Differential responses to chemoimmunotherapy in patients with metastatic malignant melanoma

An open, multicentre non-randomised study was performed to evaluate the activity and toxicity of combination chemoimmunotherapy, consisting of cisplatin, interleukin-2 and interferon-α, in metastatic malignant melanoma. Between March 1992 and September 1993, 28 patients with pathologically proven metastatic malignant melanoma, bidimensionally measurable disease and an Eastern Co-operative Oncology Group score χ1 were treated with the combination chemoimmunotherapy. The regimen consisted of cisplatin (100 mg/m² on day 0), interleukin-2 (Proleukin, Chiron, Middlesex, U.K.) 18 x 10⁶ IU/m²/d continuous intravenous infusion on days 3-7 and 17-22, with interferon-α (Roferon-A, Roche, Hertfordshire, U.K.) 9 x 10⁶U/d subcutaneously on days 3, 5, 7, 17, 19, 21 during the interleukin-2 infusions. The treatment cycle lasted 28 days. Among 27 assessable patients, 5 patients achieved partial responses, for an overall response rate of 18% (95% CI 6-37%). Median progression-free survival was 44 days (range 8-279) and median overall survival was 264 days (range 41-1432). Differential responses were noted in 41% of patients and responses were more frequent in non-visceral disease (skin, lymph node and soft tissue disease) (P = 0.04). These results indicate that differential responses to chemoimmunotherapy are common in patients with metastatic melanoma. This may account for the broad range of response rates reported in the literature.