Celgene & BMS v. Accord & MSN: Azacitidine Patent Consent Judgment with Injunction
Celgene, Bristol-Myers Squibb, and Celgene International successfully secured a consent judgment and permanent injunction against MSN Laboratories and MSN Pharmaceuticals, blocking generic azacitidine tablet entry under ANDA No. 218435. The case, asserting two patents covering oral azacitidine formulations, closed after 799 days with all claims dismissed with prejudice.
Consent injunction blocks generic oral azacitidine entry in ANDA dispute
Filed on 22 December 2021 in the District of Delaware before Judge Jennifer L. Hall, this Hatch-Waxman infringement action was brought by Celgene Corp., Bristol-Myers Squibb Company, and Celgene International SARL against Accord Healthcare Ltd., MSN Laboratories Private Limited, and MSN Pharmaceuticals Inc. The plaintiffs asserted U.S. Patent Nos. 8,846,628 and 11,571,436 against MSN’s ANDA No. 218435, which sought FDA approval for 200 mg and 300 mg azacitidine tablets referencing NDA 214120.
The case closed on 29 February 2024 via a consent judgment that permanently enjoins MSN — including its successors and assigns — from making, importing, selling, or distributing its ANDA product in the United States until expiry of both patents-in-suit. All claims and counterclaims were dismissed with prejudice, with no award of costs or fees to either side. The court explicitly retained jurisdiction to enforce the consent judgment and resolve any future disputes arising from it.
At 799 days, the case ran for roughly 26 months before resolution — consistent with the typical timeline for a negotiated ANDA consent judgment, which often follows completion of claim construction or the exchange of technical expert reports. The consent structure, rather than a contested trial outcome, suggests the parties reached a commercial accommodation, though the specific terms of any licensed entry date or market access arrangement are not disclosed in the public record. MSN retains the right to maintain its Paragraph IV certifications and to conduct activities protected under 35 U.S.C. § 271(e)(1).
Filing to settlement in 799 days
799 days — approximately 26 months from filing to consent judgment
Permanent injunction against MSN until expiry of both azacitidine patents
What a consent judgment with injunction means in ANDA litigation
A consent judgment is a court-endorsed agreement between the parties, carrying the same enforceability as a litigated order. Here, MSN agreed to be permanently enjoined from commercialising its ANDA product until both patents expire. This is a common resolution in Hatch-Waxman cases — it gives the patentee certainty of exclusion without the risk of trial, while potentially allowing the generic a negotiated future entry date not visible in the public record.
Injunction by agreementAll claims dismissed with prejudice — no costs awarded to either side
The consent judgment dismisses all claims, counterclaims, affirmative defenses, and motions with prejudice, meaning neither party can re-litigate the same issues in a new action. Unusually, no costs or attorneys’ fees were awarded to either side, which is consistent with a mutually negotiated resolution rather than a clear-cut win or loss. The court retains jurisdiction to enforce the judgment, providing plaintiffs a mechanism to act swiftly if MSN breaches the injunction.
With prejudice, no fee awardMSN enjoined from all U.S. commercialisation — including third-party assistance
The injunction is notably broad: it covers not only MSN’s direct commercialisation of its ANDA product but also any assistance or cooperation with third parties infringing the patents in connection with azacitidine products referencing NDA 214120. This third-party restriction limits MSN’s ability to partner with or supply a distributor seeking to bring a competing product to market under a related reference drug pathway, reinforcing the plaintiffs’ exclusivity position.
Broad third-party scopeMSN retains Paragraph IV rights and safe harbour protections
Despite the injunction, the consent judgment preserves MSN’s right to maintain its Paragraph IV certifications against both patents-in-suit and any other patent, and to engage in research or development activities protected under 35 U.S.C. § 271(e)(1). The FDA also remains free to approve ANDA No. 218435. These carve-outs suggest MSN may be positioning for a future entry once the patents expire or if it successfully challenges patent validity through a separate proceeding.
Future entry not foreclosedFull party and counsel information
| Role | Nom | Type | Détail |
|---|---|---|---|
| Demandeur | Celgene, Corp. | Entreprise | Pharmaceutical IP holding and commercial arm — holder of US8846628 and US11571436 covering oral azacitidineSearch in Eureka ↗ |
| Défendeur | Accord Healthcare, S.A.R.L. | Entreprise | Generic pharmaceutical manufacturer and its U.S. affiliate seeking ANDA approval for azacitidine tabletsSearch in Eureka ↗ |
| Plaintiff counsel | Amy K. Wigmore | Attorney | Counsel for Celgene, Corp.Search in Eureka ↗ |
| Plaintiff counsel | Andrew J. Danford | Attorney | Counsel for Celgene, Corp.Search in Eureka ↗ |
| Plaintiff counsel | Brian E. Farnan | Attorney | Counsel for Celgene, Corp.Search in Eureka ↗ |
| Plaintiff counsel | David Mlaver | Attorney | Counsel for Celgene, Corp.Search in Eureka ↗ |
| Plaintiff counsel | Gerard A. Salvatore | Attorney | Counsel for Celgene, Corp.Search in Eureka ↗ |
| Plaintiff counsel | Heather M. Petruzzi | Attorney | Counsel for Celgene, Corp.Search in Eureka ↗ |
| Plaintiff counsel | Joseph J. Farnan , Jr. | Attorney | Counsel for Celgene, Corp.Search in Eureka ↗ |
| Plaintiff counsel | Li-tsung A. Chen | Attorney | Counsel for Celgene, Corp.Search in Eureka ↗ |
| Plaintiff counsel | Michael J. Farnan | Attorney | Counsel for Celgene, Corp.Search in Eureka ↗ |
| Plaintiff counsel | Nora Q.E. Passamaneck | Attorney | Counsel for Celgene, Corp.Search in Eureka ↗ |
| Defendant counsel | Corey Weinstein | Attorney | Counsel for Accord Healthcare, Ltd.Search in Eureka ↗ |
| Defendant counsel | Neal Seth | Attorney | Counsel for Accord Healthcare, Ltd.Search in Eureka ↗ |
| Defendant counsel | Stamatios Stamoulis | Attorney | Counsel for Accord Healthcare, Ltd.Search in Eureka ↗ |
| Defendant counsel | Wesley E. Weeks | Attorney | Counsel for Accord Healthcare, Ltd.Search in Eureka ↗ |
| Presiding judge | Judge Jennifer L. Hall | Juge en chef | Delaware District Court — Chief JudgeSearch in Eureka ↗ |
Stipulation of dismissal — official text
The consent judgment is structured as a full injunctive resolution: MSN is permanently barred from commercialising its ANDA product in the U.S. until both patents expire. The breadth of the injunction — covering direct acts, third-party assistance, and any azacitidine product referencing NDA 214120 — leaves MSN with no near-term path to market. The no-costs provision and preservation of Paragraph IV rights are consistent with a negotiated resolution, suggesting the parties may have agreed on a confidential future entry date not reflected in the public judgment.
