple transactions at prices ranging from $46.94 to $46.99, inclusive. The reporting persons undertake to provide to Kodiak Sciences Inc. (the "Issuer"), any security holder of the Issuer, or the staff of the Securities and Exchange Commission (the "Staff"), upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F3 · ownership.nature: After giving effect to the transaction reported herein and as a result of their ownership interest in (i) Baker Brothers Life Sciences Capital L.P. and (ii) Life Sciences, Felix J. Baker and Julian C. Baker may be deemed to have an indirect pecuniary interest in Common Stock reported in column 5 of Table I beneficially owned by Life Sciences, a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital, L.P., a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital (GP), LLC, due to their interest in Life Sciences and Baker Brothers Life Sciences Capital, L.P.'s right to receive an allocation of a portion of the profits from Life Sciences.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000818 · doc4_6873.xml · nonDerivative · entry 1

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 987,117

F1 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667, L.P. ("667") and Baker Brothers Life Sciences, L.P. ("Life Sciences", and together with 667, the "Funds") in multiple transactions at prices ranging from $46.94 to $46.99, inclusive. The reporting persons undertake to provide to Kodiak Sciences Inc. (the "Issuer"), any security holder of the Issuer, or the staff of the Securities and Exchange Commission (the "Staff"), upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F2 · ownership.nature: After giving effect to the transaction and as a result of their ownership interest in (i) Baker Biotech Capital, L.P. and (ii) 667, Julian C. Baker and Felix J. Baker each may be deemed to have an indirect pecuniary interest in common stock ("Common Stock") of the Issuer reported in column 5 of Table I directly held by 667, a limited partnership of which the sole general partner is Baker Biotech Capital, L.P., a limited partnership of which the sole general partner is Baker Biotech Capital (GP), LLC, due to their interest in 667 and Baker Biotech Capital, L.P.'s right to receive an allocation of a portion of the profits from 667.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000748 · doc4_6833.xml · nonDerivative · entry 16

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 10,791,092

F12 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667 and Life Sciences in multiple transactions at prices ranging from $48.32 to $49.29, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the Staff, upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F3 · ownership.nature: After giving effect to the transaction reported herein and as a result of their ownership interest in (i) Baker Brothers Life Sciences Capital L.P. and (ii) Life Sciences, Felix J. Baker and Julian C. Baker may be deemed to have an indirect pecuniary interest in Common Stock reported in column 5 of Table I beneficially owned by Life Sciences, a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital, L.P., a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital (GP), LLC, due to their interest in Life Sciences and Baker Brothers Life Sciences Capital, L.P.'s right to receive an allocation of a portion of the profits from Life Sciences.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000748 · doc4_6833.xml · nonDerivative · entry 15

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 986,932

F12 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667 and Life Sciences in multiple transactions at prices ranging from $48.32 to $49.29, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the Staff, upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F2 · ownership.nature: After giving effect to the transaction and as a result of their ownership interest in (i) Baker Biotech Capital, L.P. and (ii) 667, Julian C. Baker and Felix J. Baker each may be deemed to have an indirect pecuniary interest in common stock ("Common Stock") of the Issuer reported in column 5 of Table I directly held by 667, a limited partnership of which the sole general partner is Baker Biotech Capital, L.P., a limited partnership of which the sole general partner is Baker Biotech Capital (GP), LLC, due to their interest in 667 and Baker Biotech Capital, L.P.'s right to receive an allocation of a portion of the profits from 667.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000748 · doc4_6833.xml · nonDerivative · entry 14

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 10,707,260

F11 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667 and Life Sciences in multiple transactions at prices ranging from $48.63 to $48.88, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the Staff, upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F3 · ownership.nature: After giving effect to the transaction reported herein and as a result of their ownership interest in (i) Baker Brothers Life Sciences Capital L.P. and (ii) Life Sciences, Felix J. Baker and Julian C. Baker may be deemed to have an indirect pecuniary interest in Common Stock reported in column 5 of Table I beneficially owned by Life Sciences, a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital, L.P., a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital (GP), LLC, due to their interest in Life Sciences and Baker Brothers Life Sciences Capital, L.P.'s right to receive an allocation of a portion of the profits from Life Sciences.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000748 · doc4_6833.xml · nonDerivative · entry 13

