Hamill Laura

SEC source: 0001751804-26-000005 · edgardoc.xml · nonDerivative · entry 2

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 6,832

F1 · kind: Shares sold to satisfy tax obligations arising out of the vesting of previously granted restricted stock units.

SEC source: 0001751804-26-000005 · edgardoc.xml · nonDerivative · entry 1

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 8,524

F1 · kind: Shares sold to satisfy tax obligations arising out of the vesting of previously granted restricted stock units.

SEC source: 0001751804-26-000002 · edgardoc.xml · nonDerivative · entry 1

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 8,538

F1 · kind: These restricted stock units are granted pursuant to the Issuer's 2007 Amended and Restated Non-Employee Directors Stock Award Plan. Each restricted stock unit represents a contingent right to receive one ordinary share upon the vesting of the unit. Subject to the Reporting Person's continuous service and certain additional conditions, these units will vest in full on July 23, 2027.

SEC source: 0001193125-26-271069 · ownership.xml · derivative · entry 1

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 175,800

Underlying: Common Stock · 175,800 shares

Expires 2036-06-12

F1 · kind: This transaction represents a grant of options pursuant to the terms of the Issuer's Amended and Restated Non-Employee Director Compensation Policy which provides for an equity grant upon a director's appointment or election to the Board of Directors.

F2 · derivative.exercise_date: The shares subject to this option shall vest in 36 equal monthly installments following June 12, 2026, such that all of the shares shall be fully vested and exercisable on June 12, 2029, subject to the Reporting Person's continuous service to the Issuer as of each such vesting date.

SEC source: 0001751804-25-000004 · form4-09192025_060901.xml · derivative · entry 8

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 33,450 shares

Expires 2035-06-30

F1 · date: Pursuant to the Agreement and Plan of Merger (the "Merger Agreement"), dated as of August 4, 2025, by and among Y-mAbs Therapeutics, Inc. (the "Issuer"), Yosemite Merger Sub, Inc. ("Purchaser"), Perseus BidCo US, Inc., a Delaware corporation ("Parent"), and Stark International Lux, a Luxembourg private limited liability company ("Ultimate Parent"), on September 16, 2025, Purchaser completed a tender offer for shares of common stock of the Issuer (each, a "Share") and thereafter merged with and into the Issuer, with the Issuer continuing as the surviving corporation and an indirect wholly owned subsidiary of Parent (the "Merger").

F5 · price: At the Effective Time, pursuant to the Merger Agreement, each stock option ("Option") outstanding as of immediately prior to the Effective Time, whether vested or unvested, was cancelled and converted into the right to receive cash, without interest, equal to the product of (a) the total number of Shares subject to such Option immediately prior to the Effective Time, multiplied by (b) the excess of the Merger Consideration over the exercise price payable per Share under such Option. Any Options with an exercise price equal to or in excess of the Merger Consideration were cancelled for no consideration.

F5 · derivative.exercise_date: At the Effective Time, pursuant to the Merger Agreement, each stock option ("Option") outstanding as of immediately prior to the Effective Time, whether vested or unvested, was cancelled and converted into the right to receive cash, without interest, equal to the product of (a) the total number of Shares subject to such Option immediately prior to the Effective Time, multiplied by (b) the excess of the Merger Consideration over the exercise price payable per Share under such Option. Any Options with an exercise price equal to or in excess of the Merger Consideration were cancelled for no consideration.

SEC source: 0001751804-25-000004 · form4-09192025_060901.xml · derivative · entry 7

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 14,545 shares

Expires 2034-06-11

F1 · date: Pursuant to the Agreement and Plan of Merger (the "Merger Agreement"), dated as of August 4, 2025, by and among Y-mAbs Therapeutics, Inc. (the "Issuer"), Yosemite Merger Sub, Inc. ("Purchaser"), Perseus BidCo US, Inc., a Delaware corporation ("Parent"), and Stark International Lux, a Luxembourg private limited liability company ("Ultimate Parent"), on September 16, 2025, Purchaser completed a tender offer for shares of common stock of the Issuer (each, a "Share") and thereafter merged with and into the Issuer, with the Issuer continuing as the surviving corporation and an indirect wholly owned subsidiary of Parent (the "Merger").

F5 · price: At the Effective Time, pursuant to the Merger Agreement, each stock option ("Option") outstanding as of immediately prior to the Effective Time, whether vested or unvested, was cancelled and converted into the right to receive cash, without interest, equal to the product of (a) the total number of Shares subject to such Option immediately prior to the Effective Time, multiplied by (b) the excess of the Merger Consideration over the exercise price payable per Share under such Option. Any Options with an exercise price equal to or in excess of the Merger Consideration were cancelled for no consideration.

F5 · derivative.exercise_date: At the Effective Time, pursuant to the Merger Agreement, each stock option ("Option") outstanding as of immediately prior to the Effective Time, whether vested or unvested, was cancelled and converted into the right to receive cash, without interest, equal to the product of (a) the total number of Shares subject to such Option immediately prior to the Effective Time, multiplied by (b) the excess of the Merger Consideration over the exercise price payable per Share under such Option. Any Options with an exercise price equal to or in excess of the Merger Consideration were cancelled for no consideration.

