PRLD

SEC source: 0001193125-26-265965 · ownership.xml · derivative · 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: No plan indicated

Ownership: Indirect · See Footnotes

Disclosed balance after: 38,000

Underlying: Common Stock · 38,000 shares

Expires 2036-06-08

F1 · shares: Includes 38,000 non-qualified stock options ("Stock Options") exercisable solely into common stock ("Common Stock") of Prelude Therapeutics Incorporated (the "Issuer") granted by the Issuer to Dr. Paul C. Scherer, a full-time employee of Baker Bros. Advisors LP (the "Adviser"), on June 9, 2026, in his capacity as a director of the Issuer, pursuant to the Issuer's 2020 Equity Incentive Plan (the "Incentive Plan"). The Stock Options have a strike price of $3.94 per share, and vest on the earlier of the first anniversary of the grant date or the date of the next annual meeting of stockholders of the Issuer, subject to Dr. Scherer's continued service on the board of directors of the Issuer (the "Board") through such vesting date or an earlier change in control of the Issuer. The Stock Options expire on June 8, 2036.

F1 · derivative.exercise_date: Includes 38,000 non-qualified stock options ("Stock Options") exercisable solely into common stock ("Common Stock") of Prelude Therapeutics Incorporated (the "Issuer") granted by the Issuer to Dr. Paul C. Scherer, a full-time employee of Baker Bros. Advisors LP (the "Adviser"), on June 9, 2026, in his capacity as a director of the Issuer, pursuant to the Issuer's 2020 Equity Incentive Plan (the "Incentive Plan"). The Stock Options have a strike price of $3.94 per share, and vest on the earlier of the first anniversary of the grant date or the date of the next annual meeting of stockholders of the Issuer, subject to Dr. Scherer's continued service on the board of directors of the Issuer (the "Board") through such vesting date or an earlier change in control of the Issuer. The Stock Options expire on June 8, 2036.

F2 · ownership.nature: Dr. Scherer serves on the Board as a representative of 667, L.P. ("667") and Baker Brothers Life Sciences, L.P. ("Life Sciences", and together with 667, the "Funds") and their affiliates and control persons.

F4 · ownership.nature: 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 for the benefit of 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 for the benefit of 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 for the benefit of the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held for the benefit of 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.

F6 · ownership.nature: Pursuant to the policies of the Adviser, Dr. Scherer does not have a right to any of the Issuer's securities issued as compensation for his service on the Board and the Funds are entitled to an indirect proportionate pecuniary interest in such securities. The Funds each own an indirect proportionate pecuniary interest in such securities. Solely as a result of their ownership interest in (i) the general partners of the Funds and (ii) the Funds, Felix J. Baker and Julian C. Baker may be deemed to have an indirect pecuniary interest in the shares of Common Stock, Stock Options and Common Stock issued upon exercise of Stock Options (i.e. no direct pecuniary interest) issued as compensation for such Board service.

F7 · ownership.nature: Pursuant to the policies of the Adviser, the Adviser has voting and dispositive power over the Stock Options and any Common Stock received as a result of the exercise of the Stock Options.

F8 · ownership.nature: The acquisition of Stock Options reported on this form represents a single grant to Dr. Scherer of 38,000 Stock Options on Table II. This grant of 38,000 Stock Options to Dr. Scherer is reported for each of the Funds as each has an indirect pecuniary interest in such securities.

F9 · 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, Julian C. Baker and Felix J. Baker each may be deemed to have an indirect pecuniary interest in the Stock Options reported in column 9 of Table II held for the benefit of 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.

SEC source: 0001193125-26-265965 · ownership.xml · derivative · 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: No plan indicated

Ownership: Indirect · See Footnotes

Disclosed balance after: 38,000

Underlying: Common Stock · 38,000 shares

Expires 2036-06-08

F1 · shares: Includes 38,000 non-qualified stock options ("Stock Options") exercisable solely into common stock ("Common Stock") of Prelude Therapeutics Incorporated (the "Issuer") granted by the Issuer to Dr. Paul C. Scherer, a full-time employee of Baker Bros. Advisors LP (the "Adviser"), on June 9, 2026, in his capacity as a director of the Issuer, pursuant to the Issuer's 2020 Equity Incentive Plan (the "Incentive Plan"). The Stock Options have a strike price of $3.94 per share, and vest on the earlier of the first anniversary of the grant date or the date of the next annual meeting of stockholders of the Issuer, subject to Dr. Scherer's continued service on the board of directors of the Issuer (the "Board") through such vesting date or an earlier change in control of the Issuer. The Stock Options expire on June 8, 2036.

F1 · derivative.exercise_date: Includes 38,000 non-qualified stock options ("Stock Options") exercisable solely into common stock ("Common Stock") of Prelude Therapeutics Incorporated (the "Issuer") granted by the Issuer to Dr. Paul C. Scherer, a full-time employee of Baker Bros. Advisors LP (the "Adviser"), on June 9, 2026, in his capacity as a director of the Issuer, pursuant to the Issuer's 2020 Equity Incentive Plan (the "Incentive Plan"). The Stock Options have a strike price of $3.94 per share, and vest on the earlier of the first anniversary of the grant date or the date of the next annual meeting of stockholders of the Issuer, subject to Dr. Scherer's continued service on the board of directors of the Issuer (the "Board") through such vesting date or an earlier change in control of the Issuer. The Stock Options expire on June 8, 2036.

F2 · ownership.nature: Dr. Scherer serves on the Board as a representative of 667, L.P. ("667") and Baker Brothers Life Sciences, L.P. ("Life Sciences", and together with 667, the "Funds") and their affiliates and control persons.

F3 · ownership.nature: After giving effect to the transaction reported herein 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 the Stock Options reported in column 9 of Table II held for the benefit of 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: 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 for the benefit of 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 for the benefit of 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 for the benefit of the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held for the benefit of 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.

