WALTHAM, Mass. (AP) -- Cancer drug developer ImmunoGen Inc. said Wednesday it is planning a new offering of stock.
ImmunoGen said it has not determined how many shares it may sell or the price for the potential offering. Morgan Stanley and Jefferies & Co. will be the joint book-running managers for the proposed sale. The company had 77.3 million shares on the market as of May 1.
Shares of ImmunoGen gave up a penny to $17.36 Wednesday and lost 91 cents, or 5.2 percent, to $16.45 in after-hours trading following the announcement.
The company did not say how it would use cash raised by the offering.
ImmunoGen helped develop the breast cancer treatment T-DM1, which combines the active agent in Roche's drug Herceptin with another drug and a chemical that keeps the drugs linked until they reach a cancer cell where the cocktail can be released. Roche reported positive data for T-DM1 in early June, and ImmunoGen shares have risen 25 percent since then.