BRNS

SEC source: 0001856079-26-000002 · primary_doc.xml · nonDerivative · entry 1

Oxford Science Enterprises plc · CIK 0001856079 · former 10% owner

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

F1 · security: Ordinary Shares may be represented by American Depositary Shares, each of which represents one Ordinary Share.

F2 · price: Pursuant to the terms of the Merger Agreement between Barinthus Biotherapeutics plc (the "Issuer") and Clywedog Therapeutics, Inc., the Issuer's board of directors has determined that each of the Issuer's outstanding Ordinary Shares (represented by American Depositary Shares) will be converted into the right to receive 0.111 shares of Beacon Topco, Inc.'s common stock, plus cash in lieu of any fractional shares resulting from the exchange, in accordance with the scheme of arrangement.

SEC source: 0001104659-26-106343 · tm2625057-8_4seq1.xml · derivative · entry 7

Wright Robin · CIK 0001851640 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 20,174 shares

Expires 2035-06-10

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106343 · tm2625057-8_4seq1.xml · derivative · entry 6

Wright Robin · CIK 0001851640 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 19,516 shares

Expires 2034-05-10

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106343 · tm2625057-8_4seq1.xml · derivative · entry 5

Wright Robin · CIK 0001851640 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 19,197 shares

Expires 2033-05-11

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106343 · tm2625057-8_4seq1.xml · derivative · entry 4

Wright Robin · CIK 0001851640 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 18,604 shares

Expires 2032-06-15

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106343 · tm2625057-8_4seq1.xml · derivative · entry 3

Wright Robin · CIK 0001851640 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 34,328 shares

Expires 2031-05-01

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106343 · tm2625057-8_4seq1.xml · derivative · entry 2

Wright Robin · CIK 0001851640 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 20,394 shares

Expires 2030-01-07

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106343 · tm2625057-8_4seq1.xml · nonDerivative · entry 1

Wright Robin · CIK 0001851640 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

F1 · security: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F3 · shares: Pursuant to the Merger Agreement and in connection with the effectiveness of the Scheme, at the Effective Time, each Share of the Issuer was converted into the right to receive 0.111 shares of common stock, $0.0001 par value per share, of Topco (the "Topco Common Stock").

F3 · price: Pursuant to the Merger Agreement and in connection with the effectiveness of the Scheme, at the Effective Time, each Share of the Issuer was converted into the right to receive 0.111 shares of common stock, $0.0001 par value per share, of Topco (the "Topco Common Stock").

SEC source: 0001104659-26-106342 · tm2625057-7_4seq1.xml · derivative · entry 6

Scheeren Joseph · CIK 0001852070 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 20,174 shares

Expires 2035-06-10

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106342 · tm2625057-7_4seq1.xml · derivative · entry 5

Scheeren Joseph · CIK 0001852070 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 19,516 shares

Expires 2034-05-10

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106342 · tm2625057-7_4seq1.xml · derivative · entry 4

Scheeren Joseph · CIK 0001852070 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 19,197 shares

Expires 2033-05-11

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106342 · tm2625057-7_4seq1.xml · derivative · entry 3

Scheeren Joseph · CIK 0001852070 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 18,604 shares

Expires 2032-06-15

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106342 · tm2625057-7_4seq1.xml · derivative · entry 2

Scheeren Joseph · CIK 0001852070 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 34,328 shares

Expires 2031-05-01

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106342 · tm2625057-7_4seq1.xml · nonDerivative · entry 1

Scheeren Joseph · CIK 0001852070 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

F1 · security: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F3 · shares: Pursuant to the Merger Agreement and in connection with the effectiveness of the Scheme, at the Effective Time, each Share of the Issuer was converted into the right to receive 0.111 shares of common stock, $0.0001 par value per share, of Topco (the "Topco Common Stock").

F3 · price: Pursuant to the Merger Agreement and in connection with the effectiveness of the Scheme, at the Effective Time, each Share of the Issuer was converted into the right to receive 0.111 shares of common stock, $0.0001 par value per share, of Topco (the "Topco Common Stock").

