Thursday, March 10, 2011

Primary Screen Establishes Demonstrated Utility

GlaxoSmithKline Inc. v. Pharmascience Inc. / rosiglitazone (NOC) 2011 FC 239 Hughes J

The question of exactly how much utility is necessary to satisfy the utility requirement is a crucial, particularly for pharmaceutical patents. It is well-established that “an inventor is not required to meet regulatory testing standards in order to demonstrate utility”: Pfizer v. Novopharm / sildenafil (NOC) 2010 FCA 242 [97]. It is also reasonably clear that human testing is not required to established utility based on sound prediction: Merck / lovastatin 2010 FC 1265 [510]. In GlaxoSmithKline / rosiglitazone (NOC) Hughes J went further and held [117] that the “primary screen,” described [115] as “the first test that you would, do to look for efficacy [and] the basis on which our department would progress or wish to progress a compound further,” is sufficient to establish demonstrated utility.

The claim in question was to rosiglitazone, an anti-diabetic drug in the thiazolidinedione class of drugs. The primary screen in question was a single murine oral glucose tolerance test, run at only a single dosage level [99-101]. The holding was expressly not based on sound prediction. GSK had not run a sound prediction argument at all [77]; this may have been because the test results on rosiglitazone were not disclosed in the patent itself, as they had reached the patent department too late to be included [32j], and so GSK anticipated trouble with requirement that the factual basis for sound prediction be disclosed. (A similar primary screen on a different compound was the only test data in the patent itself.)

A caveat is that this holding was premised on the particular promise of the patent, which was interpreted [98] as promising only that the claimed compounds were better than nothing (ie a control), and that they were of potential use in treating hypoglycaemia. A patent which promised more might require a correspondingly greater demonstration of utility. (I will discuss problems raised by the focus on the promise of the patent in a subsequent post.) Also, in principle it might be that a different primary screen, or different results, would not satisfy the requirement. Nonetheless, this decision does establish a low threshold for demonstrated utility in pharmaceutical patents. This is consistent with the “scintilla of utility” standard that is generally applicable when the patent itself does not establish a higher threshold: Pfizer v. Novopharm / sildenafil (NOC) 2010 FCA 242 [94].

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