Phio Pharmaceuticals Announces Positive Safety Monitoring Committee Recommendation to Advance INTASYL PH-762 Skin Cancer Clinical Trial to Fifth Dose Escalation Cohort
Phio Pharmaceuticals (NASDAQ: PHIO) reported positive safety results from the fourth cohort of its Phase 1b clinical trial for PH-762, their lead siRNA compound for skin cancer treatment. The Safety Monitoring Committee recommended advancing to the fifth and expected final dose escalation cohort.
The trial has treated 15 total patients across four cohorts, including 13 with cutaneous squamous cell carcinoma (cSCC), one with metastatic melanoma, and one with Merkel cell carcinoma. Notable results from the first three cohorts showed complete response in 4 of 9 cSCC patients, with additional patients showing near complete or partial responses. No dose-limiting toxicities or serious adverse events were reported.
Phio Pharmaceuticals (NASDAQ: PHIO) ha riportato risultati positivi in termini di sicurezza dal quarto gruppo del suo studio clinico di Fase 1b per PH-762, il loro principale composto siRNA per il trattamento del cancro della pelle. Il Comitato di Monitoraggio della Sicurezza ha raccomandato di procedere al quinto e previsto ultimo gruppo di aumento della dose.
Lo studio ha trattato 15 pazienti in totale suddivisi in quattro gruppi, inclusi 13 con carcinoma squamoso cutaneo (cSCC), uno con melanoma metastatico e uno con carcinoma a cellule di Merkel. I risultati significativi dei primi tre gruppi hanno mostrato una risposta completa in 4 su 9 pazienti con cSCC, con altri pazienti che hanno manifestato risposte quasi complete o parziali. Non sono state segnalate tossicità limitanti la dose né eventi avversi gravi.
Phio Pharmaceuticals (NASDAQ: PHIO) informó resultados positivos de seguridad en la cuarta cohorte de su ensayo clínico de Fase 1b para PH-762, su compuesto principal de siRNA para el tratamiento del cáncer de piel. El Comité de Monitoreo de Seguridad recomendó avanzar a la quinta y esperada cohorte final de escalada de dosis.
El ensayo ha tratado a 15 pacientes en total en cuatro cohortes, incluyendo 13 con carcinoma de células escamosas cutáneo (cSCC), uno con melanoma metastásico y uno con carcinoma de células de Merkel. Resultados destacados de las primeras tres cohortes mostraron una respuesta completa en 4 de 9 pacientes con cSCC, con pacientes adicionales mostrando respuestas casi completas o parciales. No se reportaron toxicidades limitantes de dosis ni eventos adversos graves.
Phio Pharmaceuticals (NASDAQ: PHIO)는 피부암 치료를 위한 주요 siRNA 화합물인 PH-762의 1b상 임상시험 네 번째 코호트에서 긍정적인 안전성 결과를 보고했습니다. 안전성 모니터링 위원회는 다섯 번째이자 예상되는 최종 용량 증량 코호트로 진행할 것을 권고했습니다.
이 임상시험은 4개의 코호트에서 총 15명의 환자를 치료했으며, 이 중 13명은 피부 편평세포암(cSCC), 1명은 전이성 흑색종, 1명은 메르켈 세포암 환자입니다. 처음 세 코호트에서 주목할 만한 결과는 9명의 cSCC 환자 중 4명에서 완전 반응을 보였고, 추가 환자들은 거의 완전하거나 부분 반응을 나타냈습니다. 용량 제한 독성이나 심각한 이상 반응은 보고되지 않았습니다.
Phio Pharmaceuticals (NASDAQ: PHIO) a rapporté des résultats positifs en matière de sécurité pour la quatrième cohorte de son essai clinique de phase 1b portant sur PH-762, leur principal composé siRNA destiné au traitement du cancer de la peau. Le comité de surveillance de la sécurité a recommandé de passer à la cinquième cohorte d'escalade de dose, prévue comme la dernière.