SEC source: 0001751804-25-000004 · form4-09192025_060901.xml · derivative · entry 6

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 13,950 shares

Expires 2033-06-08

F1 · date: Pursuant to the Agreement and Plan of Merger (the "Merger Agreement"), dated as of August 4, 2025, by and among Y-mAbs Therapeutics, Inc. (the "Issuer"), Yosemite Merger Sub, Inc. ("Purchaser"), Perseus BidCo US, Inc., a Delaware corporation ("Parent"), and Stark International Lux, a Luxembourg private limited liability company ("Ultimate Parent"), on September 16, 2025, Purchaser completed a tender offer for shares of common stock of the Issuer (each, a "Share") and thereafter merged with and into the Issuer, with the Issuer continuing as the surviving corporation and an indirect wholly owned subsidiary of Parent (the "Merger").

F5 · price: At the Effective Time, pursuant to the Merger Agreement, each stock option ("Option") outstanding as of immediately prior to the Effective Time, whether vested or unvested, was cancelled and converted into the right to receive cash, without interest, equal to the product of (a) the total number of Shares subject to such Option immediately prior to the Effective Time, multiplied by (b) the excess of the Merger Consideration over the exercise price payable per Share under such Option. Any Options with an exercise price equal to or in excess of the Merger Consideration were cancelled for no consideration.

F5 · derivative.exercise_date: At the Effective Time, pursuant to the Merger Agreement, each stock option ("Option") outstanding as of immediately prior to the Effective Time, whether vested or unvested, was cancelled and converted into the right to receive cash, without interest, equal to the product of (a) the total number of Shares subject to such Option immediately prior to the Effective Time, multiplied by (b) the excess of the Merger Consideration over the exercise price payable per Share under such Option. Any Options with an exercise price equal to or in excess of the Merger Consideration were cancelled for no consideration.

SEC source: 0001751804-25-000004 · form4-09192025_060901.xml · derivative · entry 5

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 16,000 shares

Expires 2032-07-15

F1 · date: Pursuant to the Agreement and Plan of Merger (the "Merger Agreement"), dated as of August 4, 2025, by and among Y-mAbs Therapeutics, Inc. (the "Issuer"), Yosemite Merger Sub, Inc. ("Purchaser"), Perseus BidCo US, Inc., a Delaware corporation ("Parent"), and Stark International Lux, a Luxembourg private limited liability company ("Ultimate Parent"), on September 16, 2025, Purchaser completed a tender offer for shares of common stock of the Issuer (each, a "Share") and thereafter merged with and into the Issuer, with the Issuer continuing as the surviving corporation and an indirect wholly owned subsidiary of Parent (the "Merger").

F5 · price: At the Effective Time, pursuant to the Merger Agreement, each stock option ("Option") outstanding as of immediately prior to the Effective Time, whether vested or unvested, was cancelled and converted into the right to receive cash, without interest, equal to the product of (a) the total number of Shares subject to such Option immediately prior to the Effective Time, multiplied by (b) the excess of the Merger Consideration over the exercise price payable per Share under such Option. Any Options with an exercise price equal to or in excess of the Merger Consideration were cancelled for no consideration.

F5 · derivative.exercise_date: At the Effective Time, pursuant to the Merger Agreement, each stock option ("Option") outstanding as of immediately prior to the Effective Time, whether vested or unvested, was cancelled and converted into the right to receive cash, without interest, equal to the product of (a) the total number of Shares subject to such Option immediately prior to the Effective Time, multiplied by (b) the excess of the Merger Consideration over the exercise price payable per Share under such Option. Any Options with an exercise price equal to or in excess of the Merger Consideration were cancelled for no consideration.

SEC source: 0001751804-25-000004 · form4-09192025_060901.xml · derivative · entry 4

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 11,000 shares

Expires 2031-06-10

F1 · date: Pursuant to the Agreement and Plan of Merger (the "Merger Agreement"), dated as of August 4, 2025, by and among Y-mAbs Therapeutics, Inc. (the "Issuer"), Yosemite Merger Sub, Inc. ("Purchaser"), Perseus BidCo US, Inc., a Delaware corporation ("Parent"), and Stark International Lux, a Luxembourg private limited liability company ("Ultimate Parent"), on September 16, 2025, Purchaser completed a tender offer for shares of common stock of the Issuer (each, a "Share") and thereafter merged with and into the Issuer, with the Issuer continuing as the surviving corporation and an indirect wholly owned subsidiary of Parent (the "Merger").

F5 · price: At the Effective Time, pursuant to the Merger Agreement, each stock option ("Option") outstanding as of immediately prior to the Effective Time, whether vested or unvested, was cancelled and converted into the right to receive cash, without interest, equal to the product of (a) the total number of Shares subject to such Option immediately prior to the Effective Time, multiplied by (b) the excess of the Merger Consideration over the exercise price payable per Share under such Option. Any Options with an exercise price equal to or in excess of the Merger Consideration were cancelled for no consideration.

F5 · derivative.exercise_date: At the Effective Time, pursuant to the Merger Agreement, each stock option ("Option") outstanding as of immediately prior to the Effective Time, whether vested or unvested, was cancelled and converted into the right to receive cash, without interest, equal to the product of (a) the total number of Shares subject to such Option immediately prior to the Effective Time, multiplied by (b) the excess of the Merger Consideration over the exercise price payable per Share under such Option. Any Options with an exercise price equal to or in excess of the Merger Consideration were cancelled for no consideration.

