Phio Pharmaceuticals (PHIO) Corporate presentation summary

Disease focus and clinical need

• Cutaneous squamous cell carcinoma (cSCC) is the second most common solid tumor, with rising incidence due to an aging population and high recurrence rates; untreated cases can be fatal, with mortality nearly double that of melanoma.

• Surgical excision is the standard of care, but lesion size, location, and patient comorbidities complicate treatment and can lead to significant disfigurement and need for reconstructive surgery.

Technology platform and mechanism

• INTASYL siRNA technology selectively silences genes, reactivating immune cells to enhance tumor cell killing.

• The platform uses a unique, patented chemistry for precise gene targeting, stability, and efficient delivery without formulation enhancers.

• PH-762, an INTASYL-based PD-1 silencer, boosts anti-tumor immunity by increasing IFN-γ release and T cell activity within tumors.

Clinical development and results

• Phase 1b trial of PH-762 in cSCC and other skin cancers completed in March 2026, with 22 patients treated across five escalating dose cohorts.

• PH-762 demonstrated a favorable safety profile, with no immune or treatment-limiting toxicities and a safe 20-fold dose escalation.

• Final cohort showed 85% pathological response and 100% tumor clearance in 4 of 6 responders; no recurrence observed at study end.