Delaware Supreme Court sides with GSK, Pfizer on expert testimony in Zantac case

The Delaware Supreme Court ruled that expert testimony tying Zantac to cancer was not admissible, siding with arguments from GSK (GSK), Pfizer (PFE) and Boehringer Ingelheim. The court found that the trial judge, who was overseeing roughly 75,000 lawsuits, made a mistake in letting the cases move forward to trial. The opinion states, “This Court accepted an interlocutory appeal from the Superior Court’s decision denying a series of motions that sought to exclude several expert reports proffered by the plaintiffs in support of their position that Zantac containing ranitidine-or its generic-is capable of causing the ten types of cancers at issue in this case. In their motions, the defendants raised several objections to the methodologies that the plaintiffs’ experts employed to support their general causation conclusions. The Superior Court, however, concluded that all those objections amounted to disputes that were questions for the jury, not the trial judge. In so doing, the court referred to the “liberal thrust” of Delaware’s evidentiary rules as favoring the admissibility of expert testimony, concluded that Delaware’s rule is distinct from the analogous federal rule, and held that the expert’s general causation conclusions could be based on the alleged disease-causing agent, rather than the product at issue in this case. We reverse. First, the Superior Court erred in adopting a standard that favored or presumed the admissibility of expert testimony. Under our rules and existing precedent, the proponent of an expert opinion bears the burden of establishing that the opinion is based on sufficient facts or data and on dependable principles and methods that are reliably applied to the facts of the case. Unless these sufficiency and reliability elements are established by a preponderance of the evidence, the opinion is not admissible. Delaware’s evidentiary rules governing expert testimony are consistent with federal law. A trial judge must act as the gatekeeper of expert testimony and should not dismiss challenges to the sufficiency or reliability of an expert opinion by viewing the disputes as questions for the jury to weigh. Second, the trial court erred in framing the general causation question at issue in this case. General causation addresses whether the substance at issue is capable of causing the harm alleged. The court concluded that the experts could base their conclusions on studies regarding the alleged disease-causing agent rather than the product at issue in the case, without establishing a reliable bridge between the product at issue and the scientific data regarding the toxic agent. In so holding, the trial court failed to require the experts to apply a reliable scientific methodology to reach their conclusion that the exposure to the toxic agent in the studies on which the experts relied was comparable to the exposure to the toxic agent caused by the product. That holding was inconsistent with Delaware law.”