A New York federal judge has excluded testimony from all expert witnesses for the women in the multi-district litigation that alleges that Bayer’s contraceptive Mirena causes a rare disease involving spinal fluid.
Mirena Device Controversy
The Mirena contraceptive device is a hormone-releasing intrauterine device. It is placed into the uterus by a trained healthcare provider during an office visit. It works by releasing levonorgestrel (LNG), a synthetic steroid hormone.
The plaintiffs claim that LNG causes idiopathic intracranial hypertension (IIH), or pseudotumor cerebri. This is a rare disease that causes increased cerebrospinal fluid pressure in the brain. If left untreated, IIH can cause headaches, vision problems, or blindness. IIH has been described as “the clinical syndrome of raised intercranial pressure, in the absence of space-occupying lesions or vascular lesions, without enlargement of the cerebral ventricles, for which no causative factor can be identified.”
In 2016, the Southern District of New York dismissed a multi-district litigation of approximately 1,300 plaintiffs who claimed the Mirena caused injuries to the uterus or surrounding tissues. The trial court excluded all of the plaintiffs’ expert witnesses under Daubert because of numerous problems with their testimony. The U.S. Court of Appeals for the Second Circuit affirmed the dismissal and the United States Supreme Court denied the writ of certiorari.
In the current suit, more than 800 women allege that Mirena causes idiopathic intracranial hypertension. The plaintiffs and Bayer agreed that the outcome of the suit would depend on the plaintiffs’ ability to prove general causation, or whether Mirena can cause intracranial hypertension, so the district court ordered expedited briefing on Bayer’s motions to exclude the testimony of the plaintiffs’ general causation experts.
Judge Paul Engelmayer of the U.S. District Court for the Southern District of New York excluded the testimony of all seven of the plaintiffs’ general causation experts. The court found that the expert testimony was inadmissible under the Daubert standard. The court said, “In brief, although plaintiffs’ experts in this litigation have now so opined, outside of this litigation, no medical organization, regulatory agency, article in peer-reviewed scientific literature, or other research has found that use of Mirena is a cause of IIH [idiopathic intracranial hypertension].”
In its 156-page ruling excluding the experts, the court examined the factual background of the Mirena product; LNG; IIH; risk factors and characteristics; the state of scientific research regarding the causes of IIH; and whether contraceptive devices that use LNG, like Mirena, can cause IIH. The court spent over 100 pages of the opinion examining each expert’s background, methodology and theories, and reviewed the extent to which each experts’ theories used the Bradford Hill criteria, or “the metrics that epidemiologists use to distinguish a causal connection from a mere association.”
Judge Engelmayer noted that several of the plaintiffs’ experts failed to adequately explain their conclusion that Mirena causes intracranial hypertension. He suggested that the failure of the experts to explain the weight that they gave to each of the Bradford-Hill factors was one of the reasons that he doubted the objectivity and reliability of their opinions.