Phio Pharmaceuticals cleared a manufacturing hurdle that was quietly blocking its path to a Phase 2b trial: on October 13, the company announced completion of its first commercial-scale cGMP batch of PH-762 drug substance, the material needed to actually dose patients under a regulated protocol. Without that batch, a Q1 2027 trial start was a target on paper. Now it is a target with supply behind it.
PH-762 is an siRNA therapy delivered intratumorally that silences PD-1 in skin tumors, with cutaneous squamous cell carcinoma as the lead indication. Phio completed its Phase 1b treatment phase and, in September 2026, submitted an FDA briefing package to support the neoadjuvant Phase 2b design. That regulatory groundwork and this manufacturing batch are the two concrete prerequisites the company needed to bridge from Phase 1b results to an enrolling trial.
The manufacturing step matters more than a typical process announcement because siRNA therapeutics are notoriously difficult to scale while maintaining the chemical consistency regulators require for clinical use. A cGMP batch produced at commercial scale, rather than at lab or pilot scale, gives the FDA confidence the material patients receive matches what was characterized in preclinical and early clinical work. The FDA’s cGMP guidance for investigational drugs treats manufacturing control as a patient safety question, not just a quality formality, so this completion also reduces the regulatory risk of a clinical hold tied to chemistry, manufacturing, and controls deficiencies.
Phio is a small-cap company with a single clinical asset, which means the Q1 2027 enrollment date is the only near-term event that will tell investors and partners whether the program is real. The date to watch is not the trial start announcement itself but the first site activation filing, which will confirm the IND is in good standing with FDA after the September briefing package review.
Source link: https://www.sec.gov/Archives/edgar/data/1533040/000143774926032505/phio20261008_8k.htm
PH-762: the facts in one place
- Also written: PHIO-762-2301, INTASYL siRNA PH-762
- Sponsor: Phio Pharmaceuticals Corp.
- Mechanism: Self-delivering siRNA (INTASYL) that locally silences PD-1 mRNA in the tumor microenvironment, reducing PD-1 expression on T cells
- Indication studied: Cutaneous squamous cell carcinoma, melanoma, and Merkel cell carcinoma
- Phase: Phase 1b completed; Phase 2b planned
- Enrollment: 22
- Primary endpoint: Safety and dose-limiting toxicities (dose-escalation trial)
- Headline result: 65% overall pathological response rate in cutaneous squamous cell carcinoma patients; 85% in highest-dose cohort; no dose-limiting toxicities or serious adverse events
- Registry identifier: NCT06014086
- Current status: Phase 1b completed; FDA briefing package submitted September 2026; Phase 2b neoadjuvant trial for cutaneous squamous cell carcinoma anticipated to initiate Q1 2027
- Enrollment completion: November 25, 2025
- Safety Monitoring Committee positive wrap-up: February 10, 2026
- FDA briefing package submission: September 14, 2026
- First commercial-scale cGMP batch completion: October 13, 2026
Jon Napitupulu is Director of Media Relations at The Clinical Trial Vanguard. Jon, a computer data scientist, focuses on the latest clinical trial industry news and trends.
