Clinical trial of recombinant leukocyte A interferon as initial therapy for favorable histology non-Hodgkin's lymphomas and chronic lymphocytic leukemia. An Eastern Cooperative Oncology Group pilot study.

Twenty patients with disseminated favorable histology non-Hodgkin's lymphomas (16 patients) or chronic lymphocytic leukemia (four patients) who had not received previous chemotherapy were treated with recombinant leukocyte A interferon (IFL-rA) (Hoffmann-La Roche, Nutley, NJ). Treatment was administered in a moderate dose (12 X 10(6) U/m2) by intramuscular (IM) injection three times weekly for 8 weeks, followed by weekly maintenance therapy for an additional 16 weeks in patients responding to therapy. Five patients with stable disease at 8 weeks received four additional weeks of three-times-weekly treatment at an escalated dose (25 X 10(6) U/m2). Interferon was tolerated without severe toxicity by most patients, although treatment was discontinued prematurely due to side effects in four patients. Objective tumor responses (one complete response [CR] and six partial responses [PRs]) were seen in seven of 16 patients with lymphoma (44%). One of four patients with chronic lymphocytic leukemia also experienced a PR. Median time-to-progression from initiation of therapy among responding patients was 26 + weeks (range, 7 + to 84 + weeks). This study has demonstrated single agent antitumor activity of IFL-rA given in a tolerable outpatient dosage regimen in patients with advanced favorable histology non-Hodgkin's lymphomas, and serves as a basis for further trials of IFL-rA combined with chemotherapy as initial therapy for such patients in the future.