The Board initially denied institution of Mylan Pharmaceuticals’ petition for inter parties review of U.S. Patent No. RE44,186, owned by AstraZeneca. After a rare grant of Mylan’s request for rehearing, the Board reconsidered the record and decided to institute the IPR. The decision to institute focused on the content of Mylan’s expert testimony; and although not mentioned in the decision, the replacement of one APJ in the PTAB panel for the decision on rehearing might have played a role in the grant of the request for rehearing and the decision to institute the IPR on rehearing even though both decisions were unanimous.

The ‘186 patent covers saxagliptin, a small molecule cyclopropyl-fused pyrrolidine-based inhibitor of dipeptidyl peptidase IV, an enzyme that is responsible for inhibiting the cleavage of peptides that regulate insulin secretion. Mylan asserted that the claims of the ‘186 patent are obvious in view of a number of publications. The grant of the rehearing and the decision to institute the IPR turned on whether there was sufficient evidence to demonstrate that a skilled artisan would be motivated to modify a lead compound to arrive at the claimed compound with a reasonable expectation of success.

As the claims are directed to a new chemical compound, a determination of obviousness follows a two pronged test of 1) whether one of skill in the art would have selected one or more lead compounds for further development and 2) whether the prior art would have supplied sufficient motivation to modify a lead compound to arrive at the compound claimed with a reasonable expectation of success. Otsuka Pharma. Co. Ltd. v. Sandoz, Inc. 678 F. 3d 1280, 1292 (Fed. Circ. 2012). The Board applied this approach in both the initial decision and the decision on rehearing, with differing results.

The grant of the rehearing and the decision to institute the IPR turned on whether there was sufficient evidence to demonstrate that a skilled artisan would be motivated to modify a lead compound to arrive at the claimed compound with a reasonable expectation of success.

In the initial decision, the Board accepted Mylan’s designation of the lead compound and the analysis focused on whether a skilled artisan would modify the lead compound to increase its stability. The Board stated that it was known that the lead compound was stable in its original form and Mylan did not explain why one of skill in the art would have sought to increase the stability of this compound. Therefore, the Board initially concluded that Mylan failed to establish sufficient motivation for modifying the lead compound and denied institution.

However, Mylan’s request for rehearing persuaded the Board to reconsider the evidence and asserted that the Board incorrectly analyzed the data in the asserted references. While the initial decision was silent in regard to the Mylan’s expert testimony, reconsideration of this testimony was key to instituting the IPR. The Board primarily relied upon the evidence provided by the Mylan’s witness to establish that a skilled artisan would add bulkier alkyl groups to increase stability of the compound.

In the request for rehearing, Mylan also requested a new panel. The request pointed out that the authoring APJ was a partner at opposing counsel’s firm and this APJ appeared as co-counsel with AstraZeneca’s lead counsel in several other lawsuits against generic drug companies. Mylan did not suggest that there was any actual impropriety; however, the mere appearance of possible impropriety is sufficient to justify reconsideration of the petition by a newly composed panel. Aetna Life Ins. Co. v. Lavoie, 475 U.S. 813, 825 (1986).

Since 2013, 16 requests for rehearing of a decision to institute a IPR have been granted. Ten of the IPRs were instituted after rehearing and 5 petitions for IPR were denied after rehearing (one is currently under consideration). In this rehearing, the Board carefully reconsidered the expert testimony and the evidence provided in the art. It is unknown whether the make-up of the panel played a role in the decision to take a second look at the evidence, but upon reconsideration the Board was satisfied that there was sufficient evidence to modify the lead compound.