Genentech Inc v. Zenara Pharma Pvt Ltd

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiffs: Genentech, Inc. (Delaware); Hoffmann-La Roche Inc. (New Jersey); PTC Therapeutics, Inc. (Delaware)
  • Defendants: Zenara Pharma Private Limited (India); Biophore Pharma Inc. (New Jersey); Biophore India Pharmaceuticals Private Limited (India)
  • Plaintiff's Counsel: Robinson Miller LLC
• Case Identification: 2:26-cv-06555, D.N.J., 06/04/2026
• Venue Allegations: Venue is alleged to be proper in the District of New Jersey because Defendant Biophore Pharma Inc. is incorporated in and has a regular and established place of business in New Jersey, and because the foreign defendants are subject to personal jurisdiction in the United States and may be sued in any judicial district.
• Core Dispute: Plaintiffs allege that Defendants' Abbreviated New Drug Application (ANDA) to market a generic version of the spinal muscular atrophy drug EVRYSDI® (risdiplam) infringes six U.S. patents covering the risdiplam compound, its specific crystalline form, and methods of its use.
• Technical Context: The technology concerns risdiplam, the active ingredient in EVRYSDI®, which is the first approved oral therapy for treating spinal muscular atrophy (SMA), a rare and serious genetic neurodegenerative disease.
• Key Procedural History: This action was filed under the Hatch-Waxman Act following Plaintiffs' receipt of a Paragraph IV certification notice letter from Defendants. The complaint notes that a related Indian patent, which shares priority with two of the asserted U.S. patents, was the subject of litigation in India where a defendant entity was prohibited from manufacturing or selling risdiplam.

Case Timeline

Date	Event
2012-02-10	Priority Date for '955 Patent
2014-05-15	Priority Date for '754 Patent and '646 Patent
2017-03-07	'955 Patent Issued
2017-10-03	Priority Date for '444 Patent and '273 Patent
2018-05-15	'754 Patent Issued
2018-10-19	Priority Date for '789 Patent
2020-02-01	EVRYSDI® (powder for oral solution) initially approved by FDA
2022-12-27	'444 Patent Issued
2023-11-28	'646 Patent Issued
2024-10-22	'789 Patent Issued
2025-02-11	EVRYSDI® (tablets) approved by FDA
2025-07-08	'273 Patent Issued
2026-04-23	Date of Zenara Notice Letter
2026-06-04	Complaint Filing Date

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 9,586,955 - "Compounds for Treating Spinal Muscular Atrophy"

• Patent Identification: U.S. Patent No. 9,586,955, "Compounds for Treating Spinal Muscular Atrophy," issued March 7, 2017 Compl. ¶¶56-57

The Invention Explained

• Problem Addressed: The patents-in-suit address spinal muscular atrophy (SMA), a neurodegenerative disease characterized by the loss of motor neurons, leading to progressive muscle weakness and paralysis US 11,534,444 B2, col. 1:26-34 At the time of the invention, there was no approved oral treatment for SMA US 11,534,444 B2, col. 2:31-33
• The Patented Solution: The '955 Patent claims a class (genus) of chemical compounds having a pyridopyrimidinone core structure Compl. ¶59 These compounds are designed as small-molecule splicing modifiers that act on the survival of motor neuron 2 (SMN2) gene to produce more functional SMN protein, thereby compensating for the genetic defect in SMA patients Compl. ¶38 US 11,534,444 B2, col. 1:26-34 The patent defines the scope of the invention through a Markush structure with several variable substituent groups (R1, R2, Ra, Rb, etc.) Compl. ¶59
• Technical Importance: The invention provided a foundational chemical scaffold for developing orally-administered small-molecule drugs for SMA, a field which previously relied on supportive care or was exploring more complex biological therapies US 11,534,444 B2, col. 2:31-45

Key Claims at a Glance

• The complaint asserts independent claim 1 and dependent claim 11 Compl. ¶87
• Independent Claim 1 claims:
  • A compound of Formula (IIa1) or a form thereof, comprising a pyridopyrimidinone core.
  • Wherein R1 is a heterocyclyl group with specified optional substitutions.
  • Wherein R2 is a heteroaryl group with specified optional substitutions.
  • Wherein Ra, Rb, and Rc are selected from specified chemical groups (e.g., hydrogen, halogen, alkyl).
  • Wherein R3, R4, R5, R6, and R7 are further specified substituent groups on the R1 and R2 moieties.
• The complaint notes that Defendants did not contest infringement of claims 1-4, 6-8, 11, and 20 in their notice letter Compl. ¶87

U.S. Patent No. 11,534,444 - "Treatment of SMA"

• Patent Identification: U.S. Patent No. 11,534,444, "Treatment of SMA," issued December 27, 2022 Compl. ¶66

