In construing a claim involving a method for treating obesity, the US District Court for the District of Delaware determined that a phrase in the preamble stating that the method of treatment had “reduced adverse effects” was not a claim limitation. Takeda Pharm. Co. Ltd. v. Actavis Labs. FL, Inc., Case No. 15-451-RGA (D. Del. June 6, 2016) (Andrews, J.)

In September 2014, Takeda obtained approval from the US Food and Drug Administration (FDA) to launch Contrave®—a prescription weight loss product combining naltrexone and bupropion. When Actavis sought FDA approval for a generic version of Contrave® in 2015, Takeda filed suit asserting two method of treatment patents.

Various independent claims of the patents cover “[a] method of treating overweight or obesity having reduced adverse effects” comprising “administering” a “weight loss effective amount of a first and second compound” (i.e., naltrexone and bupropion). The court held a Markman hearing and construed three key terms: (1) “administering”; (2) “weight loss effective amount of a first and second compound”; and (3) “having reduced adverse effects.”

Administering. The parties first disagreed over the actions that would constitute “administering.” Actavis’ proposed construction limited administering to the physical act of delivering the compounds into the body, while Takeda wanted the construction to “include the act of a physician prescribing or otherwise directing a patient to take the drug.” The court reviewed the patents’ specifications and claim language and ultimately agreed with Actavis’ proposed construction.

While the court noted that prior courts had come to differing conclusions regarding the construction of “administering,” the court found that the patent specification and claims consistently distinguished between “administering” and a physician’s prescribing activities. Specifically, one patent stated that a prescribing physician could choose the “route of administration” and “manner of administration”—clearly delineating between a physician’s acts and the ultimate act of “administering.”

Weight loss effective amount. The parties next argued over whether the phrase “weight loss effective amount of a first and second compound” required each compound (i.e., both naltrexone and bupropion) to be individually present in an amount that was weight loss effective (Actavis’ position) or if only the combined amount had to be weight loss effective (Takeda’s position). The court agreed with Takeda based on the information included in the patent specification. The court noted that the specification consistently focused on the “combination of two or more compounds” and that the specification stated that naltrexone by itself was not an effective drug for weight loss in humans. This evidence convinced the court to adopt Takeda’s position.

Having reduced adverse effects. Finally, the parties disagreed over whether the phrase “having reduced adverse effects,” constituted an additional limitation when it was found only in the preamble. First, the court noted that in general, statements of an intended result of a method claim in a preamble are typically not considered to be claim limitations. However, if the preamble recites steps or structure emphasized in the specification as important or if the patentee relies on the preamble for patentability during prosecution, the preamble should be considered limiting.

Actavis argued that the phrase should be limiting because the specification repeatedly touted embodiments with reduced adverse effects and because the prosecution history included arguments that having reduced adverse effects was an unexpected result. The court, however, agreed with Takeda. It stated that there was no reason to part from prior case law—that “having reduced adverse effects” was simply the “intended result” of the method and did not change the steps of the claim. Furthermore, the court noted that at least one independent claim (containing the same preamble language) included language relating to “having reduced adverse effects” in the body of the claim. Finally, the court found that none of the statements in the prosecution history regarding unexpected results were used to distinguish the claims at issue from the prior art—and therefore did not suggest that the preamble was limiting.