SEC source: 0001104659-26-106341 · tm2625057-6_4seq1.xml · derivative · entry 6

Phillips Anne M. · CIK 0001627680 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 20,174 shares

Expires 2035-06-10

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106341 · tm2625057-6_4seq1.xml · derivative · entry 5

Phillips Anne M. · CIK 0001627680 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 19,516 shares

Expires 2034-05-10

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106341 · tm2625057-6_4seq1.xml · derivative · entry 4

Phillips Anne M. · CIK 0001627680 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 19,197 shares

Expires 2033-05-11

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106341 · tm2625057-6_4seq1.xml · derivative · entry 3

Phillips Anne M. · CIK 0001627680 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 18,604 shares

Expires 2032-06-15

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106341 · tm2625057-6_4seq1.xml · derivative · entry 2

Phillips Anne M. · CIK 0001627680 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 34,328 shares

Expires 2031-05-01

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106341 · tm2625057-6_4seq1.xml · nonDerivative · entry 1

Phillips Anne M. · CIK 0001627680 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

F1 · security: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F3 · shares: Pursuant to the Merger Agreement and in connection with the effectiveness of the Scheme, at the Effective Time, each Share of the Issuer was converted into the right to receive 0.111 shares of common stock, $0.0001 par value per share, of Topco (the "Topco Common Stock").

F3 · price: Pursuant to the Merger Agreement and in connection with the effectiveness of the Scheme, at the Effective Time, each Share of the Issuer was converted into the right to receive 0.111 shares of common stock, $0.0001 par value per share, of Topco (the "Topco Common Stock").

SEC source: 0001104659-26-106340 · tm2625057-5_4seq1.xml · derivative · entry 7

Morgon Pierre A. · CIK 0001851636 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 20,174 shares

Expires 2035-06-10

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106340 · tm2625057-5_4seq1.xml · derivative · entry 6

Morgon Pierre A. · CIK 0001851636 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 19,516 shares

Expires 2034-05-10

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106340 · tm2625057-5_4seq1.xml · derivative · entry 5

Morgon Pierre A. · CIK 0001851636 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 19,197 shares

Expires 2033-05-11

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106340 · tm2625057-5_4seq1.xml · derivative · entry 4

Morgon Pierre A. · CIK 0001851636 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 18,604 shares

Expires 2032-06-15

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106340 · tm2625057-5_4seq1.xml · derivative · entry 3

Morgon Pierre A. · CIK 0001851636 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 34,328 shares

Expires 2031-05-01

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106340 · tm2625057-5_4seq1.xml · derivative · entry 2

Morgon Pierre A. · CIK 0001851636 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 20,394 shares

Expires 2030-01-10

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106340 · tm2625057-5_4seq1.xml · nonDerivative · entry 1

Morgon Pierre A. · CIK 0001851636 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

F1 · security: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F3 · shares: Pursuant to the Merger Agreement and in connection with the effectiveness of the Scheme, at the Effective Time, each Share of the Issuer was converted into the right to receive 0.111 shares of common stock, $0.0001 par value per share, of Topco (the "Topco Common Stock").

F3 · price: Pursuant to the Merger Agreement and in connection with the effectiveness of the Scheme, at the Effective Time, each Share of the Issuer was converted into the right to receive 0.111 shares of common stock, $0.0001 par value per share, of Topco (the "Topco Common Stock").

SEC source: 0001104659-26-106338 · tm2625057-4_4seq1.xml · derivative · entry 4

Hooftman Leon · CIK 0002027157 · Chief Medical Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 140,000 shares

Expires 2035-02-03

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106338 · tm2625057-4_4seq1.xml · derivative · entry 3

Hooftman Leon · CIK 0002027157 · Chief Medical Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 195,166 shares

Expires 2034-06-03

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106338 · tm2625057-4_4seq1.xml · nonDerivative · entry 2

Hooftman Leon · CIK 0002027157 · Chief Medical Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

F1 · security: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F3 · shares: Represents restricted share units ("RSUs") previously granted to the Reporting Person, vesting of which was subject to completion of the transactions contemplated by the Merger Agreement. Each RSU represented the contingent right to receive one Share of the Issuer. At the Effective time, each RSU, whether or not then vested, was automatically released in consideration of the assumption of such RSU by Topco and converted into an RSU relating to the common stock, $0.0001 par value per share, of Topco (the "Topco Common Stock").

F3 · price: Represents restricted share units ("RSUs") previously granted to the Reporting Person, vesting of which was subject to completion of the transactions contemplated by the Merger Agreement. Each RSU represented the contingent right to receive one Share of the Issuer. At the Effective time, each RSU, whether or not then vested, was automatically released in consideration of the assumption of such RSU by Topco and converted into an RSU relating to the common stock, $0.0001 par value per share, of Topco (the "Topco Common Stock").

