This study compared two doses of Intron-A (artificial alpha interferon) for treating Kaposi’s sarcoma (KS) in HIV-positive individuals.
This was an open label study (both investigators and volunteers knew which treatment was being given). Participants were randomly assigned to receive either 8 million units or 1 million units of Intron-A by injection (needle) in combination with AZT (500 mg/day). The primary endpoint of the study was complete or partial tumor improvement two months in a row. Tumor improvement was based on the measurement of lesions chosen at the start of the study, and on the appearance of new lesions.
One hundred and eighteen patients were randomized in 15 Canadian university specialty clinics. One hundred and seven of the 118 patients were eligible. There were no notable differences in characteristics between the treatment groups at the study start. Ninety-nine percent of the patients were male and 61% had been on prior AZT therapy. Thirty-nine percent had CD4 counts over 200.
The tumor response rate in the high-dose interferon group was 30% compared to 8% in the low-dose group. In addition, progression of KS was delayed in the high-dose compared to the low-dose group. The proportion of patients who had to reduce their dose because of toxicity (side effects) was greater in the high-dose group (46% vs 15% in the low-dose group). The major hematological (blood) problem was neutropenia (shortage of immune cells): 62% of high-dose and 39% of low-dose patients experienced grade II toxicity or worse.
High-dose Intron-A (8 million units per day) added to a regimen of AZT (500 mg/day) increases tumor response and delays tumor progression, compared to a similar low-dose regimen (1 million units per day). The use of high-dose Intron-A is also associated with increased levels of hematological toxicity (toxic blood levels), particularly neutropenia (shortage of immune cells).