L'essai a traité 15 patients au total répartis en quatre cohortes, dont 13 atteints de carcinome épidermoïde cutané (cSCC), un avec un mélanome métastatique et un avec un carcinome à cellules de Merkel. Les résultats notables des trois premières cohortes ont montré une réponse complète chez 4 des 9 patients cSCC, avec d'autres patients présentant des réponses quasi complètes ou partielles. Aucune toxicité limitant la dose ni événement indésirable grave n'a été rapporté.
Phio Pharmaceuticals (NASDAQ: PHIO) berichtete über positive Sicherheitsdaten aus der vierten Kohorte seiner Phase-1b-Studie für PH-762, ihre führende siRNA-Verbindung zur Behandlung von Hautkrebs. Das Sicherheitsüberwachungskomitee empfahl den Übergang zur fünften und erwarteten letzten Dosiseskalationskohorte.
Die Studie behandelte insgesamt 15 Patienten in vier Kohorten, darunter 13 mit kutanem Plattenepithelkarzinom (cSCC), einen mit metastasiertem Melanom und einen mit Merkelzellkarzinom. Bemerkenswerte Ergebnisse der ersten drei Kohorten zeigten eine vollständige Remission bei 4 von 9 cSCC-Patienten, weitere Patienten zeigten nahezu vollständige oder partielle Remissionen. Es wurden keine dosislimitierenden Toxizitäten oder schwerwiegenden Nebenwirkungen berichtet.
- Strong safety profile demonstrated through four escalating dose cohorts with no serious adverse events
- Complete response (100% tumor clearance) achieved in 4 of 9 cSCC patients from previous cohorts
- Additional positive responses including one near complete (>90%) and one partial (>50%) clearance
- No patients showed clinical progression of disease
- Four patients showed pathologic non-response (<50% clearance) to treatment
- Pathology results from fourth cohort still pending
Insights
Phio's PH-762 shows excellent safety profile across four cohorts with promising early efficacy signals in skin cancer patients.
The Safety Monitoring Committee's recommendation to advance to the fifth and likely final dose escalation cohort represents a significant milestone for Phio's PH-762 INTASYL therapy. With no dose-limiting toxicities, serious adverse events, or clinically relevant treatment-emergent adverse reactions reported across all four cohorts (15 patients total), the drug demonstrates a remarkably clean safety profile - particularly important for local treatments where tolerability directly impacts clinical adoption.
The preliminary efficacy signals are noteworthy: complete responses in 4 of 9 cSCC patients (44%), with an additional patient showing >90% clearance and another with >50% clearance. This translates to a 67% objective response rate in the evaluable cSCC population - impressive for an early-phase trial targeting difficult-to-treat skin cancers. The lack of disease progression across all patients further supports the drug's potential clinical benefit.
The trial's diversity across three cancer types (cSCC, melanoma, and Merkel cell carcinoma) demonstrates the platform's potential versatility. The intratumoral administration route allows for direct targeting of the tumor microenvironment while potentially minimizing systemic exposure. The projected completion of enrollment in Q3 2025 indicates the company is maintaining its clinical timeline.
If the fifth cohort maintains this safety profile while potentially showing enhanced efficacy at the highest dose, it would strongly position PH-762 for advancement to more definitive efficacy-focused trials, representing a critical developmental milestone for Phio's INTASYL platform technology.
-Phio's lead clinical siRNA compound PH-762 demonstrates supportive safety profile in fourth cohort, permitting dose escalation in expected final cohort
Marlborough, Massachusetts--(Newsfile Corp. - June 25, 2025) - Phio Pharmaceuticals Corp. (NASDAQ: PHIO) is a clinical-stage siRNA biopharmaceutical company developing therapeutics using its proprietary INTASYL® gene silencing technology to eliminate cancer. Phio announced today that the Safety Monitoring Committee (SMC) recommended dose escalation in its Phase 1b clinical trial designed to evaluate the safety and tolerability of intratumoral (IT) PH-762 in the treatment of Stages 1, 2, and 4 cutaneous squamous cell carcinoma (cSCC), Stage 4 melanoma, and Stage 4 Merkel cell carcinoma.
