Three trials over an alleged link between the acne drug Accutane and serious gastrointestinal problems have resulted in verdicts of more than $20 million in New Jersey and Florida state courts. Hundreds of other such cases have been filed in New Jersey, and several of those are scheduled for trial this fall. But at oral argument on Aug. 19 at the federal appeals court in Atlanta, it looked like plaintiffs proceeding in federal court may have a much harder time.

The fight at the Eleventh U.S. Circuit Court of Appeals was over an expert witness who contends the drug causes inflammatory bowel disease, or IBD, which includes disorders like Crohn’s disease and ulcerative colitis.