citation(s): (2002), 22 C.P.R. (4th) 466 (F.C.T.D. per Dawson J.) online: 2002 FCT 1138 , November 5, 2002
Case Comment © 2005 Donald M. Cameron, Cameron MacKendrick LLP
Sertraline was patented and used for the treatment of depression under the trade-mark Zoloft.
Pfizer obtained a second patent for use of sertraline for the treatment of anxiety-related disorders including Obsessive Compulsive Disorder (OCD) and Panic Disorder (PD), a new use for an old drug.
The judge found that the prior art taught:
Dawson J. found the alleged invention to be obvious: no inventive step
required or undue experimentation.
Pfizer Canada Inc. markets and sells sertraline in Canada under the trade-mark Zoloft.
 Sertraline is not a new drug. On August 31, 1982, Canadian Letters Patent No. 1,130,815 (" '815 Patent ") were issued to Pfizer in relation to the use of sertraline for the treatment of depression. The '065 Patent discloses and claims new uses for sertraline for disorders which are distinct from depression. The patent states:
Sertraline may be used to prevent or alleviate anxiety and the symptoms associated with anxiety-related disorders in patients treated with the drug. It is therefore useful in the treatment and management of anxiety-related disorders such as panic disorder, generalized anxiety disorder, agoraphobia, simple phobias, social phobia, posttraumatic stress disorder, obsessive-compulsive disorder and avoidant personality disorder.
 The '815 Patent has expired. Upon its expiration Apotex received a NOC for Apo-Sertraline for the treatment of depression only.
Apotex alleged that the patent is invalid on the basis of obviousness .
 Without conducting experiments with sertraline it was not known that sertraline would be effective for treatment of OCD and PD. The most that could be said was that it was worth a try to do a trial with sertraline.
 Notwithstanding, as Mr. Justice Wetston noted in Apotex Inc. v. Wellcome Foundation Ltd. (1998) 79 C.P.R. (3d) 193; affirmed (2000) 10 C.P.R. (4th) 65 (F.C.A.) at paragraph 243 "[t]here is no inventiveness in following an obvious and well-charted route using known techniques and processes involving known compositions unless the inventor encounters difficulties that could not have been reasonably expected by a person versed in the art or overcome by the application of ordinary skill". However, having considered the totality of the evidence adduced by affidavit and the transcripts of the cross-examinations, and bearing in mind that the test for obviousness is difficult to satisfy, and that the solution to the problem must be plain as day or crystal clear without the need for experimenting or serious thought, I am satisfied that Pfizer has failed to meet its burden to establish on a balance of probabilities that the allegation of obviousness is not justified.
 In the case before him, Justice Wetston was satisfied that the prior art "would not have led an unimaginative skilled technician to the invention without undue experimentation" (at paragraph 264). This expression of the test was found to be without error by the Court of Appeal (at paragraph 63).
 I conclude on the evidence that a skilled psychiatrist keeping up with developments in his field would be taught by the literature that SSRIs, of which sertraline is one, were logical candidates for further investigation for both OCD and PD, that sertraline was in trials with respect to OCD, that sertraline was probably one of the SSRIs that would be a cornerstone of OCD treatment and that preliminary results suggested that drugs, including sertraline, should have anti-panic activity. I see no inventive step or undue experimentation required in that circumstance for the notional skilled psychiatrist to prescribe sertraline for OCD or PD.
 The inventive step, that is the discovery that the use of sertraline will aid in the treatment of PD and OCD, was clearly advocated and recommended as of November 2, 1989. ...
Cameron's Canadian Patent & Trade Secrets Law: Home Page; Index
JurisDiction Home Page