The main purpose of this study is to estimate the proportion of patients with a type of skin cancer called melanoma who are progression free, (that is, the cancer has not gotten substantially worse), when treated with Anti-CD137 (4-1BB) (BMS-663513) at 0.1 mg/kg, 1 mg/kg or 5 mg/kg every 3 weeks or 1 mg/kg every 6 weeks

Inclusion Criteria:

• Subjects must have been previously treated with one line of systemic anti-cancer therapy (non-experimental or experimental) for metastatic disease, and relapsed, failed to respond (CR or PR) or did not tolerate that regimen. If the treatment has been administered as an adjuvant and/or neoadjuvant therapy, the subject must have documented disease progression from the last treatment and also received one additional line of systemic therapy for metastatic disease.
• Men and women, who are at least 18 years of age

Exclusion Criteria:

• Ocular or mucosal melanoma
• Complete surgical resection of all identifiable sites of disease
• Symptomatic brain metastasis. Subjects with signs or symptoms suggestive of brain metastasis are not eligible unless brain metastases are ruled out by computerized axial tomography (CT) scan or magnetic resonance imaging (MRI). Subjects with stable brain metastasis and those who were previously treated with radiotherapy or surgery must have no current evidence of symptomatic brain metastasis and are off steroid therapy for at least 4 weeks prior to randomization