Alimta® (pemetrexed disodium)

Case Name: Eli Lilly & Co. v. Apotex, Inc., No. 2020-1328, 2020 WL 7490251 (Fed. Cir. Dec. 21, 2020) (Circuit Judges Prost, Bryson, and Stoll presiding; Opinion by Stoll, J.) (Appeal from S.D. Ind., Pratt, J.)

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

Nature of the Case and Issue(s) Presented: The ’209 patent described methods of administering an antifolate in combination with a methylmalonic acid-lowering agent. Antifolates blocked the function of certain enzymes in the folic acid pathway, thereby impeding the growth of cancer cells. The ’209 patent described a method of administering an antifolate—that reducd toxicity without adversely affecting the therapeutic effect—following pretreatment with a methylmalonic acid-lowering agent. The specification identified “Pemetrexed Disodium (ALIMTA)” as the “most preferred” antifolate.

During prosecution, the Examiner rejected under § 112 claims reciting “ALIMTA,” explaining that the use of a trade name rendered the claim indefinite and was improper under MPEP guidelines. In response, Lilly cancelled its claims reciting “ALIMTA” and instead prosecuted claims to pemetrexed disodium.

Both parties moved for summary judgment on the question of infringement under the doctrine of equivalents. In its decision granting judgment in favor of Lilly, the district court rejected the argument that Lilly’s amendment to replace “ALIMTA” with “pemetrexed disodium” was a narrowing amendment. As a result, prosecution history estoppel did not apply to bar Lilly from asserting infringement based on the doctrine of equivalents. Apotex appealed and the Federal Circuit affirmed.

Why Eli Lilly Prevailed: The intrinsic record supported the district court’s conclusion that Lilly did not make a narrowing amendment. The Federal Circuit noted that the patent application equated “ALIMTA” with “pemetrexed disodium.”More particularly, the specification twice referred to “pemetrexed disodium.” Both instances were made in association with ALIMTA. Further, the specification did not use “ALIMTA” to refer to pemetrexed alone or to any other salt form of pemetrexed. Thus, the intrinsic evidence supported the district court’s conclusion that “ALIMTA” was synonymous with “pemetrexed disodium.”

Apotex argued that the district court erred by concluding that ALIMTA meant only pemetrexed disodium. Specifically, Apotex argued that the Examiner concluded that “ALIMTA” had two possible meanings: “pemetrexed” and “pemetrexed disodium.” The Federal Circuit rejected this argument, finding that the Examiner rejected the claims reciting “ALIMTA” as indefinite because ALIMTA was a trade name and not because it covered multiple forms of pemetrexed.