F6 · ownership.nature: Pursuant to the policies of the Adviser, Dr. Scherer does not have a right to any of the Issuer's securities issued as compensation for his service on the Board and the Funds are entitled to an indirect proportionate pecuniary interest in such securities. The Funds each own an indirect proportionate pecuniary interest in such securities. Solely as a result of their ownership interest in (i) the general partners of the Funds and (ii) the Funds, Felix J. Baker and Julian C. Baker may be deemed to have an indirect pecuniary interest in the shares of Common Stock, Stock Options and Common Stock issued upon exercise of Stock Options (i.e. no direct pecuniary interest) issued as compensation for such Board service.

F7 · ownership.nature: Pursuant to the policies of the Adviser, the Adviser has voting and dispositive power over the Stock Options and any Common Stock received as a result of the exercise of the Stock Options.

F8 · ownership.nature: The acquisition of Stock Options reported on this form represents a single grant to Dr. Scherer of 38,000 Stock Options on Table II. This grant of 38,000 Stock Options to Dr. Scherer is reported for each of the Funds as each has an indirect pecuniary interest in such securities.

SEC source: 0001572451-26-000003 · primarydocument.xml · derivative · entry 1

Bonita David P · CIK 0001572451 · Director · 10% owner

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 38,000

Underlying: Common Stock · 38,000 shares

Expires 2036-06-08

F1 · derivative.exercise_date: The option award will fully vest upon the earlier of (a) the Issuer's next annual stockholder meeting, or (b) the one-year anniversary of the grant date, such to the Reporting Person's provision of service to the Issuer on each vesting date.

F2 · ownership.direct: Pursuant to an agreement with OrbiMed Advisors LLC and OrbiMed Capital GP VI LLC, the Reporting Person is obligated to transfer any securities issued under any such stock options or other awards, or the economic benefit thereof, to OrbiMed Advisors LLC and OrbiMed Capital GP VI LLC, which will in turn ensure that such securities or economic benefits are provided to OrbiMed Private Investments VI, LP.

SEC source: 0001435618-26-000006 · primarydocument.xml · derivative · entry 1

Babler Martin · CIK 0001435618 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 38,000

Underlying: Common Stock · 38,000 shares

Expires 2036-06-08

F1 · derivative.exercise_date: The option award will fully vest upon the earlier of (a) the Issuer's next annual stockholder meeting, or (b) the one-year anniversary of the grant date, such to the Reporting Person's provision of service to the Issuer on each vesting date.

SEC source: 0001236927-26-000003 · primarydocument.xml · derivative · entry 1

FRIEDMAN PAUL A · CIK 0001236927 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 38,000

Underlying: Common Stock · 38,000 shares

Expires 2036-06-08

F1 · derivative.exercise_date: The option award will fully vest upon the earlier of (a) the Issuer's next annual stockholder meeting, or (b) the one-year anniversary of the grant date, such to the Reporting Person's provision of service to the Issuer on each vesting date.

SEC source: 0001617541-26-000005 · primarydocument.xml · derivative · entry 1

Dorton Katina · CIK 0001617541 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 38,000

Underlying: Common Stock · 38,000 shares

Expires 2036-06-08

F1 · derivative.exercise_date: The option award will fully vest upon the earlier of (a) the Issuer's next annual stockholder meeting, or (b) the one-year anniversary of the grant date, such to the Reporting Person's provision of service to the Issuer on each vesting date.

SEC source: 0001620368-26-000003 · primarydocument.xml · derivative · entry 1

Sandor Victor · CIK 0001620368 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 38,000

Underlying: Common Stock · 38,000 shares

Expires 2036-06-08

F1 · derivative.exercise_date: The option award will fully vest upon the earlier of (a) the Issuer's next annual stockholder meeting, or (b) the one-year anniversary of the grant date, such to the Reporting Person's provision of service to the Issuer on each vesting date.

SEC source: 0001489966-26-000004 · primarydocument.xml · derivative · entry 1

Morris Charles Q · CIK 0001489966 · Chief Medical Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 450,000

Underlying: Common Stock · 450,000 shares

Expires 2036-04-30

F1 · derivative.exercise_date: The stock option vests as to 25% of the total shares on May 1, 2027, and thereafter vests as to 1/48 of the total shares monthly until fully vested, subject to the Reporting Person's provision of service to the Issuer on each vesting date.

SEC source: 0001231919-26-000422 · form4-04282026_090449.xml · derivative · entry 2

RA CAPITAL MANAGEMENT, L.P. · CIK 0001346824 · 10% owner

RA Capital Healthcare Fund LP · CIK 0001315082 · 10% owner

Kolchinsky Peter · CIK 0001384859 · 10% owner

Shah Rajeev M. · CIK 0001619841 · 10% owner

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

10b5-1 filing: No plan indicated

Ownership: Indirect · See footnotes

Disclosed balance after: 1,407,000

Underlying: Common Stock · 1,407,000 shares

Expires not disclosed

F1 · kind: On April 27, 2026, RA Capital Healthcare Fund, L.P. (the "Fund") entered into an Exchange Agreement with the Issuer pursuant to which the Fund exchanged, for no additional consideration, 1,407,000 shares of the Issuer's Common Stock for a pre-funded warrant exercisable for up to 1,407,000 shares of the Issuer's Common Stock at an exercise price of $0.0001 per share (the "Pre-Funded Warrant").

F1 · price: On April 27, 2026, RA Capital Healthcare Fund, L.P. (the "Fund") entered into an Exchange Agreement with the Issuer pursuant to which the Fund exchanged, for no additional consideration, 1,407,000 shares of the Issuer's Common Stock for a pre-funded warrant exercisable for up to 1,407,000 shares of the Issuer's Common Stock at an exercise price of $0.0001 per share (the "Pre-Funded Warrant").

F4 · derivative.exercise_date: The Pre-Funded Warrant has no expiration date and is exercisable immediately. Notwithstanding the foregoing, the Fund shall not be entitled to exercise the Pre-Funded Warrant to the extent that it would cause the aggregate number of shares of Common Stock beneficially owned by the Fund, together with its Attribution Parties (as defined in the Pre-Funded Warrant), to exceed 9.99% of the total number of issued and outstanding shares of Common Stock of the Issuer following such exercise.