SEC source: 0001751804-25-000004 · form4-09192025_060901.xml · derivative · entry 3

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 27,000 shares

Expires 2030-06-23

F1 · date: Pursuant to the Agreement and Plan of Merger (the "Merger Agreement"), dated as of August 4, 2025, by and among Y-mAbs Therapeutics, Inc. (the "Issuer"), Yosemite Merger Sub, Inc. ("Purchaser"), Perseus BidCo US, Inc., a Delaware corporation ("Parent"), and Stark International Lux, a Luxembourg private limited liability company ("Ultimate Parent"), on September 16, 2025, Purchaser completed a tender offer for shares of common stock of the Issuer (each, a "Share") and thereafter merged with and into the Issuer, with the Issuer continuing as the surviving corporation and an indirect wholly owned subsidiary of Parent (the "Merger").

F5 · price: At the Effective Time, pursuant to the Merger Agreement, each stock option ("Option") outstanding as of immediately prior to the Effective Time, whether vested or unvested, was cancelled and converted into the right to receive cash, without interest, equal to the product of (a) the total number of Shares subject to such Option immediately prior to the Effective Time, multiplied by (b) the excess of the Merger Consideration over the exercise price payable per Share under such Option. Any Options with an exercise price equal to or in excess of the Merger Consideration were cancelled for no consideration.

F5 · derivative.exercise_date: At the Effective Time, pursuant to the Merger Agreement, each stock option ("Option") outstanding as of immediately prior to the Effective Time, whether vested or unvested, was cancelled and converted into the right to receive cash, without interest, equal to the product of (a) the total number of Shares subject to such Option immediately prior to the Effective Time, multiplied by (b) the excess of the Merger Consideration over the exercise price payable per Share under such Option. Any Options with an exercise price equal to or in excess of the Merger Consideration were cancelled for no consideration.

SEC source: 0001751804-25-000004 · form4-09192025_060901.xml · nonDerivative · entry 2

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

F1 · date: Pursuant to the Agreement and Plan of Merger (the "Merger Agreement"), dated as of August 4, 2025, by and among Y-mAbs Therapeutics, Inc. (the "Issuer"), Yosemite Merger Sub, Inc. ("Purchaser"), Perseus BidCo US, Inc., a Delaware corporation ("Parent"), and Stark International Lux, a Luxembourg private limited liability company ("Ultimate Parent"), on September 16, 2025, Purchaser completed a tender offer for shares of common stock of the Issuer (each, a "Share") and thereafter merged with and into the Issuer, with the Issuer continuing as the surviving corporation and an indirect wholly owned subsidiary of Parent (the "Merger").

F3 · shares: Represents restricted stock units ("RSUs") granted to the Reporting Person pursuant to the Issuer's 2018 Equity Incentive Plan. Each RSU represents a contingent right to receive one share of Common Stock on the vesting dates of the RSU.

F4 · price: At the Effective Time, pursuant to the Merger Agreement, each RSU award outstanding as of immediately prior to the Effective Time, whether vested or unvested, was cancelled and converted into the right to receive an amount in cash, without interest, equal to the product of (a) the total number of Shares issuable in settlement of such RSU award immediately prior to the Effective Time, multiplied by (b) the Merger Consideration.

SEC source: 0001751804-25-000004 · form4-09192025_060901.xml · nonDerivative · entry 1

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

F1 · date: Pursuant to the Agreement and Plan of Merger (the "Merger Agreement"), dated as of August 4, 2025, by and among Y-mAbs Therapeutics, Inc. (the "Issuer"), Yosemite Merger Sub, Inc. ("Purchaser"), Perseus BidCo US, Inc., a Delaware corporation ("Parent"), and Stark International Lux, a Luxembourg private limited liability company ("Ultimate Parent"), on September 16, 2025, Purchaser completed a tender offer for shares of common stock of the Issuer (each, a "Share") and thereafter merged with and into the Issuer, with the Issuer continuing as the surviving corporation and an indirect wholly owned subsidiary of Parent (the "Merger").

F2 · price: Pursuant to the terms of the Merger Agreement, the Shares were tendered at the Offer Acceptance Time (as defined in the Merger Agreement) in exchange for the right to receive $8.60 per Share, in cash, without interest, subject to any applicable withholding of taxes (the "Merger Consideration"). At the effective time of the Merger (being such date and at such time as the certificate of merger in respect of the Merger was duly filed with the Secretary of State of the State of Delaware in accordance with the DGCL) (the "Effective Time"), each issued and outstanding Share was cancelled in exchange for the Merger Consideration.

SEC source: 0001765581-25-000090 · edgardoc.xml · nonDerivative · entry 2

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 6,933

F2 · kind: Shares sold to satisfy tax obligations arising out of the vesting of previously granted restricted stock units.

SEC source: 0001765581-25-000090 · edgardoc.xml · nonDerivative · entry 1

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 8,738

F1 · kind: These restricted stock units are granted pursuant to the Issuer's 2007 Amended and Restated Non-Employee Directors Stock Award Plan. Each restricted stock unit represents a contingent right to receive one ordinary share upon the vesting of the unit. Subject to the Reporting Person's continuous service and certain additional conditions, these units will vest in full on July 24, 2026.

SEC source: 0001415889-25-019050 · form4-07022025_040718.xml · derivative · entry 2

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 33,450

Underlying: Common Stock · 33,450 shares

Expires 2035-06-30

F2 · security: Stock options granted to the Reporting Person pursuant to the Issuer's 2018 Equity Incentive Plan.

F3 · derivative.exercise_date: The stock options vest in equal monthly installments until the first anniversary of the date of grant, subject to the Reporting Person's continued service to the Issuer on each vesting date, and are exercisable immediately upon vesting.

