Federal Circuit Upholds Rejection of Patent Claims for Cancer Treatment

In ImmunoGen, Inc. v. Coke Morgan Stewart, the US Court of Appeals for the Federal Circuit upheld the district court’s rejection of patent claims concerning a particular dosing regimen for cancer treatment. According to Lois D. Mermelstein, reporting in IP Update, the court determined that the claims were obvious, even though the specific motivation of the inventor was not known at the time.

ImmunoGen had sought to patent a dosage protocol for administering IMGN853, an existing cancer drug, based on adjusted ideal body weight (AIBW).

The Federal Circuit upheld the finding that the dosing strategy would have been obvious to a person of ordinary skill in the art, regardless of the inventors’ subjective reasoning.

ImmunoGen argued that, at the time of invention, there was no awareness that the drug caused ocular toxicity, so no one would have been motivated to adopt this dosing approach and claimed that lack of motivation to solve that specific problem meant the claims could not have been obvious. 

However, the Federal Circuit agreed with the district court’s original ruling that the regimen itself could still be considered obvious, emphasizing that knowledge of ocular toxicity from similar drugs was widespread and that AIBW dosing, although not used for IMGN853 specifically, was well-known and accessible to a person of ordinary skill in the art (POSITA).

The Court concluded that there was a reasonable expectation of success in using this regimen and rejected ImmunoGen’s argument that a specific motivation was required.

For attorneys advising patent applicants, this decision reinforces that obviousness does not depend on the inventor’s specific motivation or the recognition of a particular problem. Courts may find a claimed invention obvious if there is any known problem in the field that could logically lead a POSITA to combine known elements. This reinforces the broad scope of the motivation-to-combine analysis in patent law.

Mermelstein writes, “The motivation to combine analysis is not limited by the problem or need recognized by the inventors. Instead, any problem known at the time of the invention can provide a reason for combining elements as claimed.”