MEDIMMUNE TO GET ANOTHER $ 13 MIL. FROM MERCK FOR AIDS R&D

MEDIMMUNE TO GET ANOTHER $ 13 MIL. FROM MERCK FOR AIDS R&D -- this time for work on monoclonal antibodies to prevent HIV under an agreement-in-principle announced Oct. 22. Merck already has committed $ 13 mil. to MedImmune in research and milestone funding under a November 1990 agreement for the development of an AIDS vaccine derived from the Bacille Calmette Guerin (BCG) bacteria and for the use of other MedImmune proprietary technologies. Under the latest agreement, Merck will pay $ 13 mil. to cover MedImmune's development work on anti-HIV MAbs over the next three years, beginning in the fourth quarter of 1991, the Gaithersburg, Md.-based R&D firm announced. MedImmune will retain worldwide copromotion rights to any commercialized products that come out of the program. MedImmune and its collaborators at New York University have developed "more than 40" MAbs that target parts of the AIDS virus, the company said, including the gp41 envelope protein, the V3 loop of gp120 and the CD4 binding site of gp120. The lead monoclonal antibody in development at the company, MEDI-488, which binds to the V3 loop of the AIDS envelope protein, has been shown in vitro to neutralize "all of the divergent laboratory strains of the AIDS virus that were tested," MedImmune said. Other MAbs identified by MedImmune and other companies have been shown to neutralize only certain strains of HIV. On the same day that MedImmune announced its long-term collaboration with Merck, Repligen reported that it is reacquiring from Merck certain rights to MAbs that are potential anti- infectives against the AIDS virus. Merck and Repligen had been studying anti-HIV MAbs under a 1989 joint agreement. However, the Merck-Repligen five-year-old collaborative agreement for the development of AIDS vaccines, employing envelope protein sub-units to stimulate antibodies to HIV, is unaffected by the agreement-in- principle to buy back rights to the MAbs. Repligen said Oct. 22 that it plans to continue to develop and fund the anti-HIV MAb program on its own. Repligen has approximately $ 50 mil. in cash reserves, much of it raised during a May 1991 secondary public offering. Repligen President and CEO Sandford Smith said the company's "initial clinical strategy" upon reacquisition of the rights to the MAbs "will be to rapidly evaluate this product candidate in AIDS patients. Additional clinical applications may include prevention of mother-neonate transmission of HIV and post-exposure infection." At recent AIDS meetings, Merck scientists have presented data indicating that one of the Repligen MAbs has been effective in preventing HIV infection in chimps. On Oct. 18, Merck presented data on post-HIV exposure protection in chimps that were first injected with HIV and then given an infusion of a Repligen monoclonal antibody to the V3 loop. Merck's Emilio Emini, PhD, reported that both chimps have remained free of HIV infection since March 1991. One chimp, given the MAb 24 hours after HIV exposure, has remained free of HIV infection for 44 weeks post- challenge. The other chimp, given the MAb 10 minutes after viral challenge, has remained free of infection for 20 weeks. The MAb, C beta 1 is a "monoclonal, virus-neutralizing mouse- human IgG1 chimeric antibody directed against the V3 loop of the HIV-1 IIIb variant," according to an abstract of the studies. The data were presented to the National Cooperative Vaccine Development Groups for AIDS at the International Conference on Advances in AIDS Vaccine Development in Marco Island, Fla. At the Seventh International AIDS Conference in Florence in June, Emini reported that a chimp injected with the C beta 1 MAb and then challenged with an infectious dose of HIV has shown no signs of infection since the September 1990 experiment. The chimp still has shown no infection, Repligen said Oct. 22. That trial compared the MAb-treated chimp to a control chimp, which did show signs of infection shortly after the challenge. MedImmune, which went public earlier this year via an initial stock offering that netted $ 24 mil. ("The Pink Sheet" April 15, T&G-3), was one of 10 health care start-ups that received a total of $ 60.3 mil. in funding from Healthcare Ventures I. The fund, which is operated by Healthcare Investment Corp. of Edison, N.J., is run by four former industry execs, including Chairman Wallace Steinberg (previously VP-J&J Development Corp.) and President James Cavanaugh (formerly SK&F Labs president) Healthcare Ventures II, which closed in November 1990, raised $ 101 mil. and funded 11 new companies plus five from the first fund and the group is in the process of raising between $ 100 mil. and $ 200 mil. for Healthcare Ventures III.