Eisai Obtains Favorable Decision in Patent Infringement Litigation Related to Lenvatinib in the U.S.

Eisai Co., Ltd. (“the Company”) announced today that the Company received a favorable decision on May 28, 2025 regarding the lawsuit filed in the U.S. District Court for the District of New Jersey (“the Court”) in November 2019 against generic drug manufacturer Shilpa Medicare Limited (“Shilpa”), which submitted an Abbreviated New Drug Application (“ANDA”) for a generic version of Lenvima, for infringement of U.S. Patent No. 11,186,547 ("the ‘547 Patent"). The ‘547 Patent relates to Lenvima® (generic name: lenvatinib mesylate), an orally available multiple receptor tyrosine kinase inhibitor discovered by the Company. As a result of this decision, Shilpa now is not able to receive approval from the U.S. Food and Drug Administration (“FDA”) to sell its generic version of lenvatinib mesylate until after the ’547 Patent and related exclusivity expires in February 2036.¹

The ‘547 Patent is directed to highly pure lenvatinib mesylate as found in the Company’s Lenvima product. The Court’s decision upheld the validity of the ‘547 Patent. This is a major step forward in maximizing the value of Lenvima for patients based on the intellectual property of the Company.

The Company settled a prior patent infringement lawsuit against SUN Pharmaceutical Industries Ltd. and SUN Pharmaceutical Industries Inc. (collectively “SUN Pharma”) for their ANDA submission. Under the settlement agreement, SUN Pharma will be permitted to launch its generic lenvatinib product in the United States as of July 1, 2030, unless certain defined contingencies occur earlier than that date; other terms of the settlement agreement are confidential. The Company also commenced patent infringement lawsuits against two other generic producers (Dr. Reddy’s Laboratories and Torrent) for their ANDA submissions in 2024.

Sales revenue of Lenvima in the U.S. for the fiscal year ended March 31, 2025 was 229.6 billion yen (US$1,505 million). The judgment should not have any impact on the consolidated financial forecasts for the fiscal year ending March 31, 2026.

¹Shilpa can appeal this decision to U.S. Court of Appeals for the Federal Circuit.

^*Please note that actual business results may change due to several factors since the above-mentioned forecasts were made based on information available as of today.