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www.phiopharma.com ITicker: PHIO (NASDAQ) Phio PharmaceuticalsTumor-Injected Immunotherapy in Skin CancerMaking Our Immune Cells More Effective in Killing Tumor Cells Phio Corporate Presentation Feb 2026
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Forward Looking StatementsThis presentation 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. Examples of forward-looking statements contained in this press release include, among others, the possibility that our INTASYL® siRNA gene silencing technology will make the body’ s immune cells more effective in killing cancer cells, the timing of our studies and trials, including the planned toxicology study for PH-762, the expectation that commercially viable drug product will be available in 2026, the advancement of the drug development pathway of PH-762 toward an NDA approval, the potential for additional potential applications across the INTASYL portfolio, and statements regarding our commercial and clinical strategy, development plans and timelines and other future events.ࣟࣟ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.ࣟ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.ࣟࣟTicker: PHIO (NASDAQ) Ticker: PHIO (NASDAQ) www.phiopharma.com
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•Targets 2ndLargest Incidence of Solid Tumors (cutaneous squamous cell carcinoma)~1.8M incidents/ ~$20B addressable market)Treatment regimens unsatisfiedMortality approaches melanoma•Proprietary INTASYL®siRNA Gene Silencing TechnologyBroadly patented into 2040’sDemonstrated safe and effective in recently completed Phase 1b Trial•Ultra-Lean Virtual Infrastructure Management’s extensive experience in dermatology-related drug developmentHistory of FDA drug approvals and commercial launches Phio Pharmaceutical’s V alue Proposition Ticker: PHIO (NASDAQ) www.phiopharma.com
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Phio’s History of InnovationNobel Prize Winning Technology Ticker: PHIO (NASDAQ) www.phiopharma.com Phio Co-Founder Awarded Nobel Prize for RNAi DiscoveryResulted in the development of INTASYL®PortfolioPatented Short Interfering RNA drug technologyAbility to precisely silences designated genes in the human genomeMaking our Bodies’ Immune Cells More Effective in Killing Tumor Cells
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Selectively silences the signal from a designated geneSuppresses protein production which in presence of tumors causes our immune cells to be ineffective Re-activates the body’s immune cells (T Cells)Making immune cells more effective in killing tumors INTASYL®siRNAConfirmed Results of Intratumoral Therapy Ticker: PHIO (NASDAQ) www.phiopharma.com
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INTASYL®Patented Chemistry StructureAsymmetric siRNA Duplex Passenger StrandGuide StrandPrecise Sequence Design:Permits exceptional gene target specificityPhosphorothioates: Protects stabilityCholesterol: Enables intact drug delivery to any cell type or tissue through endocytosis Ticker: PHIO (NASDAQ) www.phiopharma.com3 Essential Components Selectively Designed and Sequenced Fragments of RNA 3 Critical Elements
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INTASYL®siRNA Intratumoral TherapyMode of Action Ticker: PHIO (NASDAQ) www.phiopharma.com
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Intellectual Property Multi-layered Patent Protection to2044•INTASYL chemistry•Specific drug compounds•Specific gene targets•Immuno-oncology and therapeutic indications54 Patents Issued Ticker: PHIO (NASDAQ) www.phiopharma.com Portfolio Encompasses Issued And Pending Patents In Key Countries
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Proprietary INTASYL Silencing CompoundsTherapeutic TargetPD-1, BRD4, CTLA4, TIGIT, LAG3, TIM3, CBLB, SHP-1, STAT-3, MDM2, ADORA2, MMP-1, CD96, CISH, CSK, DGKα, DGKζ, DMNT3A, HK2, IL-6, KLRC1, PD-L1, PRDM, PTEN, TBX21, TET2 OncologyAuto-ImmuneCTGF, COX2, TGFB1, TGFB2, SPP1Hypertrophic Scarring TYR, COX2Cosmetic Pigmentation MMP1, COX2Cosmetic Wrinkles BRD4HPV , HSV INTASYL®: The Versatility of Gene Silencing PlatformOpportunities to Monetize Ticker: PHIO (NASDAQ) www.phiopharma.com
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www.phiopharma.com ITicker: PHIO (NASDAQ) Phio StrategyInternal Focus on Select Development ProgramsMonetize Non-Strategic Portfolio via Out-License
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Focused Self-Directed Clinical DevelopmentPH-762 PD-1 silencerPhase 1b StudyStages I & II cSCCStage IV cSCC, melanoma, and Merkel cell carcinomaPH-894 BRD4 silencerPotential IndicationsHead and Neck SCCHepatocellular carcinoma (HCC)HPV-related SCCProstate CancerStage IV melanomaProgramDiscovery Preclinical Proofof ConceptIND Enabling StudiesIND ClearanceClinical Phase Ticker: PHIO (NASDAQ) www.phiopharma.com
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www.phiopharma.com ITicker: PHIO (NASDAQ)Intratumoral PH-762 Program Selection Rationale PD-1 Gene Silencing in Skin Cancer Therapy
