This section highlights FDA-related milestones and regulatory updates for drugs developed by Phio Pharmaceuticals (PHIO).
Over the past two years, Phio Pharmaceuticals has reported clinical trial outcomes, regulatory submissions, approvals, and other FDA events for drugs and therapies such as
PH-894 and PH-762. For definitions of regulatory abbreviations such as NDA, BLA, or PDUFA, see the event status legend.
Select a button below to view the list of FDA events for that drug.
PH-894 FDA Regulatory Events
PH-894 is a drug developed by Phio Pharmaceuticals for the following indication: Antitumor cytotoxic agent.
This drug is under review by the U.S. Food and Drug Administration (FDA).
Below is a timeline of key regulatory milestones for this therapy.
- Drug:
- PH-894
- Announced Date:
- August 11, 2026
- Indication:
- Antitumor cytotoxic agent
Announcement
Phio Pharmaceuticals Corp. announced the receipt of a U.S. Notice of Allowance for a patent covering PH-894, further strengthening the Company's intellectual property portfolio.
Read Announcement
PH-762 (INTASYL) FDA Regulatory Timeline and Events
PH-762 (INTASYL) is a drug developed by Phio Pharmaceuticals for the following indication: Murine colorectal cancer.
This drug is under review by the U.S. Food and Drug Administration (FDA).
Below is a timeline of key regulatory milestones for this therapy.
- Drug:
- PH-762 (INTASYL)
- Announced Date:
- March 30, 2026
- Indication:
- Murine colorectal cancer
Announcement
Phio announced today that it has entered into a cGMP drug product manufacturing services agreement with a U.S. manufacturer for clinical supply for future clinical trials.
AI Summary
Phio announced today that it has entered into a cGMP drug product manufacturing services agreement with a U.S. manufacturer to produce clinical supply for future clinical trials. The agreement secures Good Manufacturing Practice production from a U.S.-based partner, which Phio’s CEO said provides quality, expertise and strategic advantages for the company.
This manufacturing pact supports Phio’s lead program, PH-762, an INTASYL compound designed to silence the PD-1 gene involved in several forms of skin cancer. PH-762 was evaluated in a Phase 1b trial for cutaneous squamous cell carcinoma, melanoma and Merkel cell carcinoma, and is being developed as a potential non-surgical treatment option.
By arranging a cGMP supplier now, Phio aims to ensure compliant, timely drug supply for upcoming clinical work and to reduce manufacturing risk. The company also reports cash and cash equivalents projected to sustain operations into the first half of 2027.
Read Announcement- Drug:
- PH-762 (INTASYL)
- Announced Date:
- February 10, 2026
- Indication:
- Murine colorectal cancer
Announcement
Phio announced that the Safety Monitoring Committee (SMC) has concluded its planned safety review for all patients treated with the INTASYL compound PH-762 in Phio's Phase 1b clinical trial.
AI Summary
Phio announced that the Safety Monitoring Committee (SMC) has concluded its planned safety review for all patients treated with the INTASYL compound PH-762 in the company’s Phase 1b trial. The SMC review aligns with the trial’s safety findings: no serious adverse events or dose‑limiting toxicities were identified across all five dose‑escalation cohorts, supporting tolerability at the tested levels.
In the final cohort at the highest dose concentration, 85% of patients showed a pathological response (6 of 7), and 4 of the 6 responders achieved a complete response with 100% tumor clearance. Phio said these efficacy results, together with the favorable safety profile, support continued evaluation of this highest dose.
Phio also reported CMC progress: drug substance material for a non‑human primate study is expected in March 2026, a prerequisite for a pivotal human trial, and cGMP manufacturing is planned for the second half of 2026.
Read Announcement- Drug:
- PH-762 (INTASYL)
- Announced Date:
- January 20, 2026
- Indication:
- Murine colorectal cancer
Announcement
Phio announced today a summary of the pathology results and safety outcomes across all cohorts in its Phase 1b dose escalation clinical trial with the INTASYL compound PH-762 for the treatment of skin cancer.
