By Karen Pihl-Carey

Antigenics LLC plans to raise $46 million in an initial public offering (IPO) of common stock to fund clinical trials of its lead product, the cancer vaccine Oncophage, as well as preclinical and development activities.

The number of shares and price range were not disclosed in the New York-based company¿s SEC registration statement. Minneapolis-based US Bancorp Piper Jaffray will lead the offering, co-managed by BancBoston Robertson Stephens Inc., of New York.

Formed in March 1994, Antigenics focuses on heat-shock protein-based immunotherapeutics, which modulate the immune system to fight disease. The company¿s platform is based on 18 years of research by the company¿s chief scientific officer, Pramod Srivastava, who founded the company with Antigenics CEO Garo Armen.

Oncophage consists of purified, patient-specific heat shock protein-peptide complexes and is in six Phase II or Phase I/II trials in renal cell carcinoma, metastatic melanoma, colorectal cancer and gastric cancer. The therapy is manufactured when a patient¿s tumor is removed and shipped frozen overnight to Antigenics¿ manufacturing facility. The company purifies Oncophage from the tumor tissue in less than 10 hours, then ships it frozen back to the patient. The patient is injected with Oncophage on an outpatient basis four to six weeks after surgery, and then once per week for four to six weeks.

Antigenics intends to begin soon Phase II trials of Oncophage to treat sarcoma and low-grade indolent non-Hodgkin¿s lymphoma, as well as a pivotal Phase III trial in renal cell carcinoma by mid-2000.

Aside from cancer, the company is conducting preclinical studies in infectious diseases and autoimmune disorders. The company expects to file an investigational new drug application with the FDA in 2000 for a therapeutic for its first infectious disease indication, genital herpes. In animal models, heat shock proteins indicate they could be valuable in diabetes and multiple sclerosis.

With its IPO, Antigenics will have the funds to move along its pipeline and to cover general corporate purposes, which could include an increase in its administrative staff. The company may use a portion of the proceeds to increase its manufacturing capacity or to acquire complementary businesses or products, although it has no definitive plans to do so. In addition to its corporate offices in New York, Antigenics has a research, development and manufacturing facility in Woburn, Mass.

For the nine months ended Sept. 30, the company reported a net loss of $11 million and pro forma cash and cash equivalents of $50.88 million, according to the company¿s SEC filing. Antigenics has an accumulated deficit of $28.5 million. It has not generated any revenues since its inception.