Food and Drug Administration, U.S. Department of Health and

The Food and Drug Administration today approved the use of alpha interferon to treat Kaposi's Sarcoma -- a systemic cancer which primarily affects AIDS patients. The approval is based in part on a study by scientists at the National Institute of Allergy and Infectious Diseases. (Results of this study will be published in the Nov. 26 issue of the medical journal Lancet.) Alpha interferon is a natural protein present in the body in small amounts. In recent years, gene-splicing techniques have permitted enough of the substance to be produced for research and therapy. Alpha interferon treatments have previously been shown effective against a rare leukemia and genital warts.

FDA Commissioner Frank E. Young, M.D., Ph.D, said today's announcement marks an important advance in the fight against AIDS-related disease, as well as a practical application of biotechnology. He said, "This new use for alpha interferon shows biotechnology's emerging role in helping modern medicine fight some of the most serious diseases which plague mankind. The revolutionary gains being made through biotechnology can improve the nation's health and provide new hope to patients with AIDS and other serious diseases." The interferons, or hormone-like proteins, were discovered in the late 1950s as naturally occurring anti-infective agents present at low levels within the body.

Quantities for research and treatment were made possible by recombinant DNA or gene-splicing techniques. In gene-splicing, a gene containing the code for alpha interferon is inserted in harmless bacteria, which then produce large amounts of the substance.

Through the classification of different types of interferons, the identification of their specific receptor sites in the human body, and the development of gene-splicing techniques in the last decade, it is now possible to produce the amounts of the specific substance needed to make alpha interferon a practical therapeutic agent.

Schering Corp. of Kenilworth, N.J., and Hoffmann-La Roche of Nutley, N.J., will market slightly different molecular versions of the licensed alpha interferon treatment for this indication under the Intron-A and Roferon brand names, respectively. Both of these genetically engineered alpha interferon products were first approved in June 1986 as treatments for hairy cell leukemia -- a rare adult form of leukemia. In June 1988, Intron-A was also approved for treating genital warts.

Kaposi's Sarcoma is ordinarily a rare cancer that affects older men of Mediterranean descent. However, the incidence dramatically increased in the early 1980s, with nearly all the newly reported cases involving young, homosexual men. This rise in the incidence of Kaposi's Sarcoma was one of the first important clues that led to uncovering the spread of AIDS.

Kaposi's Sarcoma is most often manifested by the appearance of large purplish lesions on the skin, but internal lesions can also develop. The form of Kaposi's Sarcoma associated with AIDS tends to spread far more extensively throughout the body. Although the disease is rarely the actual cause of death for AIDS patients, it can spread throughout the body and greatly weaken the patient's physical condition.

Standard treatments for Kaposi's Sarcoma have included chemotherapy and radiation treatments. In AIDS patients, however, chemotherapy can further raise the patient's risk of acquiring severe opportunistic infections. Radiation therapy can treat localized tumors, but not the systemic tumor growth that often occurs in AIDS patients.

In several human studies, 40 to 45 percent of certain patients with Kaposi's Sarcoma who received high doses of alpha interferon responded with a significant reduction in the size of their tumors. These patients tended to be at less advanced stages of AIDS -- they tended to have T4-helper cell counts of above 200 -- and tended to not have experienced any of the severe opportunistic infections that are often associated with AIDS. T4-helper cells are the blood cells that play an essential role in the body's immune system. Healthy people normally have T4-helper cell levels of 800 to 1,000, while people at advanced stages of AIDS can have T4-helper cell counts of less than 200.

The studies demonstrating the safety and efficacy of alpha interferon in treating Kaposi's Sarcoma involved the efforts of industry, investigators at several universities and investigators at the National Institute of Allergy and Infectious Diseases. These studies were critical in determining the patient population likely to benefit from alpha interferon therapy.

Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases, said, "One of these studies, conducted by Dr. H. Clifford Lane, demonstrated that alpha interferon was an effective anti-Kaposi's Sarcoma agent in patients with less advanced stages of immunologic decline. Dr. Lane's study also found evidence that alpha interferon may, to some extent, diminish AIDS virus activity." Dr. Fauci said that the National Institute for Allergy and Infectious Diseases is conducting additional studies of alpha interferon. Volunteers at early stages of HIV infection are being sought for a study comparing treatment with alpha interferon plus zidovudine (commonly known as AZT) to treatment with zidovudine or alpha interferon alone. Interested individuals should call Victoria Davey, R.N., at (301) 496-7196.

Patients at more advanced stages of AIDS tend to be less responsive to alpha interferon treatment.

Reported adverse reactions to alpha interferon include flu-like symptoms and other reactions of varying severity.

Broadcasters: Kaposi's is pronounced with the emphasis on the first syllable -- KAP-o-sees.