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 980,287

F11 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667 and Life Sciences in multiple transactions at prices ranging from $48.63 to $48.88, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the Staff, upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F2 · ownership.nature: After giving effect to the transaction and as a result of their ownership interest in (i) Baker Biotech Capital, L.P. and (ii) 667, Julian C. Baker and Felix J. Baker each may be deemed to have an indirect pecuniary interest in common stock ("Common Stock") of the Issuer reported in column 5 of Table I directly held by 667, a limited partnership of which the sole general partner is Baker Biotech Capital, L.P., a limited partnership of which the sole general partner is Baker Biotech Capital (GP), LLC, due to their interest in 667 and Baker Biotech Capital, L.P.'s right to receive an allocation of a portion of the profits from 667.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000748 · doc4_6833.xml · nonDerivative · entry 12

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 10,704,974

F10 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667 and Life Sciences in multiple transactions at prices ranging from $47.28 to $48.15, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the Staff, upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F3 · ownership.nature: After giving effect to the transaction reported herein and as a result of their ownership interest in (i) Baker Brothers Life Sciences Capital L.P. and (ii) Life Sciences, Felix J. Baker and Julian C. Baker may be deemed to have an indirect pecuniary interest in Common Stock reported in column 5 of Table I beneficially owned by Life Sciences, a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital, L.P., a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital (GP), LLC, due to their interest in Life Sciences and Baker Brothers Life Sciences Capital, L.P.'s right to receive an allocation of a portion of the profits from Life Sciences.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000748 · doc4_6833.xml · nonDerivative · entry 11

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 980,106

F10 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667 and Life Sciences in multiple transactions at prices ranging from $47.28 to $48.15, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the Staff, upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F2 · ownership.nature: After giving effect to the transaction and as a result of their ownership interest in (i) Baker Biotech Capital, L.P. and (ii) 667, Julian C. Baker and Felix J. Baker each may be deemed to have an indirect pecuniary interest in common stock ("Common Stock") of the Issuer reported in column 5 of Table I directly held by 667, a limited partnership of which the sole general partner is Baker Biotech Capital, L.P., a limited partnership of which the sole general partner is Baker Biotech Capital (GP), LLC, due to their interest in 667 and Baker Biotech Capital, L.P.'s right to receive an allocation of a portion of the profits from 667.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000748 · doc4_6833.xml · nonDerivative · entry 10

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 10,662,260

F9 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667 and Life Sciences in multiple transactions at prices ranging from $47.79 to $47.84, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the Staff, upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F3 · ownership.nature: After giving effect to the transaction reported herein and as a result of their ownership interest in (i) Baker Brothers Life Sciences Capital L.P. and (ii) Life Sciences, Felix J. Baker and Julian C. Baker may be deemed to have an indirect pecuniary interest in Common Stock reported in column 5 of Table I beneficially owned by Life Sciences, a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital, L.P., a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital (GP), LLC, due to their interest in Life Sciences and Baker Brothers Life Sciences Capital, L.P.'s right to receive an allocation of a portion of the profits from Life Sciences.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000748 · doc4_6833.xml · nonDerivative · entry 9

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 976,720

F9 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667 and Life Sciences in multiple transactions at prices ranging from $47.79 to $47.84, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the Staff, upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F2 · ownership.nature: After giving effect to the transaction and as a result of their ownership interest in (i) Baker Biotech Capital, L.P. and (ii) 667, Julian C. Baker and Felix J. Baker each may be deemed to have an indirect pecuniary interest in common stock ("Common Stock") of the Issuer reported in column 5 of Table I directly held by 667, a limited partnership of which the sole general partner is Baker Biotech Capital, L.P., a limited partnership of which the sole general partner is Baker Biotech Capital (GP), LLC, due to their interest in 667 and Baker Biotech Capital, L.P.'s right to receive an allocation of a portion of the profits from 667.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000748 · doc4_6833.xml · nonDerivative · entry 8

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 10,661,506

F8 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667 and Life Sciences in multiple transactions at prices ranging from $47.19 to $48.00, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the Staff, upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F3 · ownership.nature: After giving effect to the transaction reported herein and as a result of their ownership interest in (i) Baker Brothers Life Sciences Capital L.P. and (ii) Life Sciences, Felix J. Baker and Julian C. Baker may be deemed to have an indirect pecuniary interest in Common Stock reported in column 5 of Table I beneficially owned by Life Sciences, a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital, L.P., a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital (GP), LLC, due to their interest in Life Sciences and Baker Brothers Life Sciences Capital, L.P.'s right to receive an allocation of a portion of the profits from Life Sciences.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000748 · doc4_6833.xml · nonDerivative · entry 7

