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| Merrimack CEO Robert Mulroy |
Sanofi ($SNY) is breaking it off with oncology partner Merrimack Pharmaceuticals ($MACK), handing back full rights to MM-121, a treatment that has three times failed to hit the mark in midstage studies.
MM-121 is an antibody designed to block ErbB3, a receptor tied to tumor growth, and the drug's promise in breast, ovarian and lung cancers convinced Sanofi to sign a deal worth up to $470 million in 2009 to get its hands on the treatment. Since then, however, the injection has failed to meet the endpoint of progression-free survival in Phase II trials in each of those cancers, notching a third failure in November that sent Merrimack's shares down nearly 40%.
As is industry standard, Merrimack followed each clinical setback with affirmations of MM-121's potential in various patient subpopulations. Sanofi was apparently unconvinced.
However, Merrimack is keeping the faith on its thrice-thwarted treatment, planning to review the Phase II data and approach the FDA about potential registration paths, CEO Robert Mulroy said.
"Regaining MM-121 is an opportunity to capitalize on our leadership position among the other oncology companies that are pursuing ErbB3," Mulroy said in a statement. "With these data and the feedback we've received from our committed investigators, we believe MM-121 has the potential to be a foundational therapy for use across multiple solid tumor types, and we plan to continue its development through subsequent strategic partnerships."
The news sent Merrimack's shares down more than 10% in premarket trading Friday, undoing some of the company's gains tied to a promising pancreatic cancer therapy.
Early last month, Merrimack announced that MM-398, an injectable chemotherapy, hit its primary endpoint of overall survival in a Phase III combo trial, extending the lives of metastatic pancreatic cancer patients. Those results will fuel an FDA application later this year, the biotech said, a welcome bit of good news that sent the company's shares up 90%, well above their MM-121-fueled nadir of last fall.
- read the statement
Special Report: 2011 Fierce 15 - Merrimack Pharmaceuticals