Phase II study of recombinant leukocyte A interferon (rIFN-alpha A) in disseminated malignant melanoma.

Thirty-one patients with disseminated malignant melanoma received intramuscular recombinant leukocyte A interferon (rIFN-alpha A), 50 X 10(6) units/m2 three times weekly for a planned treatment duration of 3 months. Seven objective regressions (23%), which ranged in duration from 3 to 11.2+ months, were observed. Forty-two percent of 12 patients who were fully active (Eastern Cooperative Oncology Group [ECOG] performance score, 0) responded compared to 11% of 19 patients with impairment of performance status (ECOG, 1-3). Prior chemotherapy did not influence response rate. For all patients the median time to progression and of survival was 2 months and 6 months, respectively. Four patients had partial regressions in soft tissue (3, 4.6 months), pulmonary (7 months), and prostatic lesions (3 months). The latter was biopsy-proven and assessed by serial computerized tomography (CT) scans. Three had complete regressions of soft tissue disease (2 patients, 6.4 and 10+ months each), and liver involvement (11.2+ months). The major toxicities were moderate to severe fatigue (87%), anorexia (58%), and confusion (23%). Performance score deteriorated in 84% of patients during the time they were receiving rIFN-alpha A. Among the 13 patients whose tumors did not progress for at least 12 weeks, 7 required dose reductions or termination of treatment due to toxicities. Hematologic and hepatic toxicity was transient and of little clinical significance. The study indicates that rIFN-alpha A has some antitumor activity accompanied by difficult side effects in patients with disseminated malignant melanoma.