F4 · derivative.expiration_date: The Pre-Funded Warrant has no expiration date and is exercisable immediately. Notwithstanding the foregoing, the Fund shall not be entitled to exercise the Pre-Funded Warrant to the extent that it would cause the aggregate number of shares of Common Stock beneficially owned by the Fund, together with its Attribution Parties (as defined in the Pre-Funded Warrant), to exceed 9.99% of the total number of issued and outstanding shares of Common Stock of the Issuer following such exercise.

F2 · ownership.nature: Held directly by the Fund.

F3 · ownership.nature: RA Capital Management, L.P. (the "Adviser") is the investment manager for the Fund. The general partner of the Adviser is RA Capital Management GP, LLC (the "Adviser GP"), of which Dr. Peter Kolchinsky and Mr. Rajeev Shah are the managing members. Each of the Adviser, the Adviser GP, the Fund, Dr. Kolchinsky and Mr. Shah disclaims beneficial ownership of any of the reported securities, except to the extent of its or his respective pecuniary interest therein.

SEC source: 0001231919-26-000422 · form4-04282026_090449.xml · nonDerivative · entry 1

RA CAPITAL MANAGEMENT, L.P. · CIK 0001346824 · 10% owner

RA Capital Healthcare Fund LP · CIK 0001315082 · 10% owner

Kolchinsky Peter · CIK 0001384859 · 10% owner

Shah Rajeev M. · CIK 0001619841 · 10% owner

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

10b5-1 filing: No plan indicated

Ownership: Indirect · See footnotes

Disclosed balance after: 6,475,882

F1 · kind: On April 27, 2026, RA Capital Healthcare Fund, L.P. (the "Fund") entered into an Exchange Agreement with the Issuer pursuant to which the Fund exchanged, for no additional consideration, 1,407,000 shares of the Issuer's Common Stock for a pre-funded warrant exercisable for up to 1,407,000 shares of the Issuer's Common Stock at an exercise price of $0.0001 per share (the "Pre-Funded Warrant").

F1 · price: On April 27, 2026, RA Capital Healthcare Fund, L.P. (the "Fund") entered into an Exchange Agreement with the Issuer pursuant to which the Fund exchanged, for no additional consideration, 1,407,000 shares of the Issuer's Common Stock for a pre-funded warrant exercisable for up to 1,407,000 shares of the Issuer's Common Stock at an exercise price of $0.0001 per share (the "Pre-Funded Warrant").

F2 · ownership.nature: Held directly by the Fund.

F3 · ownership.nature: RA Capital Management, L.P. (the "Adviser") is the investment manager for the Fund. The general partner of the Adviser is RA Capital Management GP, LLC (the "Adviser GP"), of which Dr. Peter Kolchinsky and Mr. Rajeev Shah are the managing members. Each of the Adviser, the Adviser GP, the Fund, Dr. Kolchinsky and Mr. Shah disclaims beneficial ownership of any of the reported securities, except to the extent of its or his respective pecuniary interest therein.

SEC source: 0001193125-26-170468 · ownership.xml · derivative · 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: No plan indicated

Ownership: Indirect · See Footnotes

Disclosed balance after: 20,105,994

Underlying: Common Stock · 2,137,651 shares

Expires not disclosed

F1 · shares: 667, L.P. ("667") and Baker Brothers Life Sciences, L.P. ("Life Sciences", and together with 667, the "Funds") purchased 114,601 and 2,137,651 warrants to purchase common stock of Prelude Therapeutics Incorporated (the "Issuer") ("Prefunded Warrants"), respectively, for $4.4399 per warrant pursuant to an underwritten public offering that closed on April 21, 2026.

F2 · derivative.exercise_date: The Prefunded Warrants have no expiration date and are exercisable at an exercise price of $0.0001 per share immediately at any time at the option of the holder on a 1-for-1 basis into Common Stock to the extent that after giving effect to such conversion the holders thereof, together with their affiliates and any members of a Section 13(d) group with such holders, would beneficially own, for purposes of Rule 13d-3 under the Securities Act of 1934, as amended, no more than 4.99% of the outstanding shares of Common Stock (the "Maximum Percentage") immediately prior to and following such exercise.

F3 · derivative.exercise_date: By written notice to the Issuer, the Funds may from time to time increase or decrease the Maximum Percentage applicable to that Fund to any other percentage not in excess of 19.99%. Any such increase will not be effective until the 61st day after such notice is delivered to the Issuer.

F2 · derivative.expiration_date: The Prefunded Warrants have no expiration date and are exercisable at an exercise price of $0.0001 per share immediately at any time at the option of the holder on a 1-for-1 basis into Common Stock to the extent that after giving effect to such conversion the holders thereof, together with their affiliates and any members of a Section 13(d) group with such holders, would beneficially own, for purposes of Rule 13d-3 under the Securities Act of 1934, as amended, no more than 4.99% of the outstanding shares of Common Stock (the "Maximum Percentage") immediately prior to and following such exercise.

F2 · ownership.nature: The Prefunded Warrants have no expiration date and are exercisable at an exercise price of $0.0001 per share immediately at any time at the option of the holder on a 1-for-1 basis into Common Stock to the extent that after giving effect to such conversion the holders thereof, together with their affiliates and any members of a Section 13(d) group with such holders, would beneficially own, for purposes of Rule 13d-3 under the Securities Act of 1934, as amended, no more than 4.99% of the outstanding shares of Common Stock (the "Maximum Percentage") immediately prior to and following such exercise.

F5 · 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 directly 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 directly 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 directly by the Funds.

F6 · 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.

F7 · ownership.nature: After giving effect to the transactions reported herein and as a result of their ownership interest in (i) Baker Brothers Life Sciences Capital, L.P. and (ii) Life Sciences, Julian C. Baker and Felix J. Baker each may be deemed to have an indirect pecuniary interest in the securities reported in column 9 of Table II held directly 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.

