Issue 05/5 | February 10, 2005
Merck's Fosamax® Patent Held Invalid by a Panel Divided Over the Definition of "About"

Highlighting the factions of the court on issues argued this week in Phillips, the federal circuit held invalid claims from Merck's dosing patent on its blockbuster FOSAMAX®, based on the patentee's failure to clearly define the claim term "about." Applicants using claim terms such as "about" should redouble their efforts to ensure that a proper definition, consonant with the scope of their invention, is clearly set forth in the specification.

In Merck & Co., Inc. v. Teva Pharmaceuticals, USA, Inc., No. 04-1005 (Fed. Cir. Jan. 28, 2005), the federal circuit held Claims 23 and 37 of Merck's '329 dosing patent invalid as obvious based on an erroneous claim construction.

Merck's '329 patent claims a once-weekly dosing regimen of "about 70 mg of alendronate monosodium trihydrate on an alendronic acid basis." A separate claim was directed to the use of a 35mg dose. The district court construed the term "about" in accordance with the specification to mean "the equivalent of 70/35 mg of alendronic acid when taking into account molecular weight variances for its derivatives that carry accessories," and dismissed Teva's argument that the claims were anticipated by a July 1996 prior art reference or rendered obvious in view of a combination of the July 1996 reference and an April 1996 reference.

On appeal, the federal circuit found the patentees had not clearly established the meaning of "about 70/35 mg" in the specification, and therefore, resort to the ordinary meaning -- here approximately -- was appropriate. Under the modified claim construction, the federal circuit found that the differences between the claimed inventions and the 1996 prior art articles would have been obvious, based on e.g., the prior art teachings of 80 mg and 40 mg dosing once weekly rather than the claimed 70 mg and 35 mg. The federal circuit also found clear error in the district court's decision to give the two 1996 references little probative weight, as well as its failure to ascertain the required motivation to combine the references to achieve the claimed invention.

In a scathing dissent, Judge Rader disagreed that the patentees had failed to clearly establish the meaning of the full phrase, citing language in the specification to the effect "that the phrase . . .means that the amount of the biphosphonate compound selected is based on 70 mg of alendronic acid." The use of such language, in combination with setting off the phrase from the rest of the sentence in quotes "unmistakably notif[ied] a reader of the patent that the patentee exercised the option to define the entire phrase without respect to its ordinary meaning as understood by one of ordinary skill in the art." In addition, Judge Rader criticized the majority for "paying only lip-service to the . . . basic jurisprudential principle according trial courts proper deference," concluding that the majority had a "truth in advertising problem."

To view the full decision visit

To discuss these topics further, please feel free to contact the author Michael R. Dzwonczyk, (mdzwonczyk@sughrue.com), at Sughrue Mion, PLLC in Washington DC, USA.

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