Tipping the Scales in IPR with Effective Expert Testimony

Expert testimony is a feature of most IPRs, and effective expert testimony can make or break a party’s position. When evaluating expert testimony, the PTAB may consider several issues. First, are the expert’s qualifications sufficient? Second, even if the expert does not technically qualify as a “person of ordinary skill in the art,” should the expert’s testimony be given weight? The PTAB’s decision in Lupin Ltd. v. Horizon Therapeutics, Inc. (IPR2016-00829) addresses these questions and illustrates several ways to effectively use expert testimony.

In this case, the patent owner challenged the qualifications of the petitioner’s expert, a medical doctor with decades of experience in the field. The petitioner argued that the expert lacked certain certifications and formal training, and so the expert’s testimony should not be given weight. The PTAB disagreed, concluding that the expert’s experience was actually “more relevant” than specialized certificates and training, with respect to this particular disease.

The PTAB also found that even if the expert was not one of ordinary skill in the art, his testimony could still be accorded weight because it was supported by prior art. Moreover, the PTAB accorded a particular passage in a prior art reference more weight because “it expressly supports [the] testimony [of the petitioner’s expert].” Thus, both the expert’s testimony and the prior art gained significance because they were in agreement.


This decision illustrates that in an IPR, the qualifications of a witness as one of ordinary skill in the art can be flexible. Parties in IPR should not overlook practical experience in the field of the patent as an alternative to proving expertise with specialized certificates and particular training.

In addition, the decision serves as a reminder that both expert testimony and references are stronger when they agree. Consistency may overcome the expert not actually being a person of ordinary skill in the art.