Intratumoral PH-762 for Cutaneous Carcinoma

The goal of this clinical trial is to evaluate the safety and tolerability of intratumoral injections of PH-762 in squamous cell carcinoma, melanoma, or Merkel cell carcinomas of the skin, to understand what the body does to the PH-762, and to observe how the tumor responds to the drug. Participants will receive four injections of PH-762 at weekly intervals, into a single tumor, followed by surgical removal of the tumor approximately two weeks later.

PH-762 is a potent RNAi molecule targeting PD-1. PH-762 can inhibit the immune checkpoint PD-1 in the tumor and thereby impede tumor growth. As a preoperative therapy, it may decrease the lesion size and has the potential to improve surgical morbidity. Intratumoral immunotherapy aims to use the tumor as a 'self-vaccine'. The local immune stimulation can induce robust priming of an anti-tumor immune response while generating systemic (abscopal) tumor responses, mediated by properly activated anti-tumor immune cells in the circulation. Local delivery of immunotherapy is expected to minimize systemic exposure and off-target toxicities. This is a non-comparative study of neoadjuvant monotherapy using PD-1 targeting self-delivering RNAi (PH-762) in adult subjects with cutaneous squamous cell carcinoma, melanoma, or Merkel cell carcinoma. The study treatment consists of four intratumoral injections of PH-762 at weekly intervals, into a single tumor lesion. Excision of the tumor will occur approximately two weeks following the fourth dose of IT PH-762, and the subjects will be followed for an additional 11 weeks.