CMP Development v. Amneal Pharmaceuticals: Defendant Wins on the Merits After 908 Days
CMP Development, LLC sued Amneal Pharmaceuticals over five U.S. patents covering CaroSpir®, a spironolactone oral suspension (25 mg/5 mL). After 908 days of litigation in the Delaware District Court, Judge Noreika entered judgment for Amneal, finding that the ANDA No. 215572 products would not infringe any of the six asserted claims across the five patents.
Five Spironolactone Patents, One ANDA: How Amneal Prevailed on the Merits
CMP Development, LLC filed this Hatch-Waxman infringement action on April 16, 2021, in the U.S. District Court for the District of Delaware before Judge Maryellen Noreika. The suit concerned five U.S. patents — US10624906, US10660907, US10888570, US9757394, and US10493083 — all relating to CaroSpir®, CMP's branded spironolactone oral suspension formulated at 25 mg/5 mL. CMP alleged that Amneal's ANDA No. 215572, seeking FDA approval for a generic equivalent, would infringe claims across those patents.
Following a Memorandum Opinion issued on September 29, 2023 (D.I. 123), Judge Noreika entered a final judgment on October 11, 2023 in favor of Amneal. The court found that the products described in ANDA No. 215572 would not infringe claims 1 and 8 of US10624906, claims 1 and 10 of US10660907, and claims 1 and 7–10 of US10888570. The basis of termination is recorded as judgment on the merits for the defendant. The specific reasoning and claim-construction conclusions are contained in the Memorandum Opinion; the specific terms of the judgment beyond the non-infringement findings are not further disclosed in the available record.
The case ran for approximately 908 days — a duration consistent with Hatch-Waxman litigation that proceeds through full merits adjudication rather than early settlement. A defendant win on the merits in an ANDA non-infringement action suggests the patent claims were construed or applied in a way that did not encompass the generic formulation. What drove that outcome — whether claim construction, formulation differences, or both — is set out in the Memorandum Opinion but not restated here. The disposition clears a potential 30-month stay obstacle for Amneal's ANDA, though the regulatory and commercial timeline remains subject to FDA action.
See Complete Case & Patent Analysis →Filing to Judgment on the merits for Defendant in 908 days
908 days from filing to judgment — longer than the median Hatch-Waxman ANDA case in Delaware
US10624906, US10660907 & US10888570 — Spironolactone Oral Suspension Formulations
Any company developing or commercialising a spironolactone oral suspension — particularly at a 25 mg/5 mL concentration — should assess freedom to operate against the five patents asserted in this case. While the court found Amneal's specific ANDA formulation non-infringing, the patents remain in force. A different formulation approach, different excipient ratios, or a different concentration could present a distinct infringement risk profile. Paediatric oral suspension developers, compounding pharmacy formulators, and generic manufacturers outside Amneal's specific ANDA should not assume this judgment protects their own products.
Official order — verbatim text
The October 11, 2023 judgment order is expressly grounded in the September 29, 2023 Memorandum Opinion (D.I. 123), making it a merits-based, reasoned adjudication rather than a default or procedural ruling. The order names specific claim sets — claims 1 and 8 of US10624906, claims 1 and 10 of US10660907, and claims 1 and 7–10 of US10888570 — providing Amneal with targeted non-infringement coverage for its ANDA product. The specificity of the claim enumeration suggests the court conducted a full claim-by-claim analysis, though the underlying reasoning is contained in the Memorandum Opinion rather than the order itself.
Judgment for defendant: what the merits ruling means for both parties
Merits judgment: court finds no infringement on all asserted claims
A judgment on the merits for the defendant in a Hatch-Waxman case means the court fully adjudicated the non-infringement question and ruled in the generic's favour. It is not a procedural dismissal. Judge Noreika's October 11, 2023 order, grounded in the September 29 Memorandum Opinion, is a binding judicial determination that Amneal's ANDA No. 215572 products do not infringe the asserted claims. The 30-month stay tied to this litigation is extinguished by the judgment.
Non-infringement on all six claim setsCMP Development loses exclusivity argument for CaroSpir® formulation
CMP Development's bid to block Amneal's generic entry via five asserted patents failed on the merits. The court's finding that none of the asserted claims are infringed removes the litigation-based barrier to Amneal's ANDA approval. CMP retains ownership of the patents, but this judgment significantly weakens their ability to use these specific claims to exclude this particular ANDA product. Whether CMP pursues appeal is not disclosed in the available record.
