DCT

2:25-cv-17100

Genentech Inc v. Natco Pharma Ltd

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Key Events
Complaint

I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 2:25-cv-17100, D.N.J., 10/31/2025
  • Venue Allegations: Venue is alleged to be proper in the District of New Jersey because Defendant Zydus Pharmaceuticals (USA) Inc. is incorporated and has an established place of business in New Jersey, and the foreign defendants are subject to personal jurisdiction in the district.
  • Core Dispute: Plaintiffs allege that Defendants' submission of Abbreviated New Drug Applications (ANDAs) to market generic versions of the spinal muscular atrophy drug EVRYSDI® (risdiplam) infringes a patent covering specific weight-based methods of treatment.
  • Technical Context: The technology concerns a specific oral dosing regimen for risdiplam, a small-molecule splicing modifier, intended to treat spinal muscular atrophy (SMA), a serious neurodegenerative disease.
  • Key Procedural History: This action was initiated under the Hatch-Waxman Act following Plaintiffs' receipt of Paragraph IV notice letters from Defendants, which asserted that the patent-in-suit is invalid, unenforceable, or will not be infringed by their proposed generic products.

Case Timeline

Date Event
2017-10-03 ’273 Patent Priority Date
2024-10-21 Zydus Notice Letter Received
2025-07-08 ’273 Patent Issue Date
2025-09-17 Natco Notice Letter Received
2025-10-31 Complaint Filing Date

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

U.S. Patent No. 12,350,273 - “Treatment of SMA”

The Invention Explained

  • Problem Addressed: The patent describes spinal muscular atrophy (SMA) as a severe neurodegenerative disorder for which there was no approved oral treatment that could provide stabilization or improvement of motor function, representing a significant unmet medical need for a convenient and effective therapy (’273 Patent, col. 2:36-47).
  • The Patented Solution: The invention claims specific methods of administering risdiplam (identified as the compound of formula (I)) using a dual-regimen, weight-based dosing scheme. Based on clinical trial results, the patent discloses that administering a 0.25 mg/kg daily dose to patients weighing less than 20 kg and a fixed 5 mg daily dose to patients weighing 20 kg or more was surprisingly found to be an optimum dosage for increasing functional protein levels (’273 Patent, col. 2:60-col. 3:5).
  • Technical Importance: This dosing regimen identified a therapeutic window that provides clinical benefit while avoiding toxicities, such as retinal degeneration, that were found to be associated with higher exposures to the drug (’273 Patent, col. 3:7-12).

Key Claims at a Glance

  • The complaint asserts independent claims 1 and 8 (Compl. ¶¶ 65, 75).
  • Claim 1 elements include:
    • A method of treating spinal muscular atrophy (SMA) in a human patient in need thereof
    • comprising administering to the patient a pharmaceutical composition comprising a compound of formula (I)
    • at a once daily oral dose of 5 mg
    • wherein the patient has a body weight of more than or equal to 20 kg
  • Claim 8 elements include:
    • A method of treating spinal muscular atrophy (SMA) in a human patient in need thereof
    • comprising administering to the patient a pharmaceutical composition comprising a compound of formula (I)
    • at a once daily oral dose of 0.25 mg/kg
    • wherein the patient has a body weight of less than 20 kg

III. The Accused Instrumentality

Product Identification

  • The accused instrumentalities are the proposed generic risdiplam products for oral solution described in Natco’s ANDA No. 219848 and Zydus’s ANDA No. 219902 (Compl. ¶1).

Functionality and Market Context

  • The proposed products are generic versions of Plaintiffs' EVRYSDI®, an SMN2 splicing modifier indicated for the treatment of SMA (Compl. ¶¶ 36, 42, 51). The complaint alleges that, pursuant to FDA regulations, the proposed product labeling for the generic versions will essentially copy the EVRYSDI® label (Compl. ¶¶ 66, 76). This label instructs physicians and patients to administer the drug according to a specific dosing regimen determined by the patient's age and body weight, as detailed in a dosing table included in the complaint. The dosing table from the EVRYSDI® label specifies a 5 mg daily dose for patients weighing 20 kg or more and a 0.25 mg/kg daily dose for patients two years of age or older weighing less than 20 kg (Compl. ¶40, Table 1). The ANDA products are intended to be bioequivalent to and compete directly with EVRYSDI®, which is identified as the first and only orally administered therapy for SMA (Compl. ¶¶ 1, 43).