SEC source: 0001193125-26-170468 · ownership.xml · derivative · 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: No plan indicated

Ownership: Indirect · See Footnotes

Disclosed balance after: 1,678,273

Underlying: Common Stock · 114,601 shares

Expires not disclosed

F1 · shares: 667, L.P. ("667") and Baker Brothers Life Sciences, L.P. ("Life Sciences", and together with 667, the "Funds") purchased 114,601 and 2,137,651 warrants to purchase common stock of Prelude Therapeutics Incorporated (the "Issuer") ("Prefunded Warrants"), respectively, for $4.4399 per warrant pursuant to an underwritten public offering that closed on April 21, 2026.

F2 · derivative.exercise_date: The Prefunded Warrants have no expiration date and are exercisable at an exercise price of $0.0001 per share immediately at any time at the option of the holder on a 1-for-1 basis into Common Stock to the extent that after giving effect to such conversion the holders thereof, together with their affiliates and any members of a Section 13(d) group with such holders, would beneficially own, for purposes of Rule 13d-3 under the Securities Act of 1934, as amended, no more than 4.99% of the outstanding shares of Common Stock (the "Maximum Percentage") immediately prior to and following such exercise.

F3 · derivative.exercise_date: By written notice to the Issuer, the Funds may from time to time increase or decrease the Maximum Percentage applicable to that Fund to any other percentage not in excess of 19.99%. Any such increase will not be effective until the 61st day after such notice is delivered to the Issuer.

F2 · derivative.expiration_date: The Prefunded Warrants have no expiration date and are exercisable at an exercise price of $0.0001 per share immediately at any time at the option of the holder on a 1-for-1 basis into Common Stock to the extent that after giving effect to such conversion the holders thereof, together with their affiliates and any members of a Section 13(d) group with such holders, would beneficially own, for purposes of Rule 13d-3 under the Securities Act of 1934, as amended, no more than 4.99% of the outstanding shares of Common Stock (the "Maximum Percentage") immediately prior to and following such exercise.

F2 · ownership.nature: The Prefunded Warrants have no expiration date and are exercisable at an exercise price of $0.0001 per share immediately at any time at the option of the holder on a 1-for-1 basis into Common Stock to the extent that after giving effect to such conversion the holders thereof, together with their affiliates and any members of a Section 13(d) group with such holders, would beneficially own, for purposes of Rule 13d-3 under the Securities Act of 1934, as amended, no more than 4.99% of the outstanding shares of Common Stock (the "Maximum Percentage") immediately prior to and following such exercise.

F4 · ownership.nature: After giving effect to the transactions reported herein 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 the securities reported in column 9 of Table II held directly 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.

F5 · 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 directly 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 directly 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 directly by the Funds.

F6 · 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: 0000947871-26-000461 · ownership.xml · nonDerivative · entry 2

ORBIMED ADVISORS LLC · CIK 0001055951 · Director · 10% owner

OrbiMed Capital GP VI LLC · CIK 0001682115 · Director · 10% owner

ORBIMED CAPITAL LLC · CIK 0001157524 · Director · 10% owner

OrbiMed Genesis GP LLC · CIK 0001808744 · Director · 10% owner

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

10b5-1 filing: No plan indicated

Ownership: Indirect · See footnotes

Disclosed balance after: 1,126,126

F1 · shares: These securities were purchased in an underwritten public offering.

F4 · ownership.nature: These securities are held of record by OrbiMed Genesis Master Fund, L.P. ("Genesis Master Fund"). OrbiMed Genesis GP LLC ("Genesis GP") is the general partner of Genesis Master Fund. OrbiMed Advisors is the managing member of Genesis GP. By virtue of such relationships, Genesis GP and OrbiMed Advisors may be deemed to have voting and investment power with respect to the securities held by Genesis Master Fund. OrbiMed Advisors exercises voting and investment power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the shares held by Genesis Master Fund.

F5 · ownership.nature: This report on Form 4 is filed by OrbiMed Advisors, GP VI, OrbiMed Capital and Genesis GP. Each of the Reporting Persons disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. OrbiMed Advisors and GP VI have designated a representative, David Bonita, a member of OrbiMed Advisors, to serve on the Issuer's board of directors. This report on Form 4 shall not be deemed an admission that any such person or entity is a beneficial owner of such securities for the purpose of Section 16 of the Exchange Act, or for any other purpose.

SEC source: 0000947871-26-000461 · ownership.xml · nonDerivative · entry 1

ORBIMED ADVISORS LLC · CIK 0001055951 · Director · 10% owner

OrbiMed Capital GP VI LLC · CIK 0001682115 · Director · 10% owner

ORBIMED CAPITAL LLC · CIK 0001157524 · Director · 10% owner

OrbiMed Genesis GP LLC · CIK 0001808744 · Director · 10% owner

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

10b5-1 filing: No plan indicated

Ownership: Indirect · See footnotes

Disclosed balance after: 11,808,945

F1 · shares: These securities were purchased in an underwritten public offering.

F2 · ownership.nature: These securities are held of record by OrbiMed Private Investments VI, LP ("OPI VI"). OrbiMed Capital GP VI LLC ("GP VI") is the general partner of OPI VI and OrbiMed Advisors LLC ("OrbiMed Advisors") is the managing member of GP VI. By virtue of such relationships, OrbiMed Advisors and GP VI may be deemed to have voting power and investment power over the securities held by OPI VI and, as a result, may be deemed to have beneficial ownership over such securities. OrbiMed Advisors exercises voting and investment power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the securities held by OPI VI.

F5 · ownership.nature: This report on Form 4 is filed by OrbiMed Advisors, GP VI, OrbiMed Capital and Genesis GP. Each of the Reporting Persons disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. OrbiMed Advisors and GP VI have designated a representative, David Bonita, a member of OrbiMed Advisors, to serve on the Issuer's board of directors. This report on Form 4 shall not be deemed an admission that any such person or entity is a beneficial owner of such securities for the purpose of Section 16 of the Exchange Act, or for any other purpose.

