Antiretroviral therapy in combination with interferon for AIDS-related Kaposi's sarcoma

In vitro studies have shown that 3'-azido-3'-deoxythymidine (zidovudine, AZT) and interferon synergistically inhibit the replication of the human immunodeficiency virus type 1 (HIV) in peripheral blood mononuclear cells at concentrations achievable in patients. Interferon alfa can cause lesions to regress in patients with acquired immunodeficiency syndrome (AIDS)-related Kaposi's sarcoma (KS). Although zidovudine has no significant effect on the regression of these lesions, it does have antiviral activity in these patients as manifested by a decline in serum HIV antigen. However, when used separately, the two drugs can have serious side effects in some patients. In addition, the development of zidovudine-resistant strains has been noted in patients with advanced HIV disease receiving zidovudine for nine months or longer. Three in vivo trials have been initiated to assess possible advantages of combination therapy with zidovudine and interferon alfa in patients with AIDS-related KS. The incidence of serious adverse reactions, therapeutic efficacy, and the rate of emergence of zidovudine-resistant strains of HIV were evaluated. Preliminary results indicate that combination therapy with interferon alfa and zidovudine can safely be administered to patients with AIDS-related KS in doses that elicit antitumor and antiviral responses and discourage the potential emergence of zidovudine-resistant HIV strains.