Pharma Patents: New Insights To Satisfy Written Description For Claimed Ranges

By Jonathan B. (J.B.) Fitzgerald, Ph.D., J.D., Glen K. Thurston, Ph.D., and Jeffrey D. Morton, Ph.D., J.D., Snell & Wilmer L.L.P.

In pharmaceutical patents, ranges are often recited in patent claims to broaden the scope of the claim coverage. In particular, pharmaceutical patents often claim compositions of drugs across a specified concentration range. Claims may also include a temperature range or pH range used in making a drug. Additionally, treatment claims using the drug may rely on a claimed dosage range. Claiming these ranges can be effective in broadening the coverage around a drug composition as well as broaden claim coverage related to methods of making the drug composition and using the drug composition in a treatment.

To obtain a patentable claim that contains a range requires, among others, that the range has sufficient written description support in the patent specification. The threshold issue of the written description requirement is showing possession of the claimed subject matter. Under past case law, showing possession of a claim did not require that the specification provide verbatim support of the elements of the claim.  

In the recently decided case Indivior UK Limited v. Dr. Reddy’s Laboratories S.A.¹ (Indivior), the Federal Circuit had an occasion to evaluate the standard for meeting the written description requirement for a claimed range. In Indivior, the Federal Circuit invalidated certain claims that recited ranges, alleging that the claims failed to meet the written description requirement despite the fact that the claimed ranges could be derived by referencing tables in the specification. Thus, the Indivior case has seemingly raised the written description standard for claims that refer to ranges by requiring explicit, and possibly verbatim, support of the range in the specification.

This article describes the claimed ranges in Indivior that were invalidated for failing to meet the written description requirement; illustrates how Indivior, with respect to claimed ranges, departs from prior case law regarding the threshold for meeting the written description standard; and outlines potential ways Indivior may impact pharmaceutical patents that claim ranges related to drug compositions.

Claimed Ranges Failed To Meet The Written Description Requirement

In Indivior, the patent at issue covered orally dissolvable films. The claims in the patent were directed to orally dissolvable films that contained various therapeutic agents. At issue in Indivior was whether certain ranges of the therapeutic agents recited in the claims contained sufficient written description support in the specification.

The threshold question for meeting the written description requirement is whether the disclosure conveys to a person of skill in the art that the inventor(s) had possession of the claimed subject matter at the time of filing.² The Federal Circuit found that the claimed ranges of “about 40 wt % to about 60 wt %” and “48.2 wt % to 58.6 wt %” failed to meet this threshold because these ranges were not expressly recited in the specification, and, with regard to the range of “about 40 wt % to about 60 wt %,” the specification did not recite the end values (i.e., “40 wt %” or “60 wt %”).

Despite failing to expressly recite these claimed ranges, there was support for these ranges in the specification. For example, one of the tables in the specification contained formulations of various components of the film composition that, when added together, fell within the range of “about 40 wt % to about 60 wt %.” However, the court took the position that the values in the table did not constitute ranges; instead, the values only constituted particular examples of the weight percentage of components within the film compositions. According to the court, more clarity was needed, beyond the formulations described in the table, to provide written description support of the claimed range.

Further, the tables in the specification also arguably provided written support for the range of “48.2 wt % to 58.6 wt %.” Specifically, at least two separate tables in the specification provided the polymer components, along with the weight percentages of the polymer components, in the film compositions. Using these weight percentages of polymer components, one could arrive at the range of “48.2 wt % to 58.6 wt %.” The court, however, took the position that arriving at the claimed range through use of polymer components described in different tables in the specification amounted to “cobbling together numbers after the fact.” According to the court, the polymer components described in the table failed to provide a statement of the invention and, thus, failed to meet the threshold of the written description requirement needed to support the claimed range.

