Health Law Daily Patients unable to establish general causation between IUD and intracranial condition
Thursday, June 13, 2019

Patients unable to establish general causation between IUD and intracranial condition

Jeffrey H. Brochin, J.D.

General causation was threshold issue in the medical device litigation, and the knowledge of lay jurors is not sufficient to decide issue of complex science.

A federal court in New York has granted the motion for summary judgment filed by Bayer HealthCare Pharmaceuticals, Inc., Bayer Pharma AG and Bayer Oy (Bayer) the developers and manufacturers of the Mirena® intrauterine device (IUD), upon determining that once the court excluded the patients’ expert witness testimony, summary judgment was legally required. Although the law does not rigidly require proof of general causation by expert testimony, neither can causation be established by a collection of lay evidence (In Re Mirena IUD Levonorgestrel-Related Products Liability Litigation (No. II), June 11, 2019, Engelmayer, P.).

General causation the threshold issue. The Mirena IUD is a hormone-releasing contraceptive device which releases the synthetic hormone levonorgestrel (LNG). Patients who used the IUD claimed that LNG caused them to suffer from idiopathic intracranial hypertension (IIH), also known as pseudotumor cerebri (PTC), an uncommon disease marked by increased cerebrospinal fluid (CSF) pressure in the skull. A review of records filed since 2014 demonstrated that an important issue common to all of the proceedings was that of general causation, that is, whether the hormonal component in Mirena was capable of causing intracranial hypertension.

Patient expert witness testimony excluded. The patients proposed to call seven expert witnesses as to general causation, each of whom would assert that using the Mirena IUD could cause a woman to develop IIH; and Bayer proposed to call twelve expert witnesses who claimed that existing evidence and scholarship did not permit that conclusion. Each of the combined 19 experts was the subject of Daubert briefing and oral argument, and on October 24, 2018, the court issued its decision excluding the patients’ seven expert witnesses.

Possibility of Bayer admissions. Following the Daubert ruling, the court directed counsel to confer as to next steps in the case including whether to proceed to summary judgment on the limited issue of general causation. The court recognized that in the absence of expert evidence, the patients might argue that there had been admissions by Bayer that established general causation by Mirena of IIH, and they therefore directed patients’ counsel to identify the alleged admissions as to general causation.

The instant motion for summary judgment. The court’s ruling on Bayer’s Daubert motions left the patients without any expert testimony as to general causation, and Bayer therefore moved for summary judgment arguing that summary judgment in its favor in a pharmaceutical product liability case was categorically required where the patients lacked expert evidence as to general causation. They also argued that as to any theoretical alternative in which corporate admissions of general causation might be substituted for the requisite expert evidence, the patients also lacked such admissions.

Requirement of expert testimony. The court noted that there was much force to Bayer’s argument, it being well established that expert testimony is required to establish causation where the issue of causation is beyond the knowledge of lay jurors. Each jurisdiction typically adheres to that principle. Although expert testimony is not generally required where a lay juror can infer causation from common knowledge and lay experience, in products liability cases involving complex causation issues, expert testimony regarding both general causation and specific causation must be entered into evidence.

No cherry picking of experts’ testimony. The patients proposed that although the court excluded their expert witnesses as to general causation and although no definitive mechanism for PTC/IIH was established, they could nevertheless draw on aspects of the excluded testimony to establish ‘pieces of the larger specific causation puzzle.’ The court rejected the patients’ argument that a lay fact-finder could, by connecting snippets of excluded expert testimony conclude that Mirena was a cause of IIH, and, specifically the assertion that a jury could find general causation by connecting and extrapolating from the disparate propositions they proposed to extract from the excluded expert testimony.

Accordingly, the court held that the remaining evidence failed to supply a basis on which a jury could find the required element of general causation. In the absence of a genuine dispute of material fact as to causation, summary judgment was granted.

The cases are Nos. 17-MD-2767 (PAE) and 17-MC-2767 (PAE).

Attorneys: Eric Michael Terry (TorHoerman Law LLC) for Mary Burdette.

Companies: Bayer Healthcare Pharmaceuticals Inc.

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