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Infringement Decision on Fosamax® Drug Patent Upheld

October 30, 2003

Decision icon Decision

Last Month at the Federal Circuit - November 2003

Judges: Newman (author), Prost, and Mayer (dissenting)

In Merck & Co. v. Teva Pharmaceuticals U.S.A., Inc., No. 03-1168 (Fed. Cir. Oct. 30, 2003), the Federal Circuit affirmed the district court’s judgment that Teva Pharmaceuticals, U.S.A., Inc. et al. (collectively “Teva”) infringe U.S. Patent No. 4,621,077 (“the ‘077 patent”) and that the ‘077 patent was not invalid.

Merck & Company, Inc. (“Merck”) owns the ‘077 patent, which claims a method of treatment consisting of administering to a patient an effective amount of a drug product marketed as Fosamax®. Teva filed an ANDA for a generic version of the drug, stating that it did not literally infringe the ‘077 patent because the claim specifies an acid, while Teva’s ANDA describes a salt that is actually used in practice. Alternatively, Teva argued that Merck was not entitled to any patent-term extension because the FDA approved the salt but not the acid.

On appeal, the infringement issue turned on the proper construction of the claim, specifically, whether the claimed acid could include salts. The Federal Circuit found that throughout the specification of the ‘077 patent, the inventors had described the acid-active agent as encompassing the acid and its salt forms. The Court also noted evidence supporting Merck’s position that those skilled in the art used the same lexicography as did the inventors when referring to the acid in the form of the salt. The Court concluded that persons in this field would understand that the acid is the active agent and that the acid is administered when it is in the form of the salt. The Federal Circuit rejected the contrary testimony by Teva’s expert, who conceded that while he was an expert in chemistry, he was not an expert in pharmacology. The other pharmacology experts in the case agreed that the acid is customarily administered as the acid salt.

The Federal Circuit also rejected Teva’s allegation that patent-term restoration, granted for an extended regulatory-review period of Fosamax®, was invalid because the FDA had only approved the salt for use. The Court found that the relevant statutory scheme defined “product” to include “any salt or ester of the active ingredient.”

Teva also asserted an invalidity defense based on an allegation that the ‘077 patent was anticipated by a prior art patent (“the Blum patent”). Blum claimed the acid in question and stated that it could be used for water softening and as a sequestering agent, and was suitable for use in cosmetic and pharmaceutical preparations. Teva contended that because Blum specifically mentioned pharmaceutical preparations, one of ordinary skill in the art would realize that the claimed compound would be useful for therapeutic purposes, as is claimed in the ‘077 patent. The Federal Circuit rejected Teva’s argument, however, finding that Blum’s disclosure was not sufficient to anticipate the ‘077 patent method claims because there was no suggestion of the claimed therapeutic use.

Judge Mayer dissented, and while he joined the Court in upholding the validity of the ‘077 patent, he found that a plain reading of the specification of the ‘077 patent sufficiently distinguished between acid and salt forms of the claimed drug. Therefore, he reasoned that the district court had erred in its claim construction by concluding that the term “acid” should be construed as encompassing both acids and salts. Also, because in Judge Mayer’s view the ‘077 patent did not claim a product (the salt) that was subject to regulatory review, patent-term extension was likewise inappropriate.