The Delaware Superior Court took the mass tort world by surprise with its May 31, 2024, refusal to exclude the plaintiffs’ experts’ causation opinions in the Zantac litigation, breaking with the federal MDL court’s prior exclusionary order and applying Delaware Rule of Evidence 702 “with a liberal thrust favoring admission.” The ruling was so unexpected that some outlets questioned whether Delaware courts would become a new preferred venue for mass tort plaintiffs. But, in a rare move, the Delaware Supreme Court granted the defendants’ request for interlocutory appeal — despite the Superior Court’s refusal to certify the order — and has now restored order, reversing the Superior Court’s decision and remanding for further proceedings. In re Zantac (Ranitidine) Litig., — A.3d —, 2025 WL 1903760 (Del. July 10, 2025).
The Zantac MDL plaintiffs were dealt a crushing blow in December 2022, when the Southern District of Florida excluded the plaintiffs’ causation experts in one of the most careful and thorough Federal Rule of Evidence 702 orders we have seen (as we discussed previously). In response to that ruling, would-be plaintiffs tested their luck in other venues, with nearly 75,000 complaints being pursued in Delaware state court — despite that nearly 80% of those complaints came from plaintiffs who had originally registered their claims in the MDL. Moreover, nearly 90% of the Delaware plaintiffs claimed to suffer from one of the five types of cancer for which the MDL plaintiffs acknowledged there was insufficient evidence of causation.
In light of that background and Delaware’s history as a generally defense-friendly jurisdiction, many observers were taken aback when the Delaware Superior Court denied the defendants’ motion to exclude the plaintiffs’ expert’s causation opinions. The court’s explanation was perhaps even more surprising, concluding that Defendant’s arguments went to weight rather than admissibility and were questions for the jury and distinguishing the MDL court’s ruling largely by claiming that differences between Delaware law and federal law required a different result. Although the Superior Court’s decision did not mention the interim amendments to FRE 702 that took effect in December 2023 and warned against “incorrect” opinions that held “the critical questions of the sufficiency of an expert’s basis, and the application of the expert’s methodology, are questions of weight and not admissibility,” the juxtaposition of the amendments with the Superior Court’s reasoning further underscored the Superior Court’s ultimate message: DRE 702 is to be approached differently than FRE 702.
But that message was wrong. The Delaware Supreme Court began its analysis by noting that “[w]e have interpreted DRE 702 to be consistent with its analogue, [FRE] 702” and that, because “Delaware follows FRE 702,” both the comments to FRE 702 and federal caselaw are helpful to Delaware courts “in discharging their gatekeeping function regarding expert testimony.” Moreover, it explained that the recent amendments to FRE 702 “are not substantive and instead only clarified the existing federal standard.” As such, the commentary accompanying the amendments “offers additional guidance” in interpreting DRE 702, even though it has not yet been amended to conform to the new language of FRE 702.
That proved important, because two of the major errors that the Delaware Supreme Court addressed fell neatly into the categories that the 2023 amendments to FRE 702 were intended to remedy. First, the Superior Court cited a “liberal thrust” toward admitting expert opinion. But one purpose of the 2023 amendments to FRE 702 was to underscore that the proponent of expert opinion bears the burden of proving, to a preponderance of the evidence, that each admissibility requirement has been met. And, as the Delaware Supreme Court noted, the United States Supreme Court’s Daubert opinion may have used the term “liberal thrust” but “did not, however, adopt a ‘liberal thrust’ or presumption favoring admissibility.”
Second, the Superior Court had “abdicated its gatekeeping role by passing crucial questions of sufficiency and reliability to the jury.” While the Delaware Supreme Court did not cite FRE 702 in its analysis of the numerous examples of this abdication, it closely tracked the sentiment underpinning the amendments. As the committee note to the FRE 702 amendments explained, “many courts have held that the critical questions of the sufficiency of an expert’s basis, and the application of the expert’s methodology, are questions of weight and not admissibility. These rulings are an incorrect application of Rules 702 and 104(a).” And, as the Delaware Supreme Court noted, the Superior Court had erred by “dismiss[ing the defendants’] objections and label[ing] them questions for the jury” rather than addressing the arguments and “determining whether the challenged experts reliably applied appropriate methodologies.”
A third major issue, though not caused by diverging from the federal (and Delaware) admissibility standard itself, is one that could have been avoided by following the federal Zantac MDL court’s opinion. The Superior Court had framed the general causation inquiry as asking not on whether the product at issue — ranitidine — can cause cancer, but whether NDMA — an alleged contaminant in ranitidine — causes cancer. In addressing that same issue, the federal MDL court kept the focus firmly on whether ranitidine — including whatever NDMA each dose carries, if any — causes cancer. As the Delaware Supreme Court noted, the Superior Court’s analysis failed to address the gaps created by plaintiffs’ experts’ reliance on studies of NDMA rather than studies on ranitidine, which did not show an increased cancer risk.
As a result of these issues — each of which reflects a departure from FRE 702, federal case law, and/or the federal Zantac MDL court’s analysis – the Delaware Supreme Court reversed and remanded. To borrow a section heading from the Delaware Supreme Court’s decision, the message is clear: “Delaware follows the federal standard.”
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