SEC source: 0000947871-26-000462 · ownership.xml · nonDerivative · entry 2

Bonita David P · CIK 0001572451 · Director · 10% owner

10b5-1 filing: No plan indicated

Ownership: Indirect · See footnotes

Disclosed balance after: 1,126,126

F1 · shares: These securities were purchased in an underwritten public offering.

F4 · ownership.nature: These securities are held of record by OrbiMed Genesis Master Fund, L.P. ("Genesis Master Fund"). OrbiMed Genesis GP LLC ("Genesis GP") is the general partner of Genesis Master Fund. OrbiMed Advisors is the managing member of Genesis GP. By virtue of such relationships, Genesis GP and OrbiMed Advisors may be deemed to have voting and investment power with respect to the securities held by Genesis Master Fund. OrbiMed Advisors exercises voting and investment power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the shares held by Genesis Master Fund.

F5 · ownership.nature: Each of the Reporting Person, OrbiMed Advisors, GP VI, OrbiMed Capital and Genesis GP disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of his or its pecuniary interest therein, if any. This report on Form 4 shall not be deemed an admission that any such person or entity is a beneficial owner of such securities for the purpose of Section 16 of the Exchange Act, or for any other purpose.

SEC source: 0000947871-26-000462 · ownership.xml · nonDerivative · entry 1

Bonita David P · CIK 0001572451 · Director · 10% owner

10b5-1 filing: No plan indicated

Ownership: Indirect · See footnotes

Disclosed balance after: 11,808,945

F1 · shares: These securities were purchased in an underwritten public offering.

F2 · ownership.nature: These securities are held of record by OrbiMed Private Investments VI, LP ("OPI VI"). OrbiMed Capital GP VI LLC ("GP VI") is the general partner of OPI VI and OrbiMed Advisors LLC ("OrbiMed Advisors") is the managing member of GP VI. The Reporting Person is a member of OrbiMed Advisors. By virtue of such relationships, OrbiMed Advisors and GP VI may be deemed to have voting power and investment power over the securities held by OPI VI and, as a result, may be deemed to have beneficial ownership over such securities. OrbiMed Advisors exercises voting and investment power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the securities held by OPI VI.

F5 · ownership.nature: Each of the Reporting Person, OrbiMed Advisors, GP VI, OrbiMed Capital and Genesis GP disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of his or its pecuniary interest therein, if any. This report on Form 4 shall not be deemed an admission that any such person or entity is a beneficial owner of such securities for the purpose of Section 16 of the Exchange Act, or for any other purpose.

SEC source: 0001825005-26-000002 · primarydocument.xml · derivative · entry 1

Combs Andrew · CIK 0001825005 · Chief Chemistry Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 230,000

Underlying: Common Stock · 230,000 shares

Expires 2036-02-03

F1 · derivative.exercise_date: The stock option vests as to 25% of the total shares on Feb 4, 2027, and thereafter vests as to 1/48 of the total shares monthly until fully vested, subject to the Reporting Person's provision of service to the Issuer on each vesting date.

SEC source: 0001824632-26-000002 · primarydocument.xml · derivative · entry 1

Scherle Peggy · CIK 0001824632 · Chief Scientific Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 230,000

Underlying: Common Stock · 230,000 shares

Expires 2036-02-03

F1 · derivative.exercise_date: The stock option vests as to 25% of the total shares on Feb 4, 2027, and thereafter vests as to 1/48 of the total shares monthly until fully vested, subject to the Reporting Person's provision of service to the Issuer on each vesting date.

SEC source: 0001752888-26-000002 · primarydocument.xml · derivative · entry 1

Lim Bryant David · CIK 0001752888 · CLO, CFO, Corp Sec.

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 275,000

Underlying: Common Stock · 275,000 shares

Expires 2036-02-03

F1 · derivative.exercise_date: The stock option vests as to 25% of the total shares on Feb 4, 2027, and thereafter vests as to 1/48 of the total shares monthly until fully vested, subject to the Reporting Person's provision of service to the Issuer on each vesting date.

SEC source: 0001824633-26-000002 · primarydocument.xml · derivative · entry 1

Vaddi Krishna · CIK 0001824633 · Director · CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 837,000

Underlying: Common Stock · 837,000 shares

Expires 2036-02-03

F1 · derivative.exercise_date: The stock option vests as to 25% of the total shares on Feb 4, 2027, and thereafter vests as to 1/48 of the total shares monthly until fully vested, subject to the Reporting Person's provision of service to the Issuer on each vesting date.

SEC source: 0001620368-25-000005 · primarydocument.xml · derivative · entry 1

Sandor Victor · CIK 0001620368 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 121,285

Underlying: Common Stock · 121,285 shares

Expires 2035-11-04

F1 · derivative.exercise_date: The option award vests over a one year period equally one-twelfth per month, subject to Reporting Person's continued service to the Company on each vesting date.

SEC source: 0001617541-25-000005 · primarydocument.xml · derivative · entry 1

Dorton Katina · CIK 0001617541 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 76,000

Underlying: Common Stock · 76,000 shares

Expires 2035-10-16

F1 · derivative.exercise_date: The option award vests over a three year period equally one-thirty-sixth per month, subject to Reporting Person's continued service to the Company on each vesting date.

SEC source: 0001683913-25-000004 · primarydocument.xml · derivative · entry 3

Huang Jane · CIK 0001683913 · President, CMO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 18,750

Underlying: Common Stock · 9,375 shares

Expires not disclosed

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.

F1 · derivative.exercise_price: Each Restricted Stock Unit ("RSU") represents a contingent right to receive one share of Issuer's Common Stock.

F3 · derivative.exercise_date: The RSUs were granted on May 2, 2022 and vest according to the reporting person's employment agreement. The RSUs vested as to 1/4 of the total shares on April 4, 2023, and 1/16 of the remaining shares shall vest quarterly thereafter until fully vested, subject to the continued service of the Reporting Person to the Issuer through each vesting date.