SEC source: 0001415889-25-019050 · form4-07022025_040718.xml · nonDerivative · entry 1

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 30,905

F1 · shares: Represents restricted stock units ("RSUs") granted to the Reporting Person pursuant to the Issuer's 2018 Equity Incentive Plan. Each RSU represents a contingent right to receive one share of the Issuer's common stock on the vesting date of the RSUs. The RSUs vest in full on the earlier of the first anniversary of the date of grant or the date immediately preceding the date of the Issuer's annual meeting of stockholders held in 2026, subject to the Reporting Person's continued service to the Issuer on the vesting date.

SEC source: 0001765581-24-000066 · edgardoc.xml · nonDerivative · entry 1

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 5,231

F1 · kind: These restricted stock units are granted pursuant to the Issuer's 2007 Amended and Restated Non-Employee Directors Stock Award Plan. Each restricted stock unit represents a contingent right to receive one ordinary share upon the vesting of the unit. Subject to the Reporting Person's continuous service and certain additional conditions, these units will vest in full on July 25, 2025.

SEC source: 0001104659-24-071402 · tm2417212-5_4seq1.xml · derivative · entry 2

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 14,545

Underlying: Common Stock · 14,545 shares

Expires 2034-06-11

F2 · security: Stock options granted to the Reporting Person pursuant to the Issuer's 2018 Equity Incentive Plan.

F3 · derivative.exercise_date: The stock options vest in equal monthly installments until the first anniversary of the date of grant, subject to the Reporting Person's continued service to the Issuer on each vesting date, and are exercisable immediately upon vesting.

SEC source: 0001104659-24-071402 · tm2417212-5_4seq1.xml · nonDerivative · entry 1

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 5,825

F1 · shares: Represents restricted stock units ("RSUs") granted to the Reporting Person pursuant to the Issuer's 2018 Equity Incentive Plan. Each RSU represents a contingent right to receive one share of the Issuer's common stock on the vesting date of the RSUs. The RSUs vest in full on the earlier of the first anniversary of the date of grant or the date immediately preceding the date of the Issuer's annual meeting of stockholders held in 2025, subject to the Reporting Person's continued service to the Issuer on the vesting date.

SEC source: 0001209191-23-047817 · doc4.xml · derivative · entry 4

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 37,500 shares

Expires 2032-06-07

F3 · price: On July 16, 2023, the Issuer's Board of Directors vested in full each unvested Company Stock Option. Pursuant to the Merger Agreement, each Company Stock Option that was not in the money as of the Effective Time was cancelled for no consideration at the Effective Time.

F3 · derivative.exercise_date: On July 16, 2023, the Issuer's Board of Directors vested in full each unvested Company Stock Option. Pursuant to the Merger Agreement, each Company Stock Option that was not in the money as of the Effective Time was cancelled for no consideration at the Effective Time.

F3 · derivative.expiration_date: On July 16, 2023, the Issuer's Board of Directors vested in full each unvested Company Stock Option. Pursuant to the Merger Agreement, each Company Stock Option that was not in the money as of the Effective Time was cancelled for no consideration at the Effective Time.

SEC source: 0001209191-23-047817 · doc4.xml · derivative · entry 3

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 75,000 shares

Expires 2031-12-22

F3 · price: On July 16, 2023, the Issuer's Board of Directors vested in full each unvested Company Stock Option. Pursuant to the Merger Agreement, each Company Stock Option that was not in the money as of the Effective Time was cancelled for no consideration at the Effective Time.

F3 · derivative.exercise_date: On July 16, 2023, the Issuer's Board of Directors vested in full each unvested Company Stock Option. Pursuant to the Merger Agreement, each Company Stock Option that was not in the money as of the Effective Time was cancelled for no consideration at the Effective Time.

F3 · derivative.expiration_date: On July 16, 2023, the Issuer's Board of Directors vested in full each unvested Company Stock Option. Pursuant to the Merger Agreement, each Company Stock Option that was not in the money as of the Effective Time was cancelled for no consideration at the Effective Time.

SEC source: 0001209191-23-047817 · doc4.xml · derivative · entry 2

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 70,390 shares

Expires 2031-07-26

F3 · price: On July 16, 2023, the Issuer's Board of Directors vested in full each unvested Company Stock Option. Pursuant to the Merger Agreement, each Company Stock Option that was not in the money as of the Effective Time was cancelled for no consideration at the Effective Time.

F3 · derivative.exercise_date: On July 16, 2023, the Issuer's Board of Directors vested in full each unvested Company Stock Option. Pursuant to the Merger Agreement, each Company Stock Option that was not in the money as of the Effective Time was cancelled for no consideration at the Effective Time.

F3 · derivative.expiration_date: On July 16, 2023, the Issuer's Board of Directors vested in full each unvested Company Stock Option. Pursuant to the Merger Agreement, each Company Stock Option that was not in the money as of the Effective Time was cancelled for no consideration at the Effective Time.

SEC source: 0001209191-23-047817 · doc4.xml · derivative · entry 1

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 37,500 shares

Expires 2033-05-31

F1 · price: This Form 4 reports securities disposed of pursuant to the terms of the Agreement and Plan of Merger entered into by and among the Issuer, MediPacific, Inc. (Parent) and MediPacific Sub, Inc., a wholly-owned subsidiary of Parent (Purchaser), dated as of July 16, 2023 (Merger Agreement), pursuant to which the Purchaser completed a tender offer for the shares of common stock of the Issuer and thereafter merged with and into the Issuer effective as of August 31, 2023 (Effective Time).

