DCT
1:25-cv-00500
Onyx Therap Inc v. Somerset Therap LLC
Key Events
Complaint
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Onyx Therapeutics, Inc. (Delaware)
- Defendant: Somerset Therapeutics, LLC (Delaware)
- Plaintiff’s Counsel: Morris, Nichols, Arsht & Tunnell LLP
- Case Identification: 1:25-cv-00500, D. Del., 05/01/2025
- Venue Allegations: Plaintiff alleges venue is proper in the District of Delaware because Defendant is a Delaware corporation and, on information and belief, manufactures and sells generic drugs within the district.
- Core Dispute: Plaintiff alleges that Defendant’s proposed generic carfilzomib drug product, for which it filed an Abbreviated New Drug Application (ANDA), infringes a patent covering a pharmaceutical composition for enzyme inhibition.
- Technical Context: The technology relates to formulations that improve the aqueous solubility of proteasome inhibitors—a class of drugs used in cancer therapy, particularly for multiple myeloma—by combining them with a cyclodextrin excipient.
- Key Procedural History: The complaint notes that in prior litigation (C.A. No. 1:16-cv-00988), the U.S. District Court for the District of Delaware found Claim 31 of the patent-in-suit not invalid following a bench trial, a decision the U.S. Court of Appeals for the Federal Circuit affirmed.
Case Timeline
| Date | Event |
|---|---|
| 2004-12-07 | U.S. Patent No. 7,737,112 Priority Date |
| 2010-06-15 | U.S. Patent No. 7,737,112 Issues |
| 2012-07-20 | FDA grants accelerated approval for Plaintiff's KYPROLIS® product |
| 2019-05-XX | Bench trial commences in prior litigation involving the '112 Patent |
| 2020-05-04 | D. Del. issues opinion finding Claim 31 of the '112 Patent not invalid |
| 2021-03-08 | Federal Circuit affirms the D. Del. decision |
| 2025-03-11 | Defendant sends Notice Letter regarding its ANDA filing |
| 2025-05-01 | Complaint for patent infringement filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 7,737,112 - "Composition For Enzyme Inhibition"
The Invention Explained
- Problem Addressed: The patent's background section describes that certain potent proteasome inhibitors, specifically peptide epoxy ketones, have "low aqueous solubility," which makes it "difficult to formulate compositions with optimal bioavailability" for therapeutic use (Compl. Ex. A, ’971 Patent, col. 1:23-27).
- The Patented Solution: The invention claims to solve this problem by formulating the proteasome inhibitor with a cyclodextrin, particularly a substituted beta-cyclodextrin like sulfobutylether beta-cyclodextrin (SBECD), which "significantly enhanced" the inhibitor's solubility (Compl. Ex. A, ’971 Patent, col. 2:32-36). The patent also discloses that selecting an appropriate pH via a buffer is important to balance solubility, which is higher at lower pH, against chemical stability, which is lower at lower pH, as illustrated in Figures 1 and 2 of the patent (Compl. Ex. A, ’971 Patent, col. 2:19-24, 37-44).
- Technical Importance: This formulation technology enables the practical delivery of a class of otherwise difficult-to-administer therapeutic compounds for treating conditions like cancer (Compl. Ex. A, ’971 Patent, col. 1:15-18).
Key Claims at a Glance
- The complaint asserts infringement of claims 1-9, 14, 18-24, and 29-31, with Claim 1 being the lead independent claim (Compl. ¶34).
- The essential elements of independent Claim 1 are:
- A pharmaceutical composition comprising a practically insoluble peptide epoxy ketone proteasome inhibitor or a pharmaceutically acceptable salt thereof; and
- a substituted cyclodextrin selected from hydroxypropyl beta-cyclodextrin and sulfobutyl ether beta-cyclodextrin (SBECD).
- The complaint does not explicitly reserve the right to assert dependent claims, but the assertion of specific dependent claims (e.g., claims 2-9) implies this.
III. The Accused Instrumentality
Product Identification
- Defendant’s proposed generic drug product that is the subject of Abbreviated New Drug Application (ANDA) No. 220194 ("Proposed ANDA Product") (Compl. ¶3).
Functionality and Market Context
- The Proposed ANDA Product is a generic version of Plaintiff’s KYPROLIS® (carfilzomib) for injection, a treatment for relapsed or refractory multiple myeloma (Compl. ¶¶5, 10).
