A federal appeals court on Thursday sided with two women who developed breast cancer after taking the hormone therapy drug Prempro and sent their cases back for more proceedings.

The 8th U.S. Circuit Court of Appeals said a federal magistrate judge abused his discretion when he blocked expert testimony from a doctor on behalf of Pamela Kuhn and Shirley Davidson.

Kuhn took Prempro, which is used to treat symptoms of menopause, for a little more than three years, while Davidson took it for a year and nine months, the court said. Both women developed breast cancer and sued the drug’s manufacturer, Wyeth. The company moved to block any expert testimony about the use of Prempro increasing breast cancer risk when taken for three years or less.

The magistrate judge sided with Wyeth and precluded testimony from a doctor who said that short-term use of Prempro increases the risk of breast cancer.

“We conclude that the magistrate judge abused his discretion in precluding Dr. (Donald) Austin’s expert testimony, and thus we reverse and remand for further proceedings,” Judge Roger Wollman wrote for two members of the three-judge panel.

Judge James Loken dissented.

Wyeth is now a subsidiary of Pfizer Inc., which spokesman Chris Loder said is considering its legal options.

The district court’s ruling “was well supported by the evidence, which included findings from the Women’s Health Initiative (WHI) showing no evidence that Prempro use for three years or less increases the risk of breast cancer,” Loder said in a statement.

Erik Walker, an Austin, Texas-based attorney for Davidson and Kuhn, applauded the appeals court’s decision.

“We did think the court had gone into the realm of the jury” instead of acting as a gatekeeper, Walker said.

A hearing has not been set yet for either Kuhn or Davidson.

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