Kaposi's sarcoma and the acquired immune deficiency syndrome. Treatment with recombinant interferon alpha and analysis of prognostic factors.

Interferon alfa-2a (Roferon-A, Hoffmann-La Roche Inc., Nutley, NJ) was used to treat sequential groups of patients with Kaposi's sarcoma associated with the acquired immune deficiency syndrome (AIDS). Major antitumor effects (complete or partial responses) were observed in 38% of the patients treated initially with high-dose interferon alfa-2a and in 17% of patients in whom the dose was increased after low-dose treatment failed. A low dose of interferon alfa-2a was ineffective; one patient (3%) showed a partial response. Patients whose tumors responded to interferon treatment showed a significantly lower rate of opportunistic infection, as well as a longer survival than nonresponders. The status of pretreatment immune function was important in predicting the response to interferon treatment. The implication of these findings with respect to understanding the mechanism of action of interferon and the definition of the most appropriate patients for interferon treatment are discussed.