F3 · derivative.expiration_date: The RSUs were granted on May 2, 2022 and vest according to the reporting person's employment agreement. The RSUs vested as to 1/4 of the total shares on April 4, 2023, and 1/16 of the remaining shares shall vest quarterly thereafter until fully vested, subject to the continued service of the Reporting Person to the Issuer through each vesting date.

SEC source: 0001683913-25-000004 · primarydocument.xml · nonDerivative · entry 2

Huang Jane · CIK 0001683913 · President, CMO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 86,917

F2 · shares: Represents shares withheld by the Issuer to satisfy the tax withholding obligation in connection with the vesting of RSUs.

SEC source: 0001683913-25-000004 · primarydocument.xml · nonDerivative · entry 1

Huang Jane · CIK 0001683913 · President, CMO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 90,272

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.

F1 · price: Each Restricted Stock Unit ("RSU") represents a contingent right to receive one share of Issuer's Common Stock.

SEC source: 0001562180-25-005346 · primarydocument.xml · derivative · entry 3

Huang Jane · CIK 0001683913 · President, CMO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 28,125

Underlying: Common Stock · 9,375 shares

Expires not disclosed

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.

F1 · derivative.exercise_price: Each Restricted Stock Unit ("RSU") represents a contingent right to receive one share of Issuer's Common Stock.

F3 · derivative.exercise_date: The RSUs were granted on May 2, 2022 and vest according to the reporting person's employment agreement. The RSUs vested as to 1/4 of the total shares on April 4, 2023, and 1/16 of the remaining shares shall vest quarterly thereafter until fully vested, subject to the continued service of the Reporting Person to the Issuer through each vesting date.

F3 · derivative.expiration_date: The RSUs were granted on May 2, 2022 and vest according to the reporting person's employment agreement. The RSUs vested as to 1/4 of the total shares on April 4, 2023, and 1/16 of the remaining shares shall vest quarterly thereafter until fully vested, subject to the continued service of the Reporting Person to the Issuer through each vesting date.

SEC source: 0001562180-25-005346 · primarydocument.xml · nonDerivative · entry 2

Huang Jane · CIK 0001683913 · President, CMO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 80,897

F2 · shares: Represents shares withheld by the Issuer to satisfy the tax withholding obligation in connection with the vesting of RSUs.

SEC source: 0001562180-25-005346 · primarydocument.xml · nonDerivative · entry 1

Huang Jane · CIK 0001683913 · President, CMO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 84,252

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.

F1 · price: Each Restricted Stock Unit ("RSU") represents a contingent right to receive one share of Issuer's Common Stock.

SEC source: 0000950170-25-086307 · ownership.xml · derivative · 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: No plan indicated

Ownership: Indirect · See Footnotes

Disclosed balance after: 76,000

Underlying: Common Stock · 76,000 shares

Expires 2035-06-11

F1 · shares: Includes 76,000 non-qualified stock options ("Stock Options") exercisable solely into common stock ("Common Stock") of Prelude Therapeutics Incorporated (the "Issuer") granted by the Issuer to Dr. Paul C. Scherer, a full-time employee of Baker Bros. Advisors (GP) LLC (the "Adviser GP"), on June 12, 2025, in his capacity as a director of the Issuer, pursuant to the Issuer's 2020 Stock Incentive Plan, as Amended and Restated (the "Incentive Plan"). The Stock Options have a strike price of $1.04 per share, and vest on the earlier of the first anniversary of the grant date or the date of the next annual meeting of stockholders of the Issuer, subject to Dr. Scherer's continued service on the board of directors of the Issuer (the "Board") through such vesting date or an earlier change in control of the Issuer. The Stock Options expire on June 11, 2035.

F1 · derivative.exercise_date: Includes 76,000 non-qualified stock options ("Stock Options") exercisable solely into common stock ("Common Stock") of Prelude Therapeutics Incorporated (the "Issuer") granted by the Issuer to Dr. Paul C. Scherer, a full-time employee of Baker Bros. Advisors (GP) LLC (the "Adviser GP"), on June 12, 2025, in his capacity as a director of the Issuer, pursuant to the Issuer's 2020 Stock Incentive Plan, as Amended and Restated (the "Incentive Plan"). The Stock Options have a strike price of $1.04 per share, and vest on the earlier of the first anniversary of the grant date or the date of the next annual meeting of stockholders of the Issuer, subject to Dr. Scherer's continued service on the board of directors of the Issuer (the "Board") through such vesting date or an earlier change in control of the Issuer. The Stock Options expire on June 11, 2035.

F2 · ownership.nature: Dr. Scherer serves on the Board as a representative of 667, L.P. ("667") and Baker Brothers Life Sciences, L.P. ("Life Sciences", and together with 667, the "Funds") and their affiliates and control persons.

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 for the benefit of the Funds. 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 for the benefit of 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 for the benefit of the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held for the benefit of 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.

F6 · ownership.nature: Pursuant to the policies of the Adviser, Dr. Scherer does not have a right to any of the Issuer's securities issued as compensation for his service on the Board and the Funds are entitled to an indirect proportionate pecuniary interest in such securities. The Funds each own an indirect proportionate pecuniary interest in such securities. Solely as a result of their ownership interest in (i) the general partners of the Funds and (ii) the Funds, Felix J. Baker and Julian C. Baker may be deemed to have an indirect pecuniary interest in the shares of Common Stock, Stock Options and Common Stock issued upon exercise of Stock Options (i.e. no direct pecuniary interest) issued as compensation for such Board service.

F7 · ownership.nature: Pursuant to the policies of the Adviser, the Adviser has voting and dispositive power over the Stock Options and any Common Stock received as a result of the exercise of the Stock Options.

F8 · ownership.nature: The acquisition of Stock Options reported on this form represents a single grant to Dr. Scherer of 76,000 Stock Options on Table II. This grant of 76,000 Stock Options to Dr. Scherer is reported for each of the Funds as each has an indirect pecuniary interest in such securities.

F9 · 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, Julian C. Baker and Felix J. Baker each may be deemed to have an indirect pecuniary interest in the Stock Options reported in column 9 of Table II held for the benefit of 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.

