Exhibit A

JOINT FILING AGREEMENT

The persons below hereby agree that the Schedule 13D to which this agreement is attached as an exhibit, as well as all future amendments to such Schedule 13D, shall be filed jointly on behalf of each of them. This agreement is intended to satisfy the requirements of Rule 13d-1(k)(1)(iii) under the Securities Exchange Act of 1934.

Dated: November 23, 2018

 
InvaGen Pharmaceuticals Inc.
   
 
By:
/s/ Deepak Agarwal
   
Name:
Deepak Agarwal
   
Title:
 Director
   
 
Cipla (EU) Limited
   
 
By:
/s/ Christos Kartalis
   
Name:
Christos Kartalis
   
Title:
 Director
   
 
Cipla Limited
   
/s/ A.S. Kumar
   
Name:
A.S. Kumar
   
Title:
Global General Counsel and Executive Vice President