Alnylam v. Moderna: LNP Delivery Patent Suit Dismissed Without Prejudice
Alnylam Pharmaceuticals filed suit against Moderna in Delaware’s District Court asserting three biodegradable lipid nanoparticle delivery patents. After 495 days of litigation, the case closed with both the complaint and Moderna’s counterclaims dismissed without prejudice — leaving all substantive IP questions unresolved and the door open to future action.
LNP Patent Dispute Ends Without a Winner — or a Precedent
On 26 May 2023, Alnylam Pharmaceuticals filed a patent infringement action against Moderna, Inc., Moderna US, Inc., and ModernaTX, Inc. in the District of Delaware before Judge Colm F. Connolly. The suit centred on three patents — US11590229B2, US11633479B2, and US11633480B2 — each directed at biodegradable lipid compositions used to deliver active agents such as mRNA, a technology central to Moderna’s COVID-19 vaccine platform and pipeline.
The case closed on 2 October 2024 under a stipulated dismissal without prejudice. Critically, the parties agreed that Moderna’s affirmative defenses and counterclaims were also dismissed without prejudice, meaning neither validity nor infringement was adjudicated on the merits. A dismissal without prejudice leaves Alnylam legally free to refile the same claims, subject to applicable statutes of limitations and any separate licensing or settlement terms not reflected in the public record.
The 495-day duration suggests the parties engaged in substantive pre-trial activity — including likely claim construction briefing and early discovery — before reaching a resolution. The simultaneous dismissal of Moderna’s counterclaims (which typically include invalidity challenges) is commercially significant: it suggests the dispute may have been resolved through negotiation rather than adjudication, though the public record does not disclose licensing terms, cross-licences, or any financial consideration exchanged.
Filing to Dismissed without Prejudice in 495 days
495 days — longer than the median first-instance pharma patent case in Delaware (~12 months)
Dismissed without prejudice: what the stipulated order means for both parties
Dismissal without prejudice leaves all claims alive
A dismissal without prejudice does not adjudicate the underlying infringement or validity questions. Under Federal Rule of Civil Procedure 41, Alnylam retains the right to bring the same patent claims against Moderna in a future action. The simultaneous dismissal of Moderna’s counterclaims — which typically assert invalidity — is equally non-final, meaning neither side obtained a binding ruling on the patents’ merits.
No merits rulingAlnylam preserves optionality on three LNP patents
Alnylam exits without a win, but crucially without a loss. The three asserted patents remain valid and enforceable — no court has found them invalid or not infringed. This preserves Alnylam’s ability to reassert them against Moderna or third parties, and may reflect a licensing arrangement reached outside the public record. The absence of a prejudice finding is a meaningful strategic asset in a field where LNP IP is intensely contested.
Patents remain enforceableModerna’s counterclaims dismissed — validity fight deferred, not won
Moderna’s affirmative defenses and invalidity counterclaims were dismissed on the same without-prejudice basis, meaning Moderna did not obtain a declaration of invalidity or non-infringement. If the parties resolved the dispute commercially, Moderna avoided a potentially adverse claim-construction ruling, but did not secure the IP clearance that a merits verdict would have provided. Moderna’s LNP freedom-to-operate posture remains dependent on whatever private arrangement underlies this dismissal.
No invalidity ruling securedLNP delivery IP remains a live battleground across the mRNA sector
The non-prejudicial dismissal does nothing to reduce competitive IP risk in the biodegradable lipid delivery space. Third-party developers of mRNA therapeutics and vaccines should note that Alnylam’s three asserted patents have not been tested or invalidated. The case is consistent with a broader pattern of LNP patent disputes — including Alnylam/Moderna arbitrations and parallel Arbutus/Genevant litigation — where commercial resolution is preferred over a binding public precedent.