SEC source: 0000950170-25-086307 · ownership.xml · derivative · 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: No plan indicated

Ownership: Indirect · See Footnotes

Disclosed balance after: 76,000

Underlying: Common Stock · 76,000 shares

Expires 2035-06-11

F1 · shares: Includes 76,000 non-qualified stock options ("Stock Options") exercisable solely into common stock ("Common Stock") of Prelude Therapeutics Incorporated (the "Issuer") granted by the Issuer to Dr. Paul C. Scherer, a full-time employee of Baker Bros. Advisors (GP) LLC (the "Adviser GP"), on June 12, 2025, in his capacity as a director of the Issuer, pursuant to the Issuer's 2020 Stock Incentive Plan, as Amended and Restated (the "Incentive Plan"). The Stock Options have a strike price of $1.04 per share, and vest on the earlier of the first anniversary of the grant date or the date of the next annual meeting of stockholders of the Issuer, subject to Dr. Scherer's continued service on the board of directors of the Issuer (the "Board") through such vesting date or an earlier change in control of the Issuer. The Stock Options expire on June 11, 2035.

F1 · derivative.exercise_date: Includes 76,000 non-qualified stock options ("Stock Options") exercisable solely into common stock ("Common Stock") of Prelude Therapeutics Incorporated (the "Issuer") granted by the Issuer to Dr. Paul C. Scherer, a full-time employee of Baker Bros. Advisors (GP) LLC (the "Adviser GP"), on June 12, 2025, in his capacity as a director of the Issuer, pursuant to the Issuer's 2020 Stock Incentive Plan, as Amended and Restated (the "Incentive Plan"). The Stock Options have a strike price of $1.04 per share, and vest on the earlier of the first anniversary of the grant date or the date of the next annual meeting of stockholders of the Issuer, subject to Dr. Scherer's continued service on the board of directors of the Issuer (the "Board") through such vesting date or an earlier change in control of the Issuer. The Stock Options expire on June 11, 2035.

F2 · ownership.nature: Dr. Scherer serves on the Board as a representative of 667, L.P. ("667") and Baker Brothers Life Sciences, L.P. ("Life Sciences", and together with 667, the "Funds") and their affiliates and control persons.

F3 · ownership.nature: After giving effect to the transaction reported herein 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 the Stock Options reported in column 9 of Table II held for the benefit of 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 for the benefit of the Funds. 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 for the benefit of 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 for the benefit of the Funds.

F5 · ownership.nature: Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held for the benefit of 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.

F6 · ownership.nature: Pursuant to the policies of the Adviser, Dr. Scherer does not have a right to any of the Issuer's securities issued as compensation for his service on the Board and the Funds are entitled to an indirect proportionate pecuniary interest in such securities. The Funds each own an indirect proportionate pecuniary interest in such securities. Solely as a result of their ownership interest in (i) the general partners of the Funds and (ii) the Funds, Felix J. Baker and Julian C. Baker may be deemed to have an indirect pecuniary interest in the shares of Common Stock, Stock Options and Common Stock issued upon exercise of Stock Options (i.e. no direct pecuniary interest) issued as compensation for such Board service.

F7 · ownership.nature: Pursuant to the policies of the Adviser, the Adviser has voting and dispositive power over the Stock Options and any Common Stock received as a result of the exercise of the Stock Options.

F8 · ownership.nature: The acquisition of Stock Options reported on this form represents a single grant to Dr. Scherer of 76,000 Stock Options on Table II. This grant of 76,000 Stock Options to Dr. Scherer is reported for each of the Funds as each has an indirect pecuniary interest in such securities.

SEC source: 0001562180-25-004790 · primarydocument.xml · derivative · entry 1

Bonita David P · CIK 0001572451 · Director · 10% owner

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 38,000

Underlying: Common Stock · 38,000 shares

Expires 2035-06-11

F1 · derivative.exercise_date: The option award will fully vest upon the earlier of (a) the Issuer's next annual stockholder meeting, or (b) the one-year anniversary of the grant date, such to the Reporting Person's provision of service to the Issuer on each vesting date.

SEC source: 0001562180-25-004786 · primarydocument.xml · derivative · entry 1

Babler Martin · CIK 0001435618 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 38,000

Underlying: Common Stock · 38,000 shares

Expires 2035-06-11

F1 · derivative.exercise_date: The option award will fully vest upon the earlier of (a) the Issuer's next annual stockholder meeting, or (b) the one-year anniversary of the grant date, such to the Reporting Person's provision of service to the Issuer on each vesting date.

SEC source: 0001562180-25-004795 · primarydocument.xml · derivative · entry 1

FRIEDMAN PAUL A · CIK 0001236927 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 38,000

Underlying: Common Stock · 38,000 shares

Expires 2035-06-11

F1 · derivative.exercise_date: The option award will fully vest upon the earlier of (a) the Issuer's next annual stockholder meeting, or (b) the one-year anniversary of the grant date, such to the Reporting Person's provision of service to the Issuer on each vesting date.

SEC source: 0001562180-25-004797 · primarydocument.xml · derivative · entry 1

Dier Mardi · CIK 0001574591 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 38,000

Underlying: Common Stock · 38,000 shares

Expires 2035-06-11

F1 · derivative.exercise_date: The option award will fully vest upon the earlier of (a) the Issuer's next annual stockholder meeting, or (b) the one-year anniversary of the grant date, such to the Reporting Person's provision of service to the Issuer on each vesting date.

SEC source: 0001562180-25-004798 · primarydocument.xml · derivative · entry 1

Sandor Victor · CIK 0001620368 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 38,000

Underlying: Common Stock · 38,000 shares

Expires 2035-06-11

F1 · derivative.exercise_date: The option award will fully vest upon the earlier of (a) the Issuer's next annual stockholder meeting, or (b) the one-year anniversary of the grant date, such to the Reporting Person's provision of service to the Issuer on each vesting date.

