Phio Pharmaceuticals Announces Positive Pathology Results in Third Cohort in INTASYL PH-762 Skin Cancer Clinical Trial
Phio Pharmaceuticals (NASDAQ: PHIO) reported positive results from the third cohort of its Phase 1b clinical trial for PH-762, a skin cancer treatment. Two out of three patients with cutaneous squamous cell carcinoma (cSCC) achieved complete pathologic response (100% tumor clearance), while one patient showed non-response. Across all three cohorts, involving 10 patients total (9 cSCC, 1 melanoma), 4 cSCC patients achieved complete response, one showed near-complete response (>90%), and one had partial response (>50%).
The trial evaluates PH-762's safety and tolerability in various skin cancer stages. Notably, no dose-limiting toxicities or significant adverse effects were observed, with the treatment being well-tolerated across all dose cohorts. The fourth cohort is currently enrolling, with trial completion expected in Q3 2025.
Phio Pharmaceuticals (NASDAQ: PHIO) ha riportato risultati positivi dal terzo gruppo della sua sperimentazione clinica di Fase 1b per PH-762, un trattamento per il cancro della pelle. Due pazienti su tre con carcinoma squamoso cutaneo (cSCC) hanno ottenuto una risposta patologica completa (100% di eliminazione del tumore), mentre un paziente non ha risposto al trattamento. Complessivamente, nei tre gruppi coinvolgenti 10 pazienti (9 con cSCC, 1 con melanoma), 4 pazienti con cSCC hanno raggiunto una risposta completa, uno ha mostrato una risposta quasi completa (>90%) e un altro una risposta parziale (>50%).
Lo studio valuta la sicurezza e la tollerabilità di PH-762 in vari stadi del cancro della pelle. In particolare, non sono state osservate tossicità limitanti la dose né effetti avversi significativi, con il trattamento ben tollerato in tutti i gruppi di dosaggio. Il quarto gruppo è attualmente in fase di arruolamento, con il completamento dello studio previsto per il terzo trimestre del 2025.
Phio Pharmaceuticals (NASDAQ: PHIO) informó resultados positivos del tercer grupo de su ensayo clínico de fase 1b para PH-762, un tratamiento para el cáncer de piel. Dos de tres pacientes con carcinoma de células escamosas cutáneo (cSCC) lograron una respuesta patológica completa (100% de eliminación del tumor), mientras que un paciente no respondió. En los tres grupos, que incluyeron un total de 10 pacientes (9 con cSCC, 1 con melanoma), 4 pacientes con cSCC lograron una respuesta completa, uno mostró una respuesta casi completa (>90%) y otro una respuesta parcial (>50%).
El ensayo evalúa la seguridad y tolerabilidad de PH-762 en varias etapas del cáncer de piel. Cabe destacar que no se observaron toxicidades limitantes de dosis ni efectos adversos significativos, y el tratamiento fue bien tolerado en todos los grupos de dosis. Actualmente se está reclutando el cuarto grupo, y se espera que el ensayo finalice en el tercer trimestre de 2025.
Phio Pharmaceuticals (NASDAQ: PHIO)는 피부암 치료제 PH-762의 1b상 임상시험 세 번째 코호트에서 긍정적인 결과를 보고했습니다. 피부 편평세포암(cSCC) 환자 3명 중 2명이 완전 병리학적 반응(종양 100% 제거)을 보였으며, 1명은 반응이 없었습니다. 총 10명(9명 cSCC, 1명 흑색종)이 참여한 세 코호트 전체에서 4명의 cSCC 환자가 완전 반응을 보였고, 1명은 거의 완전한 반응(>90%), 1명은 부분 반응(>50%)을 나타냈습니다.
이번 임상시험은 PH-762의 다양한 피부암 단계에서의 안전성과 내약성을 평가합니다. 특히, 용량 제한 독성이나 심각한 부작용은 관찰되지 않았으며, 모든 용량 코호트에서 치료가 잘 견뎌졌습니다. 현재 네 번째 코호트가 모집 중이며, 임상시험은 2025년 3분기에 완료될 예정입니다.
