Interleukin-21 in Treating Patients With Metastatic or Recurrent Malignant Melanoma

RATIONALE: Interleukin-21 may stimulate white blood cells, including natural killer cells, to kill melanoma cells. PURPOSE: This phase II trial is studying the side effects and how well interleukin-21 works in treating patients with metastatic or recurrent malignant melanoma.

OBJECTIVES: Primary * To assess the efficacy, in terms of objective response rate, nonprogression rate, time to progression, and response duration, in patients with metastatic or recurrent malignant melanoma treated with recombinant human interleukin-21 (rIL-21). * To assess the toxicity and safety of rIL-21 in patients with previously untreated metastatic or recurrent malignant melanoma. * To characterize the pharmacokinetics of rIL-21. * To characterize the effects of rIL-21 on lymphocyte cell count and soluble CD25 (sCD25) in serum as potential biomarkers for drug activity. * To evaluate the immunogenicity of rIL-21, specifically preexisting immunogenicity to the drug and antibody induction during treatment. * To assess melanoma antigenic markers for response and nonprogression on archival tissue from patients enrolled on the study. Secondary * To investigate whether rIL-21 induced sCD25 release is independent of the level of circulating sCD25. * To investigate the effect of rIL-21 on antibody induction during treatment and preexisting immunogenicity. * To assess lymphocyte cell-count changes over time in relation to rIL-21 therapy. OUTLINE: This is a multicenter study. Patients receive recombinant human interleukin-21 (rIL-21) IV on days 1-5 of weeks 1, 3 and 5. Treatment repeats every 8 weeks in the absence of disease progression or unacceptable toxicity. Patients achieving a complete response (CR) or partial response (PR) receive 2 courses beyond CR or PR. Patients with stable disease receive a maximum of 3 courses of rIL-21. Previously archived tumor tissue and blood samples are collected from patients for correlative studies. Samples are analyzed for soluble CD25, rIL-21 antibodies, circulating lymphocyte counts, preexisting immonogenicity to rIL-21 for antibody induction, and expression of common melanoma tumor antigen markers via IHC. After completion of study treatment, patients are followed at 4 weeks.