Arline MacCormack first heard about DES from her mother when she was 17.
Three decades later, MacCormack believes that the drug her mother took to prevent miscarriages caused her to develop breast cancer at age 44.
MacCormack, of Newton, is one of 53 women from around the country who are suing drug companies that made DES from about 1938 to the early 1970s.
In 1971, the Food and Drug Administration told doctors to stop prescribing DES after a study found that taking it during pregnancy appeared to increase the risk of developing a rare vaginal cancer years later for daughters in their teens and 20s.
DES, or diethylstilbestrol, is a synthetic estrogen that was prescribed to millions of women in the United States and abroad to prevent miscarriages, premature birth, and other problems.
Thousands of lawsuits have been filed since the 1970s alleging links between DES and cervical and vaginal cancer, as well as infertility problems. Many were settled before trial. The Boston case is believed to be the first major litigation alleging a link between DES and breast cancer in daughters over 40.
MacCormack, 50, said she was stunned when she was diagnosed with breast cancer six years ago after having mammograms every six months since she turned 40 because she had had several benign cysts removed.
“The characteristics of my cancer were for women over 60 typically. It wasn’t the type of cancer a 40-year-old or a 44-year-old woman gets,’’ she said.
“When I read the research that’s been done, I found I had more chance of getting it because my mom took DES,’’ she said.
The women’s lawyers say their case is supported by a recent study that suggests breast cancer risk is nearly doubled in DES daughters over 40. The average woman has about a 1 in 50 chance of developing breast cancer by 55. The study, led by Dr. Robert Hoover, a researcher at the National Cancer Institute, found the chance for DES daughters is 1 in 25.
The lawsuit alleges that 14 drug manufacturers - including Eli Lilly and Co. and Bristol-Myers Squibb Co. - withheld reports that showed DES did not prevent miscarriages and raised serious questions about the safety of the drug. “This drug, DES, was the biggest human experiment of quackery in the history of medicine,’’ said Aaron Levine, a Washington, D.C., lawyer who filed the Boston lawsuit.
Eli Lilly and Bristol-Myers Squibb declined to comment.
In court and in public documents, the companies argue that a firm link between DES and breast cancer has not been established and that the DES daughters have not shown that DES caused their cancers.
“We believe these claims are without merit,’’ Eli Lilly said in its most recent annual report.
“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,’’ Bristol-Myers Squibb argued in a court motion.
US Magistrate Judge Marianne Bowler heard testimony from a dozen experts on both sides during a hearing on the drug companies’ motions, which argue that the opinions of the women’s experts are not based on reliable science.
If Bowler grants the drug companies’ motion, the case will not go to trial, Levine said. But if she allows the plaintiffs’ experts to testify, the case can proceed to trial. Final arguments on the motion are scheduled for Jan. 19.