X0202 SCHEDULE 13D/A 0000918923 XXXXXXXX LIVE 6 Class A ordinary share, par value $0.0001 per share 06/25/2026 false 0001821586 61559X104 MoonLake Immunotherapeutics

DORFSTRASSE 29 ZUG V8 6300

JAMES KRATKY 415-525-8830 BVF PARTNERS L.P. 44 Montgomery St., 40th Floor San Francisco CA 94104 0000918923 N BIOTECHNOLOGY VALUE FUND L P a WC N DE 0.00 8302735.00 0.00 8302735.00 8302735.00 N 10.2 PN 0001803805 N BVF I GP LLC a AF N DE 0.00 8302735.00 0.00 8302735.00 8302735.00 N 10.2 OO 0001102444 N BIOTECHNOLOGY VALUE FUND II LP a WC N DE 0.00 6599722.00 0.00 6599722.00 6599722.00 N 8.1 PN 0001803806 N BVF II GP LLC a AF N DE 0.00 6599722.00 0.00 6599722.00 6599722.00 N 8.1 OO 0001660683 N Biotechnology Value Trading Fund OS LP a WC N E9 0.00 1039238.00 0.00 1039238.00 1039238.00 N 1.3 PN 0001660684 N BVF Partners OS Ltd. a AF N E9 0.00 1039238.00 0.00 1039238.00 1039238.00 N 1.3 CO 0001803809 N BVF GP HOLDINGS LLC a AF N DE 0.00 14902457.00 0.00 14902457.00 14902457.00 N 18.4 OO 0001055947 N BVF PARTNERS L P/IL a AF N DE 0.00 16001284.00 0.00 16001284.00 16001284.00 N 19.7 IA PN 0001056807 N BVF INC/IL a AF N DE 0.00 16001284.00 0.00 16001284.00 16001284.00 N 19.7 CO 0001233840 N LAMPERT MARK N a AF N X1 0.00 16001284.00 0.00 16001284.00 16001284.00 N 19.7 IN 0001920549 N Loy Spike a OO N X1 25667.00 0.00 25667.00 0.00 25667.00 N 0.03 IN Class A ordinary share, par value $0.0001 per share MoonLake Immunotherapeutics DORFSTRASSE 29 ZUG V8 6300 This Amendment No. 6 to the Schedule 13D is being filed due to a change in the percentage of the outstanding number of Shares owned by the Reporting Persons due to an increase in the number of Shares outstanding. Item 5(a) is hereby amended and restated to read as follows: The aggregate percentage of Shares reported owned by each person named herein is based on 81,134,066 Shares outstanding as of June 25, 2026, which is the total number of Shares outstanding following the closing of the Issuer's offering as reported in the Issuer's Prospectus Supplement filed with the Securities and Exchange Commission on June 24, 2026. As of the date hereof, (i) BVF beneficially owned 8,302,735 Shares, representing percentage ownership of approximately 10.2% of the Shares outstanding, (ii) BVF2 beneficially owned 6,599,722 Shares, representing percentage ownership of approximately 8.1% of the Shares outstanding, (iii) Trading Fund OS beneficially owned 1,039,238 Shares, representing percentage ownership of approximately 1.3% of the Shares outstanding, and (iv) 59,589 Shares were held in the Partners Managed Account, representing percentage ownership of less than 1% of the Shares outstanding. BVF GP, as the general partner of BVF, may be deemed to beneficially own the 8,302,735 Shares beneficially owned by BVF, representing percentage ownership of approximately 10.2% of the Shares outstanding. BVF2 GP, as the general partner of BVF2, may be deemed to beneficially own the 6,599,722 Shares beneficially owned by BVF2, representing percentage ownership of approximately 8.1% of the Shares outstanding. Partners OS, as the general partner of Trading Fund OS, may be deemed to beneficially own the 1,039,238 Shares beneficially owned by Trading Fund OS, representing percentage ownership of approximately 1.3% of the Shares outstanding. BVF GPH, as the sole member of each of BVF GP and BVF2 GP, may be deemed to beneficially own the 14,902,457 Shares beneficially owned in the aggregate by BVF and BVF2, representing percentage ownership of approximately 18.4% of the Shares outstanding. Partners, as the investment manager of BVF, BVF2, Trading Fund OS and the Partners Managed Account and the sole member of Partners OS, may be deemed to beneficially own the 16,001,284 Shares beneficially owned in the aggregate by BVF, BVF2 and Trading Fund OS and held in the Partners Managed Account, representing percentage ownership of approximately 19.7% of the Shares outstanding. BVF Inc., as the general partner of Partners, may be deemed to beneficially own the 16,001,284 Shares beneficially owned by Partners, representing percentage ownership of approximately 19.7% of the Shares outstanding. Mr. Lampert, as a director and officer of BVF Inc., may be deemed to beneficially own the 16,001,284 Shares beneficially owned by BVF Inc., representing percentage ownership of approximately 19.7% of the Shares outstanding. As of the date hereof, Mr. Loy beneficially owned 25,667 Shares, which consist of Shares issuable upon the exercise of certain options that are exercisable within sixty days hereof, representing percentage ownership of less than 1%. The foregoing should not be construed in and of itself as an admission by any Reporting Person as to beneficial ownership of any Shares owned by another Reporting Person. BVF GP disclaims beneficial ownership of the Shares beneficially owned by BVF. BVF2 GP disclaims beneficial ownership of the Shares beneficially owned by BVF2. Partners OS disclaims beneficial ownership of the Shares beneficially owned by Trading Fund OS. BVF GPH disclaims beneficial ownership of the Shares beneficially owned by BVF and BVF2. Each of Partners, BVF Inc. and Mr. Lampert disclaims beneficial ownership of the Shares beneficially owned by BVF, BVF2 and Trading Fund OS and held in the Partners Managed Account. Mr. Loy disclaims beneficial ownership of the Shares reported herein that he does not directly own. Item 5(c) is hereby amended and restated to read as follows: Other than as set forth in Item 6, none of the Reporting Persons have entered into any transactions in the securities of the Issuer during the past 60 days. Item 6 is hereby amended to add the following: On June 17, 2026, Mr. Loy was granted stock options in connection with his service as a director of the Issuer that represent a right to purchase 22,195 Shares. Such options (a) will vest in full on the earlier of (i) June 17, 2027 and (ii) the date of the Issuer's next annual general meeting of shareholders, subject to Mr. Loy's continued service to the Issuer, (b) have an exercise price of $19.19 per Share and (c) expire on June 17, 2036. BIOTECHNOLOGY VALUE FUND L P /s/ Mark N. Lampert 06/29/2026 BVF I GP LLC /s/ Mark N. Lampert 06/29/2026 BIOTECHNOLOGY VALUE FUND II LP /s/ Mark N. Lampert 06/29/2026 BVF II GP LLC /s/ Mark N. Lampert 06/29/2026 Biotechnology Value Trading Fund OS LP /s/ Mark N. Lampert 06/29/2026 BVF Partners OS Ltd. /s/ Mark N. Lampert 06/29/2026 BVF GP HOLDINGS LLC /s/ Mark N. Lampert 06/29/2026 BVF PARTNERS L P/IL /s/ Mark N. Lampert 06/29/2026 BVF INC/IL /s/ Mark N. Lampert 06/29/2026 LAMPERT MARK N /s/ Mark N. Lampert 06/29/2026 Loy Spike /s/ Spike Loy 06/29/2026