-Injection in murine tumors shows the compound is well tolerated

-Studies support ongoing clinical trial of PH-762 as a neoadjuvant therapy for treatment of cSCC, melanoma, or Merkel cell carcinoma

MARLBOROUGH, Mass., April 22, 2024 (GLOBE NEWSWIRE) — Phio Pharmaceuticals Corp. (Nasdaq: PHIO), a clinical stage biotechnology company whose proprietary INTASYL siRNA gene silencing technology is designed to make immune cells more effective in killing tumor cells, today announced it is presenting new data about its lead clinical product candidate, PH-762, an INTASYL compound.

Preclinical studies demonstrate:

• PH-762 is rapidly taken up by cells and robustly silences PD-1 mRNA and protein in lymphocytes within the tumor microenvironment (TME)
• Intratumoral injection of murine PH-762 (mPH-762) significantly inhibits tumor growth in murine tumor models and is well tolerated
• mPH-762-mediated silencing of PH-762 within the TME may generate memory-specific T cells, promoting IFN-γ release in the TME
• Studies in non-human primates demonstrate that PH-762 is well-tolerated and does not induce release of cytokines associated with cytokine release syndrome (CRS)
• These finding support the ongoing clinical trial of PH-762's safety and efficacy as a neoadjuvant therapy for treatment of cSCC, melanoma, or Merkel cell carcinoma

The data, authored by Melissa Maxwell, Linda Mahoney, and Dr. Mary Spellman, will be presented at the American Society of Gene and Cell Therapy (ASGCT) on May 8^th in Baltimore, Maryland.

About Phio Pharmaceuticals Corp.

Phio Pharmaceuticals Corp. (Nasdaq: PHIO) is a clinical stage biotechnology company whose proprietary INTASYL siRNA gene silencing technology is designed to make immune cells more effective in killing tumor cells. INTASYL is the only self-delivering RNAi technology focused on immuno-oncology therapeutics. INTASYL drugs precisely target specific proteins that reduce the body's ability to fight cancer, without the need for specialized formulations or drug delivery systems.

For additional information, visit the Company's website, www.phiopharma.com.

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Contact:
Phio Pharmaceuticals Corp.
ir@phiopharma.com

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