If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box. Checkbox not checked

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).






SCHEDULE 13D






SCHEDULE 13D






SCHEDULE 13D






SCHEDULE 13D


 
ORBIMED ADVISORS LLC
 
Signature:/s/ Carl L. Gordon
Name/Title:Carl L. Gordon/Member
Date:02/11/2026
 
ORBIMED CAPITAL GP VII LLC
 
Signature:/s/ Carl L. Gordon
Name/Title:Carl L. Gordon/Member of OrbiMed Advisors LLC
Date:02/11/2026
 
OrbiMed Genesis GP LLC
 
Signature:/s/ Carl L. Gordon
Name/Title:Carl L. Gordon/Member of OrbiMed Advisors LLC
Date:02/11/2026

 

Exhibit 1

JOINT FILING AGREEMENT

 

 The undersigned hereby agree that Amendment No. 2 to the Statement on Schedule 13D, dated February 5, 2026, with respect to the common stock, par value $0.0001 per share, of MBX Biosciences, Inc. is filed on behalf of each of us pursuant to and in accordance with the provisions of Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended. Each of the undersigned agrees to be responsible for the timely filing of this Statement, and for the completeness and accuracy of the information concerning itself contained therein. This Joint Filing Agreement may be executed in any number of counterparts, all of which taken together shall constitute one and the same instrument.

 

IN WITNESS WHEREOF, the undersigned have executed this Joint Filing Agreement as of the 11th day of February 2026.

 

  ORBIMED ADVISORS LLC
     
  By: /s/ Carl L. Gordon             
    Name: Carl L. Gordon
    Title: Member
     
  ORBIMED CAPITAL GP VII LLC
     
  By: ORBIMED ADVISORS LLC, its managing member
     
  By: /s/ Carl L. Gordon              
    Name: Carl L. Gordon
    Title: Member of OrbiMed Advisors LLC
   
  ORBIMED GENESIS GP LLC
     
  By: ORBIMED ADVISORS LLC, its managing member
     
  By: s/ Carl L. Gordon
    Name: Carl L. Gordon
    Title: Member of OrbiMed Advisors LLC