The current state of causation evidence in toxic tort litigation has generated grumbles of unreliability, understandable controversy and the feeling of a jury crap shoot. Jurors are often left weighing statistical evidence containing large data gaps and speculative extrapolations versus sympathetic claims often involving debilitating or fatal diseases. However, the emerging advances in genomics, the ever-increasing compilation of genetic data and the lower costs of individualized testing has opened the door for the use of individualized genetic evidence to support and defend toxic torts with a level of unprecedented reliability.
Genomics is the study of human genes, their interactions with other genes and the impact of environmental factors. DNA is the road map guiding and directing all living organisms. DNA regulates protein production, which affects body’s cell, tissue and organ formation and function. Humans, in general, have tumor suppression genes, DNA repair genes, genes that control cell growth and genes that affect the metabolism of toxic substances in your body. When “normal” genes are damaged (mutated) through multifactorial source(s), discussed below, your ability to combat disease is compromised, potentially leading to the development of cancer and other illnesses. While more simplistic DNA and genetic evidence is commonplace in criminal cases, paternity disputes and medical malpractice litigation, the emerging genomic-based evidence will predictably become a critical and routine practice in toxic torts.
Toxic torts are a type of personal injury suit whereby a plaintiff claims that exposure to a substance or chemical has caused a particular injury or disease. The more common toxic tort claims arise from cancers allegedly caused by exposure to asbestos, tobacco, benzene, pesticides, herbicides or more recently talcum (baby powder). For example, in February and May 2016, juries awarded verdicts of $72 million and $55 million against Johnson & Johnson (J&J), respectively, to plaintiffs who claimed their personal use of talcum powder caused gene mutations in their ovary tissue leading to cancer. The overwhelming percentage of these verdicts were for punitive damages due to the jurors’ belief that J&J failed to warn its consumers, despite 40 years of statistical evidence, of an increased risk (up to 33 percent) associated with feminine genital use of talcum powder and ovarian cancer. J&J argued that available studies prove that talc, which has been used for over 100 years, is safe. J&J also argued that the plaintiffs’ statistical evidence was inaccurate, misleading and unreliable. There are about 1,200 talcum powder cases pending with a threat of large verdicts despite no definitive understanding exactly how talc may cause cancer. Perhaps genomics and individual genetic data will provide definitive answers to the statistical causation evidence debate in analogous future cases.
To prove the causal link in toxic torts between exposure and injury, a plaintiff must prove that, first, the substance may cause the claimed injury in the general population (general causation); and that, second, the exposure did, in fact, cause the individual’s injury (specific causation). Experts typically rely on epidemiological studies (trends of exposure and disease in the general population) to prove or refute general causation. While there are an ever-increasing number of epidemiological studies, courts have shown a reluctance to allow experts to broadly rely on this data, as in Burst v. Shell Oil, No. 15-30592, 2016 U.S. App. LEXIS 9386 (5th Cir. May 23, 2016) (precluding the plaintiff’s expert opinion relying on “pure benzene” exposure studies in an attempt to link the plaintiff’s occupational gasoline fume exposure to his acute myeloid leukemia, rather than any “gasoline containing benzene” exposure studies). Even when respected epidemiological studies substantiate general causation—specific causation often becomes an insurmountable burden leading to the preclusion of experts under Frye or Daubert challenges or admissibility challenges under Federal Rule of Evidence 702 or the states’ equivalent.
To support specific causation arguments, the experts generally evaluate “relative risk,” “differential diagnoses” and dose-response data. Most courts require a relative risk of two or greater, which means that an “exposed” group is at least twice as likely (“more likely than not”) to develop a disease than the general “unexposed” population. The specific causation arguments are complex considering that diseases alternatively originate from gene mutations (improperly functioning genes) caused by multi-factorial sources including: inherited (germline) mutations; acquired (somatic) mutations that occur from natural or unknown reasons during cell division or DNA replication; and/or through environmental factors such as nutrition, lifestyle and exposure. For example, in Milward v. Rust-Oleum, No. 13-2132, 2016 U.S. App. LEXIS 7470 (1st Cir. Apr. 25, 2016), the plaintiff alleged that his occupational exposure to benzene caused acute promyelocytic leukemia. The court precluded the plaintiff’s expert’s specific causation testimony on unreliable methodology grounds because she failed to explain why she relied on favorable studies to establish an increased relative risk between an individual’s exposure to benzene and APL, while completely ignoring contrasting studies. Emerging genomics may eliminate the need for the statistical approach to causation evidence.