Phio Pharmaceuticals (NASDAQ : PHIO) a annoncé des résultats positifs issus de la troisième cohorte de son essai clinique de phase 1b pour PH-762, un traitement contre le cancer de la peau. Deux patients sur trois atteints de carcinome épidermoïde cutané (cSCC) ont obtenu une réponse pathologique complète (élimination totale de la tumeur), tandis qu’un patient n’a pas répondu au traitement. Sur l’ensemble des trois cohortes, regroupant 10 patients au total (9 cSCC, 1 mélanome), 4 patients cSCC ont obtenu une réponse complète, un a montré une réponse quasi complète (>90%) et un autre une réponse partielle (>50%).
L’essai évalue la sécurité et la tolérance de PH-762 à différents stades du cancer de la peau. Notamment, aucune toxicité limitante liée à la dose ni effet indésirable significatif n’a été observé, le traitement étant bien toléré dans toutes les cohortes. La quatrième cohorte est actuellement en cours de recrutement, avec une fin d’essai prévue pour le troisième trimestre 2025.
Phio Pharmaceuticals (NASDAQ: PHIO) meldete positive Ergebnisse aus der dritten Kohorte seiner Phase-1b-Studie für PH-762, eine Behandlung gegen Hautkrebs. Zwei von drei Patienten mit kutanem Plattenepithelkarzinom (cSCC) erreichten eine vollständige pathologische Remission (100% Tumorentfernung), während ein Patient nicht ansprach. Insgesamt erzielten in allen drei Kohorten, die insgesamt 10 Patienten umfassten (9 cSCC, 1 Melanom), 4 cSCC-Patienten eine komplette Remission, einer zeigte eine nahezu komplette Remission (>90%) und einer eine partielle Remission (>50%).
Die Studie bewertet die Sicherheit und Verträglichkeit von PH-762 in verschiedenen Stadien von Hautkrebs. Bemerkenswert ist, dass keine dosislimitierenden Toxizitäten oder signifikanten Nebenwirkungen beobachtet wurden und die Behandlung in allen Dosiskohorten gut vertragen wurde. Die vierte Kohorte wird derzeit rekrutiert, der Abschluss der Studie wird für das dritte Quartal 2025 erwartet.
- 2 out of 3 patients in third cohort achieved complete pathologic response (100% tumor clearance)
- 4 out of 9 cSCC patients across all cohorts showed complete response (100% tumor clearance)
- No dose-limiting toxicities or clinically relevant adverse effects reported
- Treatment well-tolerated across all dose cohorts
- One patient in third cohort showed non-response (<50% tumor clearance)
- 3 cSCC patients and one melanoma patient showed non-response (<50% clearance)
Insights
Phio's PH-762 shows promising 44% complete pathologic response in early cSCC trial with clean safety profile, supporting continued clinical development.
The latest data from Phio's Phase 1b trial of INTASYL PH-762 demonstrates encouraging clinical activity in cutaneous squamous cell carcinoma (cSCC). In the third cohort, 2 of 3 patients achieved complete pathologic response (100% tumor clearance), consistent with the pattern observed in earlier cohorts. Across all three cohorts to date, 4 of 9 cSCC patients (44%) have achieved complete pathologic response, with one additional patient showing >90% clearance and another showing >50% tumor clearance.
The trial's neoadjuvant design—administering treatment before planned surgical excision at day 36—allows for precise assessment of tumor response through pathological examination. Complete pathologic response indicates no viable tumor cells remained after treatment, though patients may still show visual signs of residual scar or inflammation.
Critically, the safety profile remains favorable through three escalating dose cohorts, with no dose-limiting toxicities or clinically relevant adverse effects reported. This clean safety profile is particularly noteworthy for an immunotherapy approach and supports continued dose escalation in the ongoing fourth cohort.
