Constellation Pharmaceuticals Inc. seeks to raise about $224.3 million in gross proceeds from a public offering of its common stock.

The Cambridge, Mass.-based biotech company, which develops treatments for cancers with abnormal gene expression and drug resistance, is offering 6.5 million shares for $34.5 each.

Underwriters have also been given a 30-day option to buy up to an additional 975,000 common shares from the company, Constellation said in a Dec. 10 press release.

The offering is expected to close Dec. 13, the company added.

J.P. Morgan, Jefferies and Cowen are the joint book-running managers; RBC Capital Markets is the book runner; and SunTrust Robinson Humphrey is the lead manager for the offering.