Patent attorneys generally are trained to secure the broadest claims possible for their clients but, when claiming methods of treatment, narrower often is better. Narrow claims are more likely to survive a validity challenge and, when the claims cover the method described in the client's FDA-approved label, generic competitors can have no choice but to infringe the patent.
This patent strategy can coalesce nicely with a company's drug approval strategy when the client is developing its drug for the treatment of a subpopulation of patients. While the larger population of patients may obviously be treated by the method, it is not always so obvious that the subpopulation can be treated.
This scenario played out recently in a case involving U.S.S.N. 13/077,478, in an appeal to the Patent Office Board of Patent Appeals. The case was 2016 Pat. App. LEXIS 11255 (Comm'r Pat. & Trademarks Nov. 21, 2016). The claims at issue involved the treatment of a limited subset of Parkinson's patients using a 5HT[1a] receptor agonist. Claim 1 required the patient to be:
undergoing dopamine replacement therapy for the treatment of Parkinson's Disease, wherein the patient exhibits wearing-off of anti-parkinsonian efficacy of the dopamine replacement therapy or has developed "on-off" syndrome
Because dopamine replacement therapy is the standard of care for Parkinson's treatment, this claim could be extremely valuable to its owner (listed as Motac Neuroscienes in the decision), if the drug is developed as an adjunct to dopamine replacement when the effectiveness of the dopamine replacement wears off.
The Examiner rejected the claims based largely on prior art disclosing the use of 5HT[1a] receptor agonists for the treatment of Parkinson's. On appeal, the Board agreed that the prior art disclosed the use of 5HT[1a] receptor agonists to treat autism, and even acknowledged that the prior art taught the combined use of dopamine replacement therapy and a 5HT[1a] receptor agonist. However, the prior art did not disclose the use of this combination in patients who "exhibit wearing off" of the dopamine replacement therapy, or "on-off-syndrome" associated witht he dopamine replacement therapy. As explained by the Board:
The Examiner has not established that the ordinary artisan would have expected the combination of a 5HT[1a] agonist and dopamine replacement therapy to extend the duration of "ontime" in the particular subpopulation of patients with Parkinson's disease who experience either "wearing-off" or "on-off" syndrome. We recognize that McLean, Liu, and Bonifati suggest treating Parkinson's disease patients in general with both compounds .... However, none of the cited art suggests treating the subpopulation of Parkinson's patients who experience either "wearing-off" or "on-off" syndrome. ... In addition, the Examiner has not established that "wearing-off" or "on-off" syndromes are necessary consequences of dopamine treatment, or that "wearing-off" syndrome would necessarily be treated by continued administration of combination of a 5HT[1a] agonist and dopamine replacement therapy. Therefore, the evidence of record does not demonstrate that treatment of Parkinson's disease generally will necessarily result in the treatment of either specific "wearing-off" or "on-off" syndrome.
The case makes clear that patient subpopulations are patentable in method of treatment claims. To reject the subpopulation for obviousness, the Examiner must establish either (1) that the prior art suggests this particular subpopulation, and gives a reasonable expectation of success that this subpopulation could successfully be treated, or (2) that treatment of this subpopulation would be a necessary consequence of practicing the prior art.