By Randall Osborne

In a deal worth up to $75 million, Immune Response Corp. is pairing its gene delivery technology with Schering-Plough Corp.'s alfa-2b gene to develop gene therapies for hepatitis B and C.

The first, preclinical part of the agreement provides up to $5 million for Immune Response in fees, reimbursement expenses and milestone payments related to delivery of the alfa-2b gene for hepatitis B and C treatments.

"No matter how it works after that, [Schering-Plough] has the option to access the technology for other genes," said Steven Brostoff, chief scientific officer of Carlsbad, Calif.-based Immune Response. The payments, if Schering-Plough does so, could total more than $75 million, in addition to royalties.

The deal also provides for Madison, N.J.-based Schering-Plough, which markets Intron A (interferon alfa-2b), to get rights to existing and future gene therapy methods developed by Immune Response in conjunction with type 1 interferon genes.

"As we march along, any improvements in the technology will automatically belong to [Schering-Plough]," Brostoff said.

Immune Response's GeneDrug delivery system has been shown in preclinical trials to be successful in delivering genes directly to liver cells after a single intravenous injection. The cells then produce interferon alfa-2b protein to battle the hepatitis.

Research indicates the gene delivery system may be useful not only against hepatitis, but in treating hemophilia and lowering blood cholesterol.

"Right now, they're giving [interferon] systemically, hoping enough will get to the liver to interfere with the disease," Brostoff said.

The first part of the collaboration will last for one year, said Robert Consalvo, spokesman for Schering-Plough.

"A 12-month study should tell us enough to abandon it or continue on," Consalvo told BioWorld Today. "If we're getting excellent success, we might quickly start up another gene."

On the other hand, for Immune Response to collect the full $75 million, "an awful lot of things would have to go right," Consalvo added. "We'd be happy to get one gene [delivered for successful therapy]."

Immune Response's most advanced therapy is Remune, a therapeutic vaccine for treatment of HIV. Last month, the company entered a partnership with Agouron Pharmaceuticals Inc., of La Jolla, Calif., worth up to $77 million to develop and commercialize the vaccine. (See BioWorld Today, June 12, 1998, p. 1.)

At the 12th World AIDS Conference in Geneva, Switzerland, earlier this month, David Ho, director of the Aaron Diamond AIDS Research Center in New York, discussed the concept of using therapeutic vaccines, such as Remune, after antiretroviral therapy has suppressed the disease. (See BioWorld Today, July 7, 1998, p. 1.)

"Everything's on schedule" with Remune, said Brostoff. The drug is in Phase III trials at 74 sites.

"There's a clinical endpoint trial scheduled to end in the second quarter of 1999, and there are some other Phase II trials going on," Brostoff said.

Immune Response also has programs in rheumatoid arthritis and other autoimmune diseases as well as gene therapy for cancer.

The company's stock (NASDAQ:IMNR) closed Thursday at $13.375, down $0.375. Schering-Plough's shares (NYSE:SGP) ended the day at $98, up $0.812. *