For decades, a small group of plaintiffs lawyers have been pressing claims against companies that made and sold a synthetic estrogen known as diethylstilbestrol, or DES, which was prescribed to millions of pregnant women to ward off premature births and miscarriages from 1948 to 1971. But after it was linked to a rare vaginal cancer in women whose mothers used it, DES was taken off the market. Studies have since shown that DES didn’t prevent miscarriages, and exposure to the drug in utero has been associated with numerous other illnesses including infertility and breast cancer.

Cases against drug manufacturers have settled in dribs and drabs over the past three decades, and claims against the companies have never been litigated in a large-scale class action. On January 9, plaintiffs lawyers missed a chance to strike a body blow to defendants facing breast cancer-related claims over DES, when the first such case to go before a jury settled in the midst of trial. The confidential deal with defendant Eli Lilly & Co. was reached on the second day of testimony before U.S. Magistrate Judge Marianne Bowler in Boston.

Plaintiffs lawyer Aaron Levine told Legal affiliate The Am Law Litigation Daily he had urged the plaintiffs, four Pennsylvania sisters who suffered breast cancer after their mother took DES during pregnancy, to continue with the trial and refuse to settle. “We must have asked them 100 times,” Levine said. “[We told them] that they could make a statement, they could be rich for life.”

Although the financial terms of the deal are confidential, Levine said that after speaking with jury members after the settlement was announced he estimates they would have returned a verdict of around $40 to $50 million. “We were in World War II and we were headed to the beaches of Normandy,” Levine said. “The jury was right there with us.”

Levine sued Eli Lilly and more than a dozen other pharmaceutical companies on behalf of the four sisters and 49 other plaintiffs in January 2011, after a pair of published studies linked DES exposure to breast cancer in the daughters of women who took it. None of the plaintiffs whose claims remain pending in U.S. district court in Boston currently have a trial date. Levine said their claims will likely head to mediation.

James Dillon of Foley Hoag, who represents Eli Lilly alongside co-counsel from Shook, Hardy & Bacon and Pepper Hamilton, referred comment to a company spokesperson. Eli Lilly sent an emailed statement: “While we continue to believe that Lilly’s medication did not cause the conditions alleged in this lawsuit, we believe the settlement is in the best interests of the company.”

Ross Todd is a reporter for The American Lawyer, a Legal affiliate based in New York. This article first appeared on The Am Law Litigation Daily at www.americanlawyer.com