During the week of March 18, 2019, the Patent Trial and Appeal Board (“the Board”) issued the following decision in TC 1600 instituting a post-grant review:

Hybrigenics SA v. Forma Therapeutics, Inc., No. PGR2018-00098 (Decision Granting Institution of Post-Grant Review Entered March 20, 2019). The Board instituted a post-grant review (“PGR”) sought by Hybrigenics SA (“Hybrigenics”) against U.S. Patent No. 9,840,491 (“the ’491 patent”) owned by Forma Therapeutics, Inc. (“Forma”). Hybrigenics raised three grounds for challenge: lack of written description, lack of enablement, and obviousness. PGR2018-00098, Paper 10 at 9. Forma, in turn, challenged Hybrigenics’s identification of real parties in interest. Despite finding issues with the enablement and obviousness grounds, the Board found the written description challenge was sufficiently established and instituted PGR on all grounds.

The claims at issue cover inhibitors of “ubiquitin-specific protease 7,” or USP7, which have potential to treat cancers and other disorders. The claims specifically cover compounds of a certain chemical formula and pharmaceutically acceptable salts, hydrates, solvates, prodrugs, stereoisomers, and tautomers of those compounds. Id. at 3.

The Board first considered Forma’s challenge to the identification of real parties in interest; according to Forma, a third party collaborating with Hybrigenics and two U.S. subsidiaries of Hybrigenics should have been listed. Id. at 11. The Board disagreed because Forma presented no evidence that (1) the third party controlled, directed, financed, or participated in the PGR petition; or (2) the two U.S. subsidiaries were involved in the petition, that Hybrigenics served as their proxy, or that they were intermediaries through which a real party in interest exercised control. Id. at 14–18.

Turning to the written-description grounds, Forma asked the Board to deny review under § 325(d) because a patent examiner supposedly considered Hybrigenics’s arguments during prosecution. Id. at 19. Forma had narrowed the claims to overcome a § 112 rejection and assured the examiner the added limitations had written support. Id. at 20. In the PGR petition, Hybrigenics claimed this same language was unsupported. Rejecting the § 325(d) argument, the Board found no evidence that the examiner had considered Forma’s assurances, or that the rejection overlapped with Hybrigenics’s petition arguments. Id. at 20–21. On the merits, the Board concluded it was more likely than not that the added claim language lacked support. Id. at 25. Forma had limited the possible substituents of the claimed compound from “heteroaryl” and “heterocycloalkyl,” generally, to 5- or 6-membered heteroaryl and 3- to 7-membered heterocycloalkyl, but had defined “heteroaryl” and “heterocycloalkyl” broadly in the specification with numerous examples and no guidance towards the narrower constituents it later claimed. Id. at 22–24. The Board thus instituted PGR. Id. at 26. It then briefly dismissed Hybrigenics’s second written description argument—that the broad genus of claim compounds lacked written support because the specification only gave 13 exemplary compounds—concluding that Hybrigenics failed to address the commonality of any structural features of the genus, the state of the art, the predictability of the technology, or the representativeness of the 13 examples. Id. at 27–28.

The Board next found that Hybrigenics failed to establish likely unpatentability for lack of enablement. Hybrigenics had argued that skilled artisans would be unable to synthesize the millions of claimed compounds without undue experimentation, given only four synthesis examples were disclosed in the patent and artisans would not know which of the claimed compounds were effective USP7 inhibitors. Id. at 30. But, according to the Board, Hybrigenics and its expert failed to explain why the general synthesis methods and four disclosed examples were insufficient to enable synthesis of the claimed genus, the degree of experimentation that would be needed, or why the two disclosed assays were insufficient to assess USP7 inhibition. Id. at 31–32.

Finally, the Board considered the obviousness grounds. It noted that Hybrigenics failed to establish likely unpatentability on this basis, but nevertheless instituted PGR on all grounds per PTO guidance. Hybrigenics had asserted obviousness over a prior art patent that disclosed fourteen compounds. According to Hybrigenics, skilled artisans would have modified those compounds in obvious ways, and those modified compounds rendered the claimed compounds obvious. But according to the Board, Hybrigenics used impermissible hindsight because it started with the claimed compounds and argued their substituents were obvious in light of the prior art, instead of explaining why skilled artisans would have modified the prior art compounds to arrive to the claimed compounds. Id. at 41–42. Hybrigenics had also argued that examples in the prior art patent rendered certain claimed compounds obvious, but the Board noted Hybrigenics’s expert failed to cite any prior art references that suggested the required modifications. Id. at 46-47.