Multi-district litigation over Roche’s anti-acne drug Accutane (Isotretinoin) hit a wall this week when the New Jersey Supreme Court ruled against allowing certain expert testimony.

The more than two thousand lawsuits claimed the drug was linked to Crohn’s disease and offered testimony from experts, while the drugmaker presented studies disputing the connection.

A New Jersey trial court first ordered the parties to exclude the testimony, but an appeals court later overturned that decision.