Phio Pharmaceuticals

What Phio Pharmaceuticals does

Phio Pharmaceuticals is a clinical-stage biopharmaceutical company developing siRNA-based therapeutics using its proprietary INTASYL gene silencing technology platform for immuno-oncology applications. The platform consists of chemically modified, self-delivering siRNA compounds that penetrate cells without requiring lipid nanoparticle formulations, designed to silence specific genes (PD-1, BRD4, TIGIT) that impede the immune system's ability to fight cancer. The lead clinical asset PH-762 is an intratumoral PD-1 silencer that completed Phase 1b enrollment in November 2025 across 22 patients with cutaneous squamous cell carcinoma, melanoma, and Merkel cell carcinoma, reporting approximately 65% pathological response in cSCC and no dose-limiting toxicities across five dose cohorts. Two earlier-stage programs (PH-894 targeting BRD4 and PH-804 targeting TIGIT) are advancing through preclinical development.

The company has no commercial revenue and operates as a development-stage entity with 1-10 employees based at its King of Prussia, Pennsylvania headquarters. Its business model is presently centered on advancing PH-762 through clinical development toward FDA approval, with future commercial revenue expected from pharmaceutical distribution through specialty wholesalers and oncology/hospital channels. Capital is raised primarily through small-cap public equity instruments (registered direct offerings, warrant exercises, and an ATM facility) underwritten by H.C. Wainwright & Co. Manufacturing is outsourced through CDMO partnerships with Nitto Denko Avecia (drug substance, cGMP commercial-scale from June 2026) and Pyramid Pharma Services (drug product), and FDA-engagement toxicology is being conducted at a U.S. laboratory. The intellectual property portfolio comprises 54 issued patents plus 20 pending applications across US, Canada, and Japan.

Name

Phio Pharmaceuticals

Legal name

Phio Pharmaceuticals Corp.

Website

https://phiopharma.com

Company type

Public

Founded year

2012

Operating status

Operating

Headcount range

1–10 employees

Short description

Phio Pharmaceuticals is a clinical-stage biopharmaceutical company developing INTASYL siRNA gene-silencing therapeutics, with lead candidate PH-762 (intratumoral PD-1 silencer) targeting cutaneous squamous cell carcinoma and other skin cancers.

Ownership category

akta.pro rank

Product category

Immuno-Oncology Biopharmaceuticals

NAICS

Research and Development in Biotechnology (except Nanobiotechnology) (541714), Pharmaceutical Preparation Manufacturing (325412)

SIC

Pharmaceutical Preparations (2834)

akta.pro primary industry

Lead Optimization & Preclinical Candidate Selection (HLAIALAB)

akta.pro secondary industry

In Vivo Discovery & Translational Models Platforms (humanized models, PK/PD, efficacy) (HLAAAIAK)

Keywords

• Immuno-oncology therapeutics
• SiRNA gene silencing
• RNAi drug development
• Cutaneous carcinoma therapy
• PD-1 intratumoral therapy

Headquarters

HQ city

King Of Prussia

HQ country

United States

HQ region

North America

Offices1 record

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Technology or R&D, Personnel, Operations, Marketing or Sales, Others

Revenue model

1. Therapeutic Development (Future): Pre-revenue clinical stage company. No commercial products currently marketed. Revenue expected from future commercialization of PH-762 and other INTASYL therapeutics upon regulatory approval.

Go-to-market motion2 records

Distribution channels1 record

Marketing channels6 records

Core offering

Phio Pharmaceuticals is a clinical-stage biopharmaceutical company developing siRNA-based immuno-oncology therapeutics using its proprietary INTASYL® self-delivering gene silencing technology. Its lead clinical asset PH-762 is an intratumoral PD-1 silencer in Phase 1b trials for cutaneous squamous cell carcinoma, melanoma, and Merkel cell carcinoma, with additional pipeline assets PH-894 (BRD4) and PH-804 (TIGIT) in preclinical development.

Product overview

Phio Pharmaceuticals is a clinical-stage biopharmaceutical company developing a pipeline of siRNA-based therapeutics using its proprietary INTASYL® gene silencing technology platform. The platform enables self-delivering, chemically modified siRNA compounds that silence specific genes impeding the immune system's cancer-fighting ability. The lead clinical program PH-762 (PD-1 silencer) is in Phase 1b for skin cancers, while PH-894 (BRD4 silencer) is in preclinical/IND-enabling stages. Additional pipeline compounds include PH-804 (TIGIT silencer). The company was co-founded by Nobel Prize scientist Craig Mello, who discovered RNAi.

Differentiator

Problem solved

Functional benefit

Brands

• INTASYL: Proprietary siRNA gene silencing technology platform designed to silence specific genes that hinder the immune system's ability to fight cancer, particularly in immuno-oncology.
• PH-762
• PH-894

Products and services

• PH-762 PH-762 is an INTASYL compound that silences the PD-1 gene, reducing inhibitory signals to T cells and enhancing immune-mediated killing of cancer cells. Delivered intratumorally, it is being developed as a potential non-surgical treatment for cutaneous squamous cell carcinoma, melanoma, and Merkel cell carcinoma. Currently in Phase 1b clinical trials with ~65% pathological response rate observed across all cSCC dosing cohorts (85% in highest-dose cohort) and no dose-limiting toxicities reported.
• PH-894 PH-894 is an INTASYL compound that silences the BRD4 protein, a critical regulator of gene expression involved in cancer progression and metastasis. It is being developed for potential indications including Stage IV melanoma, HNSCC, HCC, HPV-related cSCC, cervical cancer, and prostate cancer. Designed to potentially reduce immune-related adverse events compared to small molecule BRD4 inhibitors.
• PH-804 PH-804 is an INTASYL compound that silences the TIGIT protein, which inhibits Natural Killer (NK) cell activity. Preclinical studies demonstrated that NK cells treated with the compound showed increased activation and enhanced ability to kill cancer cells.

