Core Viewpoint - Phio Pharmaceuticals has received a positive recommendation from the Safety Monitoring Committee to advance its Phase 1b clinical trial of PH-762, a siRNA compound targeting skin cancer, to the fourth dose escalation cohort, indicating a supportive safety profile in the previous cohort [1][2]. Group 1: Clinical Trial Details - The Phase 1b clinical trial is a multi-center, dose-escalating study aimed at evaluating the safety and tolerability of intratumoral PH-762 in patients with cutaneous squamous cell carcinoma, melanoma, or Merkel cell carcinoma [2][6]. - In the third cohort, three patients with cutaneous squamous cell carcinoma were enrolled, and the injections were well tolerated with no serious adverse events or dose-limiting toxicities reported [2][4]. - Previous cohorts included seven patients, with the second cohort showing two patients achieving a complete response (100% tumor clearance) and one patient showing a partial response (90% clearance) [4]. Group 2: Company Insights - Phio Pharmaceuticals is a clinical-stage biopharmaceutical company focused on developing therapeutics using its proprietary INTASYL® siRNA gene silencing technology to combat cancer [1][6]. - The lead product candidate, PH-762, is designed to silence the PD-1 gene, which is implicated in various forms of skin cancer, and is being evaluated as a potential non-surgical treatment option [6][5]. - The company expresses optimism that PH-762 may provide a viable alternative to existing therapies for skin cancer [5].

Core Insights - Phio Pharmaceuticals Corp. is a clinical-stage siRNA biotechnology company focused on developing therapeutics using its proprietary INTASYL® gene silencing technology to combat cancer [1][4] - The company announced podium presentations for its lead INTASYL product candidates, PH-762 and PH-894, at the 11th Annual Immunotherapy of Cancer (ITOC) Conference in Munich, Germany [1] Product Candidates - PH-762 is an INTASYL siRNA compound targeting PD-1, currently undergoing evaluation in an ongoing clinical trial (NCT 06014086) as a neoadjuvant intratumoral therapy for cutaneous malignancies, showing promising preclinical efficacy and favorable tolerability [2][4] - PH-894 selectively silences BRD4, enhancing NK cell activation and proliferation without off-target effects, representing a novel approach to improve adoptive cell therapy [3] Conference Presentations - Melissa Maxwell, Phio's Director of Research and Program Management, will present on PH-762 during the Plenary Session 3, focusing on its preclinical advances and ongoing clinical evaluation [2] - PH-894 will be discussed in Plenary Session 11, highlighting its potential to increase NK cell activity for adoptive cell therapy [3]

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2024 Or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number 001-36304 PHIO PHARMACEUTICALS CORP. (Exact name of registrant as specified in its charter) (State or other jurisdictio ...

Exhibit 99.1 Phio Pharmaceuticals Reports 2024 Year End Financial Results and Provides Business Update Continues advancing clinical trial for INSTASYL siRNA lead product candidate PH-762 3 Cohort now fully enrolled in on-going clinical study Marlborough, Massachusetts-(Newsfile Corp.-March 31, 2025) — Phio Pharmaceuticals Corp. (Nasdaq: PHIO) is a clinical-stage biotechnology company developing therapeutics that use its INTASYL siRNA gene silencing technology designed to make the body's immune cells more ef ...

Core Insights - Phio Pharmaceuticals reported its financial results for the year ended December 31, 2024, and provided updates on its clinical trials and business strategy [1][10][14] Clinical Development - The lead product candidate, PH-762, is in a Phase 1b clinical trial for treating cutaneous squamous cell carcinoma, melanoma, and Merkel cell carcinoma, with the third cohort fully enrolled [2][3][16] - The trial has shown promising results, with complete tumor clearance in 2 patients and partial response in 1 patient from the second cohort [2][3] - The company expects to complete patient enrollment in the trial by the third quarter of 2025 [3] Financial Overview - As of December 31, 2024, the company had cash of approximately $5.4 million, down from $8.5 million in 2023 [10][19] - The company raised approximately $9.2 million through direct offerings and private placements in late 2024 and early 2025, along with an additional $2.9 million from warrant exercises [4][11] - Research and development expenses decreased by approximately $2.7 million, or 42%, compared to 2023, primarily due to cost rationalization measures [12] Cost Management - The company initiated a cost rationalization program in 2023, transitioning from discovery research to product development, which included headcount reductions and a smaller research footprint [5][6] - General and administrative expenses decreased by approximately 14% to $3.7 million in 2024, down from $4.4 million in 2023 [13] Patent and Scientific Advancements - Phio's patent portfolio includes 77 issued patents, with 69 covering its INTASYL technology, which is designed for cancer therapy [8] - The company presented new data on its INTASYL technology at several major conferences in 2024, highlighting its potential applications in immuno-oncology [9]