In 2003, an international collaboration of scientists completed the revolutionary Human Genome Project (HGP), which sequenced and mapped the complete set of human DNA, see www.genome.gov. The HGP has estimated that a human has up to 25,000 genes. The HGP has currently spawned over 2,000 genetic condition tests, has led to the discovery of over 1,800 disease (mutated) genes and has led to numerous other comprehensive studies and databases that identify and categorize mutated genes and/or associated diseases. See report.nih.gov/NIHfactsheets, and then access the HGP link.
The Million Veteran Program (MVP) is one such ongoing study where veterans within the Veterans Affairs Healthcare System provide genetic samples allowing the study of, among other things, disease genes in order to identify and categorize illnesses, associated mutated genes, and causation factors such as toxic exposure. While not directly related to the MVP, to understand the types of studies in the MVP, see Page v. McDonald, No. 15-0778, 2016 U.S. App. Vet. Claims LEXIS 424 (Vet. App. Mar. 23, 2016) (vacating denial of no medical examination determination for claim that exposure to Agent Orange mutated a tumor suppressor gene and caused colon cancer). Emerging genomic science will allow experts to steer away from statistical or general population studies and speculative extrapolations by explaining the individualized gene mutations, the multi-factorial sources thereof and resultant diseases. These studies and databases will be powerful and effective tools in proving or refuting exposure claims by making causation arguments more individualized, accurate and reliable.
Two key emerging areas providing individualized and reliable evidence are biomarkers and predisposition or susceptibility genes. For example, a plaintiff may be able to offer proof of biomarkers, which are telltale evidence at the cellular level that affirmatively prove and even quantify toxic exposure. Additionally, a plaintiff may be able to show that he or she was predisposed to a specific illness irrespective of any general population trends thereby eliminating the need for a relative risk evaluation. For example, if your family has a history of breast cancer, then you are likely to carry genes that make you susceptible to an increased risk of breast cancer. The plaintiffs will attempt to use analogous arguments supported by individualized genetic data to show that he or she had a heightened sensitivity to a particular substance, and the exposure was the specific cause of the injury. On the other side, the defendants will argue that the injury had nothing to do with an alleged toxic exposure, but rather that the injury was inevitable due to the inherited predisposition gene.
The use of individualized genetic information will be contentious. Plaintiffs who put their physical condition at issue must be willing participants in genetic sampling that can open a Pandora’s Box of other legal, moral, discriminatory and ethical issues. For example, think of scenarios that may arise under the Genetic Information Nondiscrimination Act of 2008, 122 Stat. 881, which prohibits the use of genetic information in health insurance and employment. Federal Rule of Civil Procedure 35, and states’ equivalents, allows a party to compel genetic testing. On the other hand, the U.S. Supreme Court has recognized that blood draws are “an invasion of bodily integrity implicat[ing] an individual’s most personal and deep-rooted expectations of privacy,” as held in Missouri v. McNeely, 133 S. Ct. 1552, 1558, 185 L. Ed. 2d 696 (2013).
In Meyers v. Intel, No. N11C-07-009 JRJ, 2015 Del. Super. LEXIS 285 (Super. Ct. June 11, 2015), a mother brought an action claiming that the parents’ occupational chemical exposures caused her child’s birth defects. The court denied the defendant’s motion to compel “state-of-the-art” genetic testing of the nonparty father on the basis that the court lacked authority to compel such highly invasive testing compared to his significant privacy concerns. Because both parents’ genetics were required, the defendants could not complete the desired testing.
The application of genomics and individualized genetic testing to toxic torts will become routine practice to support and defend toxic tort claims and will almost certainly create some controversial precedents in the near future. •