Surgery for patients receiving ipilimumab: Safety profile and immunological insights.

8583 Background: Ipilimumab (ipi), a monoclonal antibody blocking CTLA-4, demonstrated survival benefit in metastatic melanoma in two randomized controlled trials. With its approval by the FDA, the use of this immunotherapy is increasing. The surgical safety of ipi has not been reported. Methods: From our prospective database, we identified patients undergoing surgery within 30 days of receiving a dose of ipi or on maintenance ipi between October 2007 and August 2011. Surgical toxicity was graded 1-5 by the Clavien classification. In 10 patients matched blood and tumor infiltrating lymphocytes were harvested. Phenotype of T cell subsets were analyzed by flow cytometry. Results: 23 patients were identified who underwent 34 operations a median of 27 weeks after initiation of ipi (1-123 weeks). Indications for surgery were symptomatic, progressive, or isolated persistent disease in 52%, 39% and 9% respectively. Subcutaneous resections were the most frequent, followed by intra-abdominal and nodal procedures (...