Federal Circuit Finds Written Description for a Claimed Range Not Met by Specific Examples Within the Range

Dec 9, 2021

Reading Time : 3 min

By: Rachel J. Elsby, Megan Mahoney (Law Clerk)

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)

Share This Insight

Categories

Previous Entries

IP Newsflash

October 1, 2025

In a recent final written decision, the PTAB determined that a reference patent was not prior art, despite the petitioner’s post‑filing attempt to correct its petition. While the petitioner argued that it intended to rely on the patent application’s earlier date of publication, both the corrected petition and the expert declaration continued to reference the issued patent rather than the published application.

...

Read More

IP Newsflash

September 30, 2025

The USPTO Director recently granted a petitioner’s request for rehearing of the decision discretionarily denying institution of inter partes review, ultimately vacating the original decision, and referring the petition to the board for an institution decision.

...

Read More

IP Newsflash

September 25, 2025

In considering claims to a method of reducing cardiovascular events, the Federal Circuit held that the term a “clinically proven effective” amount did not render the claims patentable over the prior art. Specifically, the Federal Circuit held that the “clinically proven effective” amount, whether limiting or not, could not be used to distinguish the prior art because the claims also specified the exact amount of the drugs to be administered in the method. The Federal Circuit also rejected patentee’s evidence of unexpected results because that evidence was tied solely to the “clinically proven effective” limitation.

...

Read More

IP Newsflash

September 24, 2025

The Federal Circuit reversed a district court’s denial of judgment as a matter of law on non-infringement, thereby setting aside a $106 million jury verdict, after holding that prosecution history estoppel barred the patentee from asserting infringement under the doctrine of equivalents.

...

Read More

IP Newsflash

September 17, 2025

A magistrate judge in the District of Delaware issued a Report and Recommendation, that found the sole asserted claim was a “single means” claim and therefore invalid for lack of enablement. In reaching that conclusion, the magistrate judge rejected the patentee’s argument that the preamble of the claim disclosed a second element that satisfied the combination requirement of Section 112, paragraph 6 because the preamble simply recited a descriptor of the very apparatus that was the subject of the means-plus-function limitation in the body of the claim. The district court judge presiding over this case has scheduled a hearing to review the magistrate’s ruling.

...

Read More

IP Newsflash

September 9, 2025

The Federal Circuit has affirmed the PTAB’s determination that a patent challenger did not show the challenged claims were unpatentable for obviousness. The Federal Circuit concluded that substantial evidence, which included expert testimony, showed there was no motivation to combine the references.

...

Read More

IP Newsflash

August 29, 2025

In a recent order addressing four IPR proceedings, the PTAB exercised its inherent authority under 37 C.F.R. § 42.5(a) to sua sponte authorize post-hearing discovery on a potentially dispositive privity issue. The order followed a Director review decision that vacated and remanded earlier IPRs involving the same parties, patent family, and privity issue. 

...

Read More

IP Newsflash

August 29, 2025

The Patent Trial and Appeal Board denied institution of an inter partes review petition in part because it determined that a patent reference was not prior art under the common ownership exception of pre-AIA 35 U.S.C. § 103(c)(1).

...

Read More

© 2025 Akin Gump Strauss Hauer & Feld LLP. All rights reserved. Attorney advertising. This document is distributed for informational use only; it does not constitute legal advice and should not be used as such. Prior results do not guarantee a similar outcome. Akin is the practicing name of Akin Gump LLP, a New York limited liability partnership authorized and regulated by the Solicitors Regulation Authority under number 267321. A list of the partners is available for inspection at Eighth Floor, Ten Bishops Square, London E1 6EG. For more information about Akin Gump LLP, Akin Gump Strauss Hauer & Feld LLP and other associated entities under which the Akin Gump network operates worldwide, please see our Legal Notices page.