INNsight article by Sharon L. Caffrey

Epidemiology can be a powerful tool in the defense of pharmaceutical products liability matters, evidenced by the U.S. Circuit Court of Appeals’ recent decision in Bishop v. Hoffman La-Roche, Inc. (In re Accutane Prods. Liab.).¹   Experts who attempt to prove a causal connection between a drug and an outcome or injury without epidemiologic evidence of an association are required to come forward with a methodology supporting the basis of their opinion that has a sound foundation in science.  Experts who rely on scientific hypothesis—without scientific data—should not be permitted to testify in court regarding causation.  Case reports are rarely sufficient to satisfy legal causation standards, as outlined in the Reference Manual on Scientific Evidence.²  
 
Challenges to the scientific opinion of an opposing party’s expert are based upon Daubert v. Merrell Dow Pharmaceuticals, Inc.³  in federal court.  Daubert requires an expert’s opinion to be based on a scientifically sound methodology.  Without epidemiologic evidence of a causal association between a drug and an outcome or injury, the expert’s methodology may be subject to challenge.  While epidemiologic evidence of a causal association is not always required, the expert’s opinion may be vulnerable without such evidence.  In re Accutane provides an example of a successful challenge to an otherwise qualified expert’s opinion regarding the existence of  causation in the absence of epidemiologic evidence supporting such an opinion.

Plaintiffs in In re Accutane sought to introduce testimony of a highly qualified gastroenterologist, Dr. Ronald Fogel, to support their general causation claim that Accutane causes inflammatory bowel disease (IBD).  The court had previously ruled that Dr. Fogel’s opinion “overreached the underlying scientific data,” by an order dated June 15, 2007.  Dr. Fogel issued a second report, which contained more detail and explanation. 

The U.S. District Court for the Middle District of Florida noted Dr. Fogel’s qualifications and allowed him to opine about the causes of IBD: He is board-certified in gastroenterology, the head of the Division of Gastroenterology at Henry Ford Hospital, and has served on several peer-review panels and on the Gastrointestinal Drug Advisory Committee for the U.S. Food and Drug Administration.  Despite these qualifications and his reinforced expert opinion, the court found Dr. Fogel’s opinion lacking.

Dr. Fogel’s opinion was based in great part on a case-series report in a peer-reviewed journal.  The article reviewed the case reports of Accutane ingestion and IBD and discussed the biologic plausibility of IBD developing from Accutane ingestion.  However, the authors of the piece concluded only that there was a possible association and that IBD might be triggered by Accutane.  They did not find an association between Accutane and IBD. 

The court also looked at the incidence of IBD in the general population and in the subset of the population in the demographic group who use Accutane.  The court noted that more than 20 cases of IBD would be expected among persons using Accutane, absent a causal association between Accutane and IBD.  Since the author of the case series could not show that those who ingest Accutane have more occurrences of IBD than the general population, Dr. Fogel’s opinion that Accutane may trigger IBD was, in the court’s opinion, simply a hypothesis—not a basis for scientific causation.  The fact that his opinion was rooted in the article and nothing more left a “gap between hypothesis and opinion.”  The court precluded Dr. Fogel’s opinion and granted the defendants’ motion for summary judgment, and the Circuit Court upheld the trial court’s decision.   
 
The In re Accutane decision indicates the significance of evaluating the strength of the epidemiology—if any—showing a hypothesis or causal association between a drug and the purported outcome early in litigation.  Weak associations may not be sufficient to withstand a Daubert challenge.  Thus, when faced with a new products liability case, a pharmaceutical company may want to consider assessing the strength of the epidemiologic support for the plaintiff’s claims to build its defenses and assess its liability.

1. Bishop v. Hoffman La-Roche, Inc. (In re Accutane Prods. Liab.), 2010 U.S. App. LEXIS 9388 (11th Cir. Fla. May 7, 2010).
2. See Mary Sue Henifin, Federal Judicial Center, Reference Manual on Scientific Evidence: Reference Guide on Medical Testimony, 480 (2d. Ed. 2000).
3. Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993).