In re McLeay v. USPTO: Federal Circuit Affirms Non-Enablement of COVID-19 Treatment Claims
Matthew McLeay’s patent application covering verteporfin, ribavirin, and gemcitabine compositions for treating COVID-19 and cancer was rejected by the USPTO Board on enablement grounds. After 539 days on appeal, the Federal Circuit unanimously affirmed — finding claims 20–24 insufficiently enabled under 35 U.S.C. § 112.
Federal Circuit closes the door on broad COVID-19 drug combination claims
In re Matthew McLeay (Case No. 23-2338) is an ex parte patent prosecution appeal before the U.S. Court of Appeals for the Federal Circuit, arising from U.S. Patent Application No. 17/231735. The application claims compositions containing verteporfin, ribavirin, gemcitabine, or combinations thereof, and methods of using those compositions to treat COVID-19, cancer, and other diseases. The USPTO’s Patent Trial and Appeal Board (PTAB) found that claims 20–24 of the application did not satisfy the enablement requirement of 35 U.S.C. § 112.
McLeay, represented by Kutak Rock LLP, appealed the Board’s finding to the Federal Circuit on August 29, 2023. On February 18, 2025, the Federal Circuit issued its ruling affirming the Board in full. The court considered McLeay’s remaining arguments and found them unpersuasive, leaving the PTAB’s non-enablement determination intact. The application’s claims 20–24 remain unpatentable, and no patent rights will issue on those claims absent further prosecution strategy or a continuation approach with narrowed disclosure.
The 539-day appellate timeline is consistent with a fully briefed Federal Circuit ex parte appeal, though it suggests the panel gave the technical arguments careful consideration given the novel COVID-19 treatment context. The affirmance likely reflects the breadth of the claims relative to the working examples in the specification — a recurring challenge for broad pharmaceutical combination patents filed during the COVID-19 pandemic. The public record does not disclose whether McLeay has pending continuation applications that might pursue narrower, better-supported claims.
Filing to Unpatentable in 539 days
539 days on appeal — above the Federal Circuit’s typical ex parte prosecution appeal duration
Federal Circuit affirms: what the enablement ruling means for both parties
Affirmance means the Board’s ruling stands — no reversible error found
When the Federal Circuit affirms a PTAB decision, it concludes that the Board committed no reversible legal error and that substantial evidence supported its factual findings. Here, the court found McLeay’s arguments unpersuasive across all grounds raised. The Board’s non-enablement finding under 35 U.S.C. § 112 is now final at this appellate level — the specification was held insufficient to teach a skilled person how to practice the full scope of claims 20–24 without undue experimentation.
Enablement — § 112 affirmedClaims 20–24 are unpatentable — prosecution path narrows significantly
For McLeay, the affirmance closes the direct appeal route for claims 20–24 as drafted. The Federal Circuit’s rejection of all remaining arguments leaves no further appellate recourse on these claims in their current form. The applicant may still pursue continuation or continuation-in-part applications with narrowed claims more tightly tied to working examples in the specification, but any such strategy would need to address the enablement deficiency identified by the Board and now confirmed by the Federal Circuit.
No patent rights on claims 20–24USPTO’s high enablement bar for broad treatment claims upheld
The affirmance reinforces the USPTO’s enforcement of the enablement requirement against broad pharmaceutical combination claims — particularly those asserting utility across multiple unrelated disease indications such as COVID-19, cancer, and non-cancer diseases. For the patent system broadly, the ruling is consistent with the Federal Circuit’s heightened scrutiny of pandemic-era applications where claim scope may have outpaced experimental validation. Third parties seeking to develop verteporfin, ribavirin, or gemcitabine-based treatments face no blocking patent from this application.
Public domain — no blocking IPBroad antiviral combination claims face a high bar post-affirmance
This ruling signals that pharmaceutical applicants asserting wide-ranging method-of-treatment claims across both antiviral and oncology indications must ensure their specifications contain commensurate working examples. Companies in the COVID-19 therapeutics or repurposed drug space — particularly those working with photosensitising agents like verteporfin or nucleoside analogues like ribavirin and gemcitabine — can treat this application as unblocking for now, while monitoring for continuation filings that may pursue narrower claims with stronger experimental support.
Repurposed drug IP risk reducedFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | In re: MATTHEW MCLEAY | Individual | Individual inventor — applicant for US17/231735 covering antiviral/anticancer drug combinationsSearch in Eureka ↗ |
| Defendant | DERRICK BRENT, Acting Under Secretary of Commerce for Intellectual Property and Acting Director of the United States Patent and Trademark Office | Individual | Acting USPTO Director — respondent defending PTAB’s non-enablement ruling on appealSearch in Eureka ↗ |
| Plaintiff counsel | Bartholomew L. McLeay | Attorney | Counsel for In re: MATTHEW MCLEAYSearch in Eureka ↗ |
| Plaintiff counsel | Ryan Steven Hinderliter | Attorney | Counsel for In re: MATTHEW MCLEAYSearch in Eureka ↗ |
| Plaintiff law firm | Kutak Rock LLP | Law Firm | Representing In re: MATTHEW MCLEAYSearch in Eureka ↗ |
| Defendant counsel | Thomas W. Krause | Attorney | Counsel for DERRICK BRENT, Acting Under Secretary of Commerce for Intellectual Property and Acting Director of the United States Patent and Trademark OfficeSearch in Eureka ↗ |
| Presiding judge | Judge N/A | Judge | Court of Appeals for the Federal CircuitSearch in Eureka ↗ |
Official order — verbatim text
The Federal Circuit’s disposition — ‘We have considered McLeay’s remaining arguments but find them unpersuasive. We affirm the Board’s finding that claims 20–24 are not enabled’ — is a full affirmance on the merits. The phrase ‘remaining arguments’ indicates the court addressed McLeay’s substantive § 112 contentions and rejected each one. Appellate review of PTAB enablement findings applies the substantial evidence standard to underlying facts and de novo review to legal conclusions; the court’s unqualified affirmance suggests both elements were satisfied in the Board’s favour. No remand was ordered, making the unpatentability of claims 20–24 final at this appellate level.
