8-K: Phio Pharma's PH-762 Shows Strong Skin Cancer Response

Phio Pharmaceuticals announced positive pathologic results for its INTASYL PH-762 skin cancer trial, showing significant tumor clearance and a favorable safety profile at maximum dose.

Summary

• Phio Pharmaceuticals Corp. announced positive pathologic results for three patients with cutaneous squamous cell carcinoma (cSCC) in the fifth and final dose cohort of its Phase 1b dose escalation trial (NCT 06014086).
• One patient achieved 100% tumor clearance (Complete Response), a second patient achieved greater than 90% (Near Complete Response), and a third patient achieved greater than 50% (Partial Response) at Day 36.
• The Safety Monitoring Committee issued a favorable review of safety data at the maximum dose of INTASYL PH-762, confirming no dose-limiting toxicities or clinically relevant treatment-emergent adverse effects.
• To date, 18 patients with cutaneous carcinomas have completed treatment across five dose escalating cohorts in the Phase 1b trial.
• Cumulative pathologic response in 16 cSCC patients includes six with a complete response (100% clearance), two with a near complete response (>90% clearance), and two with a partial response (>50% clearance).
• A single patient with metastatic Merkel cell carcinoma had a partial response (>50% clearance).
• Six cSCC patients and one patient with metastatic melanoma had a pathologic non-response (<50% clearance).
• No patients in the study have exhibited clinical progression of disease.
• Patients receive four injections of PH-762 at weekly intervals, with pathologic response assessed approximately 5 weeks after the initial injection.

Sentiment

Score: 8

Explanation: The filing reports strong positive clinical trial results, including significant tumor clearance and an excellent safety profile at the maximum dose, which are critical milestones for a clinical-stage biopharmaceutical company. While it's a Phase 1b, the efficacy signals are very encouraging.

Positives

• 100% tumor clearance (Complete Response) in one patient with cutaneous squamous cell carcinoma (cSCC).
• Greater than 90% (Near Complete Response) in a second cSCC patient.
• Greater than 50% (Partial Response) in a third cSCC patient.
• Safety Monitoring Committee issued a favorable review of safety data at the maximum dose of INTASYL PH-762.
• No dose-limiting toxicities or clinically relevant treatment-emergent adverse effects observed throughout the trial, even with a 20-fold dose increase.
• Cumulative data from 16 cSCC patients shows 6 complete responses, 2 near complete responses, and 2 partial responses.
• No patients in the study have exhibited clinical progression of disease.
• Highlights the promise of a viable non-surgical alternative treatment for cutaneous carcinomas.

Negatives

• Six cSCC patients and one metastatic melanoma patient had a pathologic non-response (<50% clearance).

Risks

• Impact to business and operations by inflationary pressures, rising interest rates, and recession fears.
• Uncertainty regarding the development of product candidates and results from preclinical and clinical activities.
• Ability to execute on business strategies and develop product candidates with collaboration partners.
• Timeline and duration for advancing product candidates into clinical development.
• Timing or likelihood of regulatory filings and approvals.
• Success of efforts to commercialize product candidates if approved.
• Ability to manufacture and supply product candidates for clinical activities and commercial use.
• Scope of protection for intellectual property rights covering the technology platform.
• Ability to obtain future financing, market, and other conditions.
• Risks identified in the Annual Report on Form 10-K and subsequent Quarterly Reports on Form 10-Q under the caption 'Risk Factors'.

Future Outlook

The company expects its INTASYL siRNA gene silencing technology to make the body's immune cells more effective in killing cancer cells. They anticipate continued positive safety results from the clinical trial and believe PH-762 has the potential to be a well-tolerated non-surgical treatment for cutaneous carcinomas. The company may continue to screen and treat additional patients in the fifth cohort.

Management Comments

• "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." Robert Bitterman, CEO and Chairman of Phio Pharmaceuticals.
• "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. PH-762 has been well tolerated in this trial, without relevant immune-related adverse events or other toxicities." Mary Spellman, MD, Phio's acting Chief Medical Officer.

Industry Context

This announcement positions Phio Pharmaceuticals as a potential innovator in the immuno-oncology space, specifically for skin cancers. The development of a non-surgical alternative treatment for cutaneous carcinomas addresses a significant unmet medical need and could disrupt existing treatment paradigms, which often involve surgery. The positive safety profile and efficacy signals in a Phase 1b trial are crucial for advancing the drug in a competitive landscape of cancer therapeutics.

Comparison to Industry Standards

• The filing does not provide specific comparisons to other companies, projects, or results within the industry.

Stakeholder Impact

• Shareholders: Positive impact due to promising clinical trial results, potentially increasing company valuation and future prospects.
• Patients: Potential for a new, non-surgical treatment option for various skin cancers, offering improved outcomes and quality of life.
• Medical Community: Provides new data and potential therapeutic avenues for treating cutaneous carcinomas.
• Employees: Positive morale and job security due to successful drug development.

Next Steps

• May continue to screen and treat additional patients as part of the fifth cohort.
• Further clinical development of PH-762.

Key Dates

Recommendation

The reported Phase 1b results for PH-762 are highly encouraging, demonstrating significant tumor clearance (including complete responses) and an excellent safety profile at the maximum dose. For a clinical-stage biopharmaceutical company, positive early-stage clinical data, especially with a favorable safety review, significantly de-risks the asset and increases its probability of success in later stages. The potential for a non-surgical alternative for skin cancers addresses a large market and unmet need. This news is a strong positive catalyst, warranting a "strong buy" recommendation for investors with an appropriate risk tolerance for biotech.

Keywords

Phio Pharmaceuticals, PHIO, INTASYL, PH-762, siRNA, immuno-oncology, skin cancer, cutaneous squamous cell carcinoma, melanoma, Merkel cell carcinoma, Phase 1b trial, tumor clearance, complete response, partial response, biopharmaceutical, clinical trial, cancer treatment