On Friday, August 26, 2011, in Merck & Co., Inc. v. Garza, the Texas Supreme Court ruled that Merck & Co. does not have to pay a $ 32 million jury award to the family of a man who used Vioxx and subsequently died of a heart attack. In doing so, the Texas Supreme Court reaffirmed its decision in Merrell Dow Pharmaceuticals, Inc. v. Havner which set forth standards that must be met in determining whether epidemiological evidence is sufficiently reliable to prove causation.
Leonel Garza had a long history of heart disease, and took Vioxx, as prescribed by his doctor, for pain relief for the 25 days leading up to his death. After his death, his family sued Merck & Co., alleging Vioxx was defective and was marketed with inadequate warnings. At trail, Merck challenged the scientific reliability of evidence that Vioxx caused Garza’s death. The trial court overruled Merck’s objections, and the jury returned a verdict awarding $ 7 million in actual damages and $ 25 million in punitive damages. The jury verdict was reduced to $ 7.75 million because of a state cap on punitive damages.
Merck appealed, and the appellate court held that the Garza’s could not recover on their defective design, but could recover on their inadequate warning case. The appellate court rejected Merck’s argument that the Garza’s failed to meet Havner’s requirements for proving causation because they had not produced two statistically significant epidemiological studies showing that Vioxx at the dose and for the duration taken by Garza more than doubles the risk of heart attack. In doing so, the appellate court held that “Havner did not establish such a bright-line test for causation but mandated that the sufficiency of the evidence be determined from its totality.” The appellate court found there was sufficient evidence to support causation; however, it reversed the judgment for juror misconduct and remanded the case for a new trial. Merck filed a petition for review complaining that judgment should be rendered against the Garza’s.
The Texas Supreme Court agreed with Merck and clarified its ruling in Havner, holding that causation can not be established without two independent epidemiological studies showing a statistically significant doubling of the relative risk of the injury for patients taking the drug under substantially similar conditions (dose and duration, for example) to the plaintiff’s. The Havner requirements apply to all epidemiological evidence, including the clinical trials relied upon by the Garza’s at trial. If a plaintiff can meet the preliminary requirement of two independent epidemiological studies showing a statistically significant doubling of the relative risk of the injury, then the court will conduct an additional analysis that looks to each of the studies standards of reliability to determine the whether the study’s conclusions are valid based on a totality of the evidence. Ultimately, the Texas Supreme Court held the Garza’s did not present reliable evidence of general causation, and were not entitled to recover against Merck.
In conclusion, the case law is now clear that two independent epidemiological studies showing a statistically significant doubling of the relative risk of the injury are required; however, these studies must also be reliable based on the totality of the evidence in order to be sufficient evidence of causation.