X0609 4 2026-06-17 0 0001821586 MoonLake Immunotherapeutics MLTX 0001055947 BVF PARTNERS L P/IL false 44 MONTGOMERY ST. 40TH FL SAN FRANCISCO CA 94104 1 0 1 0 0000918923 BIOTECHNOLOGY VALUE FUND L P false 44 MONTGOMERY STREET 40TH FL SAN FRANCISCO CA 94104 1 0 1 0 0001803805 BVF I GP LLC false 44 MONTGOMERY STREET 40TH FL SAN FRANCISCO CA 94104 1 0 1 0 0001102444 BIOTECHNOLOGY VALUE FUND II LP false 44 MONTGOMERY STREET 40TH FL SAN FRANCISCO CA 94104 1 0 0 1 See Explanation of Responses 0001803806 BVF II GP LLC false 44 MONTGOMERY STREET 40TH FL SAN FRANCISCO CA 94104 1 0 0 1 See Explanation of Responses 0001660683 Biotechnology Value Trading Fund OS LP true P.O. BOX 309 UGLAND HOUSE GRAND CAYMAN E9 KY1-1104 CAYMAN ISLANDS 1 0 0 1 See Explanation of Responses 0001660684 BVF Partners OS Ltd. true P.O. BOX 309 UGLAND HOUSE GRAND CAYMAN E9 KY1-1104 CAYMAN ISLANDS 1 0 0 1 See Explanation of Responses 0001803809 BVF GP HOLDINGS LLC false 44 MONTGOMERY STREET 40TH FL SAN FRANCISCO CA 94104 1 0 1 0 0001056807 BVF INC/IL false 44 MONTGOMERY STREET 40TH FL SAN FRANCISCO CA 94104 1 0 1 0 0001233840 LAMPERT MARK N false 44 MONTGOMERY STREET 40TH FL SAN FRANCISCO CA 94104 1 0 1 0 0 Class A Ordinary Shares, $0.0001 par value 8302735 D Class A Ordinary Shares, $0.0001 par value 6599722 D Class A Ordinary Shares, $0.0001 par value 1039238 D Option to Buy 19.19 2026-06-17 4 A 0 22195 0.00 A 2036-06-17 Class A Ordinary Shares, $0.0001 par value 22195 22195 I See footnote Option to Buy 48.83 2035-06-05 Class A Ordinary Shares, $0.0001 par value 6682 6682 I See footnote Option to Buy 42.44 2034-06-06 Class A Ordinary Shares, $0.0001 par value 7688 7688 I See footnote Option to Buy 29.18 2033-06-08 Class A Ordinary Shares, $0.0001 par value 11297 11297 I See footnote This Form 4 is filed jointly by Biotechnology Value Fund, L.P. ("BVF"), Biotechnology Value Fund II, L.P. ("BVF2"), Biotechnology Value Trading Fund OS LP ("Trading Fund OS"), BVF Partners OS Ltd. ("Partners OS"), BVF I GP LLC ("BVF GP"), BVF II GP LLC ("BVF2 GP"), BVF GP Holdings LLC ("BVF GPH"), BVF Partners L.P. ("Partners"), BVF Inc. and Mark N. Lampert (collectively, the "Reporting Persons"). Each of the Reporting Persons is a member of a Section 13(d) group that collectively owns more than 10% of the Issuer's outstanding shares of Common Stock. Each of the Reporting Persons disclaims beneficial ownership of the securities reported herein except to the extent of his or its pecuniary interest therein. Securities owned directly by BVF. As the general partner of BVF, BVF GP may be deemed to beneficially own the securities owned directly by BVF. As the sole member of BVF GP, BVF GPH may be deemed to beneficially own the securities owned directly by BVF. As the investment manager of BVF, Partners may be deemed to beneficially own the securities owned directly by BVF. As the general parter of Partners, BVF Inc. may be deemed to beneficially own the securities owned directly by BVF. As a director and officer of BVF Inc., Mr. Lampert may be deemed to beneficially own the securities owned directly by BVF. Securities owned directly by BVF2. As the general partner of BVF2, BVF2 GP may be deemed to beneficially own the securities owned directly by BVF2. As the sole member of BVF2 GP, BVF GPH may be deemed to beneficially own the securities owned directly by BVF2. As the investment manager of BVF2, Partners may be deemed to beneficially own the securities owned directly by BVF2. As the general partner of Partners, BVF Inc. may be deemed to beneficially own the