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 976,660

F8 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667 and Life Sciences in multiple transactions at prices ranging from $47.19 to $48.00, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the Staff, upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F2 · ownership.nature: After giving effect to the transaction and as a result of their ownership interest in (i) Baker Biotech Capital, L.P. and (ii) 667, Julian C. Baker and Felix J. Baker each may be deemed to have an indirect pecuniary interest in common stock ("Common Stock") of the Issuer reported in column 5 of Table I directly held by 667, a limited partnership of which the sole general partner is Baker Biotech Capital, L.P., a limited partnership of which the sole general partner is Baker Biotech Capital (GP), LLC, due to their interest in 667 and Baker Biotech Capital, L.P.'s right to receive an allocation of a portion of the profits from 667.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000748 · doc4_6833.xml · nonDerivative · entry 6

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 10,620,351

F7 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667 and Life Sciences in multiple transactions at prices ranging from $46.28 to $46.80, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the Staff, upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F3 · ownership.nature: After giving effect to the transaction reported herein and as a result of their ownership interest in (i) Baker Brothers Life Sciences Capital L.P. and (ii) Life Sciences, Felix J. Baker and Julian C. Baker may be deemed to have an indirect pecuniary interest in Common Stock reported in column 5 of Table I beneficially owned by Life Sciences, a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital, L.P., a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital (GP), LLC, due to their interest in Life Sciences and Baker Brothers Life Sciences Capital, L.P.'s right to receive an allocation of a portion of the profits from Life Sciences.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000748 · doc4_6833.xml · nonDerivative · entry 5

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 973,398

F7 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667 and Life Sciences in multiple transactions at prices ranging from $46.28 to $46.80, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the Staff, upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F2 · ownership.nature: After giving effect to the transaction and as a result of their ownership interest in (i) Baker Biotech Capital, L.P. and (ii) 667, Julian C. Baker and Felix J. Baker each may be deemed to have an indirect pecuniary interest in common stock ("Common Stock") of the Issuer reported in column 5 of Table I directly held by 667, a limited partnership of which the sole general partner is Baker Biotech Capital, L.P., a limited partnership of which the sole general partner is Baker Biotech Capital (GP), LLC, due to their interest in 667 and Baker Biotech Capital, L.P.'s right to receive an allocation of a portion of the profits from 667.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000748 · doc4_6833.xml · nonDerivative · entry 4

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 10,609,711

F6 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667 and Life Sciences in multiple transactions at prices ranging from $46.15 to $46.69, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the Staff, upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F3 · ownership.nature: After giving effect to the transaction reported herein and as a result of their ownership interest in (i) Baker Brothers Life Sciences Capital L.P. and (ii) Life Sciences, Felix J. Baker and Julian C. Baker may be deemed to have an indirect pecuniary interest in Common Stock reported in column 5 of Table I beneficially owned by Life Sciences, a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital, L.P., a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital (GP), LLC, due to their interest in Life Sciences and Baker Brothers Life Sciences Capital, L.P.'s right to receive an allocation of a portion of the profits from Life Sciences.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000748 · doc4_6833.xml · nonDerivative · entry 3

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 972,555

F6 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667 and Life Sciences in multiple transactions at prices ranging from $46.15 to $46.69, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the Staff, upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F2 · ownership.nature: After giving effect to the transaction and as a result of their ownership interest in (i) Baker Biotech Capital, L.P. and (ii) 667, Julian C. Baker and Felix J. Baker each may be deemed to have an indirect pecuniary interest in common stock ("Common Stock") of the Issuer reported in column 5 of Table I directly held by 667, a limited partnership of which the sole general partner is Baker Biotech Capital, L.P., a limited partnership of which the sole general partner is Baker Biotech Capital (GP), LLC, due to their interest in 667 and Baker Biotech Capital, L.P.'s right to receive an allocation of a portion of the profits from 667.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001209191-20-048107 · doc4.xml · derivative · entry 4

EHRLICH JASON · CIK 0001754049 · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 379,525

Underlying: Common Stock · 6,950 shares

Expires 2028-08-29

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F4 · derivative.exercise_date: Twenty-five percent of the shares subject to the option vested on September 1, 2019 and 1/48th of the shares subject to the option vest on the same day of each month thereafter.

