Phio Pharmaceuticals has begun a toxicology study for its lead immuno‑oncology candidate PH‑762, an INTASYL® anti‑PD‑1 siRNA compound. The study is a regulatory requirement that must be completed before the company can launch a pivotal human trial and is a critical step toward an eventual FDA approval.
The study will start in the first quarter of 2026 and will use a two‑species, 90‑day repeat‑dose design in rodents and non‑human primates. Endpoints include organ toxicity, pharmacokinetics, and immunogenicity. A portion of the proceeds from a $50 million Series B financing closed on December 15, 2025, is being allocated to fund the study and to support the development of a cGMP‑compliant drug product.
PH‑762 is part of Phio’s skin‑cancer pipeline, targeting cutaneous squamous cell carcinoma, melanoma, and Merkel cell carcinoma. Interim Phase 1b data showed no dose‑limiting toxicities and promising responses, giving the company confidence to advance. The toxicology study will de‑risk the pathway and support a future NDA submission.
CEO Robert Bitterman said the non‑clinical study is a “very significant step” toward an NDA, emphasizing the company’s focus on intratumoral delivery to reduce systemic side effects. The financing also supports cGMP manufacturing, positioning PH‑762 for commercial scale.
Following the announcement, Phio’s shares rose 4.55 % and the company’s market cap increased by roughly $515 k, reflecting investor confidence in the regulatory milestone and the positive Phase 1b data.
Phio plans to complete the toxicology study by mid‑2026, after which it will file an Investigational New Drug application and begin a pivotal trial. The company’s strategy to combine a novel delivery platform with a PD‑1 target could differentiate PH‑762 in a crowded market, potentially expanding its addressable market.
The content on BeyondSPX is for informational purposes only and should not be construed as financial or investment advice. We are not financial advisors. Consult with a qualified professional before making any investment decisions. Any actions you take based on information from this site are solely at your own risk.