securities owned directly by BVF2. As a director and officer of BVF Inc., Mr. Lampert may be deemed to beneficially own the securities owned directly by BVF2. Securities owned directly by Trading Fund OS. As the general partner of Trading Fund OS, Partners OS may be deemed to beneficially own the securities owned directly by Trading Fund OS. As the investment manager of Trading Fund OS and the sole member of Partners OS, Partners may be deemed to beneficially own the securities owned directly by Trading Fund OS. As the general partner of Partners, BVF Inc. may be deemed to beneficially own the securities owned directly by Trading Fund OS. As a director and officer of BVF Inc., Mr. Lampert may be deemed to beneficially own the securities owned directly by Trading Fund OS. This option represents a right to purchase a total of 22,195 Class A Ordinary Shares of the Issuer, which will vest in full the earlier of (i) June 17, 2027 and (ii) the date of the Issuer's next annual general meeting of shareholders, subject to Spike Loy's continued service to the Issuer. This option represents a right to purchase a total of 6,682 Class A Ordinary Shares of the Issuer. This option has fully vested as of the date hereof. This option represents a right to purchase a total of 7,688 Class A Ordinary Shares of the Issuer. This option has fully vested as of the date hereof. This option represents a right to purchase a total of 11,297 Class A Ordinary Shares of the Issuer. This option has fully vested as of the date hereof. Partners, BVF Inc. and Mr. Lampert may be deemed to have a pecuniary interest in the securities reported owned herein due to a certain agreement between Partners and Spike Loy, who serves on the Issuer's board of directors and as a Managing Director of Partners, pursuant to which Mr. Loy is obligated to transfer the economic benefit, if any, received upon the sale of the shares issuable upon exercise of the securities reported owned herein to Partners. As such, Mr. Loy disclaims beneficial ownership of the securities reported herein except to the extent of his pecuniary interest therein. For purposes of Section 16 of the Securities Exchange Act of 1934, as amended, each of the Reporting Persons may be deemed to be a director by deputization of the Issuer due to a Managing Director of Partners, Spike Loy, serving on the Board of Directors of the Issuer, and his agreement to transfer to Partners the economic benefit, if any, received upon the sale of any securities of the Issuer he receives in his capacity as a director of the Issuer. BVF Partners L.P., By: BVF Inc., its general partner, By: /s/ Mark N. Lampert, President 2026-06-22 Biotechnology Value Fund, L.P., By: BVF I GP LLC, its general partner, By: /s/ Mark N. Lampert, Chief Executive Officer 2026-06-22 BVF I GP LLC, By: /s/ Mark N. Lampert, Chief Executive Officer 2026-06-22 Biotechnology Value Fund II, L.P., By: BVF II GP LLC, its general partner, By: /s/ Mark N. Lampert, Chief Executive Officer 2026-06-22 BVF II GP LLC, By: /s/ Mark N. Lampert, Chief Executive Officer 2026-06-22 BVF Partners OS Ltd., By: BVF Partners L.P., its sole member, By: BVF Inc., its general partner, By: /s/ Mark N. Lampert, President 2026-06-22 Biotechnology Value Trading Fund OS LP, By: BVF Partners L.P., its investment manager, BVF Inc., its general partner, By: /s/ Mark N. Lampert, President 2026-06-22 BVF GP Holdings LLC, By: /s/ Mark N. Lampert, Chief Executive Officer 2026-06-22 BVF Inc., By: /s/ Mark N. Lampert, President 2026-06-22 /s/ Mark N. Lampert 2026-06-22