(CN) - In a blow to pharmaceutical companies, a federal judge has agreed to let experts testify that a pregnant woman's use of synthetic estrogen increases the risk of her daughter developing breast cancer.
DES, or diethylstilbestrol, is a synthetic estrogen that was prescribed to millions of women between 1940 and 1970 in the mistaken belief that it would reduce the risk of miscarriages. In 1971, DES was shown to cause a rare vaginal tumor in women who had been exposed to the drug in utero. The FDA then banned its use in pregnant women.
Individuals who were exposed to DES during their mothers' pregnancies are referred to as "DES daughters" or "DES sons." Numerous cases have been brought by DES daughters alleging links between DES and cervical and vaginal cancer, as well as infertility.
In a case filed in 2011 in the District of Massachusetts, 53 DES daughters with breast cancer sued 14 pharmaceutical companies, including Eli Lilly and Co., Merck & Co., and Bristol-Myers Squibb. They allege that their exposure to the drug substantially increased their risk of contracting breast cancer.
Last week, U.S. Magistrate Judge Marianne Bowler agreed that the plaintiffs can have experts testify about the DES-cancer link.
"I find that the experts plaintiffs propose satisfy the requirements of providing opinions that will assist the trier of fact," Bowler wrote. "I also find and reiterate that they are all qualified as experts in their fields."
In its motion to exclude the testimony, Bristol-Myers Squibb argued that "there is not a single published study, a respected medical treatise or textbook, nor a pronouncement by one of the prominent societies dedicated to the discovery of cancer causes which claims a causal link between prenatal DES exposure and breast cancer has been proven."
But the plaintiffs countered that "it was defendants' expert, Dr. Bluming, who best portrayed the heart of this controversy when he quoted Nietzsche: 'There are no facts, there are only interpretations.'"
"This is a very important victory for DES daughters with breast cancer," said plaintiffs' attorney Julie Oliver-Zhang, also speaking for co-counsel Aaron Levine, both of Aaron Levine & Associates.
"The judge listened to 12 experts in this case and felt that it was imperative that she deliver the order from the bench that our expert is qualified and reliable."
Bowler ordered immediate mediation, "especially because of the health and the age of this group of DES daughters," Oliver-Zhang added. "We feel very positive going forward, and really the ball is in the defendant's court as to whether they'll cooperate with mediation."
Noting that "the facts of this case are somewhat unique," the judge said the plaintiffs face no small task in backing their claims with firm, scientific evidence.
"We have a relatively defined cohort of women inasmuch as no scientist today is going to give pregnant women DES today along with a control group and assess the development in their offspring of breast cancer years later," Bowler wrote on Jan. 20.
"It is therefore difficult, if not impossible, to conduct human studies to test the consistency of the association between the environmental exposure to DES in utero and the subsequent development of breast cancer. The temporal relationship between the exposure and the development of the disease, however, tracks the natural age at which breast cancer typically appears and breast cancer is not a rare disease."
Bowler's acknowledgement of the plaintiffs' "uphill battle" was not lost on the Oliver-Zhang.
"The judge is not mistaken that there is an uphill battle facing us, but we won a critical battle in this war," she said. "I've lost now five clients since the inception of this litigation to breast cancer, and I have four more who are Stage IV breast cancer victims and survivors. I have an 87-year-old mother who had to watch her daughter's breast cancer spread to her liver, her kidneys, her eye. A woman whose daughter was never able to have children because of DES. This is a terrible human tragedy that we're facing."
"It's very, very crucial that awareness and the word get out because that may actually save lives," she added. "Our hope is that there will be awareness out there that DES daughters should be vigilant about screening for breast cancer, and it is going to be a part of the discussion to have the drug companies fund additional research and educate the medical communities, so that doctors ask the right questions about exposure."
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