In a recent decision issued in Indivior UK Limited v. Dr. Reddy's Laboratories, the Federal Circuit affirmed a decision from the PTAB that a limitation to range of polymer weight percentages lacked written description support even though the specification contained specific examples within the range.
The patent at issue, Indivior's U.S. Patent No. 9,687,454 (the "'454 patent"), generally relates to orally dissolvable films containing therapeutic agents. The '454 patent issued as a continuation from an application originally filed in 2009. In 2018, Dr. Reddy's Laboratories petitioned for inter partes review of claims 1-5 and 7-14 of the '454 patent. The challenged claims were directed to dissolvable films that include therapeutic agents with a polymeric matrix defined according to its weight percentage. Specifically, claim 1 recites a polymeric matrix of about 40-60 percent of weight of the film. Claims 7 and 12 recite a range of 48.2-58.6%, and claim 8 recites 48.2%.
Dr. Reddy's argued that the 2009 priority application lacked written description support for the claimed weight percentages, and as a result, the '454 patent could not rely on that filing date to overcome an anticipatory 2011 reference, Myers. Indivior did not challenge whether Myers anticipated the claims, but instead only disputed whether the '454 patent was entitled to the 2009 priority date such that Myers could not be prior art.
The PTAB agreed with Dr. Reddy's as to the claims that recited ranges, and found those claims anticipated by Myers. According to the PTAB, a skilled artisan would not have discerned the claimed range of "about 40 wt % to about 60 wt %" because the 2009 priority application only disclosed a lower endpoint of "at least 25%" along with two specific formulations. As to claim 8, however, the PTAB determined the specific examples in the priority application disclosing a weight percent of 48.2 were sufficient written description support. The Board therefore found Dr. Reddy's failed to prove that claim 8 is invalid.
On appeal, the Federal Circuit affirmed. The Federal Circuit explained that while it is not necessary for the written description to set forth a claimed range in exact numbers, it must state the range with sufficient clarity such that a skilled artisan can reasonably discern the range-a requirement found not to be met by the '454 patent. In the case of the '454 patent there was no specific mention of a range of 40-60%. Instead, there was only a mention of "at least 25%," "at least 50%," and two tables containing specific examples, along with a general disclosure in the specification that the "film may contain any desired level of ... polymer." Although the examples in the tables, when added up, fell within the range of 40-60%, the Federal Circuit deemed that insufficient because it "amounts to cobbling numbers together after the fact."
In reaching this decision, the Federal Circuit declined to find similarity between the claims here and in previous cases involving similar range limitations, reasoning that written description cases are necessarily fact intensive and not prone to comparison. The Federal Circuit emphasized that previous opinions did not create rules applicable to all range cases.
Judge Linn dissented from the court's decision as to all claims except for claim 8. In his view, there were no relevant factual distinctions between this case and the court's earlier precedent finding adequate written description. In fact, one case not addressed by the majority presented substantially identical circumstances and found the written description requirement met. Judge Linn further noted that no decision from the court required disclosure of a discrete range as opposed to discrete values in order to support a range limitation, as held here. Nor did it make sense to create such a strict rule to show possession. Likewise, Judge Linn found fault in the majority's assertion that a skilled artisan could only identify specific percentages by plucking out values and cobbling them together because the only math required here was simple math-a summation of all the polymers in every embodiment-and the specification emphasized the importance of the aggregate percentage.
Practice Tip: Claims directed to ranges that are not explicitly disclosed in the specification may be susceptible to written description attacks. Because of the limited value of precedent in this area, parties asserting and defending against such claims should focus arguments on the specific facts of the case and what a skilled artisan would understand the inventor to have possessed based on the disclosures available.
Indivior UK Limited v. Dr. Reddy's Laboratories, S.A. & Dr. Reddy's Laboratories, Inc., No. 20-2073 (Fed. Cir. Nov. 24, 2021)
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