The Texas Supreme Court granted review for a Houston law firm on the losing end of a court of appeals decision that held 4,000 fen-phen plaintiffs are not collaterally estopped by a final judgment in a related case.

Fen-phen was a diet drug combination of drug combination fenfluramine and phentermine, shown to cause fatal pulmonary hypertension and heart valve problems. It was withdrawn from the market in 1997, and numerous mass tort lawsuits resulted in more than $13 billion in legal damages.