Regenxbio & UPenn v. Sarepta: AAV Gene Therapy Patent Struck Down Under § 101
Regenxbio and the University of Pennsylvania sued Sarepta Therapeutics over US Patent No. 10,526,617, covering adeno-associated virus (AAV) gene therapy technology, in connection with Sarepta’s SRP-9001 and SRP-9003 products. On January 5, 2024, the Delaware District Court granted summary judgment invalidating claims 1–9, 12, 15, and 18–25 under 35 U.S.C. § 101 — a decisive win for Sarepta after more than three years of litigation.
§ 101 Patent Eligibility Kills AAV Gene Therapy Claims in Delaware
Regenxbio Inc. and The Trustees of the University of Pennsylvania filed suit on September 15, 2020, in the District of Delaware against Sarepta Therapeutics, Inc. and Sarepta Therapeutics Three, LLC, asserting infringement of U.S. Patent No. 10,526,617. The patent covers adeno-associated virus (AAV) gene therapy technology, and the plaintiffs alleged that Sarepta’s SRP-9001 and SRP-9003 pipeline products — both gene therapies targeting Duchenne muscular dystrophy — infringed the asserted claims.
The case concluded on January 12, 2024, when the court entered final judgment in favor of the defendants following a January 5 ruling granting Sarepta’s motion for summary judgment. The court found claims 1–9, 12, 15, and 18–25 of US10526617 invalid under 35 U.S.C. § 101, the patent eligibility statute. Notably, the court simultaneously denied Sarepta’s non-infringement summary judgment motion and denied the plaintiffs’ motion for summary judgment of no § 101 invalidity, leaving the infringement question unresolved. Remaining motions were dismissed without prejudice as moot, preserving the possibility of reinstatement on appeal.
The timeline — approximately 1,214 days from filing to final judgment — is consistent with the pace of complex biotech patent disputes in Delaware. That the court reached a dispositive § 101 invalidity ruling without ever formally adjudicating infringement suggests that Sarepta’s eligibility challenge was strategically well-constructed and sufficiently ripe for summary disposition. What remains publicly unknown is whether an appeal to the Federal Circuit was filed, and whether the attorneys’ fees proceedings under § 285 will reopen contested questions about the litigation’s merits.
Filing to filing in 1214 days
Days from filing (Sep 2020) to final judgment (Jan 2024)
Full party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Regenxbio, Inc. | Company | Gene therapy IP licensor and UPenn spinout — holder of US10526617 (AAV technology)Search in Eureka ↗ |
| Defendant | Sarepta Therapeutics, Inc. | Company | Sarepta Therapeutics — rare disease gene therapy developer (SRP-9001, SRP-9003)Search in Eureka ↗ |
| Plaintiff counsel | Susan E. Morrison | Attorney | Counsel for Regenxbio, Inc.Search in Eureka ↗ |
| Defendant counsel | Derek James Fahnestock | Attorney | Counsel for Sarepta Therapeutics, Inc.Search in Eureka ↗ |
| Defendant counsel | Jack B. Blumenfeld | Attorney | Counsel for Sarepta Therapeutics, Inc.Search in Eureka ↗ |
| Presiding judge | Judge Unassigned | Chief Judge | Delaware District Court — Chief JudgeSearch in Eureka ↗ |
Stipulation of dismissal — official text
The judgment is structured around a pure § 101 invalidity finding, not a merits determination on infringement. By granting invalidity while denying non-infringement summary judgment, the court left open the factual question of whether Sarepta’s products actually practise the claimed technology — a deliberate judicial economy move that preserves the full dispute in the event of reversal. The ‘dismissed without prejudice as moot’ language for remaining motions is legally significant: it is not a concession on those issues and carries no preclusive effect on reinstatement. The § 285 fee provision signals the court anticipated a potential appeal.
US10526617B2 — Adeno-Associated Virus Gene Therapy Vectors
U.S. Patent No. 10,526,617 (application no. US15/782,980) is assigned to Regenxbio Inc. and relates to adeno-associated virus (AAV) vector technology used in gene therapy applications. AAV vectors are engineered viral capsids used to deliver therapeutic genetic material into target cells. The patent covers compositions and methods in this space, and was asserted against Sarepta’s SRP-9001 (delandistrogene moxeparvovec) and SRP-9003 gene therapy candidates, both targeting Duchenne muscular dystrophy. The court’s § 101 ruling suggests claims were found to be directed to natural phenomena or insufficiently inventive steps beyond them.