AI Summary
Phio reported pathology and safety results from its Phase 1b dose-escalation trial of INTASYL PH-762 in skin cancers. Twenty-two patients across five cohorts completed treatment and lesion excision. Among 20 cutaneous squamous cell carcinoma (cSCC) patients, 14 were pathologic responders (70% overall response): 10 had complete responses (100% clearance), two had major/near-clear responses (>90% clearance), and two had partial responses (>50% clearance). One metastatic Merkel cell carcinoma patient had a partial response (>50% clearance). Six cSCC patients and one melanoma patient had responses under 50%, and no patients showed disease progression.
PH-762 was well tolerated with no dose-limiting toxicities or clinically relevant treatment-emergent adverse events across five dose-escalation cohorts (drug concentration increased 20-fold from first to final cohort). Per protocol, patients received four weekly intratumoral injections and pathology was assessed two weeks after the last dose. Extended safety follow-up data are expected in the second quarter of 2026.
Read Announcement- Drug:
- PH-762 (INTASYL)
- Announced Date:
- December 23, 2025
- Indication:
- Murine colorectal cancer
Announcement
Phio announced today that it has taken a major step forward in its drug development program for PH-762.
AI Summary
Phio Pharmaceuticals said it has taken a major step forward in developing PH-762 by starting a required toxicology study in Q1 2026 as a precursor to a human pivotal trial. The company is also working to produce commercially viable drug product that meets cGMP, targeted for later in 2026. A portion of net proceeds from recent financing will fund both the toxicology study and manufacturing work.
PH-762, an INTASYL siRNA candidate for skin cancers, showed positive interim Phase 1b safety and efficacy. Eighteen patients treated; among 16 cutaneous squamous cell carcinoma patients, six had complete responses, two near-complete, and two partial; one metastatic Merkel cell carcinoma patient had a partial response. Six cSCC patients and one metastatic melanoma patient had non-response. No patients showed disease progression, and no dose-limiting toxicities or treatment-emergent adverse events were reported. PH-762 was well tolerated.
Read Announcement- Drug:
- PH-762 (INTASYL)
- Announced Date:
- November 25, 2025
- Target Action Date:
- Q1 2026
- Estimated Target Date Range:
- January 1, 2026 - March 31, 2026
- Indication:
- Murine colorectal cancer
Announcement
Pharmaceuticals Corp. announced that Pathology results for these patients are expected in Q1 2026.
AI Summary
Phio Pharmaceuticals has completed enrollment in its Phase 1b trial of INTASYL siRNA PH-762 and continues treating additional patients in the fifth, highest-dose cohort. Pathology results for these patients are expected in Q1 2026, which will inform the therapy’s activity at the top dose level.
PH-762 targets the PD-1 gene and is being tested as a neoadjuvant, intratumoral treatment for cutaneous squamous cell carcinoma, melanoma, and Merkel cell carcinoma. Per the protocol, patients receive four weekly injections and pathologic response is assessed on day 36 after the first dose (NCT# 06014086).
So far, 18 patients have completed treatment across five dose-escalation cohorts. Among 16 cSCC patients there were six complete responses, two near complete, two partial, and several non-responders; one Merkel cell patient had a partial response. No clinical progression, dose-limiting toxicities, or significant treatment-emergent adverse effects have been reported, and PH-762 has been well tolerated.
Read Announcement- Drug:
- PH-762 (INTASYL)
- Announced Date:
- November 25, 2025
- Indication:
- Murine colorectal cancer
Announcement
Phio announced today the completion of enrollment in its ongoing Phase 1b clinical trial of INTASYL siRNA PH-762. In connection with completing enrollment, Phio continues to treat additional patients in the fifth cohort at the highest dose concentration of PH-762.
AI Summary
Phio Pharmaceuticals announced completion of enrollment in its ongoing Phase 1b clinical trial of INTASYL siRNA PH-762. In connection with completing enrollment, the company is continuing to treat additional patients in the fifth cohort at the highest dose concentration. Pathology results for those additional patients are expected in Q1 2026.
PH-762 is designed to silence the PD‑1 gene and is being tested as an intratumoral, neoadjuvant treatment for certain skin cancers. In the trial, patients receive four weekly injections and pathologic response is assessed on day 36 after the first dose. The study uses dose-escalating cohorts to evaluate safety and tolerability while monitoring tumor responses.
