Mignacca v. Merck Frosst Canada Ltd., [2008] O.J. No. 4731 (S.C.J.)

The issue of overlapping national class actions concerning the same causes of action will soon come before Ontario's appellate courts, thanks to a recent order granting leave to appeal in Mignacca v. Merck Frosst Canada.

The history of the Merck case is complex. Two Ontario class proceedings relating to Merck's drug "Vioxx" were commenced almost simultaneously in 2006. The first proceeding was brought by the Saskatchewan law firm Merchant Law Group. The second was commenced by an Ontario firm, who subsequently (and successfully) sought to have the Merchant Law Group action stayed. However, the Merchant firm continued with a class proceeding it had commenced in Saskatchewan, seeking identical relief and certification of a national class.

The Saskatchewan proceeding was certified in June 2008 ([2008] S.J. No. 324]), just three weeks before the Ontario certification motion, at which Merck both opposed certification and sought a stay of the proceeding in light of the Saskatchewan court's decision to certify. However, Justice Cullity of the Ontario Superior Court certified the proceeding as a class proceeding on July 28, 2008 and refused to stay the action in Ontario.

Merck sought leave to appeal both the certification decision and the ruling with respect to the proposed stay. On November 24, 2008, Justice Bellamy granted leave to appeal the refusal to stay, while denying leave to appeal the certification order. The plaintiffs had conceded that leave to appeal ought to be granted in respect of whether a stay was appropriate for non resident plaintiffs (who would be caught by both proceedings) but not for Ontario plaintiffs. Justice Bellamy found this to be too narrow a position.

Justice Bellamy found that Justice Cullity's decision not to stay the Ontario proceeding was:

...open to very serious debate, given the potential results of allowing two overlapping multi jurisdictional class actions in different provinces to proceed in tandem. Generally, the real possibility that significant confusion may arise where plaintiffs are included in multiple actions addressing similar claims leads courts in one province to give "full faith and credit" to the judgments given by a court in another province or territory. It is seriously debatable whether, in refusing to stay this proceeding pending the Saskatchewan action's ultimate conclusion, the learned motion judge gave "full faith and credit" to the judgment of the Saskatchewan Court of Queen's Bench....

Justice Bellamy concluded that the question of overlapping class proceedings was one of national importance, given the increasing likelihood that such proceedings would be brought in multiple jurisdictions.