F2 · price: On July 16, 2023, the Issuer's Board of Directors vested in full each option to purchase shares granted under an Issuer equity plan (each, a Company Stock Option) that was outstanding and unvested as of that date. As of the Effective Time, each in-the-money Company Stock Option that was outstanding immediately prior to the Effective Time was cancelled, and, in exchange therefor, the holder of such cancelled in-the-money Company Stock Option was entitled to receive, in consideration of the cancellation of such Company Stock Option, (i) an amount in cash (less applicable tax withholdings and without interest) equal to the product of (x) the total number of shares subject to such Company Stock Option immediately prior to the Effective Time multiplied by (y) the excess of $2.13 over the applicable exercise price per share under such Company Stock Option and (ii) one contingent value right for each share subject thereto.

F1 · derivative.exercise_date: This Form 4 reports securities disposed of pursuant to the terms of the Agreement and Plan of Merger entered into by and among the Issuer, MediPacific, Inc. (Parent) and MediPacific Sub, Inc., a wholly-owned subsidiary of Parent (Purchaser), dated as of July 16, 2023 (Merger Agreement), pursuant to which the Purchaser completed a tender offer for the shares of common stock of the Issuer and thereafter merged with and into the Issuer effective as of August 31, 2023 (Effective Time).

F2 · derivative.exercise_date: On July 16, 2023, the Issuer's Board of Directors vested in full each option to purchase shares granted under an Issuer equity plan (each, a Company Stock Option) that was outstanding and unvested as of that date. As of the Effective Time, each in-the-money Company Stock Option that was outstanding immediately prior to the Effective Time was cancelled, and, in exchange therefor, the holder of such cancelled in-the-money Company Stock Option was entitled to receive, in consideration of the cancellation of such Company Stock Option, (i) an amount in cash (less applicable tax withholdings and without interest) equal to the product of (x) the total number of shares subject to such Company Stock Option immediately prior to the Effective Time multiplied by (y) the excess of $2.13 over the applicable exercise price per share under such Company Stock Option and (ii) one contingent value right for each share subject thereto.

F1 · derivative.expiration_date: This Form 4 reports securities disposed of pursuant to the terms of the Agreement and Plan of Merger entered into by and among the Issuer, MediPacific, Inc. (Parent) and MediPacific Sub, Inc., a wholly-owned subsidiary of Parent (Purchaser), dated as of July 16, 2023 (Merger Agreement), pursuant to which the Purchaser completed a tender offer for the shares of common stock of the Issuer and thereafter merged with and into the Issuer effective as of August 31, 2023 (Effective Time).

F2 · derivative.expiration_date: On July 16, 2023, the Issuer's Board of Directors vested in full each option to purchase shares granted under an Issuer equity plan (each, a Company Stock Option) that was outstanding and unvested as of that date. As of the Effective Time, each in-the-money Company Stock Option that was outstanding immediately prior to the Effective Time was cancelled, and, in exchange therefor, the holder of such cancelled in-the-money Company Stock Option was entitled to receive, in consideration of the cancellation of such Company Stock Option, (i) an amount in cash (less applicable tax withholdings and without interest) equal to the product of (x) the total number of shares subject to such Company Stock Option immediately prior to the Effective Time multiplied by (y) the excess of $2.13 over the applicable exercise price per share under such Company Stock Option and (ii) one contingent value right for each share subject thereto.

SEC source: 0001104659-23-070046 · tm2318348-6_4seq1.xml · derivative · entry 2

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 13,950

Underlying: Common stock · 13,950 shares

Expires 2033-06-08

F2 · security: Stock options granted to the Reporting Person as a non-employee director pursuant to the 2018 Equity Incentive Plan of Y-mAbs Therapeutics, Inc.

F3 · derivative.exercise_date: The stock options vest in equal monthly installments during the first year following the date of grant, subject to the Reporting Person's continued service to Y-mAbs Therapeutics, Inc. on each vesting date and are exercisable immediately upon vesting.

SEC source: 0001104659-23-070046 · tm2318348-6_4seq1.xml · nonDerivative · entry 1

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 2,330

F1 · shares: Represents restricted stock units ("RSUs") granted to the Reporting Person as a non-employee director pursuant to the 2018 Equity Incentive Plan of Y-mAbs Therapeutics, Inc. Each RSU represents a contingent right to receive one share of the Issuer's common stock on the vesting date of the RSUs. The RSUs vest in full on the earlier of the first anniversary of the date of grant or the date immediately preceding the date of the Issuer's annual meeting of stockholders held in 2024, subject to the Reporting Person's continued service to Y-mAbs Therapeutics, Inc. on the vesting date.

SEC source: 0001209191-23-033661 · doc4.xml · derivative · entry 1

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 37,500

Underlying: Common Stock · 37,500 shares

Expires 2033-05-31

F1 · derivative.exercise_date: Subject to the reporting person's continued service to the Issuer on each applicable vesting date, the option vests as to 1/12 of the total award on each monthly anniversary of the Grant Date; provided, however, that notwithstanding the monthly vesting schedule, the options shall vest in full upon the earlier of (i) the one-year anniversary of the Grant Date or (ii) the date of the next annual meeting of the stockholders.

SEC source: 0000899243-23-001877 · doc4.xml · derivative · entry 1

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 250,000

Underlying: Common Stock · 250,000 shares

Expires 2033-01-17

F1 · derivative.exercise_date: 1/48th of the shares subject to the option shall vest on a monthly basis following the grant date, subject to the Reporting Party's continued service to the Issuer through each such vesting date.

