Phase II study of rDNA alpha-2 interferon (INTRON A) in patients with multiple myeloma utilizing an escalating...

Twenty previously treated patients with multiple myeloma were treated with rDNA human alpha-2 interferon (INTRON A) in a phase II trial. Patients received an induction phase of therapy consisting of 3-100 X 10(6) IU/m2 iv given every other day pending myelosuppression. Patients then received 10 X 10(6) IU/m2 three times a week sc. In patients not responding to the iv and sc protocol, prednisone (20 mg orally) was given with each dose of INTRON A to determine whether additional responses could be produced and whether toxicity could be reduced. During the sc phases of therapy, INTRON A was escalated pending hematologic and nonhematologic toxicity. Three partial remissions were achieved in patients receiving the initial iv/sc therapy, and one additional patient responded when prednisone was added (durations of remission, 5, 6, 8, and 9 months). Myelosuppression was the dose-limiting toxic effect in both the iv and sc phases of therapy. Constitutional symptoms (flu-like) were seen in the majority of patients, but were tolerable. With the utilization of prednisone, flu-like symptoms were reduced in frequency and degree. Escalation of the dose of INTRON A was possible in the majority of patients when prednisone was added; however, only one patient (of seven) responded to combination therapy. INTRON A can produce remissions in 20% of patients with previously treated multiple myeloma. No improvement in the response rate was achieved utilizing a high-dose induction program. Although the dose of INTRON A could be escalated when prednisone was added, the response rate was not enhanced.