Eligible patients will receive 10 mg/kg ipilimumab every 3 weeks during a 10-week induction period, followed by a radiological assessment in week 12. Patients with clinical benefit (partial response, complete response or stable disease according to the immune-related response criteria) will continue with an ipilimumab administration every 3 months starting at week 24 up to week 48 until the end of the study or until disease progression,toxicities requiring discontinuation