Expert Testimony Supporting POPR Can Be An Effective Strategy

By Sue Gerber –

It is relatively uncommon for parties to submit expert declarations in the preliminary-response phase of an IPR proceeding, but recently the Patent Owner in Imperative Care, Inc. v. Inari Medical, Inc. effectively used that strategy to defeat institution in IRP2024-01256, Paper No. 10 (PTAB Feb. 7, 2025).

The patent at issue, United States Patent No. 11,774,691 (“the ’691 Patent”), described and claimed a System for Treating Embolism and Associated Devices and Methods.  Paper No. 10 at 3.  The patent described “devices for the intravascular treatment of emboli and/or thrombi within a blood vessel of a human patient.”  Id.  Importantly, the claims required that the device include a “coupled assembly with first and second chambers,” “an aspiration chamber,” and “a user-actuatable valve between the second chamber and the aspiration chamber,” “wherein the valve is configured to be closed while negative pressure is generated in the first and second chambers.”  Id. at 8 (emphasis added).

The Petitioner asserted eight grounds of invalidity.  Ground 1 asserted anticipation in light of a prior-art U.S. patent publication to Garrison (“Garrison”).  Id. at 9.  Ground 2 asserted that the ’691 patent was obvious in light of Garrison alone, and Grounds 3-8 asserted obviousness in light of Garrison in combination with a number of additional references.  Id.  Petitioner submitted an expert declaration to support its asserted grounds of invalidity.  See, e.g., id. at 21 (citing Ex. 1003).

The PTAB focused its analysis almost exclusively on whether Garrison disclosed a device that could or would generate a negative pressure in the first and second chambers when the user-actuatable valve was closed.  Petitioner argued that a syringe disclosed in Garrison generated a negative pressure and “rapid” aspiration when used.  Id. at 21.  Petitioner’s expert testified that this syringe (or “other negative pressure source”) would function in the same way as claimed in the ’691 patent when “a rapid movement of blood from the second, filter chamber to the first chamber occurs.”  Id.  

Patent Owner and its expert Mr. Brown, however, asserted that Garrison also disclosed a pump, which “would not and could not generate negative pressure in the downstream delivery location (the receptacle the Petition alleges is the first chamber) … and therefore would not generate negative pressure in any ‘first chamber’ identified by Petitioner.”  Id. at 23.  The PTAB found Patent Owner’s argument and Mr. Brown’s testimony on this point was persuasive.  Id. at 22, 24.  Mr. Brown explained that the configuration disclosed in Garrison generates negative pressure only on the inlet side of the pump and generates positive pressure on the outlet side of the pump, which is the side toward the “receptacle” that Petitioner contended satisfied the “first chamber” limitation.  Id. at 24-25.  In light of Mr. Brown’s testimony, the PTAB found that “petitioner does not explain sufficiently how a negative pressure as claimed would be generated in any alleged ‘first chamber’ in this arrangement.”  Id. at 25.  Nor did Petitioner explain “how Garrison’s aspiration pump embodiments might or should be arranged or configured in a way that generates a negative pressure in any alleged ‘first chamber’ identified by Petitioner.”  Id. at 26.  The PTAB concluded that, on this record, Petitioner failed to establish a reasonable likelihood that it would succeed in showing Garrison anticipates the ’691 patent.  Id. at 28.  Moreover, because Petitioner relied only on Garrison to establish the negative-pressure limitations in its obviousness grounds, it also failed to carry its burden for Grounds 2-8.  Id. at 30, 31.

Thus, although there are some drawbacks to exposing one’s expert at the preliminary-response stage, when expert testimony is used thoughtfully and strategically, it can be effective in defeating institution and achieving an early resolution in the Patent Owner’s favor.