To date, the drug has been well tolerated with no dose-limiting toxicities reported, and the ongoing fifth-cohort dosing will help define safety and potential efficacy at the highest tested concentration. Results from the upcoming pathology reads will guide next steps.
Read Announcement- Drug:
- PH-762 (INTASYL)
- Announced Date:
- November 7, 2025
- Indication:
- Murine colorectal cancer
Announcement
Phio announced today that its INTASYL compound PH-762 is the winner of the 2025 Immunomodulatory Solution of the Year award.
AI Summary
Phio Pharmaceuticals announced that its INTASYL® compound PH-762 won the 2025 Immunomodulatory Solution of the Year award. This honor comes from the fifth annual BioTech Breakthrough Awards program, which recognizes outstanding life sciences and biotechnology innovations worldwide.
Robert Bitterman, CEO and chairman of Phio, expressed gratitude for the award and highlighted PH-762’s potential. He said the intratumoral immunotherapy approach could boost the body’s immune response and improve cancer treatment outcomes.
Bryan Vaughn, managing director of BioTech Breakthrough, noted that PH-762 meets an important medical need by offering a non-surgical option for patients with cutaneous carcinomas. PH-762 is currently in a Phase 1b trial for various skin cancers, including squamous cell carcinoma, melanoma, and Merkel cell carcinoma.
Read Announcement- Drug:
- PH-762 (INTASYL)
- Announced Date:
- November 7, 2025
- Indication:
- Murine colorectal cancer
Announcement
Phio announced today that it will present clinical data from its ongoing Phase 1b clinical trial at the 40th Annual Meeting of the Society for Immunotherapy of Cancer (SITC), which will be held in National Harbor, Maryland from November 7-9, 2025.
AI Summary
Phio Pharmaceuticals said it will present clinical data from its ongoing Phase 1b trial at the 40th Annual Meeting of the Society for Immunotherapy of Cancer (SITC) in National Harbor, Maryland, Nov. 7–9, 2025. The company will show a poster titled "PD-1 Directed Intratumoral Immunotherapy for Cutaneous Carcinomas: A Clinical Study of INTASYL PH-762" (Abstract No. 610). The poster will be presented by Mary Spellman, M.D., on Saturday, November 8, 2025, in the Prince George ABC Exhibit Halls at the Gaylord National Resort and Convention Center.
The poster highlights results from the ongoing Phase 1b dose-escalation study of intratumoral PH-762, designed to evaluate safety and tolerability in patients with cutaneous squamous cell carcinoma, Merkel cell carcinoma, and melanoma. PH-762 is an INTASYL siRNA that targets PD-1. The trial (NCT# 06014086) is evaluating PH-762 as a potential non-surgical treatment option for these skin cancers.
Read Announcement- Drug:
- PH-762 (INTASYL)
- Announced Date:
- November 3, 2025
- Indication:
- Murine colorectal cancer
Announcement
Phio announced today the pathologic results for three patients with cutaneous squamous cell carcinoma (cSCC) who completed treatment in the fifth and final dose cohort of Phio's on-going Phase 1b dose escalation trial: 100% tumor clearance in one of three patients, > 90% clearance in the second patient, and > 50% clearance in the third patient.
AI Summary
Phio Pharmaceuticals, a clinical-stage siRNA biopharma using INTASYL® gene silencing, announced pathologic results for three patients with cutaneous squamous cell carcinoma (cSCC) in the fifth and final dose cohort of its Phase 1b trial. One patient achieved 100% tumor clearance, a second saw over 90% reduction, and a third experienced more than 50% tumor shrinkage approximately five weeks after treatment.
The study delivers four weekly injections of PH-762 directly into tumors, targeting the PD-1 gene to boost the immune response. Pathologic response is measured about five weeks after the first dose.
A Safety Monitoring Committee reviewed data at the maximum dose and reported no dose-limiting toxicities or clinically relevant adverse effects. To date, PH-762 has been well tolerated without immune-related toxicities across all cohorts.
These promising results suggest that intratumoral PH-762 could offer a non-surgical treatment option for patients with cSCC.
