Cephalon won't have to face a nationwide class-action suit over its heavy-duty painkiller for cancer patients, Actiq, since a federal judge in Philadelphia denied class status in the case this week.

The chief judge of the Eastern District of Pennsylvania, Petrese B. Tucker, departed from some other trial court judges in the Third Circuit to find that the laws of all 50 states would be implicated in the case since there are material differences between those laws. Courts have split on that threshold question, weighing whether there are conflicts among various states' unjust enrichment laws, according to Tucker's opinion.

The sole claim on which the plaintiffs had sought class status was for Cephalon's alleged unjust enrichment through its off-label marketing of Actiq.