PHIO Phio Pharmaceuticals Corporation

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 INTASYL on March 21st. The event is scheduled to take place at the 10th Immunotherapy of Cancer Conference (ITOC10), which will be held in Munich, Germany from March 21-23, 2024.

The poster, Enhancing NK cell cytotoxicity against tumor cells with a novel self-delivering RNAi compound targeting Cbl-b, reveals new preclinical data demonstrating the potential of treatment with INTASYL self-delivering siRNA Compound PH-905, formerly known as Compound 27547, to improve function of natural killer (NK) cells. The data reveals a consistent silencing of Cbl-b mRNA, which has been shown to limit NK cell activation. Cytotoxic activity of NK cells against K562 (Chronic Myelogenous Leukemia) cancer cells was also increased. By reducing the expression of Cbl-b, INTASYL promotes NK cell activation and proliferation. These preclinical data demonstrate the potential of INTASYL Compound PH-905 to improve Adoptive Cell Therapy (ACT) by targeting and silencing Cbl-b. This may result in a more effective cell therapy for hematological malignancies.

“These data underscore the versatility and potential of Phio’s INTASYL siRNA technology,” said Phio’s President & CEO Robert Bitterman. “It offers a strategy to enhance the effectiveness of ACT therapies in hematological malignancies.”

The preclinical data demonstrate the following:

• INTASYL self-delivering RNAi compound PH-905 effectively targets and silences Cbl-b in primary NK cells without negative impact on their viability.
• Silencing of Cbl-b results in increased proliferation of primary NK cells.
• INTASYL silencing of Cbl-b in primary NK cells enhanced their functional cytotoxicity towards tumor cells.
• Silencing of Cbl-b leads to enhanced fitness of NK cells through increased expression of CD98 and CD25, potentially improving NK metabolism and promoting activation in response to IL-2.
• INTASYL compound PH-905 may be used to improve the anti-tumor response of NK cells to provide a more effective cell therapy for cancer treatment.

Presentation Details are as follows:
Title:			Enhancing NK cell cytotoxicity against tumor cells with a novel self-delivering RNAi compound targeting Cbl-b
Poster Number:			P01.03
Topic:			01.Emerging concepts / New Agents
Presenting Author:			Melissa Maxwell
Date and Time:			18:00 hrs Thursday, March 21, 2024
			18:00-19:00 hrs Friday, March 22, 2024
Location:			Ludwig Maximilian University Campus Großhadern,
			Lecture Room 3, Marchioninistrasse 15
			81377 Munich, Germany

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.

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 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. Examples of forward-looking statements include statements regarding the combination of an INTASYL compound targeting Cbl-b to demonstrate improved NK cell activity and to result in a more effective therapy for hematological malignancies. 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 to our business and operations by inflationary pressures, rising interest rates, recession fears, the development of our product candidates, results from our 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 identified in our 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 SEC. 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.ir@phiopharma.com

PR ContactMichael AdamsBridge View Mediaadams@bridgeviewmedia.com