Exhibit 99.1

JOINT FILING AGREEMENT

In accordance with Rule 13d-1(k)(1)(iii) under the Securities Exchange Act of 1934, as amended, the persons named below agree to the joint filing on behalf of each of them of a Statement on Schedule 13D dated February 13, 2020 (including amendments thereto) with respect to the shares of Common Stock, $0.0075 par value, of XOMA Corporation. This Joint Filing Agreement shall be filed as an Exhibit to such Statement.

Dated: February 13, 2020

BIOTECHNOLOGY VALUE FUND, L.P.   BIOTECHNOLOGY VALUE TRADING FUND OS LP
       
By: BVF I GP LLC., its general partner   By: BVF Partners L.P., its investment manager
      By: BVF Inc., its general partner
By:

/s/ Mark N. Lampert

     
  Mark N. Lampert   By: /s/ Mark N. Lampert
  Chief Executive Officer     Mark Lampert
        President
         
BVF I GP LLC      
      BVF GP HOLDINGS LLC
By: /s/ Mark N. Lampert    
  Mark N. Lampert   By: /s/ Mark N. Lampert
  Chief Executive Officer     Mark Lampert
        Chief Executive Officer
         
BIOTECHNOLOGY VALUE FUND II, L.P.    
      BVF PARTNERS L.P.
By: BVF II GP LLC its general partner    
      By: BVF Inc., its general partner
By:

/s/ Mark N. Lampert

     
  Mark N. Lampert   By: /s/ Mark N. Lampert
  Chief Executive Officer     Mark N. Lampert
        President
         
BVF II GP LLC      
      BVF INC.
By: /s/ Mark N. Lampert    
  Mark N. Lampert   By: /s/ Mark N. Lampert
  Chief Executive Officer     Mark Lampert
        President
         
BVF PARTNERS OS LTD.      
      /s/ Mark N. Lampert
By: BVF Partners L.P., its sole member   MARK N. LAMPERT
By: BVF Inc., its general partner    
         
By:

/s/ Mark N. Lampert

 

/s/ Matthew D. Perry

  Mark N. Lampert   MATTHEW D. PERRY
  President