Spring Bank Pharmaceuticals Inc. priced an underwritten public offering of 3 million common shares at $12.50 each.

The Hopkinton, Mass.-based biopharmaceutical company expects to raise gross proceeds of $37.5 million.

Underwriters have a 30-day option to buy up to 450,000 additional common shares at the offering price.

Spring Bank expects the offering, which is subject to customary closing conditions, to close on or about Aug. 13.

Net proceeds will be used on clinical trials, nonclinical studies, research and development as well as general corporate purposes.

Jefferies and Piper Jaffray are acting as joint book-running managers for the offering.