Nippon Shinyaku.,Ltd. vs. Sarepta Therapeutics, Inc., et al

Case Background

On July 13, 2021, Plaintiff  Nippon Shinyaku Co., Ltd. filed a Patent Infringement lawsuit in the United States District Court, District of Delaware (Case number: 1:21cv1015). Judge Jennifer L. Hall presided over this case.

Cause

Nippon Shinyaku is a renowned pharmaceutical company from Japan. It initiated a patent infringement lawsuit against Sarepta Therapeutics, Inc., a Delaware-based corporation. The lawsuit accuses Sarepta of breaching contract and violating multiple patents. These patents are related to Nippon Shinyaku’s groundbreaking exon-skipping therapies designed to treat Duchenne Muscular Dystrophy (DMD). The dispute began after Sarepta filed seven Inter Partes Review (IPR) petitions with the Patent Trial and Appeal Board (PTAB).

Sarepta sought to invalidate Nippon Shinyaku’s patents. Nippon Shinyaku had invested significant resources into developing VILTEPSO® (viltolarsen). VILTEPSO® is a therapy approved by the U.S. Food and Drug Administration (FDA). It is designed to increase dystrophin levels in DMD patients. Sarepta’s product, VYONDYS 53, used similar antisense oligomer technology targeting exon 53. Nippon Shinyaku alleged that VYONDYS 53 infringed its patents. These actions created substantial conflict, damaging Nippon Shinyaku’s exclusive rights to its innovative exon-skipping therapies in the field of Duchenne Muscular Dystrophy treatment.

Injuries

Nippon Shinyaku sustained significant harm due to Sarepta’s alleged misconduct. Sarepta’s actions undermined Nippon Shinyaku’s patent protections. This threatened Nippon Shinyaku’s ability to control the market for exon-skipping therapies, particularly for Duchenne Muscular Dystrophy treatment. The developments disrupted the company’s investments in researching and developing VILTEPSO®. VILTEPSO® is a product aimed at improving the quality of life for DMD patients. Additionally, Nippon Shinyaku experienced reputational damage within the pharmaceutical industry. The public perception of its innovative exon-skipping therapies became entangled in a legal battle over patent rights.

Damages

Nippon Shinyaku sought compensatory damages exceeding $75,000 to recover losses resulting from Sarepta’s alleged breach of contract and patent infringement lawsuit. The company argued that Sarepta’s actions directly impacted its commercial interests and threatened its market position in treating Duchenne Muscular Dystrophy with exon-skipping therapies. Nippon Shinyaku also requested treble damages, asserting that Sarepta’s infringement was willful and deliberate. Further, Nippon Shinyaku sought reimbursement for legal expenses incurred while opposing the IPR petitions and defending its intellectual property before the PTAB.

Key Arguments and Proceedings

Legal representation

  • Plaintiff(s): Nippon Shinyaku Co., Ltd.
    • Counsel for Plaintiff: Amy Michele Dudash | Guylaine Hache | Alison P. Patitucci  | Amanda S. Williamson | Christopher J. Betti | David L. Schrader | Eric Kraeutler | Jason C. White | Jitsuro Morishita | Julie S. Goldemberg | Krista Vink Venegas | Maria E. Doukas | Michael T. Sikora | Wan-Shon Lo | Zachary D. Miller
  • Defendant(s): Sarepta Therapeutics, Inc., A Delaware Corporation | The University of Western Australia
    • Counsel for Defendants: Alissa K. Lipton | Amanda P. Reeves | Anna Rathbun | Bornali R. Borah | David P. Frazier | Ernest Yakob | Graham Haviland | Jack B. Blumenfeld | Jesse Aaron Vella | Megan Elizabeth Dellinger | Michael A. Morin | Michele D. Johnson | Rebecca L. Rabenstein | Ryan P. O’Quinn | William B. Raich | Yoonjin Lee

Claims

Nippon Shinyaku asserted multiple legal claims against Sarepta. First, the company sought a declaratory judgment to establish that it had not infringed Sarepta’s UWA patents and to declare those patents invalid. Second, Nippon Shinyaku alleged that Sarepta infringed its NS patents by manufacturing, selling, and promoting VYONDYS 53. Nippon Shinyaku emphasized that Sarepta’s actions violated the terms of a mutual confidentiality agreement, constituting a breach of contract. By filing the IPR petitions, Sarepta had allegedly acted in bad faith, further exacerbating the harm to Nippon Shinyaku’s business interests and intellectual property rights.

Defense

Sarepta Therapeutics, Inc. argued that it did not breach the Mutual Confidentiality Agreement (MCA) with Nippon Shinyaku Co., Ltd., as its actions were consistent with its contractual obligations. Further, Sarepta emphasized its right to file Inter Partes Review (IPR) petitions to challenge the validity of Nippon Shinyaku’s patents, asserting these filings were lawful under U.S. patent laws. They claimed Nippon Shinyaku misinterpreted the MCA’s terms and asserted that its patents were either invalid or unenforceable due to non-compliance with patent laws, including novelty, non-obviousness, and written description requirements.

Furthermore, Sarepta contended that it did not infringe Nippon Shinyaku’s patents, either literally or under the doctrine of equivalents. Sarepta highlighted that its product, Vyondys 53, utilized independently developed antisense oligonucleotide technology and was lawfully approved and marketed. The defense also invoked equitable doctrines, including unclean hands, accusing Nippon Shinyaku of bad-faith actions and repeated breaches of the MCA, which Sarepta argued precluded Nippon Shinyaku from claiming equitable relief.

Finally, Sarepta denied that Nippon Shinyaku suffered any damages or irreparable harm, stating that the Plaintiff lacked evidence of willful infringement or entitlement to injunctive relief. Sarepta sought dismissal of all claims, emphasizing the invalidity of Nippon Shinyaku’s allegations under patent and contract law.

Jury Verdict

On December 20, 2024, the jury delivered a verdict in the patent infringement lawsuit between Nippon Shinyaku and Sarepta Therapeutics, awarding $115,222,850 in lost profits damages to Sarepta and the University of Western Australia (UWA) for U.S. sales. The jury concluded that Sarepta and UWA had established their entitlement to these damages by a preponderance of the evidence.

Court Documents:

Documents are available for purchase upon request at jurimatic@exlitem.com