SEC source: 0001104659-26-106338 · tm2625057-4_4seq1.xml · nonDerivative · entry 1

Hooftman Leon · CIK 0002027157 · Chief Medical Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 361,530

F1 · security: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F3 · shares: Represents restricted share units ("RSUs") previously granted to the Reporting Person, vesting of which was subject to completion of the transactions contemplated by the Merger Agreement. Each RSU represented the contingent right to receive one Share of the Issuer. At the Effective time, each RSU, whether or not then vested, was automatically released in consideration of the assumption of such RSU by Topco and converted into an RSU relating to the common stock, $0.0001 par value per share, of Topco (the "Topco Common Stock").

F3 · price: Represents restricted share units ("RSUs") previously granted to the Reporting Person, vesting of which was subject to completion of the transactions contemplated by the Merger Agreement. Each RSU represented the contingent right to receive one Share of the Issuer. At the Effective time, each RSU, whether or not then vested, was automatically released in consideration of the assumption of such RSU by Topco and converted into an RSU relating to the common stock, $0.0001 par value per share, of Topco (the "Topco Common Stock").

SEC source: 0001104659-26-106337 · tm2625057-3_4seq1.xml · derivative · entry 6

Hammacher Alex · CIK 0001851633 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 20,174 shares

Expires 2035-06-10

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106337 · tm2625057-3_4seq1.xml · derivative · entry 5

Hammacher Alex · CIK 0001851633 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 19,516 shares

Expires 2034-05-10

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106337 · tm2625057-3_4seq1.xml · derivative · entry 4

Hammacher Alex · CIK 0001851633 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 19,197 shares

Expires 2033-05-11

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106337 · tm2625057-3_4seq1.xml · derivative · entry 3

Hammacher Alex · CIK 0001851633 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 18,604 shares

Expires 2032-06-15

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106337 · tm2625057-3_4seq1.xml · derivative · entry 2

Hammacher Alex · CIK 0001851633 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 34,328 shares

Expires 2031-05-01

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106337 · tm2625057-3_4seq1.xml · nonDerivative · entry 1

Hammacher Alex · CIK 0001851633 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

F1 · security: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F3 · shares: Pursuant to the Merger Agreement and in connection with the effectiveness of the Scheme, at the Effective Time, each Share of the Issuer was converted into the right to receive 0.111 shares of common stock, $0.0001 par value per share, of Topco (the "Topco Common Stock").

F3 · price: Pursuant to the Merger Agreement and in connection with the effectiveness of the Scheme, at the Effective Time, each Share of the Issuer was converted into the right to receive 0.111 shares of common stock, $0.0001 par value per share, of Topco (the "Topco Common Stock").

SEC source: 0001104659-26-106336 · tm2625057-2_4seq1.xml · derivative · entry 7

Enright William · CIK 0001705564 · Director · Chief Executive Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 600,000 shares

Expires 2035-02-03

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F6 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106336 · tm2625057-2_4seq1.xml · derivative · entry 6

Enright William · CIK 0001705564 · Director · Chief Executive Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 443,981 shares

Expires 2034-01-02

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F6 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106336 · tm2625057-2_4seq1.xml · derivative · entry 5

Enright William · CIK 0001705564 · Director · Chief Executive Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 440,000 shares

Expires 2033-01-03

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F6 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106336 · tm2625057-2_4seq1.xml · derivative · entry 4

Enright William · CIK 0001705564 · Director · Chief Executive Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 359,605 shares

Expires 2032-03-14

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F6 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106336 · tm2625057-2_4seq1.xml · derivative · entry 3

Enright William · CIK 0001705564 · Director · Chief Executive Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 176,130 shares

Expires 2031-05-01

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F6 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106336 · tm2625057-2_4seq1.xml · nonDerivative · entry 2

Enright William · CIK 0001705564 · Director · Chief Executive Officer

10b5-1 filing: No plan indicated

Ownership: Indirect · By Trust

Disclosed balance after: 0

F1 · security: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F3 · shares: Pursuant to the Merger Agreement and in connection with the effectiveness of the Scheme, at the Effective Time, each Share of the Issuer was converted into the right to receive 0.111 shares of common stock, $0.0001 par value per share, of Topco (the "Topco Common Stock").

F3 · price: Pursuant to the Merger Agreement and in connection with the effectiveness of the Scheme, at the Effective Time, each Share of the Issuer was converted into the right to receive 0.111 shares of common stock, $0.0001 par value per share, of Topco (the "Topco Common Stock").