Five patients were enrolled in the fourth cohort of the Phase 1b clinical trial (NCT 06014086). Four of the enrolled patients were diagnosed with cSCC and one patient with Merkel cell carcinoma. As with the previous three cohorts, injections were well-tolerated and there were no dose-limiting toxicities, serious adverse events, or clinically relevant treatment-emergent adverse reactions reported.
Pathology results related to the efficacy of PH-762 in the fourth cohort will be forthcoming.
"We are encouraged by the continuing safety profile of PH-762 having now progressed through four escalating dose concentrations, and we anticipate that IT administration of the highest dose concentration of PH-762 in cohort 5 will result in a similar safety profile," said Mary Spellman, MD, Phio's acting Chief Medical Officer.
To date, a total of 15 patients with cutaneous carcinomas have been treated with PH-762 in Cohorts 1 through 4. These cohorts included 13 patients with cSCC, one patient with metastatic melanoma, and one patient with Merkel cell carcinoma.
Pathological response at Day 36 (planned tumor excision) in the previous three cohorts demonstrated complete response (
Phio expects to complete enrollment in the expected final cohort in this trial in the third quarter of 2025.
"The continuing favorable safety profile of PH-762 through the fourth cohort provides promise of a well-tolerated treatment for skin cancer," said Robert Bitterman, CEO and Chairman of Phio Pharmaceuticals.
About Phio Pharmaceuticals Corp.
Phio Pharmaceuticals Corp. (NASDAQ: PHIO) is a clinical-stage siRNA biopharmaceutical company advancing its INTASYL® gene silencing technology focused on immuno-oncology therapeutics. Phio's INTASYL compounds are designed to enhance the body's immune cells to more effectively kill cancer cells. Phio's lead clinical program is an INTASYL compound, PH-762, that silences the PD-1 gene implicated in various forms of skin cancer. The on-going Phase 1b trial (NCT# 06014086) is evaluating PH-762 for the treatment of cutaneous squamous cell carcinoma, melanoma and Merkel cell carcinoma. PH-762 is a potential non-surgical treatment for skin cancers.
For additional information, visit the Company's website, www.phiopharma.com.
Forward-Looking Statements
This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements can be identified by words such as "intends," "believes," "anticipates," "indicates," "plans," "expects," "suggests," "may," "would," "should," "potential," "designed to," "will," "ongoing," "estimate," "forecast," "target," "predict," "could" and similar references, although not all forward-looking statements contain these words. Examples of forward-looking statements contained in this press release include, among others, the possibility that our INTASYL® siRNA gene silencing technology will make the body's immune cells more effective in killing cancer cells and statements regarding our commercial and clinical strategy, development plans and timelines and other future events.
These statements are based only on our current beliefs, expectations and assumptions and are subject to inherent uncertainties, risks and changes in circumstances that are difficult to predict and many of which are outside of our control. Our actual results may differ materially from those indicated in the forward-looking statements as a result of a number of important factors, including, but not limited to, the impact to our business and operations by inflationary pressures, rising interest rates, recession fears, the development of our product candidates, results from our preclinical and clinical activities, our ability to execute on business strategies, our ability to develop our product candidates with collaboration partners, and the success of any such collaborations, the timeline and duration for advancing our product candidates into clinical development, the timing or likelihood of regulatory filings and approvals, the success of our efforts to commercialize our product candidates if approved, our ability to manufacture and supply our product candidates for clinical activities, and for commercial use if approved, the scope of protection we are able to establish and maintain for intellectual property rights covering our technology platform, our ability to obtain future financing, market and other conditions and those identified in our Annual Report on Form 10-K and subsequent Quarterly Reports on Form 10-Q under the caption "Risk Factors" and in other filings the Company periodically makes with the SEC. Readers are urged to review these risk factors and to not act in reliance on any forward-looking statements, as actual results may differ from those contemplated by our forward-looking statements. Phio does not undertake to update forward-looking statements to reflect a change in its views, events or circumstances that occur after the date of this release, except as required by law.
Contact:
Phio Pharmaceuticals Corp.
Jennifer Phillips: jphillips@phiopharma.com
Corporate Affairs
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FAQ
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