Read Announcement- Drug:
- PH-762 (INTASYL)
- Announced Date:
- September 18, 2025
- Indication:
- Murine colorectal cancer
Announcement
Phio Pharmaceuticals Corp announced that Phio Pharmaceuticals is a presenting company at the Life Sciences Future Conference to be held September 25 - 26, 2025.
AI Summary
Phio Pharmaceuticals announced it will present at the Life Sciences Future Conference on September 25–26, 2025, in King of Prussia, PA. President and CEO Robert Bitterman will give a detailed update on the on-going Phase 1b clinical trial of PH-762, Phio’s INTASYL® siRNA therapy targeting the PD-1 gene in skin cancers.
The trial is testing PH-762 in cutaneous squamous cell carcinoma, melanoma, and Merkel cell carcinoma as a potential non-surgical treatment. Bitterman will share recent advances, outline the strategy for completing the treatment phase, and discuss next steps for the development program. He and the management team will also hold one-on-one meetings throughout the conference.
Read Announcement- Drug:
- PH-762 (INTASYL)
- Announced Date:
- September 3, 2025
- Indication:
- Murine colorectal cancer
Announcement
Phio Pharmaceuticals Corp announced that Phio Pharmaceuticals is a presenting company at the H.C. Wainwright 27th Annual Global Investment Conference to be held September 8 – 10, 2025.
AI Summary
Phio Pharmaceuticals Corp. will take part in the H.C. Wainwright 27th Annual Global Investment Conference on September 8–10, 2025, in New York City. Robert Bitterman, Phio’s President and CEO, will present on September 10 from 1:30 to 2:00 PM EST. He will share an update on the ongoing Phase 1b clinical trial of PH-762, Phio’s leading INTASYL® siRNA therapy for skin cancers like cutaneous squamous cell carcinoma, melanoma, and Merkel cell carcinoma.
During his presentation, Mr. Bitterman will outline Phio’s strategy and next steps for PH-762 following the treatment phase of the study. He’ll also be available for one-on-one investor meetings throughout the conference. Interested investors can schedule meetings through their H.C. Wainwright representative or by emailing Phio’s investor relations team.
Read Announcement- Drug:
- PH-762 (INTASYL)
- Announced Date:
- June 25, 2025
- Indication:
- Murine colorectal cancer
Announcement
Phio Pharmaceuticals Corp. announced 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.
AI Summary
Phio Pharmaceuticals recently announced that its Safety Monitoring Committee (SMC) has recommended a dose escalation in its Phase 1b clinical trial. The trial is testing the safety and tolerability of intratumoral PH-762 for treating various skin cancers, including Stages 1, 2, and 4 cutaneous squamous cell carcinoma (cSCC), Stage 4 melanoma, and Stage 4 Merkel cell carcinoma.
In the fourth cohort, five patients were enrolled—four with cSCC and one with Merkel cell carcinoma. The injections were well-tolerated, with no dose-limiting toxicities, serious adverse events, or clinically significant treatment-related reactions observed. This positive outcome has encouraged the dose increase for the anticipated fifth cohort, suggesting that a higher dose may also maintain a favorable safety profile. Researchers are hopeful that PH-762 will continue to be a promising non-surgical treatment for these difficult-to-treat skin cancers.
Read Announcement- Drug:
- PH-762 (INTASYL)
- Announced Date:
- June 24, 2025
- Indication:
- Murine colorectal cancer
Announcement
Phio Pharmaceuticals Corp. announced today that Mr. Robert Bitterman, CEO and Chairman of the Board, Phio Pharmaceuticals will present an update on the company's proprietary INTASYL siRNA technology and progress on the on-going clinical trial with lead compound PH-762 for treatment of skin cancers.
AI Summary
Phio Pharmaceuticals Corp., a clinical-stage siRNA biopharmaceutical company, announced that its CEO and Chairman, Mr. Robert Bitterman, will soon update stakeholders on their proprietary INTASYL® gene silencing technology. During the presentation, Mr. Bitterman will review the progress of the on-going Phase 1b clinical trial of PH-762, the company’s lead compound for treating skin cancers. PH-762 is designed to target and silence specific genes involved in cancer progression, and recent early trial results have shown promise in terms of safety and efficacy. The update, which includes a live Q&A session, is scheduled for Monday, June 30, 2025, at 10:00 am EST. This presentation is part of Phio's ongoing efforts to develop innovative, non-surgical treatment options for various forms of skin cancer, highlighting the company’s commitment to advancing cancer therapies through its INTASYL technology.