SEC source: 0001209191-20-048107 · doc4.xml · nonDerivative · entry 3

EHRLICH JASON · CIK 0001754049 · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 33,984

F1 · kind: The sales reported in this Form 4 were effected pursuant to a 10b5-1 trading plan.

F3 · price: The price reported in Column 4 is a weighted-average price. The shares were sold in multiple transactions ranging from $47.05 to $47.66, inclusive.

SEC source: 0001209191-20-048107 · doc4.xml · nonDerivative · entry 2

EHRLICH JASON · CIK 0001754049 · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 38,343

F1 · kind: The sales reported in this Form 4 were effected pursuant to a 10b5-1 trading plan.

F2 · price: The price reported in Column 4 is a weighted-average price. The shares were sold in multiple transactions ranging from $46.00 to $46.93, inclusive. The Reporting Person undertakes to provide the Issuer, any security holder of the Issuer, or the Staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in these footnotes.

SEC source: 0001209191-20-048107 · doc4.xml · nonDerivative · entry 1

EHRLICH JASON · CIK 0001754049 · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 40,934

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

SEC source: 0001638599-20-000748 · doc4_6833.xml · nonDerivative · entry 2

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 10,606,135

F1 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667, L.P. ("667") and Baker Brothers Life Sciences, L.P. ("Life Sciences", and together with 667, the "Funds") in multiple transactions at prices ranging from $46.50 to $47.13, inclusive. The reporting persons undertake to provide to Kodiak Sciences Inc. (the "Issuer"), any security holder of the Issuer, or the staff of the Securities and Exchange Commission (the "Staff"), upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F3 · ownership.nature: After giving effect to the transaction reported herein and as a result of their ownership interest in (i) Baker Brothers Life Sciences Capital L.P. and (ii) Life Sciences, Felix J. Baker and Julian C. Baker may be deemed to have an indirect pecuniary interest in Common Stock reported in column 5 of Table I beneficially owned by Life Sciences, a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital, L.P., a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital (GP), LLC, due to their interest in Life Sciences and Baker Brothers Life Sciences Capital, L.P.'s right to receive an allocation of a portion of the profits from Life Sciences.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001638599-20-000748 · doc4_6833.xml · nonDerivative · entry 1

BAKER BROS. ADVISORS LP · CIK 0001263508 · Director · 10% owner

667, L.P. · CIK 0001551139 · Director · 10% owner

Baker Bros. Advisors (GP) LLC · CIK 0001580575 · Director · 10% owner

Baker Brothers Life Sciences LP · CIK 0001363364 · Director · 10% owner

BAKER FELIX · CIK 0001087940 · Director · 10% owner

BAKER JULIAN · CIK 0001087939 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 972,272

F1 · price: The price reported in Column 4 is a weighted average price. These shares were traded by 667, L.P. ("667") and Baker Brothers Life Sciences, L.P. ("Life Sciences", and together with 667, the "Funds") in multiple transactions at prices ranging from $46.50 to $47.13, inclusive. The reporting persons undertake to provide to Kodiak Sciences Inc. (the "Issuer"), any security holder of the Issuer, or the staff of the Securities and Exchange Commission (the "Staff"), upon request, full information regarding the number of shares traded at each separate price within the range set forth in this footnote.

F2 · ownership.nature: After giving effect to the transaction and as a result of their ownership interest in (i) Baker Biotech Capital, L.P. and (ii) 667, Julian C. Baker and Felix J. Baker each may be deemed to have an indirect pecuniary interest in common stock ("Common Stock") of the Issuer reported in column 5 of Table I directly held by 667, a limited partnership of which the sole general partner is Baker Biotech Capital, L.P., a limited partnership of which the sole general partner is Baker Biotech Capital (GP), LLC, due to their interest in 667 and Baker Biotech Capital, L.P.'s right to receive an allocation of a portion of the profits from 667.

F4 · ownership.nature: Baker Bros. Advisors LP (the "Adviser") serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

SEC source: 0001209191-20-043313 · doc4.xml · derivative · entry 5

EHRLICH JASON · CIK 0001754049 · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 386,475

Underlying: Common Stock · 6,950 shares

Expires 2028-08-29

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F5 · derivative.exercise_date: Twenty-five percent of the shares subject to the option vested on September 1, 2019 and 1/48th of the shares subject to the option vest on the same day of each month thereafter.