This open-label single arm study will assess the efficacy, safety and tolerability of Vemurafenib in previously treated patients with metastatic melanoma. Patients will receive oral Vemurafenib [RG7204; PLEXXIKON: PLX4032] at a dose of 960 mg b.i.d. continuously until disease progression or withdrawal from study and will be assessed at regular intervals for tumour response and tolerability. Target sample size is <100 patients.