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PH-762 Lead Program Selection Rationale PD-1 Gene Silencing Ticker: PHIO (NASDAQ) www.phiopharma.comPD-1 validated in monoclonal antibody (mAB) skin cancer trials mAB systemically infused to attack PD-1 on tumor surfaceRisk MitigationIntratumoral INTASYL®silences (turning off) PD-1 at its source in T-cellLimited number of novel clinical trials in cSCC being conducted Competitive Landscape
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U.S. Market Opportunity in cSCC Significant Incidence to All Solid Tumors1 cSCC 51%(1.8M incidence2)Melanoma 3%(108K incidence1)All other solid tumors(1.6M incidence1)46%1Annual incidence in the U.S. excluding basal cell carcinoma (BCC), cancer .org, 20222skincancer .org, 2021Ticker: PHIO (NASDAQ) www.phiopharma.com
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FDA Clearance for PH-762 IND Market Opportunity•FDA IND clearance to study Stage IV melanoma and Merkel cellcarcinoma, Stages I, II and IV cutaneous Squamous Cell Carcinoma (cSCC)•~1.4 million incidences in cSCC Stages I and II (≤ 3 cm in length) •Currently no FDA approved drug therapy for Stages I and II cSCC•Invasive surgery is current standard of careTicker: PHIO (NASDAQ) www.phiopharma.com
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Cosmetic/ Recovery Implications in Invasive SurgerySurgical Excision and Wound Tumor size, location and patient’s health presents a need for non-surgical option
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www.phiopharma.com ITicker: PHIO (NASDAQ) INTASYL®PH-762 Intratumoral Therapy Profile
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•Design: Up to 24 patients in 5 escalating dose concentration•22 patients completed treatment•4 intratumoral injections over 3 weeks with resection of residual lesion at week 5•Endpoints: Safety, Pathology Tumor Results, PK Analysis•Treatment Phase Completed: January 2026•Investigation Sites:Banner MD Anderson, Centricity Research, Integrity Research, Paradigm Clinical Research Centers, Skin Cancer and Dermatology Institute PH-762 Phase 1b Dose-Escalating TrialPurpose: Select Next Trial Dose for Safety & Pathology * *Clinicaltrials.gov NCT06014086Ticker: PHIO (NASDAQ) www.phiopharma.com
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INTASYL®Self-Delivering TechnologyPH-762 Value Proposition Ticker: PHIO (NASDAQ) www.phiopharma.comMulti-FacetedEfficacySafetyConvenienceEconomics
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Clinical Efficacy through Dose EscalationFinal Cohort yields 85% Pathological Response 100% Tumor Clearance in 4 of 6 Responders Cohort 10123456781.14 mg/mL 2.39 mg/mL 5.01 mg/mL 10.50 mg/mL 22.0 mg/mLNumber of Patients<50% Clearance>50% Clearance>90% Clearance100% ClearanceDoseCohort 5Cohort 2Cohort 4Cohort 3
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•No immune related or treatment limiting toxicities in any patients to date through 5 dose escalating cohorts, a 20-fold increase in drug concentration•Direct injection into tumor (intratumoral) essentially eliminates off-target SAEs typically associated with systemic infusion of monoclonal antibodies•Limited drug quantity is injected in sterile buffered saline solution -No lipid nanoparticles or viral vectors in formulation PH-762Favorable Safety and Tolerability Profile Ticker: PHIO (NASDAQ) www.phiopharma.com
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•Administered in physician’s office•Avoids logistics of systemic infusion centers•Minimizes aftercare associated with surgery•Flexible dosing to accommodate lesion size PH-762Patient/Physician Convenience Ticker: PHIO (NASDAQ) www.phiopharma.com
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•Office visits drive MD practice economics•Relatively low production cost•U.S. sourcing for API and drug productPH-762Economics Ticker: PHIO (NASDAQ) www.phiopharma.com
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PH-762 Intratumoral Therapy for cSCC Tissue Sparing with Safety and Convenience Ticker: PHIO (NASDAQ) www.phiopharma.com•Eliminates or Shrinking the Tumor-Minimizes surgical excision and reconstructive surgery-Preserves skin integrity, promotes faster healing and reduces pain•Favorable Safety Profile•Patient Convenience in an MD Office
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www.phiopharma.com ITicker: PHIO (NASDAQ) INTASYL®PH-894 Intratumoral Therapy Profile
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Secondary ProgramIntratumoral PH-894: BRD4 Gene Silencer•BRD4 Implicated in Numerous Potential Cancers-Melanoma, Prostate, Breast, Cervical, Lung, Liver, Head and Neck, cSCC•PH-894 has a Dual Mode of Action -Direct tumor killing-Activation of immune cells•PH-894 is Precisely Selective for BRD4 Gene-Eliminates toxicity associated with other previously studied non-selective development compounds-PH-894 has clean toxicology profile in non-human primate•PH-894 has completed the required IND enabling studies -Ticker: PHIO (NASDAQ) www.phiopharma.com
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www.phiopharma.com ITicker: PHIO (NASDAQ) Phio Pharmaceuticals INTASYL®siRNA Precision Silencing TechnologyEstablished safety and efficacy for PH-762Extensive Intellectual PropertyLeadership Validated by Track RecordCutaneous Carcinomas Market ~$20 BillionMaking our Immune Cells More Effective in Killing Tumor Cells