Salix v. Carnegie Pharmaceuticals: Colazal® Patent Dispute Settled in 90 Days
Salix Pharmaceuticals, Inc., Salix Pharmaceuticals, Ltd., and Bausch Health Ireland, Ltd. brought a patent infringement action against Carnegie Pharmaceuticals, LLC in the District of New Jersey over two patents protecting Colazal® balsalazide disodium capsules 750 mg. The parties reached a confidential settlement and license agreement, resulting in dismissal with prejudice in just 90 days.
Colazal® Balsalazide Patent Suit Ends in Confidential License Deal
Filed on 3 July 2024 in the District of New Jersey, this infringement action pitted the Salix/Bausch Health pharmaceutical group — plaintiffs Salix Pharmaceuticals, Inc., Salix Pharmaceuticals, Ltd., and Bausch Health Ireland, Ltd. — against Carnegie Pharmaceuticals, LLC, a generic drug developer. The asserted patents, US7452872B2 and US7625884B2, cover balsalazide disodium formulations underlying Colazal®, a branded 750 mg capsule treatment for ulcerative colitis. The suit is consistent with standard Hatch-Waxman or ANDA-style patent enforcement intended to protect a branded pharmaceutical franchise against generic entry.
The case closed on 1 October 2024 — just 90 days after filing — through a Confidential Settlement and License Agreement between the parties. Pursuant to Federal Rule of Civil Procedure 41(a)(1)(ii) and (c), all claims and counterclaims were dismissed with prejudice. The dismissal with prejudice means Carnegie Pharmaceuticals is barred from relitigating the same infringement claims; the license component suggests Carnegie may have obtained conditional rights to commercialise the product, though the specific terms remain undisclosed.
A 90-day resolution is notably rapid for pharmaceutical patent litigation, which typically extends one to three years through claim construction and trial. The speed of settlement suggests either parties reached a pragmatic commercial agreement quickly — possibly tied to a future generic launch date — or Carnegie faced a strong infringement position at the outset. The confidential nature of the settlement prevents confirmation of any royalty, market entry date, or licensing conditions from the public record.
Filing to Dismissed with Prejudice in 90 days
90 days — notably fast resolution for a pharmaceutical ANDA-type patent dispute
Dismissed with prejudice after confidential settlement: what this means for both parties
Rule 41 dismissal with prejudice after negotiated settlement
The dismissal was entered under Fed. R. Civ. P. 41(a)(1)(ii) and (c), which requires stipulation by all parties and court approval when counterclaims are pending. ‘With prejudice’ means the action is terminated on the merits — Salix and Bausch Health cannot re-file the same claims, and Carnegie cannot relitigate the infringement issues. A simultaneously executed Confidential Settlement and License Agreement governed the commercial resolution separate from the court order.
Rule 41(a)(1)(ii) + LicenseSalix/Bausch Health secures finality and likely licensing income
By resolving with prejudice, Salix and Bausch Health lock in a clean, final disposition — no residual litigation risk from this defendant on these two patents. The accompanying license agreement typically signals that the patent holder has extracted value: a royalty stream, a controlled generic market entry date, or both. The Colazal® IP position is reinforced rather than weakened, as the settlement does not constitute a validity concession.
Patent position preservedCarnegie obtains a license but forfeits future challenge rights
Carnegie Pharmaceuticals agreed to dismissal with prejudice, meaning it cannot re-open this specific infringement dispute. In exchange, the license agreement plausibly grants Carnegie a pathway to market — potentially including a defined launch date for its balsalazide disodium 750 mg product. The confidentiality of terms prevents public confirmation of any royalty rate or entry timeline. Dismissal with prejudice closes the door on any invalidity counterclaims Carnegie may have raised in this action.
License likely; re-litigation barredConfidential pharma settlements set precedent for generic entry timing
For the ulcerative colitis treatment market, the resolution suggests Salix and Bausch Health retain control over the Colazal® competitive landscape through negotiated licensing rather than courtroom adjudication. Other generic manufacturers targeting balsalazide disodium formulations should treat US7452872B2 and US7625884B2 as live enforcement risks — the speed of settlement may reflect the strength of the claim construction position, raising the bar for future challengers.
Colazal® IP remains enforceableFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Salix Pharmaceuticals, Inc. | Company | Pharmaceutical group (Salix/Bausch Health) — holder of US7452872B2 and US7625884B2Search in Eureka ↗ |
| Co-Plaintiff | Salix Pharmaceuticals, Ltd. | Company | Search in Eureka ↗ |
| Co-Plaintiff | Bausch Health Ireland, Ltd. | Company | Search in Eureka ↗ |
| Defendant | CARNEGIE PHARMACEUTICALS, LLC | Company | Carnegie Pharmaceuticals, LLC — generic pharmaceutical developerSearch in Eureka ↗ |
| Plaintiff counsel | Harvey Bartle , IV | Attorney | Counsel for Salix Pharmaceuticals, Inc.Search in Eureka ↗ |
| Plaintiff law firm | Morgan, Lewis & Bockius, LLP | Law Firm | Representing Salix Pharmaceuticals, Inc.Search in Eureka ↗ |
| Presiding judge | Judge N/A | Judge | New Jersey District CourtSearch in Eureka ↗ |
Official order — verbatim text
The stipulated dismissal language confirms that both the underlying infringement claims and Carnegie’s counterclaims — which would typically include patent invalidity and unenforceability defences — are terminated with prejudice. The reference to a Confidential Settlement and License Agreement distinguishes this from a pure walk-away: Carnegie received something of commercial value, and Salix/Bausch Health received finality. No merit-based ruling on infringement or patent validity was issued; the patents’ enforceability is therefore unchanged.
