Background
Merck & Co. owned a patent (U.S. Patent No. 5,994,329) covering a method of treating and preventing osteoporosis through once-weekly administration of alendronate monosodium trihydrate — the active ingredient in Merck’s blockbuster drug Fosamax. Alendronate is a bisphosphonate compound that inhibits bone resorption, and Merck had originally marketed it as a daily treatment. The once-weekly formulation was developed to improve patient compliance (taking a pill once a week versus daily) and to reduce the gastrointestinal side effects associated with more frequent dosing. The patent claimed administration of “about 70 mg” once weekly.
Teva Pharmaceuticals filed an abbreviated new drug application (ANDA) seeking FDA approval to market generic 35 mg and 70 mg once-weekly alendronate tablets. Teva certified that Merck’s patent was invalid for obviousness, pointing to two 1996 articles published in a newsletter called Lunar News that had discussed and advocated for once-weekly dosing of alendronate as a way to improve compliance and reduce side effects. The district court upheld the patent’s validity, finding that the prior art articles were insufficient to establish obviousness and that the term “about” in the dosage claims had been redefined by the patentee to mean “exactly.” Teva appealed.
The Court’s Holding
The Federal Circuit reversed in an opinion by Judge Gajarsa, finding the asserted patent claims invalid for obviousness and incorrectly construed.
On claim construction, the court rejected Merck’s argument that the specification had redefined “about” to mean “exactly” through statements about molecular weight calculations. The lexicographer doctrine requires that a patentee’s redefinition of a term be “clear and unambiguous” — and ambiguous specification language does not suffice. Because the specification’s statements about molecular weight could be read either as a mathematical explanation or as a true redefinition, the language was ambiguous and insufficient to override “about”‘s ordinary meaning of “approximately.”
On obviousness, the court found that the Lunar News articles — despite not being peer-reviewed publications and being written by an author without formal pharmacology credentials — clearly taught once-weekly dosing of alendronate and provided motivation to use that dosing regimen. The district court had improperly discounted the prior art based on the author’s credentials and the newsletter’s lack of peer review; what matters is what the prior art teaches, not the prestige of its source. The prior art taught exactly what was claimed: once-weekly dosing of alendronate for osteoporosis treatment.
On commercial success as a secondary consideration of non-obviousness, the court gave it reduced weight because Merck’s own patent on the daily alendronate formulation had prevented competitors from testing once-weekly dosing during the relevant period. When commercial exclusivity blocks others from independently pursuing an idea, evidence that the patent holder successfully commercialized it carries less probative value on whether the idea was obvious to skilled practitioners.
Key Takeaways
- The lexicographer doctrine allows patent owners to redefine claim terms only when the specification contains a clear and unambiguous redefinition — ambiguous specification language that could support multiple readings cannot override the ordinary meaning of a claim term.
- Prior art does not need to be peer-reviewed or authored by credentialed experts to establish obviousness — what matters is whether the prior art teaches the claimed combination, not the prestige or format of its source.
- Commercial success as a secondary consideration of non-obviousness carries reduced probative weight when the patent owner’s existing patents prevented competitors from independently pursuing the same concept — the commercial exclusivity, not the innovation, may explain the commercial success.
- In pharmaceutical ANDA litigation, claims for new dosing regimens of known drugs face particular scrutiny for obviousness when prior art in the relevant field already suggests or advocates the same dosing approach.
- Dosage optimization — adjusting frequency or amounts of administration of a known drug — is generally not inventive unless the resulting dosing regimen produces unexpected therapeutic advantages not taught or suggested by the prior art.
Why It Matters
Merck v. Teva on the Fosamax once-weekly patent is an important decision at the intersection of pharmaceutical patent law, the obviousness doctrine, and claim construction. It illustrates how prior art in newsletters, industry publications, and non-peer-reviewed sources can defeat patent validity when the art clearly discloses the claimed concept — the format of the prior art reference matters less than its content.
The commercial success analysis is particularly notable. In pharmaceutical patent litigation, brand companies frequently invoke commercial success of a branded drug as evidence that the invention was not obvious — arguing that if it had been obvious, competitors would have developed it first. The Merck decision appropriately limits this argument in cases where the brand company’s own prior patents prevented competitors from testing the concept. If the marketplace evidence of non-obviousness is confounded by legal barriers to competition, secondary considerations lose much of their force. The decision provides a useful framework for challenging secondary considerations arguments in ANDA patent litigation. Judge Rader’s dissent, which argued that the majority had overridden the district court’s careful factual analysis without sufficient basis, previews the ongoing tension between deference to trial court findings and de novo claim construction review at the Federal Circuit.