Recombinant alfa-2b-interferon therapy in untreated, stages A and B chronic lymphocytic leukemia. A preliminary report.

Ten patients with B-chronic lymphocytic leukemia (B-CLL) (Six Stage A and four Stage B), who had not received therapy previously, were treated with recombinant alfa-2b-interferon (Schering Corporation, Kenilworth, NJ). The low dose of 1.5 MU was administered by intramuscular (IM) injection three times a week for the first week. The dose was increased to 3.0 MU thereafter until 3 months of therapy were completed. In the responding patients, treatment was continued in the same dose and schedule for 3 additional months. Interferon was tolerated without major toxicity by most patients. Objective tumor response (one complete response and four partial hematologic responses [PHR]) was observed in five of ten patients (50%). Severe autoimmune hemolytic anemia developed in one of the nonresponders at 8 weeks. Therefore, treatment had to be discontinued. Our study demonstrated single alfa-2b-interferon antitumor activity in untreated B-CLL patients with stable disease, and indicated that further trials of alfa-2b-interferon, possibly combined with chemotherapy, may be justified.