LNP IP risk persistsFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Alnylam Pharmaceuticals, Inc. | Company | RNAi therapeutics and LNP delivery technology company — holder of US11590229B2Search in Eureka ↗ |
| Defendant | Moderna, Inc. | Company | mRNA vaccine and therapeutics developer relying on lipid nanoparticle delivery technologySearch in Eureka ↗ |
| Co-Defendant | Moderna US, Inc. | Company | Search in Eureka ↗ |
| Co-Defendant | ModernaTX, Inc. | Company | Search in Eureka ↗ |
| Plaintiff counsel | Anisa K. Noorassa | Attorney | Counsel for Alnylam Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Ashley R. Altschuler | Attorney | Counsel for Alnylam Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Bhanu K. Sadasivan | Attorney | Counsel for Alnylam Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Ethan Haller Townsend | Attorney | Counsel for Alnylam Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Ian B. Brooks | Attorney | Counsel for Alnylam Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Mandy H. Kim | Attorney | Counsel for Alnylam Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Sarah Chapin Columbia | Attorney | Counsel for Alnylam Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Sarah J. Fischer | Attorney | Counsel for Alnylam Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Timothy M. Dunker | Attorney | Counsel for Alnylam Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff counsel | William G. Gaede , III | Attorney | Counsel for Alnylam Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff law firm | McDermott Will & Emery LLP | Law Firm | Representing Alnylam Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant counsel | Angela R. Madrigal | Attorney | Counsel for Moderna, Inc.Search in Eureka ↗ |
| Defendant counsel | Brian E. Farnan | Attorney | Counsel for Moderna, Inc.Search in Eureka ↗ |
| Defendant counsel | Brianna Patterson | Attorney | Counsel for Moderna, Inc.Search in Eureka ↗ |
| Defendant counsel | Brittany N. Cazakoff | Attorney | Counsel for Moderna, Inc.Search in Eureka ↗ |
| Defendant counsel | Dean Fanelli | Attorney | Counsel for Moderna, Inc.Search in Eureka ↗ |
| Defendant counsel | Elizabeth L. Stameshkin | Attorney | Counsel for Moderna, Inc.Search in Eureka ↗ |
| Defendant counsel | Elizabeth M. Flanagan | Attorney | Counsel for Moderna, Inc.Search in Eureka ↗ |
| Defendant counsel | Geoffrey D. Biegler | Attorney | Counsel for Moderna, Inc.Search in Eureka ↗ |
| Defendant counsel | Isha Agarwal | Attorney | Counsel for Moderna, Inc.Search in Eureka ↗ |
| Defendant counsel | Michael J. Farnan | Attorney | Counsel for Moderna, Inc.Search in Eureka ↗ |
| Defendant counsel | Naina Soni | Attorney | Counsel for Moderna, Inc.Search in Eureka ↗ |
| Defendant counsel | Rosalynd D. Upton | Attorney | Counsel for Moderna, Inc.Search in Eureka ↗ |
| Defendant counsel | William Chad Shear | Attorney | Counsel for Moderna, Inc.Search in Eureka ↗ |
| Defendant law firm | Cooley LLP | Law Firm | Representing Moderna, Inc.Search in Eureka ↗ |
| Defendant law firm | Farnan LLP | Law Firm | Representing Moderna, Inc.Search in Eureka ↗ |
| Presiding judge | Judge Colm F. Connolly | Judge | Delaware District CourtSearch in Eureka ↗ |
Official order — verbatim text
The stipulated dismissal language — providing that ‘affirmative defenses and counterclaims asserted in Moderna’s Counterclaims and Answer to the Complaint should be dismissed without prejudice’ — is carefully bilateral. Neither party’s substantive positions were adjudicated. The without-prejudice standard preserves all claims and defenses for potential future litigation, and the absence of any carve-out or merits finding means the three Alnylam LNP patents emerge from this proceeding legally unscathed and potentially reassertable.
US11590229B2 — Biodegradable Lipids for Active Agent Delivery
The three asserted patents — US11590229B2, US11633479B2, and US11633480B2 — share a common inventive focus: biodegradable ionisable lipid compositions engineered for the intracellular delivery of active agents, most relevantly mRNA. Filed under application numbers in the US17/651xxx series, these patents represent a relatively recent issuance in the post-COVID era of LNP patent prosecution, suggesting they were strategically prosecuted to cover lipid formulations directly relevant to next-generation mRNA therapeutics and vaccine platforms.
