Phio Pharmaceuticals Expands Global Patent Portfolio with Multiple Approvals in U.S., Canada, and Japan for INTASYL siRNA Technology

Phio Secures Three Notices of Allowance and One Patent Grant Across Key Jurisdictions

On July 15, 2026, Phio Pharmaceuticals confirmed it obtained three notices of allowance and one patent grant covering the United States, Canada, and Japan. Although the announcement does not specify which patent action corresponds to each jurisdiction, it confirms that all three major markets are included in this latest IP advancement. Notices of allowance indicate that patent applications have met all substantive requirements and are poised for issuance, marking a critical step forward in the patent approval process.

The patent grant mentioned signifies that at least one patent has been officially issued in one of these territories, providing immediate protection. Collectively, these four patent actions represent significant progress in securing Phio’s proprietary innovations internationally. The company did not disclose specific patent or application numbers, claim details, or exact jurisdictional allocations in this release.

Scope of INTASYL Gene Silencing Technology Patents

The protected intellectual property centers on Phio’s INTASYL platform — a proprietary siRNA (small interfering RNA) gene silencing technology designed to enhance immune cells’ ability to target and destroy cancer cells. The expanded patent portfolio covers INTASYL chemistry, specific gene targets, immuno-oncology compounds, and therapeutic indications across key markets. This comprehensive coverage strategically safeguards both the foundational technology and its clinical applications, complicating efforts by competitors to circumvent the portfolio.

siRNA gene silencing is a rapidly advancing area in biopharmaceutical research. Phio’s INTASYL compounds target genes involved in cancer cell survival and immune system evasion, positioning the platform within the competitive immuno-oncology landscape. With 54 issued patents, Phio is establishing a robust multi-jurisdictional IP framework around its technology. The company did not provide patent expiry dates or timelines for the formal issuance of the newly allowed patents.

CEO Robert Bitterman Highlights Strategic Importance of Patents

Robert Bitterman, President and CEO of Phio Pharmaceuticals, emphasized the milestone’s significance: "Strong patent protection is a vital part of our strategy to advance innovative immuno-oncology therapies and maximize the long-term value of our INTASYL siRNA platform." He added that the recent patent advancements across therapeutic areas and regions "will facilitate strategic partnerships, support R&D efforts, and enable eventual commercialization."

Bitterman’s remarks position the IP progress not only as a defensive measure but also as a commercial catalyst. The company views a strong, internationally recognized patent portfolio as essential for licensing, collaborations, and other business development activities. No specific partnership deals were disclosed alongside this announcement.

PH-762 and Ongoing INTASYL Clinical Development

Phio’s lead clinical candidate, PH-762, is an INTASYL compound targeting the PD-1 gene, implicated in skin cancers such as cutaneous squamous cell carcinoma, melanoma, and Merkel cell carcinoma. The Phase 1b clinical trial (NCT# 06014086) evaluated PH-762’s potential as a treatment option. Unlike systemic antibody therapies targeting PD-1, PH-762 delivers gene silencing directly to immune cells.

The company describes PH-762 as a potential non-surgical treatment for skin cancers, offering a less invasive alternative for certain patients. The expanded patent portfolio covering INTASYL compounds and gene targets relevant to PH-762 may extend the intellectual property protection for this clinical program. No updated clinical data, trial timelines, or regulatory filings were disclosed in this announcement.

Significance of U.S., Canada, and Japan Patent Approvals

The United States, Canada, and Japan represent three of the largest pharmaceutical markets globally with rigorous patent examination standards. Securing favorable patent actions simultaneously in these jurisdictions is a notable achievement for a clinical-stage company, given differing examination criteria and timelines. This geographic coverage offers Phio meaningful IP protection across North America and Asia-Pacific regions.

For Canadian stakeholders, the notice of allowance from the Canadian Intellectual Property Office signals readiness for patent issuance, subject to final formalities. Together with U.S. and Japanese approvals, this multi-jurisdictional coverage positions Phio’s INTASYL portfolio as globally competitive, aligning with the company’s long-term commercialization and partnership strategies.

Phio’s Patent Portfolio Now Totals 54 Issued Patents

Phio’s patent estate currently includes 54 issued patents, excluding the three newly allowed patents pending formal issuance. This portfolio spans INTASYL chemistry, gene silencing targets, immuno-oncology compounds, and therapeutic indications across multiple key countries. For a clinical-stage company, this extensive patent portfolio represents a significant intangible asset, although no monetary valuation was provided.

Issued patents represent fully granted protections, while notices of allowance indicate applications that have passed examination but await formal issuance. The company did not specify expected issuance dates for the recently allowed patents or geographic distribution of the 54 issued patents.

Competitive Immuno-Oncology IP Landscape

The immuno-oncology sector is highly competitive and IP-intensive, with numerous companies filing extensive patents on immune checkpoint pathways, gene silencing, and cell therapies. Phio’s INTASYL platform aims to directly enhance immune cells, particularly T cells, to improve tumor eradication. Building a strong IP moat is crucial for attracting partners and maintaining commercial exclusivity.

The broad patent coverage—including chemistry, gene targets, compounds, and indications—suggests Phio is protecting its innovations at multiple levels. If the patents issued have broad, defensible claims, they could create substantial barriers to competitors. However, claim details were not disclosed, and the commercial value depends on claim scope and enforceability.

Forward-Looking Statements and Investor Considerations

Phio’s announcement includes forward-looking statements noting that actual results may differ materially due to risks such as FDA interactions, business execution, regulatory timelines, collaboration success, and financing. The company references its latest Annual Report on Form 10-K and Quarterly Reports on Form 10-Q for additional risk disclosures, which investors should review carefully.

The forward-looking statements about commercialization, partnerships, and R&D support represent aspirations rather than guaranteed outcomes. The immediate market reaction to this announcement was not evident at the time of publication. Investors should consider this IP milestone within the broader context of Phio’s clinical and financial status, including risks inherent in clinical-stage development and patent prosecution.

INTASYL Platform’s Broader Commercial Potential

Beyond PH-762, the INTASYL platform offers gene silencing technology applicable to multiple gene targets and cancer types. The patent portfolio’s coverage of INTASYL chemistry and gene targets aims to protect both the lead compound and future derivatives. Platform-level IP protection is often the most strategically valuable in biopharmaceuticals, potentially covering future compounds and indications beyond current clinical candidates.

Phio’s mission is to eliminate cancer through INTASYL-based immuno-oncology therapies, with its IP portfolio serving as both a commercial safeguard and a signal of innovation to partners and investors. The company highlighted that recent patent advancements span multiple therapeutic areas and geographies, reinforcing its cross-indication and international IP strategy. Whether this expanded portfolio leads to partnerships or licensing deals will be disclosed in future updates.