Phio Pharmaceuticals Corp., headquartered in King of Prussia, Pennsylvania, announced on September 14, 2026 that it submitted a comprehensive briefing package to the FDA for PH-762, its lead INTASYL® gene-silencing compound, following completion of a Phase 1b study and proposing to move into a Phase 2b neoadjuvant study in cutaneous squamous cell carcinoma.
President and CEO Robert J. Bitterman said: “Delivering this comprehensive briefing package to the FDA is a key achievement for the PH-762 program and an important step toward unlocking its clinical potential in cutaneous squamous cell carcinoma. We are encouraged by the Phase 1b findings and look forward to working with the FDA as we pursue the next phase of development.”
Silencing a Gene to Wake Up the Immune System
PH-762 works by silencing the PD-1 gene using Phio’s proprietary INTASYL siRNA technology, a mechanism designed to enhance the ability of a patient’s own immune cells to kill cancer cells. The completed Phase 1b trial (NCT# 06014086) evaluated PH-762 across three forms of skin cancer, cutaneous squamous cell carcinoma, melanoma, and Merkel cell carcinoma, though the release doesn’t disclose specific response rates, patient enrollment figures, or safety data from that study. Phio positions PH-762 as a potential non-surgical treatment option for skin cancers that today are typically managed surgically.
What Comes Next
With nonclinical toxicology dosing already completed, Phio says the remaining activities needed to support the next clinical phase are expected to wrap by the first quarter of 2027, when clinical supplies for the proposed Phase 2b neoadjuvant study would also be ready; the release doesn’t detail the planned study’s size, endpoints, or expected timeline beyond that. The FDA submission effectively puts the pace of PH-762’s next phase in the agency’s hands as Phio awaits its response.
About Phio Pharmaceuticals
Phio Pharmaceuticals Corp. is a clinical-stage biopharmaceutical company advancing its proprietary INTASYL® siRNA gene silencing technology to eliminate cancer. Phio’s INTASYL compounds are designed to enhance the body’s immune cells to more effectively kill cancer cells. Phio’s lead clinical development program is an INTASYL compound, PH-762, that silences the PD-1 gene implicated in various forms of skin cancer.
