Treatment of lymphoid neoplasias with interferon. I. Human fibroblastic beta-interferon in malignant gammapathies. Phase II trial.

18 patients with malignant gammapathies (16 with myeloma and 2 with Waldenström's disease) were treated with human fibroblastic Interferon (beta IF). This was administered i.v. 6 X 10(6) units weekly (7 patients) or 3 X 10(6) units twice weekly (11 patients). during at least 3 months if tolerated. Treatment was discontinued because of side effects in three patients. Reduction of the M component, by at least 25% from the initial value, was obtained in 3 patients. In one case the disappearance of a urinary Bence Jones protein was observed. In 4 cases, there was a significant reduction of bone marrow infiltration by plasma cells. In 5 cases, major alleviation or disappearance of bone pain was observed. Duration of treatment seemed to be an important factor for activity. Immune monitoring with currently available tests, mainly natural cytoxicity, yielded no correlation with therapeutic effect in these patients. This preliminary study demonstrates the effect of fibroblastic Interferon in myeloma. However, further studies are necessary to determine the population of patients most likely to benefit from treatment, the best modalities, possible special indications, dose schedules and duration of treatment. As it is not myelosuppressive it could be indicated in the frequent situation of advanced myeloma with bone marrow failure, contra-indicating combination chemotherapy.