In yet another decision reflecting the crucial role that expert testimony on causation plays in pharmaceutical cases (see here), a New Jersey State Judge recently excluded two plaintiff experts whose testimony sought to connect the acne medication Accutane to Irritable Bowl Disease (“IBD”), particularly Crohn’s disease (“CD”). Given that this case is one of approximately 6,700 related cases that plaintiffs filed against Hoffman-La Roche Ltd., the Judge instructed defendants to submit a list of related cases that his ruling might affect.

The Court’s opinion followed a hearing examining the expert testimony of four witnesses under the New Jersey standard articulated in Kemp v. State of New Jersey, 174 N.J. 412 (2002). As Judge Nelson Johnson explained, a Kemp hearing applies a flexible inquiry that examines whether an expert can identify the factual basis for his conclusion, explain his methodology, and demonstrate that both are scientifically reliable, even if the expert’s opinion is not generally accepted by his peers.

Though acknowledging that the four witnesses examined at the Kemp hearing, including the two excluded witnesses, are “exceptionally learned and accomplished professionals,” the Court still found that the experts were “highly selective, looking no further than they wanted to – cherry picking evidence – in order to find support for their conclusion-driven testimony in support of a hypothesis made of disparate pieces, all at the bottom of the medical evidence hierarchy.” Indeed, the Court explained that the opinions of one of the experts were not “‘methodology based,’ but rather are conclusion-driven. This is an expert on a mission. As cautioned by our Supreme Court, trial courts must attend to ‘the hired gun phenomenon.’” The Court, noting that its review of the scientific literature did not reveal a single study that set out a precise biological mechanism for the development of IBD and CD, firmly stated that: “It is one thing to stand alone in the world of science, advancing a hypothesis that others do not accept. It is quite another thing to advance a hypothesis that can only be supported by disregarding valid scientific research.”

The New Jersey court’s opinion has potentially enormous implications on the thousands of cases that have been brought alleging that Accutane causes CD. In any event, the case provides us with yet another affirmation that disputes over expert testimony are—and should remain—at the forefront of any litigation strategy.