Study of Combined Ionizing Radiation and Ipilimumab in Metastatic Non-small Cell Lung Cancer (NSCLC)

Research Hypothesis: 1. Through a combination of local RT and ipilimumab an anti-tumor immune response is elicited at the irradiated site, as an in vivo, individualized immunization that is systemically effective, as reflected by objective responses outside the RT field (abscopal effect). 2. The immune response can be prospectively monitored among the treated patients. Objective 1: Evaluate the safety and therapeutic efficacy of anti-cytotoxic T-lymphocyte-associated protein -4 mono clonal Antibody (anti-CTLA-4 mAb) and concurrent local RT in NSCLC patients with metastatic disease. An open label phase II trial will evaluate the preliminary efficacy of the combination of Ipi and RT, applied to a single metastatic site. Efficacy is measured with respect to systemic tumor responses (abscopal response, outside the field of therapy) defined by immune-related Response Criteria (irRC) in all non-irradiated measurable lesions, as a demonstration of an effective anti-tumor immune response. Secondary endpoints include local response in the RT treated tumor, progression free survival, and overall survival. Objective 2: Determine the effects of RT and anti-CTLA-4 mAb on development of anti-tumor immunity. The investigators hypothesize that RT will convert the irradiated tumor into an in situ vaccine and elicit an endogenous tumor-specific cellular and humoral immune response, which in the presence of cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) blockade will promote immune-mediated destruction of the irradiated and abscopal metastases. Pre- and post-treatment tumor biopsies will be examined for changes in immune contexture, and blood for evidence of emerging anti-tumor immune responses. Associations with clinical response will be explored.