PTAB: Collateral Estoppel Precludes Patent Owner From Advancing Arguments Previously Rejected In IPRs Involving Different But Related Patents


A recent ruling from the Patent and Trial Appeal Board (PTAB) highlights the critical role that collateral estoppel (also known as issue preclusion) can play in inter partes review (IPR) proceedings. In a final written decision issued on January 13, 2020, the Board determined that Petitioner Rimfrost AS had shown, by a preponderance of the evidence, that the challenged claims of Aker Biomarine Antarctic AS's U.S. Patent No. 9,375,453 (the "'453 Patent") are obvious. (The Board reached the same conclusion with respect to Aker's proposed substitute claims and therefore also denied Aker's contingent motion to amend.) The Board based its decision in part on its finding that Aker was collaterally estopped from asserting two "reasonable expectation of success" arguments against Rimfrost's obviousness attack, since Aker had unsuccessfully raised those same arguments, no less against the same prior art, in previous IPR proceedings involving different patents within the '453 Patent's family.

The '453 Patent is directed to methods for extracting and processing polar krill oil from Antarctic krill, which are small fish that contain bioactive fatty acids. According to the '453 Patent, krill oil compositions have been found effective for treating several conditions, including (among others) high cholesterol, plaque formation, hypertension, arthritis and skin cancer. Representative independent Claim 1 recites a method for producing polar krill oil by (1) treating the krill to denature its lipid enzymes; (2) using a polar solvent to extract oil comprising specific ratios of ether phospholipids, non-ether phospholipids, triglycerides and astaxanthin esters; and (3) formulating the processed oil in capsules suitable for oral consumption.

Rimfrost filed an IPR challenging the patentability of claims 1 through 32 of the '453 Patent, arguing that they are obvious under 35 U.S.C. § 103(a). In its Petition, Rimfrost identified four different prior art combinations that purportedly disclosed the recited method of producing krill oil with the recited composition. The Board instituted trial on all four combinations.

In its Patent Owner Response, Aker did not dispute whether the asserted prior art references individually disclosed the methods and recited components of the krill oil, as set forth in the '453 Patent. Aker instead contended that a person of ordinary skill in the art would not have thought to combine those references with a reasonable expectation of...

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