By Kim Coghill

Washington Editor

Epimmune Inc. said its relationship with Pharmacia Corp. in the development of a cancer vaccine program has ended.

In a joint decision to end the collaboration, Pharmacia has agreed to return to San Diego-based Epimmune the patent rights along with relevant technology, data and materials.

The research being conducted involved combining Epimmune's proprietary cancer-specific epitope and Padre technologies with Skokie, Ill.-based G.D. Searle & Co.'s cytokine technology to develop a new class of cancer therapies designed to induce highly specific immune responses.

The move to sever ties follows the April merger between Pharmacia & Upjohn and Searle's parent, St. Louis-based Monsanto Co.

"The merger took place and they evaluated their overall portfolio," said Robert Chesnut, Epimmune executive vice president of research and development. "This was very different than what Pharmacia was doing and you can't do everything when companies merge. It is disappointing, but on the other hand, we made significant progress as a result of the collaboration and can capitalize on that in a pretty effective way."

Earlier this year, Searle had initiated clinical trials with ProGP, an engineered cytokine, and trials with ProGP plus the Epimmune breast, colon and lung cancer vaccine were scheduled to begin by the end of 2000.

Chesnut said under the collaboration, the companies initially set out to develop an ex vivo cancer vaccine. "But we realized from a commercial standpoint that that's a difficult approach to commercialize vaccines and we were working on ways of actually just delivering the antigens directly to the patients. As a result, we may decide to capitalize on that in a move forward with an in vivo vaccine.

"We can do that as a result of progress that was made both in terms of the knowledge and manufacturing of materials through the collaboration. Potentially, we will be in the clinic next year - it will just be much later next year instead of earlier in the year."

Epimmune possibly will enter a collaboration with another company in order to continue development of the cancer vaccine, Chesnut said. "We will definitely be actively pursuing another partnership. During the time when we were partners with Searle, we often had meetings with people who wanted to know if there were any rights available. There were a number of opportunities that were available at the time, so we will be pursuing those."

The relationship between the two companies dates back to 1998, when Searle helped form Epimmune through the purchase of $5 million in San Diego-based Cytel Corp. stock used to finance Epimmune. (See BioWorld Today, March 3, 1998.)

Epimmune grew out of a restructuring at Cytel following a drug development setback and the loss of two corporate partners: Pharmacia & Upjohn, of London, and Schwarz Pharma AG, of Monheim, Germany. The company was formed in October 1997 to create therapeutic and prophylactic vaccines against cancer and infectious diseases. (See BioWorld Today, Sept. 15, 1997; and March 3, 1998.)

Epimmune became a public company in July 1999. Its technology platform is based on its work in deciphering the genetic code that regulates T-cell activation and identifying antigen fragments known as epitopes that can activate highly targeted T-cell responses to tumors, viruses, bonteria and parasites.

The company has other products in development, including a therapeutic and prophylactic anti-HIV vaccine for patients on antiretroviral therapy. The vaccine is expected to enter Phase I/II studies next year, Chesnut said. A vaccine for hepatitis C also is being developed and should enter Phase I/II trials a year after the HIV product.

Epimmune's stock (NASDAQ:EPMN) closed Tuesday at $3.875, down 12.5 cents.