Imatinib Mesylate in Treating Patients With Stage III or Stage IV Melanoma That Cannot Be Removed by Surgery

This phase II trial is studying how well imatinib mesylate works in treating patients with stage III or stage IV melanoma that cannot be removed by surgery. Imatinib mesylate may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth.

PRIMARY OBJECTIVES: I. Determine the overall objective response rate (complete response and partial response) in patients with inoperable stage III or IV melanoma harboring somatic alterations in c-KIT treated with imatinib mesylate. SECONDARY OBJECTIVES: I. Determine the time to progression in patients treated with this drug. II. Determine if c-KIT mutational status by DNA sequencing, DNA copy number status by fluorescent in situ hybridization (FISH) or comparative genomic hybridization, and/or protein expression by immunohistochemistry (IHC) can best predict clinical benefit from imatinib mesylate. TERTIARY OBJECTIVES: I. To evaluate tumors resistant to small molecule inhibitors of Kit for the development of secondary Kit mutations or for changes in Kit copy number. II. To evaluate for changes in Ki-67, phospho-Akt, phospho-MEK, phospho-S6, phospho STAT3, cleaved caspase 3, IGF-1R, and Kit expression in paired tumor samples obtained from patients treated with a small molecule inhibitor of Kit. III. To analyze baseline and post-resistance blood samples for soluble cKIT levels, soluble VEGFR1, soluble VEGFR2, VEGF, PlGF, FGF, and melanoma inhibitory activity (MIA) levels, and circulating tumor cells. IV. To analyze concomitant samples of blood and tumor for imatinib levels in patients treated with imatinib. OUTLINE: This is a multi-center study. Patients are stratified according to true amplification of c-KIT by FISH vs mutations by DNA sequencing. Patients receive oral imatinib mesylate twice daily for up to 12 weeks in the absence of disease progression or unacceptable toxicity. Tumor tissue samples or unstained tissue slides/paraffin blocks may be collected. c-KIT is evaluated by IHC and comparative genomic hybridization. After completion of study treatment, patients are followed up periodically.