US17/231735 — Verteporfin, Ribavirin & Gemcitabine Treatment Compositions
U.S. Patent Application No. 17/231735 (published as US20210228485A1) covers compositions containing verteporfin, ribavirin, gemcitabine, or combinations thereof, and methods of using those compositions therapeutically. Verteporfin is an established photosensitising agent used in photodynamic therapy; ribavirin and gemcitabine are nucleoside analogues with antiviral and anticancer activity respectively. The application’s claims 20–24 assert therapeutic utility across COVID-19, oncology, and non-cancer diseases — an unusually broad multi-indication scope for a single application filed during the pandemic period.
The strategic significance of this application lies in its attempt to secure broad method-of-treatment protection across both antiviral and oncology indications for established, off-patent drug molecules. Had claims 20–24 issued, they could have created blocking IP over combination therapies involving these repurposed agents. The Federal Circuit’s affirmance eliminates that risk from this application, but the underlying science — drug repurposing for COVID-19 — remains commercially relevant, making it important for competitors to track any continuation strategy the applicant may pursue.
Should you run an FTO against US17/231735?
Any organisation developing therapeutic products based on verteporfin, ribavirin, gemcitabine, or combinations thereof — particularly for COVID-19, oncology, or repurposed-drug indications — should be aware of this application. While claims 20–24 are now confirmed unpatentable, an FTO analysis should extend to any sibling, divisional, or continuation applications in the same family that may carry forward similar or narrowed claims. R&D teams and product counsel at pharma and biotech companies working in the antiviral or photodynamic therapy space should treat this case as a starting point, not an endpoint, for FTO clearance.
PatSnap Eureka’s FTO Search Agent can map the full patent family around US17/231735, identify any continuation or CIP applications filed by McLeay, and flag related third-party patents covering verteporfin or ribavirin combination therapies. Eureka’s claim-level analysis helps IP teams assess whether their specific formulations or treatment protocols fall within the scope of surviving or pending claims — delivering a defensible FTO position without manual prior art searches across multiple patent offices.
Run a freedom-to-operate analysis on US20210228485A1 to assess your product’s exposure
Run FTO in Eureka →Similar Federal Circuit enablement appeals in pharmaceutical combination patents
Explore Federal Circuit cases involving § 112 enablement challenges to broad pharmaceutical method-of-treatment and drug combination patent applications.
What this case signals for the pharmaceutical combination patent IP landscape
The Federal Circuit’s affirmance reinforces a strict enablement standard that will shape how COVID-19 and repurposed drug patent applications are evaluated.
Broad method-of-treatment claims require commensurate experimental support
The non-enablement finding in McLeay is a reminder that claiming treatment of multiple disease categories — COVID-19, cancer, and non-cancer diseases — within a single application demands robust, disease-specific working examples. Applicants without that experimental breadth should expect similar rejections and Federal Circuit affirmances.
Repurposed drug combinations are in the public domain — for now
With claims 20–24 held unpatentable, verteporfin, ribavirin, and gemcitabine combination therapies remain unprotected by this application. R&D teams developing treatments in this space should monitor for continuation filings by McLeay that may assert narrower, better-supported claims.
MCLEAY v DERRICK — key questions answered
The Federal Circuit affirmed the USPTO Patent Trial and Appeal Board’s finding that claims 20–24 of U.S. Application No. 17/231735 are not enabled under 35 U.S.C. § 112. The court considered all of McLeay’s arguments and found them unpersuasive, leaving the Board’s unpatentability determination final.
Under 35 U.S.C. § 112, a patent specification must enable a person skilled in the art to make and use the full scope of the claimed invention without undue experimentation. Claims 20–24 broadly asserted therapeutic utility across COVID-19, cancer, and non-cancer diseases using verteporfin, ribavirin, and gemcitabine combinations. The Board — upheld by the Federal Circuit — found the specification insufficient to support that breadth of claimed utility.
The Federal Circuit’s affirmance forecloses further appeal on claims 20–24 as drafted. However, McLeay may file continuation or continuation-in-part applications with narrowed claims more closely tied to working examples in the original specification. Any such strategy would need to overcome the specific enablement deficiency identified by the Board and confirmed by the Federal Circuit.
Yes. With claims 20–24 held unpatentable and no patent issuing from this application on those claims, verteporfin, ribavirin, and gemcitabine combination therapies are not blocked by this specific application. However, companies should monitor for continuation filings by McLeay and conduct independent FTO searches covering related patents in the same therapeutic space.
The Federal Circuit reviews PTAB enablement determinations by applying substantial evidence review to underlying factual findings and de novo review to legal conclusions under § 112. The court’s unqualified affirmance without remand suggests it found both the factual record and legal analysis by the Board to be sound across all grounds McLeay raised on appeal.
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