BreastVAX: Radiation Boost to Enhance Immune Checkpoint Blockade Therapy

The study has four arms. Arms 1 and 2 differ by the order of radiation boost and pembrolizumab administration. A minimum of 6 patients will be enrolled in the safety run-in portion of the study. The Phase 2 portion of the study will include Arm 3 (pembrolizumab only arm). An estimated 27 participants will be enrolled or until futility of Arm 3 is reached. Continuation of enrollment in Arms 1 or 2 will be contingent to funding availability. Arm 4 represents our control arm in which patients will follow usual care but will be consented for blood/tissue collection using a separate protocol (Penn IRB 801539).