Additionally, the court pointed to statements in the specification that suggested that polymer components could be outside the claimed ranges as evidence that the claimed ranges failed to meet the written description requirement. For example, the court referenced a specific instance in which the specification stated that “the film may contain any desired level of polymer.” This statement, according to the court, was inconsistent with the claimed ranges, which inherently suggests that the polymer levels should be within closed-end ranges. Also, the court pointed to a reference in the specification of one embodiment in which the polymer contained “at least 25%”. This embodiment, according to the court, was inconsistent with the claimed ranges, because 25% fell significantly outside of the claimed range of “about 40 wt % to about 60 wt %.”

In summary, the Federal Circuit held that the claimed ranges failed to meet with the written description requirement because the tables in the specification provided nothing more than examples, and the specification provided references to ranges that fell outside of the claimed ranges. The Federal Circuit stated that had the specification provided an explicit recitation of the claimed ranges, the written description requirement would have been satisfied.

Indivior Departs From Prior Case Law

Indivior arguably represents a departure from long-standing principles of case law in defining the written description requirement. During the 1970s, for example, in cases before the United States Court of Customs and Patent Appeals (CCPA), the predecessor to the Federal Circuit, the CCPA found that verbatim support for claims was not required to meet the written description requirement.³

Seemingly consistently with prior case law, the dissent in Indivior argued that the majority applied a written description standard to the claimed ranges that was too demanding. In particular, the dissent took issue with the majority’s position that written description support for a closed range requires disclosure of the range in the specification. According to the dissent, disclosure of discrete values within the closed range, as was done with respect to the patent at issue, should be sufficient. Moreover, according to the dissent, the majority was incorrect in its position that using the tables in the specification to arrive at the claimed ranges amounted to “cobbling together numbers after the fact.” The dissent believed that it was well within the capability of a person of skill in the art to use these tables to arrive at the claimed ranges.  

The dissent seemed to be espousing the position consistent with prior case law that meeting the written description requirement does not require verbatim support in the specification. The majority’s response to this position was that prior case law did not create a rule on written description that was applicable to all cases involving ranges. According to the majority, broadly articulated rules in this area are inappropriate.

However, despite not articulating a broad rule, the Federal Circuit invalidated claimed ranges despite there being support for values within the ranges throughout the specification. Moreover, the Federal Circuit stated that the written description requirement for the ranges would have been satisfied had the ranges been recited in the specification. In taking this position, the Federal Circuit appears to have raised the standard for meeting the written description requirement for claims involving closed ranges by requiring explicit support for the ranges in the specification.

Impact Of Indivior On Pharmaceutical Inventions That Claim Ranges

Indivior could impact the way pharmaceutical patent applications that claim ranges are drafted. In particular, to meet the demanding written description standard for ranges described in Indivior, it may be necessary to provide verbatim support in the specification for any range that is claimed. For example, verbatim support in the specification may be necessary to support a concentration range of drug compositions, as well as ranges that relate to making the drug compositions and administering the drug compositions. Providing verbatim support for these ranges may be necessary to ensure that pharmaceutical patent applicants are able to procure broad claims that cover their drug compositions, as well as methods of making the drug compositions and using the drug compositions in treatments.

Indivior could also have a significant impact on pharmaceutical patents in a litigation context. Specifically, current pharmaceutical patents that claim ranges may be subject to invalidity challenges on the grounds that they do not meet Indivior’s threshold of the written description requirement, if the specification fails to provide verbatim support for the claimed ranges. Ultimately, the Indivior case may have put at risk countless broad claims that claim ranges related to drug compositions.

About The Authors:

Jonathan B. Fitzgerald, Ph.D., is an associate at Snell & Wilmer. He is a registered patent attorney and has a Ph.D. in molecular physiology. His primary practice area involves preparing and prosecuting patent applications in the biotechnology and the life sciences fields.

Glen Thurston, Ph.D., is a law clerk in the Salt Lake City office of Snell & Wilmer. He is attending J. Reuben Clark Law School at Brigham Young University and is not currently admitted to practice law. He plans to graduate law school in April 2022 and pursue a career in patent law.

Jeffrey D. Morton, Ph.D., P.C., is a partner at Snell & Wilmer. He is the chair of the firm’s Life Sciences and Medical Technology Industry Group and has more than 15 years of experience representing both start-up and large enterprises for their intellectual property and commercial law needs.