INTRODUCTION

On January 22, 2015, the British Columbia Court of Appeal set aside certification of a class action against Apotex Inc. and Abbott Laboratories Ltd. in Charlton v. Abbott Laboratories Ltd. (Charlton), in which the plaintiffs allege that the medicine sibutramine (sold under the brand name Meridia by Abbott), an antidepressant that is also used for weight loss, had led to an increased risk of cardiovascular events, including heart attack and stroke. The plaintiffs’ experts had not adduced any evidence on the certification application that there was a methodology to prove causation. The Court of Appeal held that where plaintiffs propose to certify a common issue regarding causation, there must be some evidence that the question may be resolved on a class-wide basis. The trial judge erred and did not properly exercise his gatekeeping function in failing to require “some evidence” of such a methodology to address the central proposed common issue of causation on a class-wide basis, and in certifying the action.

EVIDENCE ON CERTIFICATION APPLICATION 

Both the plaintiffs and defendants had provided expert evidence on the certification application regarding general causation. There had been a clinical trial conducted between 2003 and 2009 (the Sibutramine Cardiovascular Outcome Trial or “SCOUT Study”) that suggested there was an increased risk of serious cardiovascular events associated with sibutramine use by patients with pre-existing cardiovascular problems. The results of the SCOUT Study were published in The New England Journal of Medicine in September 2010 and sibutramine was voluntarily withdrawn from the Canadian market by the defendants in October 2010.

The plaintiffs alleged that the SCOUT Study determined that sibutramine increases the risk of cardiovascular events. They provided affidavit evidence from several class members. Their expert evidence in support of certification focused on two affidavits from Dr. David Fitchett. The court found that he had only a theoretical basis for his risk of cardiovascular incidents is increased for those patients who were prescribed sibutramine. In particular, the court noted that the extent of any such risk had not been studied: “The statistical evidence that is available suggests there is no measurable increase in the risk for patients without a diagnosed history of cardiovascular disease and Dr. Fitchett acknowledges he is unable to quantify the risk.” Dr. Fitchett also had not proposed a method to address that question and there was “nothing proffered by the plaintiffs illustrating how the issue of general causation on a class-wide basis is going to be litigated.”

The defendants provided evidence from several experts, including Dr. Robert Myers, who opined that “the results of the SCOUT study cannot be extrapolated to suggest any increased risk for patients for whom Meridia had been prescribed by physicians in Canada because the vast majority of patients in the SCOUT study had a history of cardiovascular disease and would not have been eligible to receive Meridia.” Dr. Myers also gave evidence that it would not be possible to determine the cause of any individual class member’s medical condition without consideration of the individual’s medical history.

KEY ISSUE ON APPEAL

The chambers judge had certified two distinct aspects of the case: an action to recover damages on behalf of persons who had suffered cardiovascular injury after taking the medicine and an action for disgorgement of all profits by Abbott and Apotex from the sale of sibutramine when it allegedly ought not to have been marketed. On appeal, the defendants did not challenge the chambers judge’s findings that pleadings disclosed a cause of action or that there was an identifiable class, rather they appealed whether the common issues could be certified, particularly the issue of general causation. The key issue on the appeal was whether there was some evidence of a methodology to establish general causation, and whether such a methodology is necessary to certify causation as a common issue.

COURT OF APPEAL’S DECISION

The Court of Appeal found that where plaintiffs seek to address questions of causation on a class-wide basis and to certify causation as a common issue, there must be some evidence of a methodology that will enable them to prove causation on a class-wide basis. The court followed the recent decision of the Alberta Court of Appeal in Andriuk v. Merrill Lynch Canada Inc., which held that where a plaintiff proposes common issues relating to causation of damages, the plaintiff must demonstrate (with evidence) that there is a workable methodology to determine such issues on a class-wide basis at a common issues trial. In Charlton, the B.C. Court of Appeal expressly rejected the plaintiffs’ argument that the requirement of a methodology to establish causation is required only in class proceedings brought on behalf of indirect purchasers in antitrust cases.

The court noted that the where there is some evidence of a methodology by which general causation may be proven, that is sufficient even if there is conflicting expert evidence regarding the interpretation of that evidence and whether it does establish general causation. Conflicting expert evidence ought not to be weighted at certification. However, as the court stated: “[T]his is not a case where the experts disagree on the extent of the risk, but rather, a case where the experts are uncertain whether there is a risk to the class as a whole and cannot describe a methodology for addressing that question.” The Court of Appeal concluded:

The evidence before the certification judge was that the question whether sibutramine causes or contributes to heart attacks, strokes, and arrhythmia on a class-wide basis is incapable of resolution. There was no evidence of a methodology for establishing that the class as a whole, as opposed to those who were wrongly prescribed sibutramine despite a history of disease, was affected or put at risk by its use of sibutramine. The appellants say the trial judge did not properly exercise his gatekeeping function; he is said to have erred by failing to consider whether the class had adduced some evidence of a method of proving the claim. I agree with that submission.

CONCLUSION

The lack of any methodology to establish causation was determinative for the court in setting aside the certification decision. The Court of Appeal also agreed with the defendants that the rest of the common issues that had been certified could not be answered on a class-wide basis without certifying the central proposed common issue regarding general causation.

This decision from the B.C. Court of Appeal recognizes that it is not enough to ask whether the form of the plaintiffs’ proposed common issue is common to all members of the proposed class, but whether there is a means to answer the issue on a class-wide basis at a common issues trial. As Justice Willcock stated: “The question that ought to have been asked at the certification hearing in relation to both types of claims, is not whether the resolution of the general causation question will advance the class claims, but rather, whether there is a reasonable prospect of doing so.” In pharmaceutical and medical device cases, this will generally require some evidence that there is a methodology to address the question of general causation before a class action will be certified.