A phase II study of sequential recombinant interleukin-2 followed by dacarbazine in metastatic melanoma

16 patients with disseminated malignant melanoma (1 with primary ocular melanoma) entered a multicentre phase II study of recombinant interleukin-2, (rIL-2) given by continuous intravenous infusion on days 1-5 at 18 x 10(6) IU/m2 per day, followed by dacarbazine 850 mg/m2 on day 8. After a 2 week rest, a second course was given. In the absence of disease progression, monthly maintenance cycles were given for up to four cycles. 16 patients received one cycle, 14 received two and 6 patients three or more. All 16 patients are evaluable for toxicity and 15 for response. 2 patients responded (13%). 1 patient with lung and pleural metastases achieved partial remission after two cycles and went off treatment after six cycles. 3 months later a complete response was noted lasting 396+ days. A second patient with lung metastases had a partial response lasting 153 days. 3 patients (20%) had stable disease. Mean rebound lymphocytosis (24-48 h after the end of rIL-2 therapy), cell count 4.9 x 10(9)/l (2.6-8.8 x 10(9)/l) was within the expected limits. Other toxicity was as expected. Thus sequential treatment with rIL-2 and dacarbazine is feasible but synergy did not occur.