Strategies for Dealing With USPTO's Obviousness Rejections Based on Overlapping Ranges
There are only limited strategies for dealing with a USPTO examiner’s obviousness rejection based on prior art disclosures of ranges of parameters that overlap with claimed ranges of those same parameters. We review this complicated aspect of U.S. patent prosecution practice as it continues to develop in the jurisprudence of the Court of Appeals for the Federal Circuit.
In the chemical arts, claims directed to a composition including ranges of various components or properties are quite common. For example, an applicant may pursue patent protection for a battery electrolyte composition that includes a solvent and several additives, with each component being included in a particular range of amounts. Similarly, claims reciting methods requiring certain conditions will typically include a range of values for each condition specified in the method. U.S. Patent and Trademark Office (USPTO) examiners routinely issue obviousness rejections based on disclosures in the prior art of ranges of parameter values that overlap with the claimed ranges for those same parameters. This is a very common rejection in the chemical (and other) arts. Yet the strategies for overcoming these rejections can be somewhat limited.
When can claims be rejected as obvious on the basis of overlapping ranges? Generally, a prima facie case of obviousness is established by a USPTO examiner where the claimed ranges overlap or lie inside ranges disclosed by the prior art. A prior art reference is considered to disclose an overlapping range with the claimed range even if the upper limit of one range is also the lower limit of the other range, meaning the ranges only “overlap” at a single point. In fact, courts have held that the ranges do not even have to actually overlap at all. It some cases, it has been held to be sufficient for the ranges to be merely close to one another for an obviousness rejection to be proper.[1]
Moreover, even if a prior art reference does not teach a specific numerical range of a claimed component, the reference may still be used by an examiner to reject the claim on the basis that the specifically recited numerical range is obvious. Stated differently, if a component is generally disclosed in the prior art, it may not be inventive to derive or otherwise arrive at a particular range of that component.[2] Therefore, an examiner may reject claims stating that the prior art only generally discloses the component but that a person of ordinary skill would be motivated to arrive at the claimed range through “routine optimization.”
However, as the U.S. Court of Appeals for the Federal Circuit (CAFC) recently explained in Modernatx, Inc. v. Arbutus Biopharma Corp.,[3] when there is not an express disclosure of a range in the prior art, the presumption of obviousness does not necessarily result even if a range can be calculated from the prior art disclosure. There must also be some showing that a person of ordinary skill in the art would have understood the reference to teach or suggest an overlapping range for the recited parameter or feature.
It should be noted that a prima facie case of obviousness based on overlapping ranges does not require that the only difference between the prior art is the range or value of a particular variable. For example, in Valeant Pharmaceuticals Int’l, Inc. vs. Mylan Pharmaceuticals Inc.,[4] the CAFC recently found that prior art ranges for solutions of structurally and functionally similar compounds that overlap with a claimed range can establish a prima facie case of obviousness.
Once a prima facie case of obviousness has been established based on overlapping ranges in the prior art, the burden shifts to the applicant to present evidence of non-obviousness to overcome the rejection. While each case is fact-specific, there exists typically four distinct strategies for rebutting an obviousness rejection based on overlapping ranges, which were summarized by the CAFC in E.I. Dupont de Nemours & Co. v. Synvina.[5] The first strategy is to show that the claimed range is critical. The second option is to make a showing that the prior art teaches away from the invention. The third possible strategy is to demonstrate that a parameter otherwise disclosed in the prior art reference was not taught as being “result-effective.” And, finally, it is possible to argue that the disclosure in the prior art reference is so broad so as not to invite routine optimization by the skilled artisan.
