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Generic and Brand Name Drug Companies Meet in Federal Court
On October 17, 2006, Mr. Justice Hughes, of the Federal Court, found for the plaintiffs in a patent infringement action brought by Daiichi Pharmaceutical Co., Ltd. and its Canadian licensee, Janssen-Ortho Inc., against generic drug manufacturer Novopharm Limited. The patent in issue relates to the antimicrobial drug levofloxacin, which is marketed in Canada under the trademark LEVAQUIN. Michael Charles, Andrew McIntosh, and Joshua Spicer of Bereskin & Parr acted for Daiichi in the case.
The main issues before the court were claim construction and the validity of the patent. Novopharm alleged the patent was invalid on grounds of anticipation, obviousness, ambiguity, and insufficient disclosure.
Levofloxacin is the S(-)-enantiomer of the previously patented racemic compound ofloxacin. Ofloxacin was a known efficacious antimicrobial drug. Levofloxacin is one of the two optical isomers of ofloxacin. The disclosure taught that levofloxacin, as compared to ofloxacin, has superior antimicrobial activity, weaker toxicity, and higher solubility, and gave examples of the synthesis of levofloxacin at 90% or higher enantiomeric excess. The single claim in controversy claimed the S(-)-enantiomer of ofloxacin without any express limitation concerning the presence of racemic ofloxacin, or the other enantiomer. Justice Hughes construed the claim as "S(-) Ofloxacin, different from that contained in the racemate, obtained in a reasonably pure state." Had Justice Hughes not so construed the claim, it would have read on S(-)-ofloxacin present in the racemate and the patent would have been invalid for anticipation.
On anticipation, Justice Hughes considered the recent House of Lords decision in Synthon v. SmithKline Beecham PLC's Patent, [2005] UKHL 59, which he characterized as having "put the matter succinctly: there are two requirements for anticipation, enablement and disclosure." Then, based on the test set out by the Supreme Court in Free World Trust v. Electro Santé Inc., [2000] 2 S.C.R. 1024, he held there was no anticipation in view of either the prior Canadian patent for ofloxacin or a prior publication disclosing ofloxacin. There was no "flag" planted at the point of the claimed invention (levofloxacin), and no direction given such that an ordinary person skilled in the art would in every case, without possibility of error, be led to levofloxacin.
In his obviousness analysis, Justice Hughes commented that the classic test as established by the Federal Court of Appeal in Beloit Canada Ltd. v. Valmet OY (1986), 8 C.P.R. (3d) 289 (F.C.A.), could come "perilously close to that for anticipation" if narrowly applied. He enumerated a list of ten factors required for a determination of obviousness on a "principled and objective basis". Justice Hughes noted that the person of ordinary skill postulated in Beloit had been supplanted by the uninventive skilled person described by the Supreme Court in Whirlpool Inc. v. Camco Inc., [2000] 2 S.C.R. 1067, who is reasonably diligent in keeping up with advances in the field. After considering the evidence in light of each of the factors, he concluded that levofloxacin was "of sufficient 'inventive ingenuity' to merit valid patent protection as set out in claim 4" (the claim at issue). He found that at the relevant time the concept of separation of racemic drugs into their enantiomers was known but that interest in it was still in its infancy, and within the field of the particular class of drug at issue was given little attention. He also pointed out that only Daiichi was motivated to pursue obtaining the enantiomers of ofloxacin as there was no evidence led otherwise.
Justice Hughes refused to find claim 4 was ambiguous for failing to specify what level of purity is required by the claim. Regarding sufficiency, he held that a paucity of toxicity and solubility data and some discrepancies in the disclosure did not invalidate.
Justice Hughes awarded the plaintiffs damages and a permanent injunction to take effect 30 days from his Judgment.
The full text of the decision can be found at http://decisions.fct-cf.gc.ca/en/2006/2006fc1234/2006fc1234.html.
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