Quantifiable outcome

• ~65% pathological response rate in cSCC across all dosing cohorts; 85% response rate in highest-dose cohort (6 of 7 patients)
• +2 more outcomes

Named customers1 record

Segments1 record

Ideal customer profiles2 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature5 records

Partnerships

Four partnerships are on record, tiered core and minor.

• Pyramid Pharma ServicescoreTechnology or Integration · 8 April 2026cGMP drug product manufacturing services agreement for PH-762 clinical supply and future commercial supply. U.S.-based CDMO partner providing sterile drug product manufacturing services.
• U.S. Laboratory (Toxicology)coreTechnology or Integration · 1 December 2025Development services agreement with a U.S. laboratory to conduct non-clinical toxicology study required by FDA prior to commencing pivotal human clinical trial for registration purposes.
• Nitto Denko Avecia, Inc.coreTechnology or Integration · 24 June 2025Comprehensive drug substance services agreement for PH-762 development including analytical and process development, method validation, cGMP manufacturing, and testing services. Avecia began commercial-scale cGMP production of PH-762 API in June 2026.
• Force Family OfficeminorGTM or Marketing PartnerForce Family Office hosts virtual fireside chats with Phio CEO Robert Bitterman to discuss siRNA therapy and skin cancer treatments. These investor-focused events feature live Q&A sessions with medical experts.

Scale indicators9 records

Recent moves6 records

Expansion highlights6 records

Broad incumbents

• Moderna: Commercial-stage biopharmaceutical company expanding from mRNA vaccines into oncology, with clinical-stage candidates in melanoma and other skin cancers. Comparable as a peer developing novel immuno-oncology modalities, though Moderna's approach is mRNA-based rather than siRNA-based like Phio's INTASYL platform.
• BioNTech: Major biopharmaceutical company with growing oncology pipeline including mRNA-based cancer immunotherapies and multiple immune checkpoint-targeting candidates. Comparable as a broader immuno-oncology peer with substantial R&D resources pursuing complementary approaches to Phio's siRNA-based gene silencing in oncology.
• Alnylam Pharmaceuticals: Leading commercial-stage RNAi therapeutics company with multiple approved siRNA-based drugs (Onpattro, Givlaari, Oxlumo, Amvuttra). Directly comparable as a peer in the siRNA therapeutics category, though Alnylam operates at vastly greater scale and focuses on broader indications rather than Phio's immuno-oncology niche.
• Bristol-Myers Squibb: Global pharmaceutical company marketing Opdivo (nivolumab), another major approved PD-1 inhibitor used across multiple oncology indications including cutaneous carcinomas. Direct competitor to Phio's PD-1 silencing approach with deep commercial reach, ongoing combination trials, and substantial immuno-oncology franchise.
• Regeneron Pharmaceuticals: Major biopharmaceutical company that developed Libtayo (cemiplimab), an FDA-approved PD-1 inhibitor indicated for cutaneous squamous cell carcinoma and other skin cancers. Direct competitive incumbent in Phio's lead indication (cSCC) with established commercial infrastructure and ongoing label-expansion programs.
• Merck & Co. Global pharmaceutical leader that markets Keytruda (pembrolizumab), the dominant FDA-approved PD-1 inhibitor widely used across cutaneous carcinomas and other oncology indications. Major competitive incumbent for any intratumoral PD-1 silencing approach given Keytruda's entrenched standard-of-care status and ongoing development of next-generation immuno-oncology combinations.

Direct peers

• Sirnaomics: Clinical-stage biopharmaceutical company developing siRNA-based therapeutics for oncology and fibrosis using proprietary PNP and GalAhead delivery platforms. Comparable as a peer in siRNA-based immuno-oncology drug development, though Sirnaomics targets different cancer indications and uses distinct delivery technology from Phio's self-delivering INTASYL.
• Arrowhead Pharmaceuticals: Clinical-stage RNAi therapeutics company developing multiple siRNA-based candidates using proprietary TRiM™ platform across oncology, cardiometabolic, and pulmonary indications. Closely comparable to Phio as a peer siRNA platform company, with overlapping gene-silencing approach but more advanced pipeline across diverse therapeutic areas.

Emerging players

• Cogent Biosciences: Clinical-stage biotechnology company developing targeted therapies for oncology indications, with a similarly small public-company footprint and clinical-stage asset focused on niche cancer populations. Comparable as a peer micro/mid-cap clinical-stage oncology company facing similar capital markets dynamics and execution considerations.
• Novavax: Clinical-stage biotechnology company developing novel vaccines and immuno-oncology therapeutics, including Matrix-M adjuvant technology used in combination approaches. Comparable as a smaller peer pursuing novel immune-based therapeutic mechanisms, though Novavax's oncology pipeline is less mature than Phio's PH-762 clinical program.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat4 records

Key risks6 records

Key highlights7 records

Customer concentration

• YouTubeyoutube.com/@PhioPharmaceuticalsCorp.
• LinkedInlinkedin.com/company/phio-pharmaceuticals-corp
• Xx.com/phio_pharma

Revenue estimate

Valuation estimate

Number of profiles

Profiles7 records

Funding overview

Funding rounds20 records

Investors3 records

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M&A2 records

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Phio Pharmaceuticals