On Wednesday, Onyx Pharmaceuticals (NASDAQ: ONXX) announced it has priced 4.4 million shares of common stock to be floated in a follow-on offering on or about Jan. 22.

The proposed price per share, $81.50, if achieved, would yield approximately $358.6 million in gross proceeds for Onyx. From this sum would be deducted underwriting discounts, commissions, and other expenses related to the offering. Onyx may, however, reap more funds (as much as $53.8 million) from the offering if underwriters exercise all or part of a proposed 660,000-share overallotment offering.

Among other things, Onyx says that it will use the proceeds from this offering to fund its clinical development programs, research and development activities, and sales and marketing activities aimed at commercializing its Kyprolis multiple myeloma drug.

Shares of Onyx dropped 5% Wednesday, closing  at $79.28.