Book a demo

Cut patent&paper research from weeks to hours with PatSnap Eureka AI!

Try now
Celgene & BMS v. Natco Pharma — Azacitidine Tablet Patent Dispute | PatSnap
Explore in Eureka
Case ID1:23-cv-01019
FiledSep 2023
ClosedMay 2024
Patent Litigation

Celgene & BMS v. Natco Pharma: Consent Judgment Blocks Generic Azacitidine

Celgene, Bristol-Myers Squibb, and Celgene International sued Indian generic manufacturer Natco Pharma in the Delaware District Court over its ANDA for 200 mg and 300 mg azacitidine tablets, the active ingredient in Onureg®. The parties resolved the dispute in 254 days via a consent judgment imposing an injunction on Natco until expiry of both asserted patents.

Resolution time
254days
254-day resolution — faster than the median Hatch-Waxman Paragraph IV case in Delaware
Patents asserted
2
US8846628B2 and US11571436B2 — azacitidine oral tablet formulations, two patents asserted
Outcome
Consent Judgment
Injunction entered by agreement; all claims dismissed with prejudice, no costs awarded
Cost ruling
No Costs
Parties stipulated: no costs, disbursements, or attorneys’ fees awarded to either side
Published by PatSnap Insights Team · Verified by PatSnap Eureka Data
Case overview

Hatch-Waxman Standoff Over Onureg® Ends in Agreed Injunction

Filed on 18 September 2023 before Judge Jennifer L. Hall in the Delaware District Court, this Hatch-Waxman infringement action was brought by Celgene Corp., Celgene International SARL, and Bristol-Myers Squibb Company against Natco Pharma Ltd. The plaintiffs asserted US Patent Nos. 8,846,628 and 11,571,436, which cover oral azacitidine tablet formulations marketed as Onureg®, an FDA-approved treatment for acute myeloid leukaemia. Natco had filed ANDA No. 218696 seeking approval for generic 200 mg and 300 mg azacitidine tablets referencing NDA 214120.

The case closed on 29 May 2024 — 254 days after filing — through a stipulated consent judgment. Under its terms, Natco is enjoined from making, importing, selling, or distributing its ANDA product in the United States until both patents-in-suit expire, unless specifically authorised by plaintiffs. All claims and counterclaims were dismissed with prejudice, with no costs or attorneys’ fees awarded to either party. The FDA is not restricted from approving ANDA 218696, and Natco retains its Paragraph IV certification rights and its safe-harbour research exemption under 35 U.S.C. § 271(e)(1).

A 254-day resolution is notably swift for Hatch-Waxman litigation, suggesting the parties reached commercial alignment well before trial became imminent. The consent judgment’s carve-outs — preserving Natco’s Paragraph IV certification and FDA approval pathway — indicate that Natco has not conceded patent validity and may revisit market entry after patent expiry or through future challenge proceedings. The public record does not disclose whether any royalty, licensing fee, or authorised generic arrangement forms part of the parties’ private agreement.

Case at a glance
Case no.1:23-cv-01019
CourtDelaware
JudgeJennifer L. Hall
FiledSeptember 18, 2023
ClosedMay 29, 2024
Duration254 days
OutcomeConsent Judgment
Verdict causeInfringement Action
BasisConsent Judgment
Prior Art Intelligence
See what prior art exists on this patent.
Eureka scans millions of patents and papers to surface prior art that may have invalidated these claims before costly litigation begins.
Check Prior Art
Case data sourced from PACER / Delaware District Court via PatSnap Eureka Litigation Intelligence Explore similar cases ↗
Case timeline

Filing to Consent Judgment in 254 days

254-day resolution — faster than the median Hatch-Waxman Paragraph IV case in Delaware

Case timeline: Complaint filed SEP 18 2023, JAN–FEB — 254 days total Horizontal timeline showing the three key events in Celgene, Corp. v Natco Pharma, Ltd. from filing to resolution. Source: PACER, Delaware District Court. SEP 18 2023 Complaint filed Pre-trial proceedings MAY 29 2024 Consent Judgment 254 DAYS TOTAL
Dismissal terms

Consent judgment entered: what the agreed injunction means for both parties

Legal mechanism

Consent judgment: an agreed injunction without admission

A consent judgment is a court-ordered resolution negotiated by both parties and entered as a binding judicial order. Here, Natco accepted an injunction blocking U.S. commercialisation of its ANDA product until both patents expire — without the court adjudicating infringement or validity on the merits. All claims were dismissed with prejudice, making the injunction immediately enforceable while preserving Natco’s right to contest patents in future proceedings.