For context, cSCC is the second most common skin cancer, with current standard of care primarily involving surgical excision. A treatment showing 44% complete response rate in a neoadjuvant setting represents a promising signal worth further investigation. The absence of disease progression in any treated patient further supports the potential therapeutic value.
As this is a Phase 1b study, these results primarily establish safety while providing early efficacy signals. The continued enrollment in a fourth, higher-dose cohort may potentially improve response rates further. The expected completion of enrollment in Q3 2025 establishes a clear timeline for complete data readout.
Positive early-stage trial results strengthen Phio's cancer immunotherapy platform, showing 44% complete response rate with favorable safety profile.
Phio Pharmaceuticals' latest clinical data for their lead candidate PH-762 represents meaningful clinical validation for their proprietary INTASYL gene silencing platform. The consistent efficacy signal across multiple cohorts—now showing complete pathologic responses in 4 of 9 cSCC patients (44%)—provides growing evidence that their siRNA approach can effectively modify the tumor microenvironment.
The clean safety profile with no dose-limiting toxicities through three escalating dose cohorts is particularly significant for an RNA-based therapeutic, as it allows for continued dose exploration that may further improve efficacy outcomes. This favorable therapeutic window is essential for eventual commercial viability.
From a market perspective, cutaneous squamous cell carcinoma represents a substantial opportunity as the second most common form of skin cancer in a "large and continually expanding" market. Current standard of care primarily involves surgical excision, creating an opening for effective neoadjuvant or potentially non-surgical alternatives.
The company's upcoming podium presentation at the Society for Investigative Dermatology Annual Meeting will provide an important platform to showcase these results to key opinion leaders in dermatology, potentially increasing clinical and investor interest in the program.
For Phio, generating consistent positive data is critical at this stage. These results specifically reinforce their INTASYL platform's potential in oncology applications. While still in early development (Phase 1b), establishing proof-of-concept for their siRNA approach in solid tumors represents an important milestone that will inform future pipeline decisions and potentially support partnership discussions as the data matures through anticipated trial completion in Q3 2025.
Complete Pathologic Response reported in 2 patients in the Third Cohort with cutaneous squamous cell carcinoma, complementing results in prior cohort
Phio to present trial results to date at a podium presentation at Society for Investigative Dermatology (SID) Annual Meeting on May 10th
Marlborough, Massachusetts--(Newsfile Corp. - May 7, 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 a complete pathologic response (
"These positive outcomes continue to indicate that PH-762 may present a viable non-surgical alternative in this large and continually expanding skin cancer market," said Robert Bitterman, President and CEO of Phio Pharmaceuticals.
Phio's ongoing Phase 1b dose escalation clinical trial (NCT 06014086) is designed to evaluate the safety and tolerability of neoadjuvant use of intratumoral PH-762 in Stages 1, 2 and 4 cSCC, Stage 4 melanoma, and Stage 4 Merkel cell carcinoma.
To date, a total of 10 patients with cutaneous carcinomas have been treated in Cohorts 1, 2 and 3. These cohorts included 9 patients with cSCC and 1 patient with metastatic melanoma. At day 36 (planned tumor excision), of the 9 patients with cSCC, 4 patients had a pathologic complete response (
To date, there were no dose-limiting toxicities or clinically relevant treatment-emergent adverse effects in the patients receiving intratumoral PH-762 in this trial. Moreover, PH-762 has been well tolerated in all enrolled patients in each escalating dose cohort. The fourth cohort is currently enrolling patients; Phio expects to complete enrollment in the trial in the third quarter of 2025.
"The continued positive pathologic responses in this clinical trial of intratumoral PH-762 for cutaneous carcinoma increases our understanding of the potential therapeutic benefit for this immunotherapy. The safety profile supports ongoing dose escalation," said Mary Spellman, MD, Phio's acting Chief Medical Officer.
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 clinical 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, the potential for PH-762 to present a viable non-surgical alternative for skin cancer, expectations regarding timing of enrollment, 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
To view the source version of this press release, please visit https://www.newsfilecorp.com/release/251072
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