Pilot Study Of Intratumoral G100, Toll-Like Receptor-4 (Tlr4) Agonist, Therapy In Patients With Merkel Cell Carcinoma (Mcc).

3083 Background: MCC is an aggressive skin cancer with suboptimal therapeutic options. Despite persistent expression of Merkel cell polyomavirus (MCPyV) proteins in ~80% of cases, these tumors are able to evade host immunity. G100 consists of a specific formulation of glucopyranosyl lipid-A (GLA), a TLR4 agonist, and is capable of directly activating dendritic cells (DCs), T cells and other effector cells and stimulating anti-tumor responses in preclinical models. Intratumoral (IT) G100 may overcome immune suppression mechanisms prevalent in MCC tumors and lead to effective local and systemic anti-tumor responses. Methods: 10 MCC patients (pts) with accessible tumor will be enrolled for G100 treatment. Pts with loco-regional MCC (Cohort A) receive 1 cycle of G100 (5 mcg/day) IT on days 1, 8 followed by definitive surgery and/or radiation (RT) starting in week 4. Pts with metastatic disease (Cohort B) receive G100 (5 mcg/day) IT on days 1, 8 and 22 of a 6-week treatment cycle. For cycles 2-4, pts receive p...