A patent application for Lumateperone tosylate, a compound used in schizophrenia treatment, was recently rejected by both an examiner and the patent registrar. The grounds for refusal? Lack of inventive step.
The applicant’s previous patent had already described and claimed Lumateperone, including a list of 30 potential salts, one of which was the tosylate salt. Furthermore, the disclosure of Lumateperone indicated to those skilled in the art (POSA) that salting would be necessary to create a Lumateperone tablet.
The Registrar’s Decision
The prior patent did not specify the crystal form but did provide a list of 30 salts. Given Lumateperone’s challenging structure, which could be resolved through salting, and the list of 30 viable salts, a POSA would likely explore these salts (it was obvious to try these salts). As such, the application was deemed to lack an inventive step.
The Appeal
The appeal centered on whether the “obvious to try” test was correctly applied by the Registrar. The district court dismissed the appellant’s argument that this test only applies when a specific solution is selected from a limited set of expected solutions with a reasonable expectation of success.
Instead, the court added a new requirement: the patent applicant must demonstrate the challenges they faced in achieving the invention. If these challenges required an inventive spark to overcome, an inventive step could be established.
The Court’s Perspective
In short, if the prior art provides a general direction that lacks detail, the applicant can’t simply establish inventive step by pointing out numerous theoretical options. It must show the unique properties of the substance, or the difficulties faced in handling it, such as issues with salinization, obtaining multiple substances, or forming stable crystals.
The Bottom Line
If guidance already exists and routine methods can easily lead to the invention, there is no inventive step.