The Invention Explained

• Problem Addressed: The patent addresses the need for a safe and effective oral treatment for SMA, noting that at the time of invention, no such approved oral therapy existed that could stabilize or improve motor function '444 Patent, col. 2:31-33 It also acknowledges the need for dosing that accounts for different patient populations, including those with different body weights '444 Patent, col. 3:1-5
• The Patented Solution: The '444 Patent claims a specific method for treating SMA by orally administering the compound risdiplam (identified by its chemical name) using a two-tiered, body-weight-based dosing regimen '444 Patent, abstract '444 Patent, claim 1 The patent specifies a dose of 0.25 mg/kg for subjects weighing less than 20 kg and a fixed dose of 5 mg for subjects weighing 20 kg or more '444 Patent, col. 16:3-12 This dosing was found to be optimal based on clinical trial data '444 Patent, col. 2:60-65
• Technical Importance: This patent protects a specific, clinically validated dosing regimen, moving beyond the mere composition of matter to how the drug is safely and effectively used in practice across different patient populations, a critical aspect for securing market exclusivity for a final drug product.

Key Claims at a Glance

• The complaint asserts at least claim 9, which depends on independent claim 1 Compl. ¶103
• Independent Claim 1 claims:
  • A method of treating SMA in a subject in need thereof.
  • Comprising administering the compound 7-(4,7-diazaspiro[2.5]octan-7-yl)-2-(2,8-dimethylimidazo[1,2-b]pyridazin-6-yl)pyrido[1,2-a]pyrimidin-4-one (risdiplam) or a salt thereof.
  • Wherein the administered dose is 0.25 mg/kg for a subject with a body weight of less than 20 kg.
  • And wherein the administered dose is 5 mg for a subject with a body weight of more than or equal to 20 kg.
• Dependent claim 9 further specifies that the 5 mg dose is administered orally to a subject with a body weight of more than or equal to 20 kg '444 Patent, claim 9 The complaint notes that Defendants did not contest infringement of claim 9 in their notice letter Compl. ¶103

Multi-Patent Capsules

• Patent Identification: U.S. Patent No. 9,969,754, "Compounds for Treating Spinal Muscular Atrophy," issued May 15, 2018 Compl. ¶62

  • Technology Synopsis: The patent claims chemical compounds with a pyridopyrimidinone core structure Compl. ¶64 Specifically, claim 36 recites the compound risdiplam by its chemical name, 7-(4,7-diazaspiro[2.5]octan-7-yl)-2-(2,8-dimethylimidazo[1,2-b]pyridazine-6-yl)pyrido[1,2-a]pyrimidin-4-one Compl. ¶64 These compounds are intended for the treatment of SMA.
  • Asserted Claims: At least claim 36 Compl. ¶95
  • Accused Features: The Zenara ANDA Product is accused of infringing because it contains risdiplam Compl. ¶95

• Patent Identification: U.S. Patent No. 11,827,646, "Compounds for Treating Spinal Muscular Atrophy," issued November 28, 2023 Compl. ¶71

  • Technology Synopsis: The patent claims methods for treating SMA in a human by administering a therapeutically effective amount of the compound risdiplam, which is identified by its chemical structure in the claims Compl. ¶73 The invention covers the general method of using risdiplam to treat SMA.
  • Asserted Claims: At least claims 1 and 11 Compl. ¶113
  • Accused Features: The Zenara ANDA Product, a generic version of risdiplam, and its proposed label instructing the treatment of SMA, are accused of infringement Compl. ¶¶113-114

• Patent Identification: U.S. Patent No. 12,122,789, "Forms of Pyrido[1,2-a]pyrimidin-4-one Derivatives, Its Formulation and Its Process of Making," issued October 22, 2024 Compl. ¶76

  • Technology Synopsis: The patent claims specific solid-state forms of risdiplam '789 Patent, abstract Claim 1 specifically covers "crystalline Form A," which is defined by a set of characteristic peaks in an X-ray powder diffraction (XRPD) pattern Compl. ¶78 The patent also claims pharmaceutical compositions and kits containing this specific solid form Compl. ¶¶79-80
  • Asserted Claims: At least claims 1 and 9 Compl. ¶123
  • Accused Features: The Zenara ANDA Product is alleged to comprise the claimed crystalline Form A of risdiplam and to be a pharmaceutical composition containing that form Compl. ¶123

• Patent Identification: U.S. Patent No. 12,350,273, "Treatment of SMA," issued July 8, 2025 Compl. ¶82

  • Technology Synopsis: The patent claims a method of treating SMA in a human patient by administering a pharmaceutical composition containing risdiplam at a specific dose '273 Patent, abstract Claim 1 specifies a once-daily oral dose of 5 mg for patients with a body weight of more than or equal to 20 kg Compl. ¶84
  • Asserted Claims: At least claim 1 Compl. ¶132
  • Accused Features: The Zenara ANDA Product and its proposed label are accused of infringement because the label will instruct physicians to administer the product at the claimed 5 mg dose for patients weighing 20 kg or more Compl. ¶¶132-133