SEC source: 0001209191-23-002879 · doc4.xml · derivative · entry 2

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 3,900

Underlying: Common Stock · 3,900 shares

Expires not disclosed

F2 · derivative.exercise_price: Each restricted stock award ("RSU") represents a contingent right to receive 1 share of the Issuer's Common Stock upon settlement for no consideration.

F3 · derivative.exercise_date: The RSUs vests as to 100% of the total RSUs on the date of the Issuer's 2024 annual meeting of shareholders, subject to the Reporting Person's provision of service to the Issuer on each vesting date.

F3 · derivative.expiration_date: The RSUs vests as to 100% of the total RSUs on the date of the Issuer's 2024 annual meeting of shareholders, subject to the Reporting Person's provision of service to the Issuer on each vesting date.

SEC source: 0001209191-23-002879 · doc4.xml · derivative · entry 1

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 10,600

Underlying: Common Stock · 10,600 shares

Expires 2033-01-05

F1 · derivative.exercise_date: The stock option vests as to 1/12 of the total shares monthly commencing on February 6, 2023 until fully vested, subject to the Reporting Person's provision of service to the Issuer on each vesting date.

SEC source: 0001104659-22-080794 · tm2221312-6_4seq1.xml · derivative · entry 1

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 16,000

Underlying: Common Stock · 16,000 shares

Expires 2032-07-14

F1 · security: Stock options granted to the Reporting Person as a non-employee director pursuant to the 2018 Equity Incentive Plan of Y-mAbs Therapeutics, Inc.

F2 · derivative.exercise_date: The stock options vest in equal monthly installments during the first year following the date of grant, subject to the Reporting Person's continued service to Y-mAbs Therapeutics, Inc., and are exercisable immediately upon vesting.

SEC source: 0001209191-22-035897 · doc4.xml · derivative · entry 1

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 37,500

Underlying: Common Stock · 37,500 shares

Expires 2032-06-07

F1 · derivative.exercise_date: Subject to the reporting person's continued service to the Issuer on each applicable vesting date, the option vests as to 1/12 of the total award on each monthly anniversary of the Grant Date; provided, however, that notwithstanding the monthly vesting schedule, the options shall vest in full upon the earlier of (i) the one-year anniversary of the Grant Date or (ii) the date of the next annual meeting of the stockholders.

SEC source: 0001209191-22-009355 · doc4.xml · derivative · entry 1

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 9,200

Underlying: Common Stock · 9,200 shares

Expires 2032-02-09

F1 · derivative.exercise_date: The stock option vests as of 1/12 of the total shares monthly beginning on March 10, 2022 until fully vested, subject to the Reporting Person's provision of service to the Issuer on each vesting date.

SEC source: 0000899243-21-049934 · doc4.xml · derivative · entry 1

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 75,000

Underlying: Common Stock · 75,000 shares

Expires 2031-12-22

F1 · derivative.exercise_date: This option shall vest in substantially equal monthly installments over three years, subject to a continued service relationship. The vested shares subject to such option shall be exercisable upon the effectiveness of the Issuer's registration statement on Form S-8, registering the shares of the Issuer's 2021 Stock Option and Incentive Plan with the U.S. Securities and Exchange Commission.

SEC source: 0001104659-21-142273 · tm2133601-7_4seq1.xml · derivative · entry 3

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 941 shares

Expires not disclosed

F2 · price: Pursuant to the terms of the Merger Agreement, at the Effective Time, each option to purchase Shares granted under an Issuer equity plan (each, a "Company Stock Option") that was outstanding and unvested immediately prior to the Effective Time vested in full. As of the Effective Time, each Company Stock Option that was outstanding immediately prior to the Effective Time was cancelled, and, in exchange therefor, the holder of such cancelled Company Stock Option was entitled to receive (without interest), in consideration of the cancellation of such Company Stock Option, an amount in cash (less applicable tax withholdings) equal to the product of (x) the total number of Shares subject to such Company Stock Option immediately prior to the Effective Time multiplied by (y) the excess, if any, of the Offer Price over the applicable exercise price per Share under such Company Stock Option.

F2 · derivative.exercise_date: Pursuant to the terms of the Merger Agreement, at the Effective Time, each option to purchase Shares granted under an Issuer equity plan (each, a "Company Stock Option") that was outstanding and unvested immediately prior to the Effective Time vested in full. As of the Effective Time, each Company Stock Option that was outstanding immediately prior to the Effective Time was cancelled, and, in exchange therefor, the holder of such cancelled Company Stock Option was entitled to receive (without interest), in consideration of the cancellation of such Company Stock Option, an amount in cash (less applicable tax withholdings) equal to the product of (x) the total number of Shares subject to such Company Stock Option immediately prior to the Effective Time multiplied by (y) the excess, if any, of the Offer Price over the applicable exercise price per Share under such Company Stock Option.

F2 · derivative.expiration_date: Pursuant to the terms of the Merger Agreement, at the Effective Time, each option to purchase Shares granted under an Issuer equity plan (each, a "Company Stock Option") that was outstanding and unvested immediately prior to the Effective Time vested in full. As of the Effective Time, each Company Stock Option that was outstanding immediately prior to the Effective Time was cancelled, and, in exchange therefor, the holder of such cancelled Company Stock Option was entitled to receive (without interest), in consideration of the cancellation of such Company Stock Option, an amount in cash (less applicable tax withholdings) equal to the product of (x) the total number of Shares subject to such Company Stock Option immediately prior to the Effective Time multiplied by (y) the excess, if any, of the Offer Price over the applicable exercise price per Share under such Company Stock Option.

