Antigenics Inc. said it plans to publicly offer about 4.5 million shares of its common stock, a follow-on sale that it said could result in net proceeds of about $48 million.

The compnay disclosed the news after the market closed Wednesday. Its shares (NASDAQ:AGEN) closed Thursday at $10.64, down 71 cents.

The New York-based company said in its prospectus it would use the proceeds to fund additional clinical trials of its lead product candidates, and for clinical trials and preclinical studies of other product candidates; for potential licenses and other acquisitions of complementary technologies and products; and for working capital, capital expenditures and other general corporate purposes. Antigenics develops products to treat cancer, infectious diseases and autoimmune disorders.

The offering is being proposed from a registration statement covering $100 million in securities that became effective in August.

Among Antigenics' products are Oncophage, a personalized cancer vaccine being tested in Phase II and III trials, and the liposomal products ATRA-IV and Aroplatin in Phase II cancer trials

For the period ended Sept. 30, Antigenics reported about 33 million shares outstanding as well as $70.5 million in cash, cash equivalents and short-term investments. In the quarter, the company reported a $13.2 million loss, compared to a $44 million loss in the corresponding prior-year quarter, an increased loss due in part to a noncash charge of $32.4 million related to the write-off of in-process research and development acquired in connection with the acquisition of The Woodlands, Texas-based Aronex Pharmaceuticals Inc.

New York-based UBS Warburg LLC is acting as the offering's lead underwriter. Needham & Co. Inc., of New York; Morgan Keegan & Co. Inc., of Memphis, Tenn.; and Ryan Beck & Co. Inc., of New York, are acting as co-managers. Antigenics said it would grant to the underwriters an option to purchase an additional 675,000 shares to cover overallotments.