8-K: Phio Pharmaceuticals Announces Positive Pathology Results in Skin Cancer Clinical Trial

Phio Pharmaceuticals reports promising results from its Phase 1b clinical trial of INTASYL PH-762, including complete pathologic responses in patients with cutaneous squamous cell carcinoma.

Summary

• Phio Pharmaceuticals announced positive results from the third cohort of its Phase 1b dose escalation clinical trial evaluating INTASYL PH-762 for skin cancer.
• Two out of three patients with cutaneous squamous cell carcinoma (cSCC) in the third cohort experienced a complete pathologic response (100% tumor clearance).
• The trial, identified as NCT 06014086, assesses the safety and tolerability of neoadjuvant use of intratumoral PH-762 in various stages of cSCC, melanoma, and Merkel cell carcinoma.
• To date, 10 patients with cutaneous carcinomas have been treated across three cohorts, including 9 with cSCC and 1 with metastatic melanoma.
• Four of the nine cSCC patients achieved a complete pathologic response, one had a near-complete response (>90% clearance), and one had a partial response (>50% clearance).
• The remaining three cSCC patients and the melanoma patient showed a pathologic non-response (<50% clearance).
• No dose-limiting toxicities or clinically relevant adverse effects have been observed, and PH-762 has been well-tolerated.
• Enrollment for the fourth cohort is ongoing, with completion expected in the third quarter of 2025.

Sentiment

Score: 8

Explanation: The document presents positive clinical trial results, indicating potential for Phio's lead drug candidate. The absence of reported toxicities and management's optimistic outlook contribute to a positive sentiment.

Positives

• The trial shows promising results with complete pathologic responses observed in multiple patients.
• PH-762 appears to be well-tolerated with no dose-limiting toxicities or clinically relevant adverse effects reported.
• The ongoing dose escalation suggests a potential for further therapeutic benefit.
• The results suggest PH-762 may be a viable non-surgical alternative for skin cancer.

Negatives

• One patient in the third cohort showed a pathologic non-response (<50% tumor clearance).
• Three cSCC patients and one metastatic melanoma patient had a pathologic non-response (< 50% clearance).

Risks

• The forward-looking statements are subject to uncertainties, risks, and changes in circumstances that are difficult to predict and outside of Phio's control.
• Actual results may differ materially due to factors including inflationary pressures, rising interest rates, recession fears, the development of product candidates, and regulatory approvals.
• The company's ability to obtain future financing and the success of collaborations are also risks.

Future Outlook

Phio expects to complete enrollment in the fourth cohort of the Phase 1b clinical trial in the third quarter of 2025 and continues to explore the potential therapeutic benefit of PH-762 for cutaneous carcinoma.

Management Comments

• Robert Bitterman, President and CEO of Phio Pharmaceuticals, stated that the positive outcomes indicate that PH-762 may present a viable non-surgical alternative in the skin cancer market.
• Mary Spellman, MD, Phio's acting Chief Medical Officer, noted that the safety profile supports ongoing dose escalation and the continued positive pathologic responses increase the understanding of the potential therapeutic benefit for this immunotherapy.

Industry Context

The announcement is relevant to the immuno-oncology and siRNA therapeutics fields, where companies are developing novel approaches to treat cancer by enhancing the body's immune response. Phio's INTASYL technology and PH-762 target the PD-1 gene, a common target in cancer immunotherapy.

Comparison to Industry Standards

• Companies like Merck (Keytruda) and Bristol-Myers Squibb (Opdivo) have established PD-1 inhibitors as standard treatments for various cancers, but these are typically administered systemically.
• Phio's approach with intratumoral injection of PH-762 offers a potential advantage in localized skin cancers by directly targeting the tumor microenvironment.
• The reported complete pathologic response rates in the Phio trial are encouraging compared to some other early-stage trials of novel immuno-oncology agents, but further studies are needed to confirm these results in larger patient populations.

Stakeholder Impact

• Positive results could benefit shareholders through increased stock value.
• Successful development of PH-762 could provide a new treatment option for patients with skin cancer.
• Employees may benefit from the company's progress and potential growth.

Next Steps

• Complete enrollment in the fourth cohort of the Phase 1b clinical trial.
• Present trial results at the Society for Investigative Dermatology (SID) Annual Meeting on May 10th.
• Continue evaluating the safety and efficacy of PH-762 in ongoing clinical trials.

Key Dates

Keywords

PH-762, INTASYL, cutaneous squamous cell carcinoma, siRNA, clinical trial, immuno-oncology, Phio Pharmaceuticals, skin cancer, pathologic response