SEC source: 0001104659-21-142273 · tm2133601-7_4seq1.xml · derivative · entry 2

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 9,339 shares

Expires not disclosed

F2 · price: Pursuant to the terms of the Merger Agreement, at the Effective Time, each option to purchase Shares granted under an Issuer equity plan (each, a "Company Stock Option") that was outstanding and unvested immediately prior to the Effective Time vested in full. As of the Effective Time, each Company Stock Option that was outstanding immediately prior to the Effective Time was cancelled, and, in exchange therefor, the holder of such cancelled Company Stock Option was entitled to receive (without interest), in consideration of the cancellation of such Company Stock Option, an amount in cash (less applicable tax withholdings) equal to the product of (x) the total number of Shares subject to such Company Stock Option immediately prior to the Effective Time multiplied by (y) the excess, if any, of the Offer Price over the applicable exercise price per Share under such Company Stock Option.

F2 · derivative.exercise_date: Pursuant to the terms of the Merger Agreement, at the Effective Time, each option to purchase Shares granted under an Issuer equity plan (each, a "Company Stock Option") that was outstanding and unvested immediately prior to the Effective Time vested in full. As of the Effective Time, each Company Stock Option that was outstanding immediately prior to the Effective Time was cancelled, and, in exchange therefor, the holder of such cancelled Company Stock Option was entitled to receive (without interest), in consideration of the cancellation of such Company Stock Option, an amount in cash (less applicable tax withholdings) equal to the product of (x) the total number of Shares subject to such Company Stock Option immediately prior to the Effective Time multiplied by (y) the excess, if any, of the Offer Price over the applicable exercise price per Share under such Company Stock Option.

F2 · derivative.expiration_date: Pursuant to the terms of the Merger Agreement, at the Effective Time, each option to purchase Shares granted under an Issuer equity plan (each, a "Company Stock Option") that was outstanding and unvested immediately prior to the Effective Time vested in full. As of the Effective Time, each Company Stock Option that was outstanding immediately prior to the Effective Time was cancelled, and, in exchange therefor, the holder of such cancelled Company Stock Option was entitled to receive (without interest), in consideration of the cancellation of such Company Stock Option, an amount in cash (less applicable tax withholdings) equal to the product of (x) the total number of Shares subject to such Company Stock Option immediately prior to the Effective Time multiplied by (y) the excess, if any, of the Offer Price over the applicable exercise price per Share under such Company Stock Option.

SEC source: 0001104659-21-142273 · tm2133601-7_4seq1.xml · nonDerivative · entry 1

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

F1 · kind: This Form 4 reports securities disposed of pursuant to the terms of the Agreement and Plan of Merger (the "Merger Agreement"), dated as of September 29, 2021, by and among the Issuer, Merck Sharp & Dohme Corp. ("Parent"), and Astros Merger Sub, Inc., a direct wholly owned subsidiary of Parent ("Merger Sub"), pursuant to which Merger Sub completed a tender offer for shares of common stock of the Issuer (each, a "Share") and thereafter merged with and into the Issuer (the "Merger") effective as of November 19, 2021 (the "Effective Time"). At the Effective Time, each issued and outstanding Share was cancelled and converted into the right to receive $180.00 in cash (the "Offer Price") without interest and subject to applicable withholding taxes.

F1 · shares: This Form 4 reports securities disposed of pursuant to the terms of the Agreement and Plan of Merger (the "Merger Agreement"), dated as of September 29, 2021, by and among the Issuer, Merck Sharp & Dohme Corp. ("Parent"), and Astros Merger Sub, Inc., a direct wholly owned subsidiary of Parent ("Merger Sub"), pursuant to which Merger Sub completed a tender offer for shares of common stock of the Issuer (each, a "Share") and thereafter merged with and into the Issuer (the "Merger") effective as of November 19, 2021 (the "Effective Time"). At the Effective Time, each issued and outstanding Share was cancelled and converted into the right to receive $180.00 in cash (the "Offer Price") without interest and subject to applicable withholding taxes.

F1 · price: This Form 4 reports securities disposed of pursuant to the terms of the Agreement and Plan of Merger (the "Merger Agreement"), dated as of September 29, 2021, by and among the Issuer, Merck Sharp & Dohme Corp. ("Parent"), and Astros Merger Sub, Inc., a direct wholly owned subsidiary of Parent ("Merger Sub"), pursuant to which Merger Sub completed a tender offer for shares of common stock of the Issuer (each, a "Share") and thereafter merged with and into the Issuer (the "Merger") effective as of November 19, 2021 (the "Effective Time"). At the Effective Time, each issued and outstanding Share was cancelled and converted into the right to receive $180.00 in cash (the "Offer Price") without interest and subject to applicable withholding taxes.

SEC source: 0001104659-21-080838 · tm2118093-17_4seq1.xml · derivative · entry 1

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 16,000

Underlying: Common stock · 16,000 shares

Expires 2031-06-10

F1 · security: Stock options granted to the Reporting Person as a non-employee director pursuant to the 2018 Equity Incentive Plan of Y-mAbs Therapeutics, Inc.

F2 · derivative.exercise_date: The stock options vest in equal monthly installments during the first year following the date of grant, subject to the Reporting Person's continued service on the board of directors of Y-mAbs Therapeutics, Inc., and are exercisable immediately upon vesting.