The strategic value of AAV platform patents is enormous — they sit at the foundation of a rapidly growing gene therapy sector with multi-billion dollar commercial implications. Regenxbio and UPenn have historically used foundational AAV patents to build broad licensing programmes across the industry. The invalidation of key claims of US10526617 under § 101 introduces meaningful uncertainty for Regenxbio’s licensing revenue stream and signals a vulnerability that competitors and licensees will be closely monitoring. Other AAV patent holders with similarly structured claims should treat this ruling as a bellwether for their own portfolios.
Should you run an FTO against US10526617B2?
Any company developing AAV-based gene therapy products — particularly those targeting neuromuscular or rare genetic diseases — should assess their exposure to US10526617 and related Regenxbio/UPenn patents. While key claims were invalidated, the Federal Circuit has not yet ruled, and the patent remains in force pending any appeal. SRP-9001 and SRP-9003 developers are directly implicated; any product using similar AAV vector constructs or delivery mechanisms should be evaluated against surviving or reinstated claims.
PatSnap Eureka’s FTO Search Agent can map the full claim scope of US10526617B2, identify related continuation and divisional patents in the Regenxbio/UPenn AAV portfolio, and flag which claims survived or remain at risk. Eureka’s claim monitoring tools allow R&D and IP teams to receive alerts if this patent is reinstated on appeal or if related patents are asserted — ensuring your gene therapy programme is never caught off-guard by a portfolio shift.
Run a freedom-to-operate analysis on US10526617B2 to assess your product’s exposure
Run FTO in Eureka →Similar AAV Gene Therapy Patent Infringement Cases in Delaware and the Federal Circuit
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What this case signals for the AAV gene therapy IP landscape
A § 101 invalidity ruling against a foundational AAV patent has broad implications for gene therapy IP strategy and competitive freedom to operate.
§ 101 Is a Live Threat to Foundational Gene Therapy Patents
This ruling confirms that even well-established, commercially significant AAV patents are vulnerable to § 101 challenges at summary judgment. Gene therapy patent holders — particularly universities licensing foundational platform technology — should audit their claim portfolios for Alice/Mayo exposure before asserting in litigation. Claims framed too closely to natural biological phenomena risk invalidation without ever reaching infringement analysis.
Sarepta’s SRP-9001/9003 Products Remain Legally Exposed on Appeal
The court’s denial of Sarepta’s non-infringement motion means the infringement question was never resolved in Sarepta’s favour. Should Regenxbio appeal and the Federal Circuit reverse the § 101 ruling — a non-trivial possibility given ongoing circuit-level debate on biotech eligibility — the case would remand with infringement still squarely in play. Sarepta’s commercial teams should treat this as an open risk until appellate finality.
Regenxbio v Sarepta — key questions answered
The Delaware District Court granted summary judgment in favour of Sarepta on January 5, 2024, ruling that claims 1–9, 12, 15, and 18–25 of U.S. Patent No. 10,526,617 are invalid under 35 U.S.C. § 101. Final judgment was entered on January 12, 2024. The court denied Sarepta’s non-infringement motion and dismissed remaining motions as moot.
35 U.S.C. § 101 sets the threshold for patent-eligible subject matter. Under the Alice/Mayo framework, claims directed to laws of nature, natural phenomena, or abstract ideas — without a sufficiently inventive application — are ineligible. In this case, the court found the asserted AAV patent claims failed this test as a matter of law, making them unenforceable regardless of infringement evidence.
Regenxbio and the University of Pennsylvania accused Sarepta’s SRP-9001 (delandistrogene moxeparvovec, a Duchenne muscular dystrophy gene therapy) and SRP-9003 of infringing US10526617B2. The court never issued a final ruling on infringement, as the § 101 invalidity finding made that question moot.
Yes. The final judgment, entered January 12, 2024, triggers the standard Federal Circuit appeal window. The court’s order expressly preserved dismissed motions for reinstatement upon reversal or remand, and the attorneys’ fees deadline was tied to the appeal timeline — indicating the court anticipated appellate proceedings. A Federal Circuit reversal would revive the infringement dispute.
The denial means the court did not conclude — as a matter of law — that SRP-9001 and SRP-9003 do not infringe US10526617. If the § 101 invalidity ruling is reversed on appeal, the infringement question would be fully revived with no prior court finding favouring Sarepta on that issue. This represents a residual legal risk for Sarepta’s gene therapy commercial programmes until Federal Circuit finality.
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