Combination of highly purified human leukocyte interferon α and 13-cis-retinoic acid for the treatment of metastiatic melanoma
The effect of 13-cis-retinoic acid and highly purified human leukocyte interferon α (Alphaferon) therapy for metastatic melanoma was studied. A group of 17 patients with disseminated malignant melanoma were treated over a 6-month period. They received 60 mg 13-cis-retinoic acid/day continuously and ten cycles of interferon α (IFNα). IFN was administered by subcutaneous injection, at a daily dose of 6×106 IU Alphaferon. The 5-day treament period was followed by an IFN-free interval of 2 weeks. We were able to observe an overall response rate of 30% with 12% complete responses (2 out of 17 patients). Sites of response included the skin, lung, liver and lymph nodes. All responses have now lasted over 6 months. Therapy was generally well tolerated and could be performed on an outpatient basis. Side-effects of this combination therapy did not exceed the established side-effects of the two substances. We also studied 2′-5′-oligoadenylate synthetase, β2-microglobulin and neopterin levels during the whole treatment course. All patients were within the normal range before treatment and a sharp rise occurred during each IFN cycle. The maximum being observed 24 h after the third injection. This indicates a high biological activity of IFNα administered cyclicly during the whole treatment course. This finding also corresponds well with the absence of neutralizing antibodies before and after the whole treatment period.