Regarding the first strategy, there are many examples in U.S. case law showing that an obviousness rejection based on overlapping ranges may be overcome if the applicant demonstrates the criticality of the claimed range. The criticality of a range may be demonstrated by showing that the claimed range achieves unexpected results relative to the prior art range. Evidence of criticality is typically demonstrated from data in the originally-filed application or in data submitted in a declaration traversing the examiner’s rejection (under 37 C.F.R. § 1.132, which states that “[w]hen any claim of an application or a patent under reexamination is rejected or objected to, any evidence submitted to traverse the rejection or objection on a basis not otherwise provided for must be by way of an oath or declaration under this section.”). However, in order for this rebuttal strategy to succeed, there are some specific requirements for demonstrating criticality of the recited range.
First, the applicant must show that the changes associated with the unexpected results relative to the prior art produce a difference in kind not merely in degree. Furthermore, the results should have both statistical and practical significance. It is the applicant’s burden to clearly explain the evidence proffered and why it is unexpected relative to the prior art.
Second, the evidence of unexpected results must be commensurate in scope with the claimed invention. This requirement can cause some difficulty during prosecution for many applicants. Practically, the requirement to be “commensurate in scope” means that the applicant must show that the unexpected results occur over the entire claimed range. The applicant should also provide a sufficient number of data points within and outside the claimed range to show that the range is, indeed, critical to achieving the unexpected results. In many instances, there is insufficient data in the original application to show that a certain unexpected result is achieved over the entire claimed range. In such instances, the examiner will likely maintain the obviousness rejection until either: (1) additional data is presented to cover the full scope of the range, or (2) the range is narrowed to correspond to the evidence of unexpected results. However, the amount of evidence that may be sufficient to show that the range is critical does not necessarily need to include evidence showing the entire scope of the claimed invention as a whole. That is, in the example of a battery composition including a solvent and several additives, each being included in a particular range of amounts, evidence to show criticality of a range focuses on the amount of the components rather than the full scope of the solvents or additives being claimed.
When drafting an application, applicants should include as much data as possible to support claims reciting ranges of values for particular components because such data may be needed during USPTO prosecution. It is important to include not only data of the invention itself, but also data of comparative samples outside of the scope of the claims. This data may ultimately be the deciding factor for an examiner as to whether a claim is patentable.
As previously noted, a second strategy for overcoming an obviousness rejection based on overlapping ranges is to show that the prior art teaches away from the claimed range. “Teaching away” is not merely a disclosure that teaches a range different from the claimed range or even that the claimed range is inferior as compared to prior art ranges. A “teaching away” is a teaching that would discourage one of skill in the art from arriving at the claimed range. This strategy does not succeed very often, because it is difficult to show that the prior art actually discourages a skilled person from arriving at the claimed range.
Regarding the third strategy, i.e., arguing that a particular claimed value or range of values was not recognized as result-effective in the prior art, the value for the component must be recognized as a result-effective amount or value for the examiner to properly state that the claimed range is obvious. This means that the prior art must teach that the component achieves a particular result in such a way that it would invite routine optimization by a person skilled in the art. USPTO examiners often fail to identify a value for a component as being result-effective. Therefore, it can be useful to challenge the propriety of the examiner’s legal conclusion of obviousness is proper when based merely on a general disclosure in the prior art.
The fourth available strategy, as previously mentioned, with regard to overlapping ranges is to argue that the disclosure in the prior art is so broad so as not to invite routine optimization by the skilled artisan. This argument is similar to another argument patent practitioners are accustomed to making in the chemical arts. It is frequently argued that when the prior art discloses a broad genus, claims directed to a narrow species are not obvious. Similar arguments may be made related to a very broad range of values disclosed in the prior art where the claimed range is relatively narrow. This argument combined with an argument of unexpected results can be a strong rebuttal of an “obviousness of ranges” rejection.
In conclusion, while an obviousness rejection based on overlapping ranges can be a challenging rejection to overcome, there are several proven strategies for overcoming these types of rejections. No matter what legal arguments are made to rebut these cases of obviousness, it is always helpful to have sufficient data presented in the original application to show the improved results of the claimed invention. Sometimes that data is the deciding factor in whether claims are granted in the United States.
