Phio Pharmaceuticals Presents New Data Showing INTASYL Compound targeting CTLA-4 Enhances Tumor Control

Intratumoral injection of INTASYL self-delivering RNAi compound targeting CTLA-4 (27790) in combination with systemic anti-PD-1 antibody therapy offers a novel approach to combination Immune Checkpoint Inhibition (ICI) therapies

MARLBOROUGH, Mass., Nov. 03, 2023 (GLOBE NEWSWIRE) -- Phio Pharmaceuticals Corp. (Nasdaq: PHIO), a clinical stage biotechnology company whose proprietary INTASYL RNAi platform technology is designed to make immune cells more effective in killing tumor cells, today announced the presentation of new preclinical data at the 38th Annual Meeting of the Society for Immunotherapy of Cancer (SITC). The event is scheduled to take place in San Diego, California, from November 1-5, 2023. Phio’s innovative preclinical study data highlights the benefit of intratumoral injection (IT) of an INTASYL compound targeting CTLA-4 (27790) in conjunction with systemic anti-PD-1 antibody therapy.

Preclinical studies have demonstrated:

• The combination of INTASYL compound 27790 with systemic anti-PD-1 antibody therapy significantly enhanced the efficacy of anti-PD-1 mAb therapy in vivo.
• The combination of INTASYL compound 27790 and anti-PD-1 elicited complete regression of ~40% of IT treated tumors in a mouse model.
• Additionally, INTASYL compound 27790 appeared to improve the efficacy of anti-PD-1 therapy toward those tumors not treated directly with 27790.
• INTASYL compound 27790 increased the percentage of reactive CD8⁺ T cells in the tumor while decreasing immunosuppressive/pro-tumor macrophages in the treated tumor micro-environment.

“These data underscore the potential of Phio’s INTASYL RNAi platform technology to offer a strategy to enhance the effectiveness of immune checkpoint inhibition therapies,” said Phio’s President & CEO Robert Bitterman, “and further demonstrate the flexibility and capabilities of the INTASYL platform.”

Presentation Details are as follows:

Title:	Intratumoral CTLA-4-targeting INTASYL self-delivering RNAi enhances tumor control in combination with systemic anti-PD-1 antibody therapy in vivo suggesting a strategy to mitigate irSAEs
Presenting Author:	Melissa Maxwell
Date and Time:	9:00 am - 8:30 pm PST on Saturday, November 4, 2023
Location:	Exhibit Halls A and B1 – San Diego Convention Center
The poster presentation will be accessible in person and will also be made available on the "Investors – Events and Presentations" section of the Company's website (click here).