A Study to Assess the Safety and Pharmacokinetics of an Inhibitor of PARP in Combination With Dacarbazine

Inclusion Criteria: * Patients must have: 1. Unresectable stage 3 or stage 4 cutaneous melanoma or unknown primary melanoma with metastases. 2. Histological or cytological confirmation of melanoma. Histological confirmation of melanoma from the primary site will suffice, unless the primary site is unknown. Exclusion Criteria: * Previous treatment with cytotoxic chemotherapy for advanced melanoma, apart from treatment for melanoma with isolated limb perfusion. * Radiotherapy (except for palliative reasons), endocrine therapy, immunotherapy or use of other investigational agents within 4 weeks prior to trial entry (or a longer period depending on the defined characteristics of the agents used). * Major surgery within 4 weeks of starting the study.