US7452872B2 & US7625884B2 — Balsalazide Disodium Formulation Patents
US7452872B2 (application 11/835897) and US7625884B2 (application 11/877589) are United States utility patents covering balsalazide disodium formulations — the active pharmaceutical ingredient in Colazal® 750 mg capsules, indicated for the treatment of mildly to moderately active ulcerative colitis. The patents protect specific formulation and composition parameters that distinguish Colazal® from generic balsalazide disodium alternatives, forming the core IP barrier to generic market entry for this product line.
For Salix Pharmaceuticals and its parent Bausch Health, these two patents represent a critical component of the Colazal® brand protection strategy. Colazal® is an established branded therapy in the inflammatory bowel disease (IBD) space, and maintaining patent exclusivity against ANDA filers is commercially significant. The filing of a rapid infringement action against Carnegie and the swift resolution with a confidential license is consistent with a well-resourced branded pharmaceutical company actively policing its IP portfolio to manage generic competition timing.
Should you run an FTO against US7452872B2 and US7625884B2?
Any company developing, manufacturing, or filing an ANDA for balsalazide disodium 750 mg capsules — or structurally similar formulations for ulcerative colitis — should treat these two patents as active enforcement risks. This case demonstrates that Salix and Bausch Health are willing to file suit rapidly and enforce these patents in the District of New Jersey. A Paragraph IV certification against either patent will almost certainly trigger a 30-month stay and a corresponding infringement action.
PatSnap Eureka’s FTO Search Agent can map the claim scope of US7452872B2 and US7625884B2 against your proposed balsalazide disodium formulation, identify prior art that was or was not considered during prosecution, and surface related continuation or divisional applications that may extend the patent family’s reach. Running this analysis before ANDA filing or formulation lock-in is essential to assess litigation exposure and inform design-around strategies.
Run a freedom-to-operate analysis on US7452872B2 to assess your product’s exposure
Run FTO in Eureka →Similar Hatch-Waxman balsalazide and IBD drug patent cases
Cases involving branded pharmaceutical patent enforcement against generic ANDA filers in the District of New Jersey, particularly in the IBD and gastrointestinal drug space.
What this case signals for the pharmaceutical patent IP landscape
A 90-day dismissal-with-prejudice outcome in a branded pharmaceutical infringement case carries distinct strategic signals for IP and commercial teams.
Speed of settlement suggests a strong initial infringement position
Pharmaceutical patent cases that settle within 90 days of filing — before any claim construction briefing — typically indicate either an unusually strong infringement read by the plaintiff, or a defendant unable to sustain the litigation cost. For Colazal®, both patents were asserted and a full license executed, consistent with Salix/Bausch Health holding a credible enforcement posture from day one.
Dismissal with prejudice extinguishes counterclaims — a key strategic win
When defendants assert invalidity counterclaims, a dismissal without prejudice would leave those claims alive. Here, dismissal with prejudice eliminates Carnegie’s invalidity arguments permanently. Competing generic manufacturers cannot benefit from any challenge Carnegie might have mounted, reinforcing the patents’ presumption of validity for any subsequent enforcement action against another filer.
Salix v CARNEGIE — key questions answered
Salix Pharmaceuticals and Bausch Health asserted two patents: US7452872B2 (application 11/835897) and US7625884B2 (application 11/877589). Both patents cover balsalazide disodium formulations underlying Colazal® 750 mg capsules, an ulcerative colitis treatment.
The case was resolved through a Confidential Settlement and License Agreement. Pursuant to Fed. R. Civ. P. 41(a)(1)(ii) and (c), all claims and counterclaims were dismissed with prejudice on 1 October 2024, approximately 90 days after filing. The specific financial or licensing terms are not publicly disclosed.
Dismissal with prejudice means Carnegie Pharmaceuticals is permanently barred from relitigating the infringement claims or invalidity counterclaims raised in this action. Carnegie cannot re-open these specific patent disputes. The simultaneously executed license agreement suggests Carnegie may have received conditional rights to market its balsalazide disodium product, though terms are confidential.
No. A negotiated settlement and dismissal with prejudice does not constitute a court finding on patent validity or invalidity. Both US7452872B2 and US7625884B2 survive the action with their presumption of validity intact. Other generic manufacturers cannot rely on any invalidity ruling from this case as there was none.
The District of New Jersey is the preferred venue for Hatch-Waxman pharmaceutical patent litigation and is home to many generic drug manufacturers and ANDA filings. Salix and Bausch Health — represented by Morgan, Lewis & Bockius LLP — selected D.N.J. consistent with standard practice for pharmaceutical infringement actions targeting generic capsule formulations of branded drugs such as Colazal®.
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