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U.S. Patent No. 4,513,006 is listed in the Orange Book as protecting Topamax (topiramate), Ortho-McNeil's (NYSE:JNJ) blockbuster anticonvulsant for the treatment of migraines and epilepsy. Mylan (NASDAQ:MYL) and Cobalt seek to market generic versions of Topamax before the '006 patent expires in September. Last year, a district court construed the claims of the '006 patent and, on summary judgment, rejected Mylan's inequitable conduct, obviousness, and non-enablement arguments. On Monday, the Federal Circuit affirmed (pdf file) those decisions.

Claim 1 of the '066 patent is drafted in a form typical of chemical compound claims. Specifically, it is directed to a

sulfamate of formula (NYSE:I) . . . wherein . . . R2, R3, R4 and R5 are independently hydrogen or lower alkyl and R2 and R3 and/or R4 and R5 together may be a group of formula (II)...
Mylan argued that the district court improperly construed the term "and" to mean "or" and, under the proper construction, the claim does not cover topiramate. The Federal Circuit disagreed, reasoning, among other things, that,
and appears in conjunction with the adverbs independently and together . . . [signaling] that and links alternatives that occur under the different conditions of independence or togetherness.

With respect to invalidity, the district court decision, released in February 2007 (before KSR), relied fairly heavily on the "teaching-suggestion-motivation" ("TSM") test to find the claims of the '066 patent invalid as obvious. Accordingly, one might think this decision would be ripe for reversal. Nevertheless, the Federal Circuit affirmed the decision, noting that "a flexible TSM test remains the primary guarantor against a non-statutory hindsight analysis such as occurred in this case."

According to the court's opinion, Ortho-McNeil scientist Dr. Bruce Maryanoff invented topiramate during a search for new antidiabetic drugs, when he "unexpectedly" . . . discovered that the compound had "powerful anticonvulsant properties." In support of its obviousness position, Mylan argued "that a person of ordinary skill in the art faced with finding a diabetes drug (as Dr. Maryanoff was) would necessarily design an FBPase inhibitor." The Federal Circuit found, however, that "even if an ordinarly skilled artisan sought an FBPase inhibitor, that person would not have chosen topiramate." According to the court,

Mylan's expert, Dr. Anderson, simply retraced the path of the inventor with hindsight, discounted the number and complexity of the alternatives, and concluded that the invention of topiramate was obvious.

The Federal Circuit also affirmed the district court's conclusion of no inequitable conduct, finding that Ortho-McNeil did not misrepresent certain prior art references to the patent office, as Mylan argued, but instead "accurately characterize[d] the references." In addition, the court affirmed the district court's conclusion that the '066 patent is not invalid for lack of enablement, finding that the claim term "anticonvulsively effective amount" is not unclear and its determination would not require undue experimentation.

In a separate decision (pdf file), released concurrently, the Federal Circuit affirmed the district court's decision against Cobalt, another ANDA filer for generic Topamax, who stipulated that it would be bound by the district court's decision in the litigation against Mylan. Cobalt retained its rights to appeal to the Federal Circuit, but stipulated that such an appeal would be based on the record in the Mylan case. Accordingly, the Federal Circuit rejected Cobalt's "indefiniteness" argument, raised in its appeal brief, because it was not presented to the district court.

RELATED READING:

  • Reuters article
  • Source: Court Affirms Decision Protecting Ortho-McNeil's Topamax Against Mylan's Generic