Voluntary Divisional Applications May Spell Double Trouble

A recent decision of the Federal Court, GlaxoSmithKline v. Apotex, confirms that, even under the post-1989 provisions of the Patent Act (the "Act"), patents that issue from voluntary divisional applications are susceptible to attacks of invalidity on the ground of double patenting. The prohibition against double patenting is one of the numerous grounds for invalidating Canadian patents. In Whirlpool v. Camco, the Supreme Court of Canada held that the prohibition against double patenting involves two branches, namely "same invention" double patenting and "obviousness" double patenting. Under the "same invention" branch, a second patent is invalid if its claims are "identical or coterminous" with those of a patent that issued earlier. Under the "obviousness" branch, a second patent is invalid if its claims are not "patentably distinct" (i.e., novel and inventive) from those of an earlier patent. The courts (including the Supreme Court) have used language in some cases that suggests that