Pfizer v. Breckenridge Pharmaceutical: Xeljanz Patent Dismissed Without Prejudice in 35 Days
Pfizer and its affiliates filed suit against Breckenridge Pharmaceutical in Delaware District Court asserting reissue patent USRE041783E covering 10 mg Xeljanz® (tofacitinib) tablets. The case closed just 35 days after filing when Pfizer voluntarily dismissed all claims without prejudice — before Breckenridge had filed any responsive pleading.
Pfizer’s swift exit: tactical withdrawal or resolved dispute?
On October 9, 2024, Pfizer Inc. together with affiliates PF Prism C.V., C.P. Pharmaceuticals International C.V., PBG Puerto Rico LLC, and PF PRISM IMB B.V. filed a patent infringement action against Breckenridge Pharmaceutical, Inc. in the District of Delaware. The asserted patent, USRE041783E — a reissue of an earlier grant — covers 10 mg Xeljanz® (tofacitinib) tablets, a JAK inhibitor approved for rheumatoid arthritis, psoriatic arthritis, and ulcerative colitis. Breckenridge’s generic 10 mg tofacitinib tablets were identified as the accused product, suggesting this action arose in the context of ANDA-related Hatch-Waxman litigation.
The case closed on November 13, 2024 — just 35 days after filing — when Pfizer unilaterally filed a notice of voluntary dismissal without prejudice pursuant to Rule 41(a)(1)(A)(i) of the Federal Rules of Civil Procedure. That rule permits a plaintiff to dismiss as of right, without a court order, provided the defendant has not yet served an answer or motion for summary judgment. The public record confirms Breckenridge had not done so. The dismissal without prejudice means Pfizer retains the ability to refile claims on USRE041783E against Breckenridge in the future.
A 35-day lifecycle is exceptionally short for patent litigation in Delaware and suggests the dismissal was driven by factors outside the courtroom — potentially a licensing arrangement, a settlement in a parallel proceeding, a commercial agreement, or a strategic recalibration of the enforcement portfolio. The absence of any responsive pleading from Breckenridge and the lack of any cost order are consistent with an amicable resolution or a deliberate tactical pause. The specific terms of any underlying agreement, if one exists, are not disclosed in the public record.
Filing to Dismissed without Prejudice in 35 days
35 days — well below the median district court patent case lifecycle of 2–3 years
Dismissed without prejudice: what Pfizer’s Rule 41 exit means for both parties
Rule 41(a)(1)(A)(i): plaintiff’s unilateral right to dismiss
Rule 41(a)(1)(A)(i) allows a plaintiff to dismiss an action without a court order by filing a notice before the defendant serves an answer or motion for summary judgment. Because Breckenridge had not filed either, Pfizer’s dismissal was automatic and self-executing. No judicial approval was required, and the court entered no merits ruling. This is among the most procedurally straightforward exits available in federal civil litigation.
Pre-answer voluntary dismissalNo prejudice: Pfizer can refile — but the clock may matter
A dismissal without prejudice does not extinguish the underlying claims. Pfizer retains the right to bring a new infringement action asserting USRE041783E against Breckenridge at a future date, subject to applicable statutes of limitation and any Hatch-Waxman timing constraints. In contrast, a dismissal with prejudice would have been a final adjudication barring refiling. The public record is silent on whether any agreement governs the timing or conditions of a potential refile.
Refile right preservedBreckenridge exits without a merits ruling — but uncertainty remains
Breckenridge faces no adverse judgment from this proceeding, and no validity or infringement determination was made. However, the without-prejudice nature of the dismissal means Breckenridge cannot treat this case as a final resolution. If its ANDA product proceeds toward market, the threat of renewed litigation on USRE041783E persists. The absence of any cost award suggests no finding of improper conduct by either party.
No merits ruling; exposure remainsGeneric tofacitinib market entry: the IP uncertainty continues
Xeljanz (tofacitinib) is a high-value JAK inhibitor franchise. A without-prejudice exit preserves Pfizer’s enforcement posture and signals that the underlying IP — including USRE041783E — has not been conceded. For generic entrants and biosimilar-adjacent competitors in the JAK inhibitor space, this case suggests ongoing vigilance over Pfizer’s reissue patent portfolio is warranted. Any commercial launch by Breckenridge would likely need to account for the continued litigation risk.
JAK inhibitor generic market riskFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Pfizer, Inc. | Company | Global biopharmaceutical company — holder of USRE041783E covering 10 mg tofacitinib tabletsSearch in Eureka ↗ |
| Co-Plaintiff | PF Prism C.V. | Individual | Search in Eureka ↗ |
| Co-Plaintiff | C.P. Pharmaceuticals International C.V. | Individual | Search in Eureka ↗ |
| Co-Plaintiff | Pbg Puerto Rico, LLC | Company | Search in Eureka ↗ |
| Co-Plaintiff | PF Prism Ibm C.V. | Individual | Search in Eureka ↗ |
| Defendant | Breckenridge Pharmaceutical, Inc. | Company | Generic pharmaceutical manufacturer targeted over 10 mg tofacitinib (Xeljanz®) ANDA productSearch in Eureka ↗ |
| Plaintiff counsel | Megan Elizabeth Dellinger | Attorney | Counsel for Pfizer, Inc.Search in Eureka ↗ |
| Plaintiff law firm | Morris, Nichols, Arsht & Tunnell LLP | Law Firm | Representing Pfizer, Inc.Search in Eureka ↗ |
| Presiding judge | Judge Colm F. Connolly | Judge | Delaware District CourtSearch in Eureka ↗ |
Official order — verbatim text
Pfizer invoked Rule 41(a)(1)(A)(i) to file a self-executing notice of dismissal, confirming that Breckenridge had not yet served any answer or motion for summary judgment — the procedural threshold for unilateral exit. The without-prejudice designation is legally significant: it preserves Pfizer’s right to re-assert USRE041783E in a future action. No merits finding was made on infringement, validity, or claim construction. The phrasing of the notice is formulaic and discloses no underlying rationale, which is consistent with either a confidential settlement or a deliberate tactical pause ahead of potential refiling.