Dismissed with prejudice
Patent holder outcome

BMS and Celgene secure patent exclusivity through expiry

The consent judgment delivers the primary commercial objective for Celgene and Bristol-Myers Squibb: Onureg® faces no generic competition from Natco until both US8846628 and US11571436 expire. The injunction covers all forms of commercial activity — manufacture, import, sale, and distribution — and extends to third-party assistance. Plaintiffs retain enforcement rights and the court retains jurisdiction to resolve any breach, providing a durable enforcement mechanism.

Exclusivity preserved
Generic challenger outcome

Natco retains ANDA and future challenge rights

Despite accepting the injunction, Natco preserved meaningful optionality. Its ANDA No. 218696 remains intact and the FDA is explicitly permitted to approve it. Natco retains its Paragraph IV certification against both patents, keeping open the possibility of a future IPR or validity challenge. The safe-harbour exemption under § 271(e)(1) is also preserved, allowing continued research activity. No admission of infringement or invalidity appears in the public record.

ANDA and § IV rights retained
Commercial implications

Oral azacitidine market remains protected — for now

The consent judgment reinforces BMS’s and Celgene’s control over the oral azacitidine segment. Other generic filers seeking to challenge Onureg® will face a strengthened enforcement precedent: plaintiffs have already demonstrated willingness to litigate and secure court-ordered relief. The preserved Paragraph IV and IPR pathways suggest the validity of US8846628 and US11571436 has not been tested in adversarial proceedings, leaving that question open for future challengers.

Generic entry deferred
Legal analysis based on PACER docket records for case 1:23-cv-01019 and PatSnap Eureka litigation intelligence Search PatSnap Eureka ↗
Parties and representation

Full party and counsel information

RoleNameTypeDetail
PlaintiffCelgene, Corp.CompanyPharmaceutical innovator — holder of US8846628B2 and US11571436B2 covering Onureg® azacitidineSearch in Eureka ↗
Co-PlaintiffBristol‑Myers Squibb CompanyCompanySearch in Eureka ↗
Co-PlaintiffCelgene International, SARLIndividualSearch in Eureka ↗
DefendantNatco Pharma, Ltd.CompanyIndian generic drug manufacturer seeking U.S. market entry via ANDA for azacitidine tabletsSearch in Eureka ↗
Plaintiff counselAmy K. WigmoreAttorneyCounsel for Celgene, Corp.Search in Eureka ↗
Plaintiff counselAndrew J. DanfordAttorneyCounsel for Celgene, Corp.Search in Eureka ↗
Plaintiff counselBrian E. FarnanAttorneyCounsel for Celgene, Corp.Search in Eureka ↗
Plaintiff counselDavid MlaverAttorneyCounsel for Celgene, Corp.Search in Eureka ↗
Plaintiff counselGerard A. SalvatoreAttorneyCounsel for Celgene, Corp.Search in Eureka ↗
Plaintiff counselHeather M. PetruzziAttorneyCounsel for Celgene, Corp.Search in Eureka ↗
Plaintiff counselJoseph J. Farnan , Jr.AttorneyCounsel for Celgene, Corp.Search in Eureka ↗
Plaintiff counselLi-tsung A. ChenAttorneyCounsel for Celgene, Corp.Search in Eureka ↗
Plaintiff counselMichael J. FarnanAttorneyCounsel for Celgene, Corp.Search in Eureka ↗
Plaintiff counselNora Q.E. PassamaneckAttorneyCounsel for Celgene, Corp.Search in Eureka ↗
Plaintiff law firmFarnan LLPLaw FirmRepresenting Celgene, Corp.Search in Eureka ↗
Defendant counselAndrew O. LarsenAttorneyCounsel for Natco Pharma, Ltd.Search in Eureka ↗
Defendant counselChristopher J. SorensonAttorneyCounsel for Natco Pharma, Ltd.Search in Eureka ↗
Defendant counselJames S. Green , Jr.AttorneyCounsel for Natco Pharma, Ltd.Search in Eureka ↗
Defendant counselJason M. WienerAttorneyCounsel for Natco Pharma, Ltd.Search in Eureka ↗
Defendant law firmSeitz Van Ogtrop & Green PALaw FirmRepresenting Natco Pharma, Ltd.Search in Eureka ↗
Presiding judgeJudge Jennifer L. HallJudgeDelaware District CourtSearch in Eureka ↗
Official verdict