Read Announcement- Drug:
- PH-762 (INTASYL)
- Announced Date:
- May 19, 2025
- Indication:
- Murine colorectal cancer
Announcement
Phio Pharmaceuticals Corp announced that Mr. Robert Bitterman, CEO and Chairman of the Board, Phio Pharmaceuticals will present an update on the company's proprietary INTASYL siRNA technology and progress on the on-going clinical trial with lead compound PH-762 for treatment of skin cancers.
AI Summary
Phio Pharmaceuticals Corp’s CEO and Chairman, Robert Bitterman, will present an update on the company’s proprietary INTASYL siRNA technology. During his presentation on May 22, 2025, Mr. Bitterman will share progress on the ongoing Phase 1b clinical trial of PH-762, the company’s lead compound for treating skin cancers. The trial focuses on cutaneous squamous cell carcinoma, melanoma, and Merkel cell carcinoma, aiming to provide a non-surgical treatment option. The presentation will outline how INTASYL technology works by silencing specific genes to enhance the body’s immune response against cancer cells. This update is expected to highlight the innovation behind Phio’s approach and offer valuable insights for investors and stakeholders on the company’s progress toward a cancer-free future with advanced gene-silencing therapeutics.
Read Announcement- Drug:
- PH-762 (INTASYL)
- Announced Date:
- May 7, 2025
- Indication:
- Murine colorectal cancer
Announcement
Phio Pharmaceuticals Corp. announced today that a complete pathologic response (100% tumor clearance) has been reported for 2 of 3 patients with cutaneous squamous cell carcinoma (cSCC) treated in the third dose cohort.
AI Summary
Phio Pharmaceuticals Corp. announced promising results from the third dose cohort of its Phase 1b trial for skin cancers. In this group, two of three patients with cutaneous squamous cell carcinoma achieved a complete pathologic response, meaning they experienced 100% tumor clearance. This result highlights the potential of PH-762 as a non-surgical treatment option for cSCC.
The trial uses Phio’s INTASYL® gene silencing technology and is designed to test the safety and tolerability of the treatment. So far, the therapy has been well tolerated with few adverse effects, which adds to optimism about its future use in the skin cancer market. Phio plans to continue enrolling patients as the trial progresses, aiming to further explore the benefits and optimal dosing of PH-762.
Read Announcement- Drug:
- PH-762 (INTASYL)
- Announced Date:
- April 9, 2025
- Indication:
- Murine colorectal cancer
Announcement
Phio announced today that the Safety Monitoring Committee (SMC) recommended dose escalation in Phio's Phase 1b clinical trial (NCT 06014086) for Phio's lead product candidate, PH-762.
AI Summary
Phio Pharmaceuticals announced that the Safety Monitoring Committee (SMC) recommended dose escalation in its ongoing Phase 1b clinical trial (NCT 06014086) for its lead product candidate, PH-762. The decision comes after observations from the third cohort, where patients with cutaneous squamous cell carcinoma were treated without any serious adverse events or dose-limiting toxicities. This favorable safety profile supports the plan to increase the dose concentration in future cohorts. The Phase 1b trial is a multi-center, dose-escalating study aimed at assessing the safety and tolerability of intratumoral PH-762 administration in skin cancer patients, including those with melanoma and Merkel cell carcinoma. This step forward suggests that PH-762 may continue to demonstrate both safety and potential effectiveness, reinforcing its promise as a possible non-surgical treatment option for various types of skin cancers.
Read Announcement- Drug:
- PH-762 (INTASYL)
- Announced Date:
- March 5, 2025
- Indication:
- Murine colorectal cancer
Announcement
Phio Pharmaceuticals Corp. announced that it has fulfilled the required enrollment for safety in its third dose cohort in its Phase 1b dose escalating clinical study for their lead compound PH-762.
