Phio Pharmaceuticals Announces Invitation for Oral Presentation at 41st Annual SITC Meeting (Society for Immunotherapy of Cancer)

Nov 6, 2026

INTASYL siRNA – Redefining the Treatment Paradigm for Cutaneous Squamous Cell Carcinoma

King of Prussia, Pennsylvania–(Newsfile Corp. – November 6, 2026) – 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 it will present clinical data from its Phase 1b clinical trial at the 41st Annual Meeting of the Society for Immunotherapy of Cancer (SITC), which will be held in Phoenix, Arizona from November 6-8, 2026.

“The growing body of clinical evidence suggests that PH-762 may offer patients and physicians a meaningful new treatment option capable of shrinking tumors prior to surgery while maintaining an attractive safety profile,” said Robert Bitterman, President and Chief Executive Officer of Phio Pharmaceuticals. “We believe these findings support PH-762’s potential to become a differentiated, tissue-sparing neoadjuvant treatment that may reduce the burden of surgery while preserving favorable clinical outcomes.”

Phio’s presentation will be made by John Strasswimmer, M.D., Ph.D., Florida Atlantic University, Delray Beach, FL; Integrity Research at Dermatology Assoc. of the Palm Beaches, Inc., Delray Beach, FL and lead investigator for the Phase 1b clinical trial. Highlights of the presentation include final results of the first Phase 1b study assessing the safety and efficacy of INTASYL PH-762 as a neoadjuvant intratumoral injection for cutaneous carcinomas. Study findings suggest PH-762 is well-tolerated and may represent a tissue-sparing neoadjuvant to the current cSCC treatment standard of MMS and/or standard excision. Additional studies are needed to further evaluate the safety and efficacy of PH-762 and a Phase 2b study is planned for the first half of 2027.

Presentation Details are as follows:

About Phio Pharmaceuticals Corp.

Phio Pharmaceuticals Corp. (NASDAQ: PHIO) is a clinical-stage biopharmaceutical company advancing its proprietary INTASYL® siRNA gene silencing technology to eliminate cancer. Phio’s INTASYL compounds are designed to enhance the body’s immune cells to more effectively kill cancer cells. Phio’s lead clinical development program is an INTASYL compound, PH-762, that silences the PD-1 gene implicated in various forms of skin cancer. The Phase 1b trial (NCT# 06014086) evaluated 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. These statements, which include statements, among other things, regarding 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 offer patients and physicians a meaningful new treatment option capable of shrinking tumors prior to surgery while maintaining an attractive safety profile, the potential for PH-762 to become a differentiated, tissue-sparing neoadjuvant treatment that may reduce the burden of surgery while preserving favorable clinical outcomes, and our expectation that a Phase 2b study will occur in the first half of 2027, 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 of future FDA interactions on the development of our product candidates; the impact to our business and operations by inflationary pressures; recession fears; the development of our product candidates, results from our nonclinical, 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 risks identified in our most recent 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 U.S. Securities and Exchange Commission. 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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