Biodegradable lipid delivery patents sit at the commercial core of the mRNA sector. The ability to deliver nucleic acid payloads efficiently and safely depends critically on the lipid nanoparticle envelope — making these patents potential gatekeepers for any company developing mRNA vaccines, oncology treatments, or gene therapies. Alnylam’s ownership of this cluster, layered on top of earlier foundational LNP IP licensed from Arbutus, creates a multi-vector IP risk that competitors cannot resolve through design-around alone without careful formulation analysis.
Should your mRNA platform team run an FTO against US11590229B2?
If your organisation is developing or commercialising biodegradable lipid nanoparticle formulations for mRNA delivery — whether for vaccines, oncology, rare disease, or any nucleic acid therapeutic — these three Alnylam patents warrant immediate FTO assessment. The dismissal without prejudice in this case provides no legal clearance. The patents are valid, issued, and have been actively asserted against a major mRNA developer within the last two years.
PatSnap Eureka’s FTO Search Agent enables R&D and IP teams to map their specific lipid compositions and formulation parameters against the claim scope of US11590229B2, US11633479B2, and US11633480B2. Eureka’s claim-level analysis surfaces design-around options and identifies claim elements most likely to present infringement risk, allowing your team to prioritise freedom-to-operate workstreams ahead of IND filing or commercial launch.
Run a freedom-to-operate analysis on US11590229B2 to assess your product’s exposure
Run FTO in Eureka →Related LNP Delivery Patent Disputes in Delaware and Federal Courts
Cases involving lipid nanoparticle and mRNA delivery patents litigated in Delaware and before the Federal Circuit — curated for IP professionals tracking the LNP enforcement landscape.
What this case signals for the mRNA and LNP delivery IP landscape
Three untested LNP patents, a dismissal without merits, and a sector where delivery IP is existential — the strategic read matters.
Dismissed without prejudice is not IP clearance — monitor for refiling
Competitors and licensees in the lipid nanoparticle space should not treat this dismissal as validation of freedom-to-operate. Alnylam’s three patents — US11590229B2, US11633479B2, and US11633480B2 — remain in force, untested by any court ruling. Any company commercialising biodegradable lipid delivery systems should conduct a fresh FTO analysis against this patent family.
Simultaneous counterclaim dismissal suggests negotiated resolution
The mirror-image structure of the dismissal — both complaint and counterclaims dropped without prejudice on the same date — strongly suggests a commercial resolution rather than a unilateral withdrawal. This pattern is consistent with a cross-licence or settlement agreement underpinning the stipulation, though no financial terms are public. Parties in parallel disputes should factor in this precedent when assessing settlement leverage.
Alnylam v Moderna — key questions answered
Alnylam asserted three patents: US11590229B2, US11633479B2, and US11633480B2. All three cover biodegradable lipid compositions for the delivery of active agents, including mRNA, and were filed under application numbers in the US17/651xxx series. The case was filed in the District of Delaware on 26 May 2023.
The public record reflects a stipulated dismissal — agreed by both parties — under which both Alnylam’s complaint and Moderna’s counterclaims were dismissed without prejudice. The record does not disclose the reason. This structure is consistent with a negotiated resolution, potentially a licence or settlement agreement, though no financial terms have been made public.
No. A dismissal without prejudice is not a finding of non-infringement or invalidity. The three Alnylam patents remain in force and legally enforceable. Moderna’s counterclaims — which typically include invalidity challenges — were also dismissed without any court ruling on their merits, so no IP clearance was obtained through this litigation.
Technically yes — a without-prejudice dismissal preserves Alnylam’s right to bring the same claims in a future action, subject to statutes of limitations and any private agreement between the parties. Whether Alnylam is contractually restricted from refiling — for example, under a confidential settlement or licence — is not determinable from the public record.
Alnylam was represented by McDermott Will & Emery LLP, with attorneys including William G. Gaede III, Sarah Chapin Columbia, and Sarah J. Fischer among others. Moderna was represented by Cooley LLP and Farnan LLP, with attorneys including Brian E. Farnan, Michael J. Farnan, Geoffrey D. Biegler, and Elizabeth L. Stameshkin, among others. The case was assigned to Judge Colm F. Connolly.
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