A recent Ontario Superior Court decision denying certification of a pharmaceutical class action could have a significant impact on the conduct of product liability class actions in the province.  In rejecting certification, the court closely analyzed the claim being advanced and the common issues proposed and concluded the action was not suitable for certification.  The court provides a helpful analysis in relation to a number of important issues that arise in many of these cases.


In Martin v AstraZeneca Pharmaceuticals, a group of plaintiffs brought a proposed class action in the Ontario Superior Court regarding an anti-psychotic drug.  The plaintiffs claimed that the various defendants had failed to warn class members that the drug could cause weight gain and associated health issues.  The plaintiffs also alleged that the defendants had been negligent in the design, manufacture and distribution of the drug.  The defendants denied these allegations, pointing to evidence that the labels included warnings regarding issues complained of. 

Statement of Claim criticized

In denying the motion for certification, the Ontario court was critical of the plaintiffs’ Statement of Claim, finding that it contained numerous deficiencies. Chief among these was the plaintiffs’ failure to explain why the labels were inadequate and whether, or even if, the labels could have been improved. Ultimately, the court found that the plaintiffs had not properly pleaded the facts and legal elements necessary to establish that the defendants had failed to warn of the risks associated with the drug or had otherwise been negligent in any manner in regard to the drug. 

Off-label allegations dismissed

The court also dismissed plaintiff allegations that the defendants had excessively promoted the drug to doctors for uses that had not been approved by Health Canada (this is known as “off-label” use).  The court found that the defendants did not have a duty to “ensure” that the drug was not distributed, marketed or sold for off-label uses.  This is because doctors had the legal right to prescribe the drug for off-label uses, regardless of the defendants' conduct.

General causation common issue denied

In a departure from the recent trend in pharmaceutical class actions, the court also refused to certify as a common issue the question of whether the drug can cause weight gain.  While such “general causation” common issues have been certified in prior pharmaceutical cases, the court found that even if this common issue were resolved in favour of the plaintiffs, it would do little to advance the case since each plaintiff would still have to prove that his or her weight gain was caused by the drug.  The court noted that, “The evidence showed this general causation question is just the beginning of the inquiry and that its resolution is dependent upon individual findings of fact with respect to each claimant.” 

Potential impact of the decision

While the full implications of this decision remain to be seen, the extensive and detailed analysis has the potential to significantly affect future pharmaceutical certification motions.  The court’s approach to the Statement of Claim, and its analysis and findings regarding the product labels, off-label use and general causation, will be helpful to defendants dealing with similar claims and more closely reflects the highly regulated nature of the pharmaceutical industry.  The decision was also written by one of the three judges on Toronto’s class action team and so it is likely to be influential in other jurisdictions.  A similar claim brought in Quebec was also dismissed at the authorization stage, and an appeal of a denial of a motion for authorization in Quebec is currently before that province’s Court of Appeal.