AI Summary
Phio Pharmaceuticals has reached a key milestone in its Phase 1b dose-escalation study for PH-762, its lead compound for treating skin cancers. The company announced that it has successfully enrolled the required number of patients in the third dose cohort needed to assess safety. Utilizing its INTASYL siRNA gene silencing technology, PH-762 is designed to enhance immune cells so they can better attack cancer cells, potentially offering a non-surgical treatment option for conditions such as cutaneous squamous cell carcinoma, melanoma, and Merkel cell carcinoma.
Following this important enrollment achievement, Phio plans to begin screening for the fourth dose cohort in early April. This progress is a vital step in determining the optimal dose and ensuring patient safety as the study advances, bringing the therapy closer to future clinical development and potential treatment options for skin cancer patients.
Read Announcement- Drug:
- PH-762 (INTASYL)
- Announced Date:
- January 13, 2025
- Indication:
- Murine colorectal cancer
Announcement
Phio Pharmaceuticals Corp announced pathologic responses for patients enrolled in the 2nd cohort, which includes 2 patients with a complete response or 100% tumor clearance.
AI Summary
Phio Pharmaceuticals Corp reported promising new results from its Phase 1b clinical trial. In the 2nd cohort of the study, two patients with cutaneous squamous cell carcinoma achieved a complete pathologic response, meaning they experienced 100% tumor clearance. These results show a significant improvement as complete response is a strong indicator of the therapy’s potential effectiveness in fighting cancer.
The study also noted that one patient experienced a partial response with a 90% reduction in tumor size, while another patient had stable disease. Importantly, the treatment was well tolerated with no dose-limiting toxicities or significant treatment-related adverse events reported. These encouraging outcomes support further evaluation of higher dose concentrations as the trial continues to assess the safety and potential benefits of PH-762 in treating skin cancers.
Read Announcement- Drug:
- PH-762 (INTASYL)
- Announced Date:
- December 19, 2024
- Indication:
- Murine colorectal cancer
Announcement
Phio Pharmaceuticals Corp. announced that the Safety Monitoring Committee (SMC) recommended dose escalation in its Phase 1b clinical trial designed to evaluate the safety and tolerability of PH-762 in the treatment of Stages 1, 2, and 4 cutaneous squamous cell carcinoma, Stage 4 melanoma and Stage 4 Merkel cell carcinoma.
AI Summary
Phio Pharmaceuticals recently announced promising results from its Phase 1b clinical trial evaluating PH-762. The trial, which treats patients with Stages 1, 2, and 4 cutaneous squamous cell carcinoma—as well as Stage 4 melanoma and Stage 4 Merkel cell carcinoma—has shown an encouraging safety profile. In the second cohort, patients diagnosed with cutaneous squamous cell carcinoma received intratumoral injections that were well tolerated, with no dose-limiting toxicities or serious adverse events reported.
Based on these strong safety outcomes and early signs of efficacy, the Safety Monitoring Committee (SMC) recommended escalating the dose to further assess PH-762’s potential benefits. This dose increase is a key step in the ongoing clinical investigation as researchers continue to monitor its safety and effectiveness in enhancing the body’s immune response against skin cancers.
Read Announcement- Drug:
- PH-762 (INTASYL)
- Announced Date:
- November 19, 2024
- Indication:
- Murine colorectal cancer
Announcement
Phio Pharmaceuticals Corp. announced it has completed the enrollment of its second patient cohort in its PH-762 Phase 1b dose-escalating clinical trial, and added a sixth clinical site in San Diego, CA.
AI Summary
Phio Pharmaceuticals Corp. announced that it has finished enrolling its second patient cohort in the PH-762 Phase 1b dose-escalation trial. The study is testing a new treatment for skin cancers such as squamous cell carcinoma, melanoma, and Merkel cell carcinoma. In this group, one patient achieved complete tumor clearance and another reached 90% tumor reduction. Along with this milestone, Phio expanded its clinical trial network by adding a sixth site in San Diego, California. The new site at Paradigm Clinical Research Centers joins five other locations across the United States, reinforcing the company’s commitment to advancing its innovative therapy. Phio’s efforts with PH-762 use its INTASYL gene silencing technology to help the immune system attack cancer more effectively, highlighting promising steps toward improved cancer treatment.Read Announcement
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