Cephalon, Inc. v. Watson Labs., Inc (D.Del.)

Case Name: Cephalon, Inc. v. Watson Labs., Inc., MDL No. 10-md-2200 (GMS), 2013 U.S. Dist. LEXIS 46572 (D. Del. Mar. 30, 2013) (Sleet, C.J.)

Drug Product and Patent(s)-in-Suit: Nuvigil® (armodafinil); U.S. Pat. No. 7,132,570 (“the ’570 patent”)

Nature of the Case and Issue(s) Presented:  Defendants contend that the asserted claims of the ’570 patent are invalid as inherently anticipated by “Preparation I of the ’855 [prior art] patent.” Specifically, Defendants assert that a person of ordinary skill in the art “will necessarily and inevitably obtain Form I armodafinil from following the prior art Preparation I process.” Defendants rely on their experts’ performing Preparation I of the ’855 patent as persons of ordinary skill in the art in the late 1990s and early 2000s, and obtaining Form I armodafinil. Conversely, Cephalon argued that Defendants’ testing did not show that Preparation I of the ’855 patent necessarily and inevitably produces a pharmaceutical composition consisting of the “specified pharmaceutically active component”—Form I armodafinil—and other pharmaceutically acceptable ingredients, as required by the asserted claims. Rather, Defendants’ testing, according to Cephalon, showed that mixtures of polymorphic forms and various uncharacterized impurities result” from reproducing Preparation I and, further, that Defendants’ experiments were flawed and insufficient because they departed from the express method taught in the ’855 patent.

After a 4-day bench trial to determine the validity of the asserted claims, the Defendants having stipulated to infringement, the court held: (i) the asserted claims of the patents-in-suit are not invalid as anticipated under 35 U.S.C. § 102(b); and (ii) the asserted claims of the patents-in-suit are not invalid as obvious under 35 U.S.C. § 103.

Why Cephalon Prevailed:  Preparation I of the ’855 patent did not inherently produce Form I armodafinil. Defendants’ experiments yielded different forms, mixtures of forms, and unknown impurities, depending on the variables selected in conducting the Preparation. Moreover, the ’855 patent does not disclose polymorphism, or the crystallization conditions needed to make any particular polymorph. This raises issues concerning the accuracy of the test methods and whether Defendants’ experts were acting in line with what a person or ordinary skill in the art at the time of the invention would have done. For example, Defendants’ experts employed a “slow cooling” process during recrystallization, but literature available at the time of the invention encouraged the use of “rapid cooling to obtain fine crystals.” Therefore, the Court found that Defendants failed to prove clearly and convincingly that Form I armodafinil claimed in the ’570 patent necessarily results from Preparation I of the ’855 patent.

Next, Defendants challenge the validity of each of the asserted claims as obvious in light of the prior art. Defendants assert that a skilled artisan would have been motivated to obtain armodafinil’s most stable polymorph—Form I—because the therapeutic effectiveness of armodafinil would have been well known in the art. Defendants rely on the ’855 patent’s disclosure of the synthesis of crystalline armodafinil and its use in pharmaceuticals, the fact that armodafinil is a crystal means that it has a most stable polymorph, and that it was known in the art that the most stable polymorph is by far the preferred in a marketed drug formulation. The court was not persuaded. Relying on the fact that polymorphism is inherently unpredictable, and based on the unique nature of armodafinil, the court concluded that a skilled artisan would not have had a reasonable expectation of success that armodafinil was polymorphic in 2002. Moreover, beyond the absence of any express disclosure, there was not implicit disclosure of Form I armodafinil in the ’855 patent.

Defendants also allege that a person of ordinary skill in the art would have expected to obtain the most stable polymorph of armodafinil using well known and merely routine techniques, such as ageing and polymorph screening, because the most stable polymorph is the easiest to obtain. The court rejected this argument because a skilled artisan would have resorted to trial and error experimentation, using a large number of conditions—again as a result of the unpredictability of polymorphs. Also, nothing in the Gu article, which Defendants’ rely on for the ageing technique, concerns any general applicable method to obtain the most stable polymorph form.