Phio Pharmaceuticals Announces Completion of Enrollment in Phase 1b Clinical Trial of INTASYL siRNA Lead Compound PH-762

Core Viewpoint - Phio Pharmaceuticals has completed enrollment in its Phase 1b clinical trial for its lead compound PH-762, which utilizes INTASYL gene silencing technology to target skin cancers [1][6]. Company Overview - Phio Pharmaceuticals Corp. is a clinical-stage siRNA biopharmaceutical company focused on developing therapeutics for cancer using its proprietary INTASYL® technology [1][6]. - The company's lead clinical program, PH-762, silences the PD-1 gene associated with various skin cancers, including cutaneous squamous cell carcinoma, melanoma, and Merkel cell carcinoma [1][6]. Clinical Trial Details - The Phase 1b trial aims to assess the safety and tolerability of intratumoral PH-762 in patients with Stages 1, 2, and 4 cutaneous squamous cell carcinoma, Stage 4 melanoma, and Stage 4 Merkel cell carcinoma [3]. - Patients in the trial receive four weekly injections of PH-762, with pathologic responses evaluated on day 36 post-initial injection [3]. Trial Progress and Results - A total of 18 patients have completed treatment across five dose-escalating cohorts, with significant pathologic responses observed: six patients achieved complete response (100% clearance), two had near complete response (>90% clearance), and two had partial response (>50% clearance) [4]. - No patients exhibited clinical progression of disease, and there were no dose-limiting toxicities or significant adverse effects reported [4][5]. Future Expectations - Pathology results for additional patients treated at the highest dose concentration are anticipated in Q1 2026 [1].