- The complaint alleges the product is a lyophilized powder for intravenous use that contains the active ingredient carfilzomib, which is a proteasome inhibitor, along with sulfobutylether beta-cyclodextrin (SBECD) and citric acid (Compl. ¶¶13, 34).
- The product is intended to be reconstituted before injection, and its proposed label will allegedly include instructions for administration that substantially copy those for KYPROLIS® (Compl. ¶30). No probative visual evidence provided in complaint.
IV. Analysis of Infringement Allegations
’112 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A pharmaceutical composition comprising a practically insoluble peptide epoxy ketone proteasome inhibitor or a pharmaceutically acceptable salt thereof | The Proposed ANDA Product is alleged to be a pharmaceutical composition that contains carfilzomib. Carfilzomib is identified in the complaint as a proteasome inhibitor, and the patent's background describes this class of compounds as having low aqueous solubility, making them difficult to formulate. | ¶34, ¶14 | col. 1:23-27 |
| and a substituted cyclodextrin selected from hydroxypropyl beta-cyclodextrin and sulfobutyl ether beta-cyclodextrin (SBECD). | The Proposed ANDA Product is alleged to contain sulfobutyl ether beta-cyclodextrin (SBECD). | ¶34 | col. 3:6-10 |
- Identified Points of Contention:
- Validity Questions: The complaint notes that Defendant's ANDA filing included a Paragraph IV Certification alleging that the '112 Patent is "invalid, unenforceable, and/or will not be infringed" (Compl. ¶20). A primary point of contention will likely be the validity of the asserted claims, especially concerning any prior art or arguments not addressed in the prior litigation that upheld Claim 31.
- Scope Questions: The infringement analysis for Claim 1 appears straightforward based on the complaint's allegations. However, a potential dispute may arise over the claim term "practically insoluble." The litigation could raise the question of whether the specific carfilzomib active pharmaceutical ingredient used in Defendant's product meets the definition of "practically insoluble" as understood in the patent.
V. Key Claim Terms for Construction
- The Term: "practically insoluble"
- Context and Importance: This term defines the type of proteasome inhibitor to which the claimed formulation applies. Its construction is critical because if Defendant can demonstrate that its active ingredient is not "practically insoluble," it may avoid infringement. Practitioners may focus on this term because its definition could be a dispositive issue for infringement.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The patent's background section frames the problem in general terms, referring to the "low aqueous solubility of some of these compounds," which could support a qualitative interpretation rather than a strict numerical limit (Compl. Ex. A, ’971 Patent, col. 1:23-25).
- Evidence for a Narrower Interpretation: The "Definitions" section of the specification provides a specific quantitative range, stating the term "refers to proteasome inhibitors that generally have a solubility of less than 0.1 mg/mL in water" and also encompasses solubilities of "less than 0.05 mg/mL and even less than 0.01 mg/mL" (Compl. Ex. A, ’971 Patent, col. 31:34-38). This explicit definition may be cited to support a narrower, more constrained meaning.
VI. Other Allegations
- Indirect Infringement: The complaint alleges induced infringement, stating that Defendant’s proposed product label will instruct healthcare providers on how to reconstitute and administer the product in a manner that allegedly infringes the ’112 Patent (Compl. ¶¶30, 31). It also alleges contributory infringement by asserting the Proposed ANDA Product will have no substantial non-infringing use (Compl. ¶32).
- Willful Infringement: The complaint alleges that Defendant had knowledge of the ’112 Patent when it filed its ANDA, as shown by its Paragraph IV certification (Compl. ¶39). It further alleges Defendant "lacked a good-faith basis" for its invalidity allegations, forming the basis for a claim of willfulness and for the case to be deemed "exceptional" under 35 U.S.C. § 285 (Compl. ¶43).
VII. Analyst’s Conclusion: Key Questions for the Case
- A central issue will be one of validity: in light of the prior Federal Circuit decision affirming the validity of Claim 31, can Defendant introduce new evidence or arguments sufficient to invalidate the asserted claims of the ’112 Patent, which are directed to a pharmaceutical composition?
- A key question for infringement will be one of definitional scope: does the term "practically insoluble," which is given a specific numerical range in the patent's specification, cover Defendant's carfilzomib formulation as described in its ANDA, or can Defendant argue its product falls outside this definition?