USRE041783E — Tofacitinib 10 mg tablet formulation (Xeljanz®)
USRE041783E is a United States reissue patent, corresponding to corrected application number US12/577790. Reissue patents are granted under 35 U.S.C. § 251 when the original patent is deemed wholly or partly inoperative or invalid due to a defective specification, drawing, or claim. The reissue process allows the patentee to correct such defects, and within two years of grant, may broaden original claims. The patent covers tofacitinib — a small-molecule JAK1/JAK3 inhibitor — in a 10 mg tablet formulation marketed as Xeljanz®, used in the treatment of rheumatoid arthritis, psoriatic arthritis, and ulcerative colitis.
Xeljanz® represents one of Pfizer’s cornerstone specialty pharmaceutical assets. The reissue designation suggests that claim scope was deliberately refined after original grant, potentially to strengthen enforceability against generic entrants filing ANDAs with Paragraph IV certifications. For competitors in the JAK inhibitor space — including companies developing tofacitinib generics, extended-release formulations, or related small-molecule immunology products — USRE041783E represents a material freedom-to-operate consideration. The active enforcement action against Breckenridge, even in its brief form, confirms Pfizer’s willingness to litigate this asset.
Should you run an FTO analysis against USRE041783E?
Any company developing, manufacturing, or commercialising tofacitinib tablets — particularly 10 mg oral solid dosage forms — should treat USRE041783E as a priority asset in a freedom-to-operate review. The without-prejudice dismissal in this case confirms that Pfizer has not abandoned enforcement. R&D teams working on JAK inhibitor formulations, generic tofacitinib ANDAs, or related immunology small molecules should assess whether their product design intersects with the reissue claims, particularly given that reissue claim language may differ from the original grant.
PatSnap Eureka’s FTO Search Agent enables IP and R&D teams to rapidly map claim scope against product specifications, identify prior art relevant to validity challenges, and surface related Pfizer prosecution history for USRE041783E. The platform’s patent family and citation analysis tools can help track downstream continuation and divisional risk, ensuring that a single FTO review covers the full tofacitinib patent landscape — not just the asserted reissue patent.
Run a freedom-to-operate analysis on USRE041783E to assess your product’s exposure
Run FTO in Eureka →Similar Hatch-Waxman tofacitinib and JAK inhibitor patent cases in Delaware
Related ANDA patent infringement actions involving tofacitinib formulations and JAK inhibitor pharmaceuticals litigated in Delaware District Court.
What this case signals for the JAK inhibitor and branded pharmaceutical IP landscape
Pfizer’s 35-day voluntary exit in Delaware raises questions about enforcement strategy and generic tofacitinib market dynamics.
Pre-answer dismissals can signal off-docket resolutions — monitor parallel proceedings
When a major pharmaceutical plaintiff exits within 35 days of filing and before any responsive pleading, it typically signals that substantive discussions occurred outside the docket. IP professionals tracking Pfizer’s Xeljanz enforcement activity should monitor parallel ANDA proceedings, licensing announcements, and Breckenridge’s regulatory timeline for any correlated activity.
USRE041783E remains live — Pfizer retains full enforcement rights on this patent
The without-prejudice dismissal leaves USRE041783E fully enforceable. Companies developing or commercialising tofacitinib formulations — including 10 mg extended-release variants — should treat this reissue patent as an active risk asset in any freedom-to-operate analysis. Reissue patents carry corrected claims that may differ materially from the original grant.
Pfizer v Breckenridge — key questions answered
Pfizer filed a Rule 41(a)(1)(A)(i) notice of voluntary dismissal without prejudice on November 13, 2024, just 35 days after filing. Because Breckenridge had not served an answer or motion for summary judgment, Pfizer was entitled to dismiss unilaterally without court approval. The public record does not disclose the reason, but the timeline is consistent with an off-docket resolution, licensing agreement, or strategic recalibration.
A dismissal without prejudice does not extinguish the underlying claims. Pfizer retains the right to file a new infringement action asserting USRE041783E against Breckenridge, subject to applicable statutes of limitation and any Hatch-Waxman procedural constraints. No merits determination was made, and no bar to refiling was established by this dismissal.
USRE041783E is a United States reissue patent corresponding to application US12/577790. It covers a 10 mg tofacitinib tablet formulation — the dosage strength marketed as Xeljanz® by Pfizer. Tofacitinib is a JAK1/JAK3 inhibitor approved for rheumatoid arthritis, psoriatic arthritis, and ulcerative colitis. Reissue patents are granted to correct defects in the original patent and may carry broadened or narrowed claims relative to the original grant.
Rule 41(a)(1)(A)(i) allows a plaintiff to dismiss an action as of right — without needing a court order — by filing a notice of dismissal before the defendant serves an answer or motion for summary judgment. In this case, Pfizer confirmed Breckenridge had not done either, making the dismissal self-executing. This is distinct from a stipulated or court-ordered dismissal, and carries no adverse cost consequences absent a contrary agreement.
Not substantially. The without-prejudice dismissal provides no res judicata or claim preclusion protection to Breckenridge. No infringement, validity, or claim construction ruling was issued. Breckenridge’s generic 10 mg tofacitinib product remains exposed to future litigation on USRE041783E if Pfizer elects to refile, particularly if Breckenridge proceeds toward an ANDA approval and commercial launch.
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