SEC source: 0001562180-25-003036 · primarydocument.xml · derivative · entry 3

Huang Jane · CIK 0001683913 · President, CMO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 37,500

Underlying: Common Stock · 9,375 shares

Expires not disclosed

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.

F1 · derivative.exercise_price: Each Restricted Stock Unit ("RSU") represents a contingent right to receive one share of Issuer's Common Stock.

F3 · derivative.exercise_date: The RSUs were granted on May 2, 2022 and vest according to the reporting person's employment agreement. The RSUs vested as to 1/4 of the total shares on April 4, 2023, and 1/16 of the remaining shares shall vest quarterly thereafter until fully vested, subject to the continued service of the Reporting Person to the Issuer through each vesting date.

F3 · derivative.expiration_date: The RSUs were granted on May 2, 2022 and vest according to the reporting person's employment agreement. The RSUs vested as to 1/4 of the total shares on April 4, 2023, and 1/16 of the remaining shares shall vest quarterly thereafter until fully vested, subject to the continued service of the Reporting Person to the Issuer through each vesting date.

SEC source: 0001562180-25-003036 · primarydocument.xml · nonDerivative · entry 2

Huang Jane · CIK 0001683913 · President, CMO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 74,877

F2 · shares: Represents shares withheld by the Issuer to satisfy the tax withholding obligation in connection with the vesting of RSUs.

SEC source: 0001562180-25-003036 · primarydocument.xml · nonDerivative · entry 1

Huang Jane · CIK 0001683913 · President, CMO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 78,232

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.

F1 · price: Each Restricted Stock Unit ("RSU") represents a contingent right to receive one share of Issuer's Common Stock.

SEC source: 0001562180-25-002779 · primarydocument.xml · nonDerivative · entry 1

Combs Andrew · CIK 0001825005 · Chief Chemistry Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 480,123

F1 · balance_after: The reported total includes 2,500 shares of common stock the reporting person has acquired since the date of his last ownership report through the issuer's Employee Stock Purchase Plan in one or more transactions exempt pursuant to Rules 16b-3(c).

SEC source: 0001562180-25-002778 · primarydocument.xml · nonDerivative · entry 1

Vaddi Krishna · CIK 0001824633 · Director · CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,999,296

SEC source: 0001562180-25-002697 · primarydocument.xml · nonDerivative · entry 2

Vaddi Krishna · CIK 0001824633 · Director · CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,324,296

F2 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $0.73 to $0.731, inclusive. The reporting person undertakes to provide to 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 purchased at each separate price within the ranges set forth herein.

SEC source: 0001562180-25-002697 · primarydocument.xml · nonDerivative · entry 1

Vaddi Krishna · CIK 0001824633 · Director · CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,309,296

F1 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $0.7294 to $0.73, inclusive. The reporting person undertakes to provide to 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 purchased at each separate price within the ranges set forth herein.

SEC source: 0001562180-25-002541 · primarydocument.xml · nonDerivative · entry 2

Vaddi Krishna · CIK 0001824633 · Director · CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,303,880

F2 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $0.7496 to $0.75, inclusive. The reporting person undertakes to provide to 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 purchased at each separate price within the ranges set forth herein.

SEC source: 0001562180-25-002541 · primarydocument.xml · nonDerivative · entry 1

Vaddi Krishna · CIK 0001824633 · Director · CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,294,774

F1 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $0.7746 to $0.7782, inclusive. The reporting person undertakes to provide to 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 purchased at each separate price within the ranges set forth herein.

SEC source: 0001562180-25-002392 · primarydocument.xml · nonDerivative · entry 2

Vaddi Krishna · CIK 0001824633 · Director · CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,264,775

F2 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $0.6993 to $0.7999, inclusive. The reporting person undertakes to provide to 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 purchased at each separate price within the ranges set forth herein.

SEC source: 0001562180-25-002392 · primarydocument.xml · nonDerivative · entry 1

Vaddi Krishna · CIK 0001824633 · Director · CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,214,775

F1 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $0.693 to $0.7512, inclusive. The reporting person undertakes to provide to 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 purchased at each separate price within the ranges set forth herein.

SEC source: 0001562180-25-000956 · primarydocument.xml · derivative · entry 1

Huang Jane · CIK 0001683913 · President, CMO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 200,000

Underlying: Common Stock · 200,000 shares

Expires 2035-02-04

F1 · derivative.exercise_date: The stock option vests as to 25% of the total shares on Feb 4, 2026, and thereafter vests as to 1/48 of the total shares monthly until fully vested, subject to the Reporting Person's provision of service to the Issuer on each vesting date.

SEC source: 0001562180-25-000960 · primarydocument.xml · derivative · entry 1

Lim Bryant David · CIK 0001752888 · CLO, CFO, Corp Sec.

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 200,000

Underlying: Common Stock · 200,000 shares

Expires 2035-02-04

F1 · derivative.exercise_date: The stock option vests as to 25% of the total shares on Feb 4, 2026, and thereafter vests as to 1/48 of the total shares monthly until fully vested, subject to the Reporting Person's provision of service to the Issuer on each vesting date.

SEC source: 0001562180-25-000958 · primarydocument.xml · derivative · entry 1

Scherle Peggy · CIK 0001824632 · Chief Scientific Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 175,000

Underlying: Common Stock · 175,000 shares

Expires 2035-02-04

F1 · derivative.exercise_date: The stock option vests as to 25% of the total shares on Feb 4, 2026, and thereafter vests as to 1/48 of the total shares monthly until fully vested, subject to the Reporting Person's provision of service to the Issuer on each vesting date.

SEC source: 0001562180-25-000957 · primarydocument.xml · derivative · entry 1

Combs Andrew · CIK 0001825005 · Chief Chemistry Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 175,000

Underlying: Common Stock · 175,000 shares

Expires 2035-02-04

F1 · derivative.exercise_date: The stock option vests as to 25% of the total shares on Feb 4, 2026, and thereafter vests as to 1/48 of the total shares monthly until fully vested, subject to the Reporting Person's provision of service to the Issuer on each vesting date.