ANDA barrier removedAmneal clears patent litigation hurdle for spironolactone oral suspension ANDA
A defendant win on the merits removes the court-imposed obstacle to FDA approval of ANDA No. 215572. Amneal can now pursue final FDA approval for its spironolactone 25 mg/5 mL oral suspension without the litigation stay holding it back. The judgment is a complete non-infringement ruling across all six claim sets asserted at trial, providing Amneal with a strong legal foundation for market entry. Regulatory timing remains subject to FDA's own review process.
Path to generic market entry openedNon-infringement ruling intensifies generic competition for CaroSpir® market
CaroSpir® is the only FDA-approved branded spironolactone oral suspension at 25 mg/5 mL — a formulation used particularly in paediatric and dysphagia patient populations. A merits judgment clearing Amneal's ANDA signals that the five-patent estate around this formulation could not withstand a non-infringement challenge. Other potential ANDA filers in this space will note the outcome. Branded price premiums tied to patent exclusivity in this niche oral suspension market face increased pressure as a result.
Generic spironolactone suspension competition likelyFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | CMP Development, LLC | Company | /Search in Eureka ↗ |
| Defendant | Amneal Pharmaceuticals, Inc. | Company | /Search in Eureka ↗ |
| Plaintiff counsel | Andrew O. Larsen | Attorney | Counsel for CMP Development, LLCSearch in Eureka ↗ |
| Plaintiff counsel | Christopher J. Sorenson | Attorney | Counsel for CMP Development, LLCSearch in Eureka ↗ |
| Plaintiff counsel | Karen L. Beckman | Attorney | Counsel for CMP Development, LLCSearch in Eureka ↗ |
| Plaintiff counsel | Kelly E. Farnan | Attorney | Counsel for CMP Development, LLCSearch in Eureka ↗ |
| Plaintiff counsel | Paige S. Stradley | Attorney | Counsel for CMP Development, LLCSearch in Eureka ↗ |
| Plaintiff counsel | Renee Mosley Delcollo | Attorney | Counsel for CMP Development, LLCSearch in Eureka ↗ |
| Plaintiff counsel | Tyler E. Cragg | Attorney | Counsel for CMP Development, LLCSearch in Eureka ↗ |
| Plaintiff law firm | Greenberg Traurig PA | Law Firm | Representing CMP Development, LLCSearch in Eureka ↗ |
| Plaintiff law firm | Richards, Layton & Finger, PA | Law Firm | Representing CMP Development, LLCSearch in Eureka ↗ |
| Defendant counsel | Anne Shea Gaza | Attorney | Counsel for Amneal Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant counsel | Dave Deonarine | Attorney | Counsel for Amneal Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant counsel | Giancarlo Scaccia | Attorney | Counsel for Amneal Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant counsel | Jeremy J. Edwards | Attorney | Counsel for Amneal Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant counsel | Jonathan D. Ball | Attorney | Counsel for Amneal Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant counsel | Jonathan R. Wise | Attorney | Counsel for Amneal Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant counsel | Kaveh V. Saba | Attorney | Counsel for Amneal Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant counsel | Lianlian Wu | Attorney | Counsel for Amneal Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant counsel | Samantha G. Wilson | Attorney | Counsel for Amneal Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant counsel | Scott J. Bornstein | Attorney | Counsel for Amneal Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant counsel | Steven A. Maddox | Attorney | Counsel for Amneal Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant counsel | Victor Sai | Attorney | Counsel for Amneal Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant law firm | Young Conaway Stargatt & Taylor, LLP | Law Firm | Representing Amneal Pharmaceuticals, Inc.Search in Eureka ↗ |
| Presiding judge | Judge Maryellen Noreika | Judge | Delaware District CourtSearch in Eureka ↗ |
R&D signals in the spironolactone oral suspension IP space
Forward-looking patent and innovation intelligence for teams working in oral suspension formulations, aldosterone antagonists, and paediatric liquid dosage forms — derived from this CMP v. Amneal litigation.
CMP Development's spironolactone patent family: depth and gaps
CMP Development assembled at least five granted U.S. patents around CaroSpir®'s 25 mg/5 mL oral suspension formulation. Analysing the application number lineage (US15/337559 through US16/878092) suggests a continuation filing strategy. Understanding the claim differentiation across these related patents — and what subject matter remains unclaimed — reveals white space for competitors developing alternative spironolactone suspension formulations.
