Merrimack Pharmaceuticals Shares Fall Amid End Of MM-121 Collaboration With Sanofi

   By Anna Prior 
 

Merrimack Pharmaceuticals Inc. (MACK) and Sanofi (SNY) have terminated their license and collaboration agreement for the development and commercialization of Merrimack's antibody MM-121 to treat different forms of cancer.

Merrimack shares slumped 15% to $6.70 in recent after-hours trading.

Sanofi will continue to fund the existing MM-121 Phase 2 program for the next six months, said Merrimack, adding that the final study completed through this collaboration is a test of MM-121 in combination with paclitaxel in patients with triple negative breast cancer.

Merrimack plans to look for other strategic partnership opportunities as it continues to develop MM-121, said Chief Executive Robert Mulroy, noting that the company's next step includes discussing Phase 2 data and potential registration paths with the U.S. Food and Drug Administration.

In October, Merrimack said a Phase 2 study of the antibody to treat ovarian cancer didn't meet the primary endpoint of progression free survival in the overall population. The company was studying MM-121 in combination with paclitaxel versus paclitaxel alone in patients with platinum-resistant or platinum-refractory advanced ovarian cancers.

Write to Anna Prior at [e-mail]

Subscribe to WSJ: http://online.wsj.com?mod=djnwires