Eli Lilly & Co. v. Dr. Reddy’s Labs., Ltd.

Plaintiff proved infringement of method-of-treatment claims under the doctrine of equivalents because in solution, the accused product and the claimed invention dissociate into the identical active ion that is responsible for the claimed treatment.

June 22, 2018

GENERICally Speaking: A Hatch Waxman Litigation Bulletin

Case Name: Eli Lilly & Co. v. Dr. Reddy’s Labs., Ltd., Civ. No. 16-0308-TWP-MPB, 2018 U.S. Dist. LEXIS 104653 (S.D. Ind. June 22, 2018) (Pratt, J.) 

Drug Product and Patent(s)-in-Suit: Alimta® (pemetrexed disodium); U.S. Patent No. 7,772,209 (“the ’209 patent”) 

Nature of Case and Issue(s) Presented: The ’209 patent described a method of administering a chemotherapy drug, pemetrexed disodium, with vitamins. Lilly asserted that Dr. Reddy’s (“DRL”) NDA drug product, which used pemetrexed ditromethamine, infringed the ’209 patent. DRL contended that its product was not a generic drug; rather, its product used a different chemical. Particularly at issue was claim 12, which the court had previously construed to refer to the liquid administration of pemetrexed disodium. Thus, the main issue at trial was whether, under the doctrine of equivalents, DRL’s pemetrexed ditromethamine product infringed the ’209, which claimed pemetrexed disodium. The court concluded that Lilly had proved infringement under the doctrine of equivalents based upon inducement and contributory infringement, and that DRL’s product would indirectly infringe the asserted claims.

Why Lilly Prevailed: First, DRL argued that Lilly could have drafted a better claim and limited its scope of protection when it claimed “pemetrexed disodium.” Lilly explained that its narrowed claim was written to overcome a rejection in view of Arsenyan, a prior-art article about a different antifolate, methotrexate. The court found that this rationale was tangential to the accused equivalent-pemetrexed ditromethamine and that Lilly had rebutted the presumption that prosecution history estoppel applied.

Next, DRL raised the Disclosure-Dedication Rule and its argument that the ’209 patent referenced U.S. Patent No. 4,997,838 to Akimoto—and that from Akimoto a POSA could find pemetrexed ditromethamine disclosed among the alternatives disclosed in Akimoto. But generic references in a written specification did not necessarily dedicate all members of a particular genus to the public. Lilly’s expert testified that Akimoto included pemetrexed and any “pharmaceutically acceptable salt thereof.” From this concession, DRL argued that tromethamine was included. Lilly responded that its expert also testified that Akimoto disclosed a genus of thousands of antifolates, and that tromethamine was not specifically disclosed in any referenced patent nor was the compound pemetrexed ditromethamine. The court decided that because Akimoto was not expressly incorporated, as required, in the ’209 patent, and in any event Akimoto did not specifically disclose pemetrexed ditromethamine as an alternative to pemetrexed disodium, the disclosure-dedication rule did not bar Lilly's doctrine of equivalents claim.

Having decided that Lilly may allege infringement under the doctrine of equivalents, the court found that a POSA in this case was an oncologist, not a chemist as proposed by DRL. The court also decided that because equivalence in this case was based on chemical properties, the “insubstantial differences” test was the more appropriate framework for evaluating equivalence. The ’209 patent inventor testified that his invention related to “using pre-treatment B12 and folic acid to mitigate the toxicity of pemetrexed when it wa given to a patient with cancer. Pemetrexed ditromethamine treated cancer patients in exactly the same way as pemetrexed disodium. When both were placed in solution, both compounds dissociated completely—resulting in free pemetrexed and therapeutically irrelevant counterions. In fact, in aqueous solution, the two products were identical. The differences in the chemical properties between pemetrexed disodium and pemetrexed ditromethamine with regards to solubility, stability, pH, and buffering capacity were irrelevant in the context of the claimed method. Lilly did not dispute that there were differences when the products were in solid form. Instead, Lilly argued that the differences were insubstantial, and the court agreed. What was ultimately injected into the patient was pemetrexed ions, and that active moiety was the same in Lilly’s product and DRL’s product.

Finally, the court addressed inducement and contributory infringement. DRL argued that Lilly could not prove DRL specifically intended to infringe because specific intent requires proof that DRL knew the acts were infringing. But, the court found, that DRL ignored the fact that specific intent could be inferred from an accused product’ labeling. Because of the above infringement finding, DRL could not avoid intent or infringement on the basis that it possessed a “good faith belief that its proposed product would not infringe.”

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