SEC source: 0001209191-21-010530 · doc4.xml · derivative · entry 1

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 11,000

Underlying: Common Stock · 11,000 shares

Expires 2031-02-09

F1 · derivative.exercise_date: The stock option vests as of 1/12 of the total shares monthly beginning on March 10, 2021 until fully vested, subject to the Reporting Person's provision of service to the Issuer on each vesting date.

SEC source: 0001179110-21-001107 · edgar.xml · derivative · entry 2

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 941

Underlying: Common Stock · 941 shares

Expires 2031-01-29

F1 · derivative.exercise_date: The shares of common stock underlying this stock option award vest in full on the one year anniversary of the grant date.

SEC source: 0001179110-21-001107 · edgar.xml · nonDerivative · entry 1

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 474

SEC source: 0001179110-20-009841 · edgar.xml · derivative · entry 1

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 9,339

Underlying: Common Stock · 9,339 shares

Expires 2030-09-15

F1 · derivative.exercise_date: The shares of common stock underlying this stock option award vest in equal quarterly installments over the first three years after the date of grant.

SEC source: 0001104659-20-076462 · a4.xml · derivative · entry 1

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 32,000

Underlying: Common stock · 32,000 shares

Expires 2030-06-23

F1 · security: Stock options granted to the Reporting Person as a non-employee director pursuant to the 2018 Equity Incentive Plan of Y-mAbs Therapeutics, Inc.

F2 · derivative.exercise_date: The stock options vest in equal monthly installments until the third anniversary of the date of grant, subject to the Reporting Person's continued service on the board of directors of Y-mAbs Therapeutics, Inc., and are exercisable immediately upon vesting.

SEC source: 0001209191-20-009316 · doc4.xml · derivative · entry 1

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 11,000

Underlying: Common Stock · 11,000 shares

Expires 2030-02-11

F1 · derivative.exercise_date: The stock option vests and becomes exercisable in 12 equal monthly installments beginning on March 12, 2020, until such time as the option is 100% vested, subject to the continuing service of the Reporting Person on each vesting date.

SEC source: 0001209191-19-050889 · doc4.xml · derivative · entry 2

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 2,268

Underlying: Common Stock · 2,268 shares

Expires 2029-09-24

F2 · derivative.exercise_date: The option vests as follows: 1/4th of the total shares subject to the option shall vest on November 8, 2019 and 1/4th of the total shares subject to the option shall vest each month thereafter on each monthly anniversary of November 8, 2019, subject to the reporting person's continuous status as a director through each such date.

SEC source: 0001209191-19-050889 · doc4.xml · derivative · entry 1

Hamill Laura · CIK 0001751804 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 6,000

Underlying: Common Stock · 6,000 shares

Expires 2029-09-24

F1 · derivative.exercise_date: The option vests as follows: 1/36th of the total shares subject to the option shall vest on October 24, 2019 and 1/36th of the total shares subject to the option shall vest each month thereafter on each monthly anniversary of October 24, 2019, subject to the reporting person's continuous status as a director through each such date.

SEC source: 0001127602-19-018210 · form4.xml · nonDerivative · entry 2

Hamill Laura · CIK 0001751804 · EVP, Worldwide Commercial Ops

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 6,340

SEC source: 0001127602-19-018210 · form4.xml · nonDerivative · entry 1

Hamill Laura · CIK 0001751804 · EVP, Worldwide Commercial Ops

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 9,840

F1 · shares: Issuance of common stock upon vesting of certain performance share awards on May 8, 2019.

SEC source: 0001127602-19-004918 · form4.xml · derivative · entry 2

Hamill Laura · CIK 0001751804 · EVP, Worldwide Commercial Ops

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 46,435

Underlying: Common Stock · 13,640 shares

Expires not disclosed

F2 · derivative.exercise_price: Each restricted stock unit represents the contingent right to receive one share of Gilead Sciences, Inc.'s common stock.

F3 · derivative.exercise_date: The restricted stock units have a four-year vesting schedule. 25% vest on each yearly anniversary of the date of grant until fully vested.

F3 · derivative.expiration_date: The restricted stock units have a four-year vesting schedule. 25% vest on each yearly anniversary of the date of grant until fully vested.

SEC source: 0001127602-19-004918 · form4.xml · derivative · entry 1

Hamill Laura · CIK 0001751804 · EVP, Worldwide Commercial Ops

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 63,100

Underlying: Common Stock · 63,100 shares

Expires 2029-02-06

F1 · derivative.exercise_date: The options have a four year vesting schedule. 25% of the options will vest on the first anniversary date of the grant. The balance will vest 6.25% quarterly thereafter until fully vested.

SEC source: 0001127602-18-029875 · form4.xml · derivative · entry 2

Hamill Laura · CIK 0001751804 · EVP, Worldwide Commercial Ops

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 32,795

Underlying: Common Stock · 32,795 shares

Expires not disclosed

F2 · derivative.exercise_price: Each restricted stock unit represents the contingent right to receive one share of Gilead Sciences, Inc.'s common stock.

F2 · price: Each restricted stock unit represents the contingent right to receive one share of Gilead Sciences, Inc.'s common stock.

F3 · derivative.exercise_date: The restricted stock units have a four-year vesting schedule. 25% vest on each yearly anniversary of the date of grant until fully vested.

F3 · derivative.expiration_date: The restricted stock units have a four-year vesting schedule. 25% vest on each yearly anniversary of the date of grant until fully vested.