American Academy of Dermatology Awards Podium Presentation to Phio Pharmaceutical's Clinical Research at 2025 Annual MeetingInterim Results from clinical study for cutaneous carcinomas presented at Late-Breaking Research SessionMarch 10, 2025 7:45 AM EDT | Source: Phio Pharmaceuticals Corp.Marlborough, Massachusetts--(Newsfile Corp. - March 10, 2025) - Phio Pharmaceuticals Corp. (NASDAQ: PHIO) is a clinical-stage biotechnology company developing therapeutics that use its INTASYL® siRNA gene si ...

Phio Pharmaceuticals Announces Completion of Enrollment in Third Safety Cohort in PH-762 Phase 1b Dose-Escalation StudyMarch 05, 2025 7:45 AM EST | Source: Phio Pharmaceuticals Corp.Marlborough, Massachusetts--(Newsfile Corp. - March 5, 2025) - Phio Pharmaceuticals Corp. (NASDAQ: PHIO) is a clinical-stage biotechnology company developing therapeutics that use its INTASYL® siRNA gene silencing technology designed to make the body's immune cells more effective in killing cancer cells. Phio annou ...

Phio Pharmaceuticals Announces Appointment of David H. Deming to Board of DirectorsFebruary 20, 2025 7:45 AM EST | Source: Phio Pharmaceuticals Corp.Marlborough, Massachusetts--(Newsfile Corp. - February 20, 2025) - Phio Pharmaceuticals Corp. (NASDAQ: PHIO) is a clinical-stage biotechnology company developing therapeutics that use its INTASYL® siRNA gene silencing technology designed to make the body's immune cells more effective in killing cancer cells. Phio announced today the appointment of ...

Phio Pharmaceuticals Announces Participation in the Renmark Financial Communications Virtual Non-Deal Roadshow SeriesRegistration Link for Presentation and live Q&A to take place, Tuesday February 4, 2025 at 2:00 pm ESTFebruary 03, 2025 7:45 AM EST | Source: Phio Pharmaceuticals Corp.Marlborough, Massachusetts--(Newsfile Corp. - February 3, 2025) - Phio Pharmaceuticals Corp. (NASDAQ: PHIO) is a clinical-stage biotechnology company developing therapeutics that use its INTASYL® siRNA gene silenc ...

Clinical Trial Results - Phio Pharmaceuticals reported pathologic complete response (100% tumor clearance) in 2 patients with cutaneous squamous cell carcinoma (cSCC) from the second cohort of its ongoing Phase 1b clinical study [1] - In the second cohort, 1 patient with cSCC showed a partial response (90% tumor clearance) and 1 patient had stable disease without progression [8] - No dose-limiting toxicities or clinically relevant treatment-emergent adverse events were observed in patients receiving intratumoral PH-762, indicating good tolerability [8] PH-762 and INTASYL Technology - PH-762 is an INTASYL compound designed to silence PD-1, potentially offering a non-surgical treatment for skin cancers [9] - INTASYL siRNA gene silencing technology enhances the ability of immune cells to kill tumor cells and has demonstrated efficacy in adoptive cell therapy [6] - The technology targets and silences genes with high specificity across various cell types and tissues without requiring formulation enhancements [6] Study Design and Progress - The ongoing Phase 1b clinical study (NCT 06014086) evaluates the safety and tolerability of neoadjuvant intratumoral PH-762 in patients with Stages 1, 2, and 4 cSCC, Stage 4 melanoma, and Stage 4 Merkel cell carcinoma [5] - The study has enrolled 6 patients with cSCC and 1 patient with metastatic melanoma to date [8] - The company plans to continue enrollment to assess higher dose concentrations of PH-762 [2] Strategic Vision and Leadership Commentary - The company's vision is to strive for a cancer-free future using INTASYL technology, as stated by CEO Robert Bitterman [2] - Mary Spellman, Phio's acting Chief Medical Officer, expressed encouragement over the profound tumor response and reassuring safety data from the second cohort [2]