Is The Pendulum Swinging Back? Salt Selection And Crystal Form Patents Not Necessarily Obvious

The validity of salt selection patents has been suspect in Canadian courts for many years, on the basis that the work performed in arriving at the invention (a salt form of a known compound) is routine work that is routinely done by every pharmaceutical company¹.

Relatively recently, a patent to a crystal form of a salt was upheld on the basis that, though the empirical work leading to the invention was routine work routinely done, the amount of work and the unpredictability of the result were such that it could not be said that the invention was "more or less self-evident"². On April 11, the Federal Court released its decision in Merck Sharpe & Dohme Corp. and Merck Canada Inc. v Pharmascience Inc.³, extending the trend that there may be inventiveness in salt selection and polymorph cases. Ultimately, the courts are increasingly saying that each case must be considered on its own facts.