III. The Accused Instrumentality

Product Identification

• The accused instrumentality is the "Zenara ANDA Product," identified as ANDA No. 221422, which seeks approval to market a generic version of EVRYSDI® (risdiplam) tablets Compl. ¶1 Compl. ¶46

Functionality and Market Context

• The Zenara ANDA Product is a pharmaceutical tablet containing the active ingredient risdiplam Compl. ¶41 Compl. ¶46 It is intended for oral administration for the treatment of spinal muscular atrophy (SMA) Compl. ¶1 Compl. ¶46 The complaint alleges that the product's application relies on the EVRYSDI® NDA and contains data demonstrating bioequivalence Compl. ¶47
• The complaint includes a dosage and administration table from the EVRYSDI® label, which Plaintiffs allege the Zenara ANDA product will essentially copy Compl. ¶43 Compl. ¶104 This table, which represents probative visual evidence, specifies dosing based on patient age and weight, including a 5 mg tablet for patients 2 years of age and older weighing 20 kg or more Compl. ¶43
• Plaintiffs allege that Defendants intend to market and sell the generic product nationwide, displacing sales of the brand-name EVRYSDI® tablets Compl. ¶15 Compl. ¶17

IV. Analysis of Infringement Allegations

U.S. Patent No. 9,586,955 Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
A compound of Formula (IIa1): ... or a form thereof, wherein:	The complaint alleges the Zenara ANDA Product contains risdiplam, which is a compound of Formula (IIa1).	¶87	col. 60:60-62
R1 is heterocyclyl; wherein, heterocyclyl is optionally substituted...	The Zenara ANDA Product contains risdiplam, which has a 4,7-diazaspiro[2.5]octan-7-yl moiety at the R1 position, alleged to be a "heterocyclyl".	¶87	col. 15:1-16:51
R2 is heteroaryl; wherein, heteroaryl is optionally substituted...	The Zenara ANDA Product contains risdiplam, which has a 2,8-dimethylimidazo[1,2-b]pyridazine-6-yl moiety at the R2 position, alleged to be a "heteroaryl".	¶87	col. 16:52-17:21
Ra is, in each instance, independently selected from hydrogen, halogen or C1-8alkyl;	In risdiplam, the substituent corresponding to Ra is hydrogen, which is permitted by the claim.	¶87	col. 15:53-54
Rb is hydrogen, halogen, C1-8alkyl or C1-8alkoxy;	In risdiplam, the substituent corresponding to Rb is hydrogen, which is permitted by the claim.	¶87	col. 15:55-56
Rc is hydrogen, halogen or C1-8alkyl;	In risdiplam, the substituent corresponding to Rc is hydrogen, which is permitted by the claim.	¶87	col. 15:57-58

U.S. Patent No. 11,534,444 Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
A method of treating spinal muscular atrophy (SMA) in a subject in need thereof	The proposed label for the Zenara ANDA Product will allegedly instruct its use for the treatment of SMA, copying the indication of the EVRYSDI® label.	¶103; ¶104	col. 5:45-47
comprising administering to said subject 7-(4,7-diazaspiro[2.5]octan-7-yl)-2-(2,8-dimethylimidazo[1,2-b]pyridazin-6-yl)pyrido[1,2-a]pyrimidin-4-one or a pharmaceutically acceptable salt thereof	The Zenara ANDA Product contains risdiplam, which is the specified compound.	¶41; ¶103	col. 16:5-9
wherein the administered dose ... is a. 0.25 mg/kg for a subject with a body weight of less than 20 kg	The proposed label for the Zenara ANDA Product will allegedly instruct a dose of 0.25 mg/kg for patients weighing less than 20 kg, based on the EVRYSDI® label.	¶43; ¶104	col. 16:10-11
and b. 5 mg for a subject with a body weight of more than or equal to 20 kg.	The proposed label for the Zenara ANDA Product will allegedly instruct a dose of 5 mg for patients weighing 20 kg or more, consistent with the EVRYSDI® label for the 5 mg tablet.	¶43; ¶104	col. 16:11-12

• Identified Points of Contention:
  • Scope and Validity Questions ('955 Patent): A potential issue is whether the specific compound risdiplam is unambiguously covered by the asserted claims of the '955 Patent. However, the complaint alleges that Defendants have not contested infringement of the key compound claims in their Paragraph IV notice letter Compl. ¶87, which may suggest that the primary dispute for this patent will concern validity (e.g., obviousness or anticipation) rather than infringement.
  • Obviousness and Carve-out Questions ('444 Patent): For the method-of-use '444 Patent, infringement will likely turn on whether the Defendants' proposed label induces infringement by instructing the claimed dosing regimen. The complaint alleges the label "essentially copies" the EVRYSDI® label, suggesting infringement Compl. ¶104 This raises the question of whether Defendants will attempt a "carve-out" of the patented method under 21 U.S.C. § 355(j)(2)(A)(viii). The central dispute, however, will likely be the validity of the claims, focusing on whether the specific weight-based dosing regimen would have been obvious to a person of ordinary skill in the art based on prior knowledge of risdiplam.