IV. Analysis of Infringement Allegations

12,350,273 Patent 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 human patient in need thereof, comprising administering to the patient a pharmaceutical composition comprising a compound of formula (I) The proposed generic products contain risdiplam (the compound of formula (I)) and their labels will instruct administration for the treatment of SMA in human patients. ¶¶ 36, 38, 66 col. 2:21-25
at a once daily oral dose of 5 mg, The proposed generic product labels will instruct a once-daily oral dose of 5 mg for a specific patient population. ¶¶ 40, 66 col. 2:60-col. 3:5
wherein the patient has a body weight of more than or equal to 20 kg. The proposed labels will instruct that the 5 mg daily dose is for patients 2 years of age and older weighing 20 kg or more. ¶¶ 40, 66 col. 2:60-col. 3:5
Claim Element (from Independent Claim 8) Alleged Infringing Functionality Complaint Citation Patent Citation
A method of treating spinal muscular atrophy (SMA) in a human patient in need thereof, comprising administering to the patient a pharmaceutical composition comprising a compound of formula (I) The proposed generic products contain risdiplam (the compound of formula (I)) and their labels will instruct administration for the treatment of SMA in human patients. ¶¶ 36, 38, 76 col. 2:21-25
at a once daily oral dose of 0.25 mg/kg, The proposed generic product labels will instruct a once-daily oral dose of 0.25 mg/kg for a specific patient population. ¶¶ 40, 76 col. 2:60-col. 3:5
wherein the patient has a body weight of less than 20 kg. The proposed labels will instruct that the 0.25 mg/kg daily dose is for patients 2 years of age or older weighing less than 20 kg. ¶¶ 40, 76 col. 2:60-col. 3:5
  • Identified Points of Contention:
    • Scope Questions: The asserted claims are for methods of treatment. Direct infringement would be committed by healthcare providers and patients who follow the administration instructions. The primary question for Defendants' liability will be whether the act of filing an ANDA with a proposed label that mirrors the innovator drug's label demonstrates the requisite intent to induce infringement by others.
    • Technical Questions: The complaint alleges that the proposed generic labels will "essentially copy" the EVRYSDI® label (Compl. ¶¶ 66, 76). A factual question will be whether the final, FDA-approved label for the generic products contains instructions that fall within the scope of the claimed methods.

V. Key Claim Terms for Construction

  • The Term: "a method of treating spinal muscular atrophy (SMA)"
  • Context and Importance: This term defines the fundamental purpose of the claimed method. Its construction is important because Defendants may argue that their product label does not explicitly instruct or guarantee "treatment," or that the term should be limited to the specific clinical outcomes described in the patent, potentially creating a non-infringement argument.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification provides a detailed and expansive definition of "treating spinal muscular atrophy," including effects such as "reduction or amelioration of the severity of SMA," "delay of the onset of SMA," "inhibition of the progression of SMA," and "increase of the survival of a subject" (’273 Patent, col. 5:46-53). This language may support a broad construction covering any administration that provides a benefit to an SMA patient.
    • Evidence for a Narrower Interpretation: The specification prominently features the results of the "BP39055" clinical study, which found a "median SMN protein increase of 151%" at the 5 mg dose level (’273 Patent, col. 2:60-64). A party could argue that this disclosure implicitly defines "treating" as achieving a specific, quantifiable biological outcome, potentially narrowing the claim's scope to methods that produce a similar effect.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges that Defendants will induce infringement by creating and distributing a product label that instructs and encourages physicians and patients to administer the generic drug according to the patented weight-based dosing method (Compl. ¶¶ 66, 76). The complaint also pleads contributory infringement, alleging the generic products are not staple articles of commerce and have no substantial non-infringing uses (Compl. ¶¶ 67, 77).
  • Willful Infringement: The complaint does not contain a specific count or explicit allegation of willful infringement.

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

  • A central legal issue will be one of inducement: does the act of submitting an ANDA with a proposed label that necessarily instructs users to perform a patented method of treatment, as required by FDA regulations, constitute sufficient proof of specific intent to encourage infringement?
  • A core validity question will likely be one of obviousness: given the state of the art at the time of the invention, was it obvious to select the specific dual-regimen of a fixed 5 mg dose for patients weighing ≥20 kg and a 0.25 mg/kg weight-based dose for patients weighing <20 kg to safely and effectively treat SMA with risdiplam?