Reckitt Benckiser Pharms, Inc. v. Watson Labs., Inc.

One of Plaintiffs’ patents was valid and infringed while the remaining patents-in-suit were either invalid or not infringed.

July 21, 2016

GENERICally Speaking: A Hatch Waxman Litigation Bulletin

Case Name: Reckitt Benckiser Pharms, Inc. v. Watson Labs., Inc., Civil No. 13-1674-RGA, 2016 U.S. Dist. LEXIS 72391 (D. Del. June 3, 2016) (Andrews, J.)

Drug Product and Patent(s)-in-Suit: Suboxone® (buprenorphine HCl / naloxone HCl); U.S. Patents Nos. 8,475,832 (“the ’832 patent”), 8,603,514 (“the ’514 patent”), and 8,017,150 (“the ’150 patent”)

Nature of the Case and Issue(s) Presented: Plaintiffs manufacture Suboxone sublingual film used for maintenance treatment of opioid dependence. Defendants filed ANDAs seeking to market a generic version of Suboxone. In response, Plaintiffs filed suit. After analyzing the evidence, the court concluded that the ’832 patent was invalid, the ’514 patent was valid and infringed, and that the ’150 patent was valid and not infringed.

Why Plaintiffs Prevailed: First, the Court determined that the claims 1, 3, and 6 of the ’832 patent were indefinite because they used the term “local pH.” The ’832 patent provided no explanation as to volume or type of solvent used to measure local pH. Nor was there any disclosure as to when the local pH was measured. Thus, the patent does not provide enough information for a person or ordinary skill to determine the meaning of local pH. Additionally, the remaining claims of the ’832 patent were obvious in view of the prior art. The prior art taught the absorption of buprenorphine across nasal mucosa at acidic pH levels. Due to the similarity between nasal and sublingual membranes, a person of ordinary skill would expect those teachings to apply to sublingual absorptions. Further, in applying the buffer, one of ordinary skill would have selected the lower end of the operative pH range to achieve proper bioabsorption. Finally, formulating dosage forms and orally dissolved films were well known in the art prior at the time of the patent.

Next, the court found that the claims of the ’514 patent were valid. Defendants argued that the ’514 patent was invalid on indefiniteness grounds, because the claims recited a “drug delivery composition comprising: (1) a cast film . . .” and a flowable matrix. The parties agreed that it is physically impossible for a cast film to be flowable. Thus, the court concluded, that a person of ordinary skill would know that the flowable matrix was an ingredient, and not a final component of the cast film. The patent itself referred to a cast film made from a wet flowable matrix. Thus, the claims were not indefinite. Further, the claims were not obvious in light of the prior art, which did not address overcoming the challenge of manufacturing a pharmaceutical film with drug content uniformity. Nor did would a person of ordinary skill be motivated to combine the prior art, due to contradictory disclosures. For those reasons, the claims of the ’514 patent were not obvious.

In view of its validity finding, the court turned to the issue of infringement of the ’514 patent. The Defendants’ generic products comprised cast fills, made from a flowable matrix as required by the patent’s claims. Further, the viscosities of the flowable matrices were within the preferred range disclosed by the patent. Thus, Defendants’ proposed ANDA products would infringe the claims of the ’514 patent.

Finally, Defendants also asserted indefiniteness and obviousness arguments against the ’150 patent. Defendants’ expert testified that a person of ordinary skill would determine the “molecular weight” of a compound by relying on the manufacturer’s reported weight, rather than by analyzing a sample, as Plaintiffs’ expert testified. Multiple ways to determine a molecular weight did not render the term indefinite—a person of ordinary skill would still know how to determine a molecular weight. Nor were the claims of the patent obvious—the ’150 patent was entitled to the priority date of an earlier filed provisional application that predated Defendants’ prior art. Thus, the claims were valid.

But the claims of the ’150 patent were not infringed. The claims of the patent required both high and low molecular weight polyethylene oxides. Defendants’ proposed ANDA products, on the other hand, only contained low molecular weight polyethylene oxides. Thus, they could not infringe all of the claims of the ’150 patent.

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