Bluebird Bio Inc. closed an underwritten public offering for gross proceeds of about $632.5 million.

The Cambridge, Mass.-based biotechnology company sold 3,892,308 common shares at $162.50 apiece. Shares issued include 507,692 common shares sold as part of the full exercise of the underwriters' overallotment option.

Goldman Sachs & Co. LLC, BofA Merrill Lynch, J.P. Morgan Securities LLC and Cowen acted as joint book-running managers, with Wells Fargo Securities as co-manager of the offering.

Bluebird Bio develops gene therapies for severe genetic diseases and cancer.