US8846628 & US11571436 — oral azacitidine tablet formulation patents
US8846628 (application number US12/466213) covers formulations and methods relating to oral azacitidine tablets, a DNA methyltransferase inhibitor used in oncology. Azacitidine was historically administered only by injection; the patents protect the formulation innovation enabling oral bioavailability at therapeutic doses. US11571436 appears to be a related continuation asserting overlapping or extended claims. Together, these patents underpin Celgene’s Onureg (azacitidine) tablets, approved for maintenance therapy in acute myeloid leukaemia (AML).
The oral azacitidine patent family represents a high-value exclusivity position in a growing oncology indication. AML maintenance therapy is a commercially significant and expanding market, making these patents prime targets for ANDA challengers seeking generic entry. The combination of a formulation patent and a later-issued continuation creates a layered exclusivity structure that complicates invalidity challenges and extends the effective window of market protection, making this patent family a strategic asset for BMS post-acquisition of Celgene.
Should you run an FTO analysis against US8846628 and US11571436?
Any company developing or planning to file an ANDA for an oral azacitidine tablet product referencing NDA 214120 faces direct exposure to US8846628 and US11571436. This case confirms that Celgene and BMS will enforce both patents through to a court-ordered injunction in Delaware. R&D and regulatory teams considering formulation work in the hypomethylating agent space — including 5-azacytidine tablet formulations at any dose — should treat these patents as live blocking assets and commission a full FTO before committing ANDA resources.
PatSnap Eureka’s FTO Search Agent enables rapid claim-by-claim mapping of US8846628 and US11571436 against proposed formulation specifications, and monitors the broader Celgene/BMS azacitidine continuation family for newly granted claims. With the court having retained jurisdiction to enforce the consent judgment, any product that comes within the scope of enjoined activity risks contempt proceedings — making ongoing claim monitoring, not just a one-time FTO, an essential risk management tool for this patent family.
Run a freedom-to-operate analysis on US8846628B2 to assess your product’s exposure
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What this case signals for the oral azacitidine and ANDA IP landscape
BMS and Celgene have demonstrated consistent willingness to enforce oral azacitidine patents through to a court-ordered injunction.
Consent injunctions in ANDA cases signal strong patent confidence
When a branded pharmaceutical plaintiff secures a consent judgment with injunction rather than settling on undisclosed commercial terms alone, it typically signals high confidence in the validity and enforceability of the asserted patents. Competitors assessing the oral azacitidine space should treat US8846628 and US11571436 as actively defended assets requiring rigorous FTO analysis before any ANDA filing.
Preserved Paragraph IV rights hint at future generic entry strategy
The explicit preservation of MSN’s right to maintain Paragraph IV certifications is a standard but strategically important carve-out. It suggests MSN has not conceded patent validity — only agreed to market delay. Companies tracking the azacitidine generic pipeline should monitor IPR or post-grant proceedings that MSN or other filers may initiate as the patent expiry horizon approaches.
Celgene v Accord — key questions answered
The case resolved via a consent judgment entered 29 February 2024, permanently enjoining MSN Laboratories and MSN Pharmaceuticals from commercialising their ANDA azacitidine tablets in the U.S. until expiry of US Patents 8,846,628 and 11,571,436. All claims were dismissed with prejudice and no costs were awarded to either party.
Celgene and Bristol-Myers Squibb asserted U.S. Patent Nos. 8,846,628 and 11,571,436. Both patents relate to oral azacitidine tablet formulations and together underpin the branded product Onureg, approved for AML maintenance therapy. The consent judgment refers to both collectively as the ‘Patents-in-Suit’.
The injunction bars MSN — including successors and assigns — from making, importing, selling, offering to sell, or distributing its ANDA azacitidine tablets in the U.S. until both patents expire. It also prohibits MSN from assisting third parties in infringing the patents in connection with any azacitidine product referencing NDA 214120, unless specifically authorised by the plaintiffs.
Not permanently. The consent judgment enjoins MSN only until expiry of the two patents-in-suit. It explicitly preserves MSN’s right to maintain its Paragraph IV certifications and to conduct activities protected under 35 U.S.C. § 271(e)(1). The FDA also remains free to approve ANDA No. 218435, suggesting MSN retains a path to market post-patent expiry or potentially via a separately negotiated launch date.
The case was filed in the U.S. District Court for the District of Delaware (Case No. 1:21-cv-01795) and was handled by Judge Jennifer L. Hall. Delaware is a common venue for Hatch-Waxman ANDA litigation given its established body of pharmaceutical patent case law.
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