Phase I/II trials of alpha-interferon alone or in combination with zidovudine as maintenance therapy following induction chemotherapy in the treatment of acquired immunodeficiency syndrome-related Kaposi's sarcoma.

Kaposi's sarcoma (KS) is a malignant neoplasm that develops in 20% to 30% of all acquired immunodeficiency syndrome (AIDS) cases. Kaposi's sarcoma primarily involves the skin, but can progress to involve the lungs, gastrointestinal tract, and liver. alpha-Interferon alone or in combination with zivoduvine has activity in acquired immunodeficiency syndrome-related KS, especially in patients with limited disease and CD4 lymphocyte counts over 400/mm3. Patients with progressive or symptomatic visceral disease, however, can be treated more effectively with cytotoxic chemotherapy. We have used a combination of doxorubicin, bleomycin, and vincristine (ABV) and have achieved response rates of over 80%. Discontinuation of therapy, however, is associated with relapse shortly after response (2 to 3 months). Thus, we have begun studies to define a safe and effective maintenance therapy. Such therapies should include antiretroviral agents since most patients succumb to other human immunodeficiency virus complications, and since human immunodeficiency virus directly, through viral proteins, and indirectly, through the induction of cellular genes, induces KS growth. Additionally, agents with antitumor activity and possible antiviral activity, such as alpha-interferon, may be potentially effective in maintenance therapies. We recently studied 21 patients in a phase I study of recombinant interferon alpha-2b (INTRON-A, Schering-Plough Corp, Kenilworth, NJ) alone following ABV chemotherapy. A dose of 10 million units, given in daily subcutaneous injections, was the maximal tolerated dose; higher doses were associated with intolerable fatigue, diarrhea, and fevers. We are currently conducting a phase I/II trial studying the combination of zivoduvine (500 mg/d) and recombinant interferon alpha-2b (5, 10, and 15 million units) as maintenance in patients with advanced or progressive KS.