Blog

Happenstance Prior Art Disclosure Of Claim Element Insufficient To Support Obviousness

This judgment was made following the hearing of an application under the PM(NOC) Regulations involving Valeant’s Glumetza™, a proprietary formulation of metformin used to treat type 2 diabetes. The patent at issue, Canadian Patent No. 2,412,671, is entitled “Tablet Shapes to Enhance Gastric Retention of Swellable Controlled-Release Oral dosage Forms.” Generic Partners was seeking an NOC to market a generic version of Valeant’s product.

Justice Fothergill found that the 671 Patent solved the problem of dosage forms exiting the stomach more rapidly than was desired with a dosage shape of specified dimensions that, when projected onto a planar surface, is an oval or a parallelogram.  After acknowledging that dosage forms that swell in the stomach to enhance gastric retention were known, the 671 Patent observed that even with swelling there was a “only a limited assurance that swelling would result in gastric retention.” The solution taught was the use of a particular shape of water swellable dosage form to reduce or entirely eliminate the unintended escape of the tablets from the stomach.

After construing Claim 1 to include a “Size Element”, a “Time Element” and a “Shape Element” Justice Fothergill considered Generic Partners’ arguments of anticipation/Gillette defence, obviousness, double patenting and insufficiency.

Under anticipation, it was argued that the 671 Patent was anticipated by the WO 107 PCT application. Justice Fothergill held that since the WO 107 reference did not disclose the “Shape Element” this was fatal to both anticipation and the Gillette defence.

Obviousness, too, failed as Justice Fothergill found that there was “no teaching or discussion of a potential correlation between the shape if a dosage form and gastric retention” in the prior art. While accepting that a prior reference authored by Hwang “depicted a oval-shaped, swellable gastric retentive dosage form”, Justice Fothergill held that this reference did not disclose the “Shape Element” of the 671 Patent because it disclosed other shapes and did not disclose a connection between the oval shape and enhanced gastric retention:

[94]  With respect to the Shape Element, Valeant says that nothing in the prior art taught or even suggested a connection between oval and parallelogram dosage shapes and enhanced gastric retention. Figure 14 in the Hwang paper is a schematic which demonstrates the general mechanism of gastric-retentive swellable dosage forms, and cannot be taken to specify a particular dosage shape. The manner in which the shape of the dosage form affects gastric retention is a critical component of the inventive concept, so disclosure of a multitude of shapes in the prior art is insufficient.

[98]  The fact that the swellable dosage form depicted in Figure 14 of the Hwang Paper appears to be oval was happenstance. Nothing in the diagram or the accompanying text suggested that the Shape Element, specifically an oval or parallelogram, was a relevant factor in improving gastric retention.

Only a brief consideration was given to the other grounds of invalidity, which Justice Fothergill also dismissed

A copy of the decision may be found here.