Phio Pharmaceuticals Reports Promising Phase 1b Results for PH-762 in Cutaneous Squamous Cell Carcinoma
核心洞察
Phio Pharmaceuticals announced positive Phase 1b trial results for INTASYL (搜索) PH-762, with one patient achieving 100% tumor clearance and two others showing greater than 90% and 50% clearance respectively in cutaneous squamous cell carcinoma (搜索).
The Safety Monitoring Committee issued a favorable safety review, confirming no dose-limiting toxicities or clinically relevant adverse effects at the maximum dose concentration across all 18 patients treated.
Cumulative results from 16 patients with cutaneous squamous cell carcinoma (搜索) showed six complete responses, two near complete responses, and two partial responses, highlighting PH-762's potential as a non-surgical treatment option.
Phio Pharmaceuticals Corp. announced positive pathologic results from the final maximum dose cohort of its Phase 1b trial evaluating INTASYL (搜索) PH-762 for cutaneous squamous cell carcinoma (搜索) (cSCC). The results, announced on November 3, 2025, demonstrated significant tumor clearance rates with one patient achieving 100% tumor clearance, a second patient showing greater than 90% clearance, and a third patient exhibiting greater than 50% clearance at approximately five weeks post-treatment.
Trial Design and Patient Population
The ongoing Phase 1b dose escalation trial (NCT# 06014086) is designed to evaluate the safety and tolerability of neoadjuvant intratumoral PH-762 in patients with Stages 1, 2, and 4 cutaneous squamous cell carcinoma (搜索), Stage 4 melanoma (搜索), and Stage 4 Merkel cell carcinoma (搜索). According to the trial protocol, patients receive four weekly injections of PH-762, with pathologic response assessed approximately five weeks after the initial injection.
To date, 18 patients with cutaneous carcinomas have completed treatment across five dose-escalating cohorts. The trial represents a significant dose escalation, with the maximum dose representing approximately a 20-fold increase compared to the first cohort.
Cumulative Efficacy Results
The cumulative pathologic response data from 16 patients with cSCC revealed encouraging outcomes: six patients achieved complete response (100% clearance), two patients demonstrated near complete response (greater than 90% clearance), and two patients showed partial response (greater than 50% clearance). Additionally, a single patient with metastatic Merkel cell carcinoma (搜索) achieved a partial response. Six patients with cSCC and one patient with metastatic melanoma (搜索) had pathologic non-response (less than 50% clearance). Notably, no patients in the study exhibited clinical progression of disease.
Safety Profile
The Safety Monitoring Committee completed its pre-specified review of safety results for the first three patients in the fifth cohort and confirmed no dose-limiting toxicities or clinically relevant treatment-emergent adverse effects at the maximum dose concentration. This favorable safety profile has been consistent throughout the trial, with no dose-limiting toxicities or clinically relevant treatment-emergent adverse effects observed in any of the 18 patients who completed treatment.
"We are pleased with the continuing safety profile of PH-762 throughout dose escalation to approximately a 20-fold increase versus that received in the first cohort," said Mary Spellman, MD, Phio's acting Chief Medical Officer. "PH-762 has been well tolerated in this trial, without relevant immune-related adverse events or other toxicities."
Therapeutic Mechanism and Potential
PH-762 is an INTASYL (搜索) compound that utilizes Phio's proprietary gene silencing technology to target the PD-1 (搜索) gene, which is implicated in various forms of skin cancer. The compound is designed to enhance the body's immune cells' ability to more effectively kill cancer cells, offering a potential non-surgical treatment alternative for cutaneous carcinomas.
"The encouraging outcomes of intratumoral PH-762 in patients who have received treatment thus far is a significant step in clinical development and highlights the promise of a viable non-surgical alternative treatment for cutaneous carcinomas," said Robert Bitterman, CEO and Chairman of Phio Pharmaceuticals.
Company Background
Phio Pharmaceuticals Corp. is a clinical-stage siRNA biopharmaceutical company focused on developing immuno-oncology therapeutics using its proprietary INTASYL (搜索) gene silencing technology. The company's lead clinical program centers on PH-762 as a potential non-surgical treatment for skin cancers including cutaneous squamous cell carcinoma (搜索), melanoma (搜索), and Merkel cell carcinoma (搜索).
The company may continue to screen and treat additional patients as part of the fifth cohort, with the trial ongoing to further evaluate the therapeutic potential of PH-762 in cutaneous carcinomas.