A Study of DEDN6526A in Patients With Metastatic or Unresectable Melanoma

Inclusion Criteria: * Adult patients, \>/= 18 years of age * Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1 * Histologically confirmed metastatic melanoma (AJCC stage IV) or unresectable melanoma (AJCC Stage III) * Prior failure of \>/= 1 prior treatment regimens for metastatic or unresectable melanoma due to disease progression or unacceptable toxicity and for whom no standard therapy is available * Measurable disease according to RECIST criteria * Adequate bone marrow, liver and renal function * Female patients of childbearing potential and male patients with female partners of childbearing potential must agree to use one highly effective form of non-hormonal contraception or two effective forms of non-hormonal contraception through the course of the study treatment and for 6 months after the last dose of study treatment Exclusion Criteria: * Treatment with cytotoxic or antibody based therapy within 21 days prior to first dose of study treatment, or with any other anti-cancer therapy within 5 half-lives of the therapy prior to first dose of study treatment * Known active infection (including HIV and atypical mycobacterial disease, but excluding fungal infection of the nail beds) * Current Grad \>/= 2 toxicity (except alopecia or anorexia) from prior therapy * Grade \>/= 2 peripheral neuropathy * History of severe allergic or anaphylactic reactions to monoclonal antibody therapies (or recombinant antibody-related fusion proteins) * Clinically significant history of liver disease, including viral or other hepatitis, current alcohol abuse, or cirrhosis * Untreated or active central nervous system (CNS) metastases (progressing or requiring anticonvulsants or corticosteroids for symptomatic control) * Evidence of significant uncontrolled concomitant disease or disorder * Pregnant or lactating women * Prior treatment with any other antibody-drug conjugate (ADC) compound containing monomethyl auristatin E (MMAE) for the treatment of melanoma * Previous participation in a clinical trial within 30 days of the day of first study drug administration (Cycle 1, Day 1)