Low-dose interferon alpha combined with zidovudine in patients with AIDS-associated Kaposi's sarcoma

Forty patients with AIDS-associated Kaposi's sarcoma (KS) treated with the combination of interferon alpha-2b (IFN-alpha) 10-20 MU day-1 and zidovudine (ZDV), 500-800 mg day-1, were evaluated for safety and efficacy. Eighteen patients (45%) had an overall response (CR+PR) at 3 months and a response persisting for a median of 14 (3-27) months. Patients with a CD4 count of less than 300 mm-3, prior to opportunistic infections or constitutional symptoms, were less likely to respond. However, between 28.5% and 36% of patients with a low CD4 count did respond to combined therapy. This is higher than would be predicted from single agent IFN-alpha therapy. Twelve of 28 patients (42.8%) receiving 10 MU day-1 of IFN-alpha (low dose) had an overall response. In addition, patients tolerated this dose of IFN-alpha better, presenting fewer flu-like symptoms and displayed a trend toward less anaemia. p24 antigen decreased in six out of nine evaluable cases, four of whom were treated with low-dose IFN-alpha. Low-dose IFN-alpha plus ZDV seems to be a useful and well-tolerated therapy for KS with antitumoral and antiviral activity. Patients without 'bad prognostic markers' are most likely to show improvement.