Official order — verbatim text

“Plaintiffs Celgene Corporation, Celgene International Sárl, and Bristol-Myers Squibb Company (collectively, “Plaintiffs”), and Defendant Natco Pharma Ltd. (“Natco”), the parties in the above-captioned action, hereby stipulate and consent to entry of judgment and an injunction in this action as follows: IT IS this ______ day of ____________, 2024: ORDERED, ADJUDGED, AND DECREED as follows: 29th May Case 1:23-cv-01019-JLH Document 20-1 Filed 05/29/24 Page 1 of 4 PageID #: 282 1. This Court has jurisdiction over the subject matter of the above action and has personal jurisdiction over the parties for purposes of this action only, including as set forth below in Paragraph 6 of this Consent Judgment. 2. As used in this Consent Judgment, the term “Natco ANDA Product” shall mean 200 mg and 300 mg azacitidine tablets manufactured, imported, sold, offered for sale, marketed, or distributed pursuant to Abbreviated New Drug Application No. 218696 in or for the United States of America, including its territories, possessions, and the Commonwealth of Puerto Rico. 3. As used in this Consent Judgment, the term “Patents-in-Suit” shall mean U.S. Patent Nos. 8,846,628 and 11,571,436. 4. Until expiration of the Patents-in-Suit, Natco, including any of its successors and assigns, is enjoined from infringing the Patents-in-Suit, on its own part or through any third party on its behalf, by making, having made, using, selling, offering to sell, importing, or distributing of the Natco ANDA Product in or for the United States of America, including its territories, possessions, and the Commonwealth of Puerto Rico, unless and to the extent otherwise specifically authorized by Plaintiffs, and is further enjoined from assisting or cooperating with any third parties in connection with any infringement of the Patents-in-Suit by any such third parties in connection with making, having made, using, selling, offering to sell, importing, or distributing of any azacitidine-containing drug product that references New Drug Application 214120 in or for the United States of America, including its territories, possessions, and the Commonwealth of Puerto Rico, unless and to the extent otherwise specifically authorized by Plaintiffs. Case 1:23-cv-01019-JLH Document 20-1 Filed 05/29/24 Page 2 of 4 PageID #: 283 5. Compliance with this Consent Judgment may be enforced by Plaintiffs and its respective successors in interest or assigns. 6. This Court retains jurisdiction to enforce the terms of this Consent Judgment and to enforce and resolve any disputes related thereto. 7. All claims, counterclaims, affirmative defenses, motions and demands in this action that are hereby dismissed with prejudice and without costs, disbursements, or attorneys’ fees to any party. 8. Nothing herein prohibits or is intended to prohibit Natco from maintaining any “Paragraph IV Certification” pursuant to 21 U.S.C. § 355(j)(2)(A)(vii)(IV) or pursuant to 21 C.F.R. § 314.94(a)(12) with respect to the Patents-in-Suit or any other patent. 9. Nothing herein restricts or is intended to restrict the U.S. Food and Drug Administration from approving Abbreviated New Drug Application No. 218696 or the Natco ANDA Product. 10. Nothing herein prohibits or is intended to prohibit Natco from engaging in any activity permitted under 35 U.S.C. § 271(e)(1).”
Source: PACER Docket, Case 1:23-cv-01019, Delaware District Court

The consent judgment is a stipulated court order — not a merits adjudication. The court did not rule on infringement or validity; instead, both parties agreed to entry of the injunction and dismissal with prejudice. The ‘with prejudice’ designation bars relitigation of the claims asserted here, but critically does not preclude Natco from challenging patent validity in separate inter partes review proceedings at the USPTO. The carve-outs in paragraphs 8–10 reflect standard Hatch-Waxman settlement practice, preserving the regulatory and research safe harbours that Natco would need to remain in the generic drug development pipeline.

PACER case 1:23-cv-01019 · Public docket record Explore in Eureka ↗
Patent at issue

US8846628B2 & US11571436B2 — Oral Azacitidine Tablet Formulations

Publication No.US11571436B2
Application No.US17/533033
Patent details
ProductOral azacitidine tablet formulations — methods of use for AML maintenance therapy
Cited in actionSeptember 18, 2023

Publication No.US8846628B2
Application No.US12/466213
Patent details
ProductAzacitidine oral tablet compositions and formulation technology
Cited in actionSeptember 18, 2023

US8846628B2 (application US12/466213) and US11571436B2 (application US17/533033) both protect oral azacitidine tablet technology underlying Onureg®, an FDA-approved agent for maintenance therapy in acute myeloid leukaemia. Azacitidine was historically delivered only by injection; the patents reflect Celgene’s development of a stable oral formulation suitable for outpatient use. US11571436 issued from a more recent application filed in November 2021, suggesting continuation or improvement claims that may extend the effective exclusivity period beyond the earlier ‘628 patent.

