Purpose: The goal of this study was to determine the therapeutic efficacy and toxicity of a four-drug chemotherapy regimen combined with natural leukocyte interferon alfa (IFN-alpha) for metastatic melanoma.
Patients and methods: Between December 1988 and December 1991, 48 consecutive unselected patients with metastatic melanoma were entered onto this phase II study. Forty-five of these patients were assessable for response and 46 for toxicity. The four-drug chemotherapy regimen was as follows: dacarbazine (DTIC) 200 mg/m2 days 1 to 5, vincristine 1 mg/m2 days 1 and 4, bleomycin 15 mg days 2 and 5 intravenously (IV), and lomustine (CCNU) 80 mg day 1 orally. IFN-alpha, initiated day 8, was administered 3 x 10(6) IU/d, subcutaneously (SC) for 6 weeks, followed by 6 x 10(6) IU three times per week. A small protocol modification was adopted from the 21st patient onwards whenever there was more than 2 months' stabilization or progression with the original protocol: IFN therapy was split into 2-week treatment periods interrupted by a 2-week rest period.
Results: Among the 45 assessable patients, the objective response rate was 62% (95% confidence limit, 48 to 77); six patients (13%) achieved a complete response (CR) and 22 (49%) a partial response (PR). Metastases in such sites as liver also responded favorably (one CR, six PR, one stable disease [SD], two progressive disease [PD]). After splitting IFN therapy for nonresponders, in two patients PD and in another two patients SD changed into regression. Three of the six patients with a CR have suffered a relapse, but the other three have been off treatment for 7, 18, and 31 months without recurrence. Most of the symptomatic patients also experienced rapid relief of symptoms. Overall toxicity of this mainly outpatient regimen seemed to be acceptable. One patient died of a septic fever with grade 4 leukopenia and thrombocytopenia. The most frequent side effects were transient fever, nausea/vomiting, fatigue, and grade I/II hematologic toxicity.
Conclusion: Results demonstrate a remarkably high response rate in combining IFN-alpha and four chemotherapeutic agents. The apparent schedule-dependency of responses must be further explored in a controlled phase III study.