The use of interferon in the treatment of multiple myeloma

Almost all patients with multiple myeloma still relapse or become refractory in 2 to 3 years. Interferon (IFN) therapy has clearly influenced the levels of abnormal serum proteins in some patients. A multiinstitutional phase II clinical trial used alfa-2b recombinant interferon (Intron A, Schering, Kenilworth, NJ) in 38 evaluable patients with relapsing and refractory multiple myeloma; two thirds of the patient population had received extensive prior treatment. Seven responded, of whom three continued to do so beyond 1 year-one with an ongoing complete remission. An additional 13 had at least a 25% decrease in abnormal paraproteins. Of nine patients who were initially refractory to chemotherapy, two responded to IFN. Of nine relapsing patients returned to chemotherapy following IFN therapy, six then responded. Thirty previously untreated patients with multiple myeloma were treated with IFN followed by melphalan and prednisone; of 24 evaluable patients, 18 responded with a median duration of 10+ months. Alfa-2b IFN apparently does not antagonize melphalan or prednisone, nor does it appear to worsen the response of the two drugs alone. Effectiveness of recombinant alfa-2b IFN in pretreated relapsing patients suggests additional trials are needed to study its effects in previously untreated patients. A significant number of patients who relapsed on their original chemotherapy and subsequent interferon will apparently respond to the reinstitution of chemotherapy.