Continuation family analysisFiling trends in paediatric oral suspension aldosterone antagonist formulations
Spironolactone oral suspension sits at the intersection of paediatric cardiology and formulation science. Patent filing activity in liquid aldosterone antagonist dosage forms — covering suspension stabilisers, taste-masking, and bioavailability enhancement — has grown alongside FDA's paediatric formulation initiatives. Monitoring this filing space helps R&D teams identify where innovation is concentrating and where design-around opportunity exists relative to the CaroSpir® patent cluster.
Paediatric liquid formulation trendsAmneal's pharmaceutical formulation patent activity beyond this ANDA
Amneal Pharmaceuticals is primarily a generic manufacturer, but generic companies increasingly file their own patents on formulation innovations, manufacturing processes, and excipient combinations. Examining Amneal's own patent portfolio in the oral liquid and suspension space can signal whether the company is developing proprietary formulation IP that could eventually compete with branded oral suspension developers beyond this ANDA context.
Generic pharma proprietary IPAdjacent oral suspension formulation IP: what the CaroSpir® claims leave open
The court's non-infringement finding suggests the CaroSpir® claims have limits that a differently engineered suspension can avoid. That boundary, once understood through claim construction, defines a design-around corridor. R&D teams exploring novel spironolactone suspension formulations — alternative suspension agents, modified release profiles, or co-formulations with other diuretics — may find meaningful white space adjacent to the CMP patent estate.
Formulation white spaceSimilar Hatch-Waxman oral suspension patent cases in Delaware District Court
Explore comparable ANDA infringement actions involving oral suspension formulation patents litigated in the Delaware District Court before Judge Noreika and peers.
What this case signals for the pharmaceutical oral suspension IP landscape
A five-patent estate failed to block a single ANDA on the merits — a meaningful data point for Hatch-Waxman strategy in formulation-focused drug patents.
Formulation patent estates may not deter well-resourced ANDA challengers
CMP asserted five patents covering CaroSpir®'s oral suspension formulation and still lost on the merits. For branded pharmaceutical IP strategies, stacking formulation patents is not a guaranteed barrier when a generic can engineer around the claimed characteristics. Early FTO analysis is critical before an ANDA is filed.
Hatch-Waxman defendants are increasingly willing to litigate to merits judgment
This case ran 908 days to a full merits ruling — no early settlement or consent judgment. Amneal deployed 12 legal representatives to defend, consistent with a high-conviction, merits-first strategy. Patent holders in oral suspension and paediatric formulation spaces should expect well-funded ANDA defendants to press to judgment rather than settle.
CMP v Amneal — key questions answered
Judgment was entered for defendant Amneal Pharmaceuticals on October 11, 2023. The Delaware District Court found that the products described in Amneal's ANDA No. 215572 do not infringe claims 1 and 8 of US10624906, claims 1 and 10 of US10660907, or claims 1 and 7–10 of US10888570. The basis of termination is recorded as judgment on the merits for the defendant.
Five patents were identified in the litigation record: US10888570, US9757394, US10493083, US10660907, and US10624906. The October 11, 2023 judgment order specifically addresses US10624906, US10660907, and US10888570. US9757394 and US10493083 are listed in the patent involvement record but are not named in the final judgment order; the available record does not explain their disposition.
CaroSpir® is an oral suspension of spironolactone at 25 mg/5 mL — the only FDA-approved branded spironolactone oral suspension, used particularly in paediatric and dysphagia patient populations. Under the Hatch-Waxman Act, Amneal's ANDA No. 215572 seeking generic approval triggered CMP's infringement suit, which is the standard mechanism for resolving patent disputes before generic market entry.
A merits judgment for the defendant means the court fully adjudicated the non-infringement question and ruled in the generic manufacturer's favour — it is not a procedural or consent dismissal. In the Hatch-Waxman context, such a judgment removes the patent-based barrier to FDA approval of the ANDA, extinguishing any remaining 30-month litigation stay tied to this case. The patents themselves remain in force but cannot be used to block this specific ANDA product.
CMP Development was represented by Greenberg Traurig PA and Richards, Layton & Finger, PA, with attorneys including Kelly E. Farnan, Andrew O. Larsen, and Christopher J. Sorenson. Amneal was represented by Young Conaway Stargatt & Taylor, LLP and additional counsel including Scott J. Bornstein, Jonathan D. Ball, and Anne Shea Gaza, among a team of 12 listed representatives.
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