From a competitive standpoint, these two patents collectively form the core IP barrier to generic oral azacitidine entry in the U.S. market. The dual-patent structure is characteristic of Celgene’s and BMS’s approach to lifecycle management in oncology: layering a composition or formulation patent with a later-issued method-of-use or improvement patent to extend the commercially relevant exclusivity window. Any generic manufacturer, biosimilar developer, or combination-therapy company operating in the AML maintenance space should treat these patents as a primary FTO consideration.

Patent data sourced from USPTO via PatSnap Eureka patent database Search patent records in Eureka ↗
Freedom to operate

Should your team run an FTO against US8846628 and US11571436?

If your R&D pipeline includes oral azacitidine formulations, azacitidine combination products, or any ANDA referencing NDA 214120, a freedom-to-operate analysis against US8846628B2 and US11571436B2 is not optional — it is a prerequisite. The consent judgment confirms that BMS and Celgene will litigate promptly in Delaware, and the dual-patent structure means that designing around one patent may not clear the other. This analysis is equally relevant for companies developing hypomethylating agent alternatives in the AML or MDS space.

PatSnap Eureka’s FTO Search Agent can map your product’s technical features against the claims of both asserted patents simultaneously, identify prior art that may inform a validity challenge, and flag related continuation applications in the Celgene/BMS portfolio that could affect your go-to-market window. Use Eureka to model patent expiry scenarios for both the ‘628 and ‘436 patents and identify whether any claim scope differences create a defensible design-around opportunity.

PatSnap Eureka FTO Search

Run a freedom-to-operate analysis on US11571436B2 to assess your product’s exposure

Run FTO in Eureka →
Related litigation

Similar Hatch-Waxman Azacitidine & Oral Oncology Patent Cases

Explore Paragraph IV patent infringement cases involving oral oncology formulations litigated in the Delaware District Court with comparable ANDA enforcement postures.

🔍
Access 40+ similar cases in PatSnap Eureka
Celgene, Corp. patent enforcement history, Delaware case history, Celgene, Corp.’s full IP portfolio, and comparable case analysis
Comparable ANDA casesBMS Hatch-Waxman historyOral oncology patent suitsNatco US litigation record
Unlock similar cases in Eureka →
Strategic implications

What this case signals for the oral oncology Hatch-Waxman IP landscape

A swift consent judgment in a Paragraph IV action over a key AML therapy carries implications beyond the two named parties.

Consent judgments are the dominant Hatch-Waxman exit in Delaware

This case resolved in under nine months without a merits ruling — consistent with a broader pattern of early negotiated exits in Delaware Paragraph IV litigation. For generic filers, the commercial calculus often favours a negotiated delay over the cost and uncertainty of full trial, particularly when the innovator holds a portfolio of layered patents as seen here.

Preserved Paragraph IV certification signals the validity fight is unfinished

Natco’s retention of its § 355(j) Paragraph IV certification is a material carve-out. It signals that Natco — or a third party acquiring its ANDA — could mount a future IPR challenge to US8846628 or US11571436. Companies monitoring the oral azacitidine space should track post-grant proceedings at the USPTO alongside this case.

🔒
Full strategic analysis in PatSnap Eureka
Unlock detailed patent expiry modelling and IPR risk scoring for the Onureg® portfolio in this Delaware District Court case.
Patent expiry timelineIPR vulnerability analysisBMS Onureg® portfolio map
Unlock full analysis →
Analysis powered by PatSnap Eureka Litigation Intelligence Explore in Eureka ↗
Frequently asked questions

Celgene v Natco — key questions answered

Still have questions? PatSnap Eureka can answer them instantly from patent and litigation data. Ask Eureka ↗
PatSnap Eureka

Track Generic Entry Risk Across Your Oral Oncology Portfolio

Consent judgments like this one can obscure undisclosed licensing terms and leave patent validity untested. Use PatSnap to monitor ANDA activity, USPTO post-grant challenges, and expiry windows for your key oncology assets.

Ask anything about this case.
PatSnap Eureka searches patents and litigation data to answer instantly.
Powered by PatSnap Eureka
Link copied to clipboard

Related Litigation Cases

Help us improve this page

Found incorrect or outdated information? Let us know and we'll get it fixed.