• PH-894: Potent and Specific Silencing of BRD4 in NK Cells

Marlborough, Massachusetts--(Newsfile Corp. - October 16, 2024) - Phio Pharmaceuticals Corp. (NASDAQ: PHIO) is a clinical-stage biotechnology company creating new pathways towards a cancer-free future by using its INTASYL^® siRNA gene silencing technology designed to make the body's immune cells more effective in killing cancer cells. Phio announced today that it is presenting data about its INTASYL compound PH-894 at the American Society of Gene & Cell Therapy's (ASGCT's) 2024 Advancing Gene and Cell Therapies for Cancer conference. The conference will take place virtually and at the Wyndham Hotel, Philadelphia Historic District, Philadelphia, PA.

Phio's presentation will focus on how its INTASYL compound PH-894 provides a promising approach for improving the functionality and cytotoxicity of Natural Killer (NK) cells, the body's first line of defense against cancer:

• PH-894 treatment leads to potent and specific silencing of BRD4 in NK cells, without affecting cell viability.
• Incorporation of PH-894 during ex vivo NK cell expansion protocols boosts NK cell numbers by enhancing their proliferation, potentially yielding more effective therapeutic doses.
• PH-894 treatment decreases the expression of CD94, an inhibitory receptor, allowing for improved cytotoxic potential by limiting NK cell inhibition.
• PH-894 may improve NK cell efficacy in adoptive cell therapies by boosting their immune capabilities.

The INTASYL compound PH-894 serves as a foundation for future NK cell-based immunotherapies and supports further exploration of BRD4 as a target in NK cell-based immunotherapies.

Presentation Details are as follows:

About Phio Pharmaceuticals Corp.

Phio Pharmaceuticals Corp. (NASDAQ: PHIO) is a clinical-stage biotechnology company creating new pathways towards a cancer-free future by using its INTASYL^® siRNA gene silencing technology designed to make the body's immune cells more effective in killing cancer cells. In non-systemic applications, INTASYL can target and silence virtually any gene with high specificity across a wide range of tissue types. INTASYL is primarily designed to enhance the ability of immune cells to kill tumor cells and can play a key role in improving adoptive cell therapy. Notably, INTASYL is the only self-delivering RNAi technology, in that it does not require specialized formulations or drug delivery systems.

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

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