Summary: The legal action initiated on August 8, 2023, involves two parties: Par Pharmaceutical, Inc. and Epic Par Innovation Company, LLC (jointly referred to as "Par"), the plaintiffs, and Zydus Pharmaceuticals (USA) Inc. and Zydus Lifesciences Ltd. (jointly referred to as "Zydus"), the defendants. The dispute centers around an alleged patent infringement related to U.S. Patent No. 11,717,524, owned by Par. This patent details the process for creating purified varenicline, a medication used to treat nicotine addiction. Par contends that Zydus violated their patent rights by introducing their product to the market after receiving notification of the patent's approval. The case also implicates Zydus Lifesciences, an international corporation, in the production and sale of varenicline tartrate. Pfizer, the original manufacturer of this medication, had previously withdrawn it from the market due to the presence of high levels of a nitrosamine impurity, which is linked to an increased risk of cancer. Par, however, successfully produced varenicline tablets with minimal levels of nitrosamine impurities, leading to the FDA's approval of their Abbreviated New Drug Application (ANDA) for varenicline tartrate products. Despite Par's efforts to inform Zydus of their patented technologies, Zydus proceeded with their ANDA and announced the launch of their tablets. Par is currently pursuing legal action against Zydus for patent infringement, seeking both preliminary and permanent injunctive relief to halt further infringement. They are also seeking a judgment that Zydus has infringed and will continue to infringe the patent through the sale of its varenicline tablets. The case is currently being adjudicated in the United States District Court for the District of Delaware.