Chimerix Inc., of Durham, N.C., priced an underwritten public offering of 2,476,995 shares of common stock at $16.50 per share to be sold by existing stockholders. Underwriters are granted a 30-day option to purchase up to 371,549 shares of stock to cover overallotments. The offering will close on Oct. 23. Chimerix will not receive any proceeds from the sale, whose purpose is to facilitate an orderly distribution of shares to increase the company’s public float.

Omeros Corp., of Seattle, filed a replacement universal shelf registration statement with the SEC due to the impending expiration of its existing universal shelf registration from 2010. The statement allows the company to sell common and preferred stock, debt securities and other securities with an aggregate offering amount not greater than $100 million.

Portola Pharmaceuticals Inc., of South San Francisco, priced a sale of 6.4 million shares of stock for $23.75 per share. Of those, Portola is selling 4.5 million and stockholders will sell an additional 1 .9 million. Portola anticipates receiving $105.9 million in proceeds before deductions and expenses. Underwriters are granted an option to buy 955,000 additional shares to cover overallotments.