V. Key Claim Terms for Construction

For U.S. Patent No. 9,586,955:

• The Term: "heterocyclyl" (from claim 1)
• Context and Importance: The definition of "heterocyclyl" is critical because the infringement allegation hinges on the accused molecule, risdiplam, falling within the scope of claim 1. Specifically, the court must determine if the "4,7-diazaspiro[2.5]octan-7-yl" group on risdiplam is a "heterocyclyl" as defined by the patent. Practitioners may focus on this term because its construction will determine literal infringement of the core compound claim.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The patent specification may provide a broad definition of "heterocyclyl" that lists numerous examples of saturated, unsaturated, monocyclic, and bicyclic ring systems containing N, O, or S, which could support including the spirocyclic structure of the accused compound US 9,586,955 B2, col. 249:36-64
  • Evidence for a Narrower Interpretation: Defendants may argue that the specific "4,7-diazaspiro[2.5]octan-7-yl" structure is not explicitly listed among the patent's examples of heterocyclyls. They may point to the disclosed embodiments to argue for a narrower construction that excludes this specific spiro-fused ring system, suggesting it was not contemplated by the inventors US 9,586,955 B2, col. 249:36-64

For U.S. Patent No. 11,534,444:

• The Term: "a subject with a body weight of more than or equal to 20 kg" (from claim 1)
• Context and Importance: While seemingly straightforward, the construction of this term is central to the method-of-use claim. The infringement case relies on the allegation that the generic drug's label will instruct administration to this precise patient population. Any ambiguity in how "body weight" is determined or applied could be a point of contention, though the primary challenge to this limitation is more likely to be validity (obviousness) rather than construction.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation (Plain Meaning): Plaintiffs will likely argue that the term should be given its plain and ordinary meaning, as it is a standard clinical parameter without any special definition provided in the patent. The specification's description of the clinical study may simply refer to patient weight without further qualification '444 Patent, col. 2:60-65, supporting a plain meaning approach.
  • Evidence for a Narrower Interpretation: The complaint does not provide sufficient detail for analysis of evidence supporting a narrower interpretation. A defendant might argue that the term must be interpreted in the specific context of the clinical trial data from which it was derived, potentially limiting its scope to the exact patient population and measurement methods used in that study, though this is a less common litigation strategy for such a term.

VI. Other Allegations

• Indirect Infringement: The complaint alleges induced infringement for the method of use patents ('444, '646, and '273 Patents), stating that the Zenara ANDA product's label will "essentially copy" the EVRYSDI® label and therefore will instruct, recommend, and encourage physicians and patients to perform the patented methods of treatment Compl. ¶104 Compl. ¶114 Compl. ¶133 The complaint also pleads contributory infringement, alleging that the Zenara ANDA Product is not a staple article of commerce and has no substantial non-infringing uses Compl. ¶105 Compl. ¶115 Compl. ¶134
• Willful Infringement: While the complaint does not contain an explicit count for willful infringement, it lays the groundwork for such a claim. Plaintiffs allege that Defendants "were aware of the" asserted patents when they submitted the ANDA and that their invalidity assertions are "devoid of a good faith basis" Compl. ¶92 Compl. ¶100 Compl. ¶110 Compl. ¶120 Compl. ¶129 Compl. ¶139 These allegations of pre-suit knowledge and litigation misconduct could support a later motion for enhanced damages under 35 U.S.C. § 284 or a finding of an exceptional case under § 285.

VII. Analyst's Conclusion: Key Questions for the Case

• A central issue for the compound and method-of-use patents ('955, '754, '444, '646, '273) will be one of validity: can Defendants prove by clear and convincing evidence that the claimed inventions-the risdiplam compound and its specific, weight-based dosing regimens for SMA-were anticipated or rendered obvious by the prior art at the time of invention?
• A key evidentiary question for the polymorph patent ('789) will be one of technical identity: what will the parties' competing analytical data (e.g., XRPD) show regarding whether the crystalline form of risdiplam in the Zenara ANDA Product is the same as the patented "crystalline Form A"?
• A dispositive legal and factual question for the method-of-use patents ('444, '646, '273) will be one of induced infringement: will the final, FDA-approved label for the Zenara ANDA Product contain instructions that direct users to perform the patented methods, and if so, can Defendants successfully "carve out" those instructions to avoid liability?