F5 · ownership.nature: Shares held by William Enright Revocable Trust, of which the Reporting Person serves as trustee. The Reporting Person disclaims beneficial ownership of the shares held by such trust for purposes of Section 16 of the Exchange Act, except to the extent of his pecuniary interest therein, if any.

SEC source: 0001104659-26-106336 · tm2625057-2_4seq1.xml · nonDerivative · entry 1

Enright William · CIK 0001705564 · Director · Chief Executive Officer

10b5-1 filing: No plan indicated

Ownership: Indirect · By Trust

Disclosed balance after: 0

F1 · security: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F3 · shares: Pursuant to the Merger Agreement and in connection with the effectiveness of the Scheme, at the Effective Time, each Share of the Issuer was converted into the right to receive 0.111 shares of common stock, $0.0001 par value per share, of Topco (the "Topco Common Stock").

F3 · price: Pursuant to the Merger Agreement and in connection with the effectiveness of the Scheme, at the Effective Time, each Share of the Issuer was converted into the right to receive 0.111 shares of common stock, $0.0001 par value per share, of Topco (the "Topco Common Stock").

F4 · ownership.nature: Shares held by William J Enright TR UA Dated 03/04/2021 Enright Family 2021 Irrevocable Trust, of which the Reporting Person serves as trustee. The Reporting Person disclaims beneficial ownership of the shares held by such trust for purposes of Section 16 of the Exchange Act, except to the extent of his pecuniary interest therein, if any.

SEC source: 0001104659-26-106323 · tm2625057-1_4seq1.xml · derivative · entry 6

DAWES KAREN A · CIK 0001261506 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 20,174 shares

Expires 2035-06-10

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106323 · tm2625057-1_4seq1.xml · derivative · entry 5

DAWES KAREN A · CIK 0001261506 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 19,516 shares

Expires 2034-05-10

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106323 · tm2625057-1_4seq1.xml · derivative · entry 4

DAWES KAREN A · CIK 0001261506 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 19,197 shares

Expires 2033-05-11

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106323 · tm2625057-1_4seq1.xml · derivative · entry 3

DAWES KAREN A · CIK 0001261506 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 18,604 shares

Expires 2032-06-15

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106323 · tm2625057-1_4seq1.xml · derivative · entry 2

DAWES KAREN A · CIK 0001261506 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Ordinary Shares · 34,328 shares

Expires 2031-05-01

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F4 · derivative.exercise_date: Pursuant to the Merger Agreement, at the Effective Time, each option to acquire Shares under the Issuer's equity plans that was outstanding as of immediately prior to the Effective Time ceased to represent a right to acquire Shares of the Issuer, and was converted into an option to acquire shares of Topco Common Stock and assumed by Topco on the same terms and conditions (including applicable vesting and exercisability conditions) as were applicable to such option immediately prior to the Effective Time.

F1 · derivative.underlying: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

SEC source: 0001104659-26-106323 · tm2625057-1_4seq1.xml · nonDerivative · entry 1

DAWES KAREN A · CIK 0001261506 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

F1 · security: The Ordinary Shares may be represented by American Depositary Shares ("ADSs" and together with the Ordinary Shares, the "Shares"), each of which currently represents one Ordinary Share.

F2 · kind: This Form 4 reports securities transacted in connection with the Agreement and Plan of Merger, dated September 29, 2025, as amended (the "Merger Agreement") by and among the Issuer, Beacon Topco, Inc. ("Topco"), a Delaware corporation and a direct wholly owned subsidiary of the Issuer, Cdog Merger Sub, Inc., a Delaware corporation and a direct wholly owned subsidiary of Topco, and Clywedog Therapeutics, Inc., a Delaware corporation. On September 9, 2026 (the "Effective Time"), in connection with the effectiveness of the scheme of arrangement under Part 26 of the United Kingdom Companies Act 2006 (the "Scheme") contemplated by the Merger Agreement, Topco acquired the entire issued share capital of the Issuer, resulting in the Issuer becoming a direct wholly owned subsidiary of Topco.

F3 · shares: Pursuant to the Merger Agreement and in connection with the effectiveness of the Scheme, at the Effective Time, each Share of the Issuer was converted into the right to receive 0.111 shares of common stock, $0.0001 par value per share, of Topco (the "Topco Common Stock").

F3 · price: Pursuant to the Merger Agreement and in connection with the effectiveness of the Scheme, at the Effective Time, each Share of the Issuer was converted into the right to receive 0.111 shares of common stock, $0.0001 par value per share, of Topco (the "Topco Common Stock").