Merrimack Pharmaceuticals' stock soars on heavy volume after drug sale deal

Shares of Merrimack Pharmaceuticals Inc. soared 34% in active premarket trade Monday, after the company announced a deal to sell some drug products to France-based Ipsen SA for up to $1.03 billion. Premarket volume of 3.2 million shares was already more than the full-day average of 3.1 million shares. Merrimack said late Sunday that it will sell its cancer treatments Onivyde and generic Doxil to Ipsen for $575 million at closing, which is expected by the end of March, and up to $450 million in regulatory approval-based milestone payments. Merrimack could also receive up to $33 million in milestone payments as part of its exclusive license agreement with Shire. Merrimack said it completed its previously-announced pipeline review, and determined that it will focus on its MM-121, MM-141 and MM-310 programs. The stock had tumbled 34% over the past three months through Friday, while the S&P 500 had gained 5.7%.

Market Pulse Stories are Rapid-fire, short news bursts on stocks and markets as they move. Visit MarketWatch.com for more information on this news.