Today we report on two cases involving the learned-intermediary doctrine. One holds that the doctrine applies in the context of clinical trials; the other holds that it applies even when no warning was given by the manufacturer. Both cases highlight the importance of causation in failure-to-warn claims.

Under the learned-intermediary doctrine, which has been adopted by most states, the manufacturer of a prescription medical product must warn doctors, not patients, of the risks associated with the product. It is then each doctor’s responsibility to convey the relevant warnings to his or her patients. Thus, to state a failure-to-warn claim against the manufacturer of a prescription medical product, a plaintiff must allege that the manufacturer failed to adequately warn a patient’s physician of the relevant risks, and that the failure to do so caused the patient’s injury. To plead causation, the plaintiff must allege that the patient’s injury would have avoided if adequate warning had been given, either because the patient’s physician would have treated the patient differently or because the patient, advised of the relevant risk by the doctor, would have refused the injurious treatment.

In Butler v. Juno Therapeutics, Inc., 2021 WL 2156742 (S.D. Tex. 2021), the plaintiffs’ daughter, who had terminal leukemia, died after receiving an experimental drug in the course of an FDA-approved clinical trial. The plaintiffs alleged that their daughter’s death was caused by the defendant manufacturer’s purported failure to warn of a risk associated with the drug. The issue for the court on summary judgment was two-fold: did the learned-intermediary doctrine apply to an experimental drug administered during a clinical trial and, if so, did it bar the plaintiffs’ claims? The court answered both questions in the affirmative.

Because there was no controlling state-court decision resolving the issue, the federal district court had to predict “whether the Texas Supreme Court would apply the learned-intermediary doctrine in the clinical-trial context.” 2021 WL 2156742, at *10.

Drawing a distinction between drugs approved by the FDA and drugs administered as a part of an FDA-approved clinical trial, the plaintiffs argued that under Texas law the learned-intermediary doctrine is limited to FDA-approved drugs. Citing state-court decisions applying the doctrine to claims implicating physical therapy bands, breast implants, and surgical mesh, the court rejected the plaintiffs’ argument, concluding that “Texas law does not limit the learned-intermediary doctrine to FDA-approved prescription drugs.” 2021 WL 2156742, at *10.

In concluding that the learned-intermediary doctrine applies to claims implicating a drug administered as a part of a clinical trial, the court—which found that the defendant manufacturer had not paid the administering physicians to participate in the clinical trial—sidestepped the question of “whether Texas courts would apply the learned-intermediary doctrine to a drug manufacturer that did pay a physician to prescribe its drug.” 2021 WL 2156742, at *9.

Having concluded that the doctrine was applicable, the court then turned to the question of “how the doctrine applies” to drugs administered as part of a clinical trial. 2021 WL 2156742, at *10. According to the court, the relevant considerations include “the existence of [a] physician-patient relationship, (2) the physician’s involvement selecting the product, and (3) the physician’s superior understanding of the interplay between the product’s dangers and the patient’s condition.” Id. (internal quotation marks omitted). Based on evidence produced during discovery, the court found that there was a doctor-patient relationship between plaintiffs’ daughter and the doctors who administered the experimental drug, that the doctors had selected the drug for their daughter, and that the doctors had been advised of its risks. The court concluded that “the Texas Supreme Court would likely apply the learned-intermediary doctrine” on these facts. Id. at *12.

Applying the doctrine, the court held that it barred the plaintiffs’ failure-to-warn claim. The court explained that to overcome the doctrine the plaintiffs had to “show that, but for the inadequate warning, [the daughter’s] doctors would have recommended different treatment, or provided additional warnings that would have led [the daughter] to withhold consent.” 2021 WL 2156742, at *12. Given that the doctors had been warned of the very risk that eventuated, and given that the daughter had consented to treatment despite having been advised of that risk, the court held that the manufacturer was entitled to summary judgment because there was no evidence that an additional warning would have altered the doctors’ recommended treatment or the daughter’s consent to that treatment. In other words, summary judgment was appropriate because there was no evidence that the manufacturer’s purported failure to warn caused the plaintiffs’ daughter’s death.

Today’s second case, Riera v. Mecta Corp., 2021 WL 2024688 (C.D. Cal. 2021), underscores how important the causation element is. The Riera plaintiffs claimed that they suffered permanent memory loss after being administered electroshock therapy with a machine manufactured by the defendant. They sued the manufacturer for failure to warn them of the risk of permanent memory loss.

The manufacturer raised the learned-intermediary doctrine as a defense, asserting that it had no duty to warn the plaintiffs directly and had only to warn their doctors. There was only one problem—the manufacturer had not warned the plaintiffs’ doctors about the risk of permanent memory lost (or anything else, it seems). The plaintiffs argued that this failing rendered the learned-intermediary doctrine inapplicable because, according to the plaintiffs, it applies “only if a manufacturer provided adequate warnings to the intermediary.” 2021 WL 2024688, at *5.

The court concluded that the manufacturer’s failure to warn the plaintiffs’ doctors of the relevant risk did not foreclose application of the learned-intermediary doctrine. The court began by explaining the doctrine’s rationale—namely, to provide lay patients in the only practicable way available highly technical information evaluated and curated by independent medical professionals who know each individual patient’s medical history and condition. The court concluded that, in light of this purpose, the learned-intermediary doctrine applies whenever “drugs or medical devices are supplied in the context of the doctor-patient relationship.” 2021 WL 2024688, at *4 (internal quotation marks omitted).

Like the Butler court, the Riera court explained that to successfully assert a failure-to-warn claim when the learned-intermediary doctrine applies, the plaintiff “must prove not only that no warning was provided or the warning was inadequate, but also that the inadequacy or absence of the warning caused the plaintiff’s injury.” 2021 WL 2024688, at *4 (internal quotation marks omitted). Given that no warning had been given the plaintiffs’ doctors, the dispositive question on summary judgment was whether the plaintiffs had produced sufficient evidence to create a genuine issue of material fact as to causation. The court found that the plaintiffs had not produced such evidence. Rather than offer evidence that their doctors would have changed their treatment recommendations had adequate warning been given, the plaintiffs argued that their doctors would have conveyed that warning to them. “But,” the court said, “whether the doctors would have relayed such warnings and risks to Plaintiffs is not the inquiry—the question is whether the risk of which Defendant failed to warn the doctors was sufficiently high that it would have changed their decisions to prescribe the product for the plaintiffs.” Id. at 5 (internal quotation marks and alterations omitted). The court found that the plaintiffs had “fail[ed] to present specific evidence sufficient to create a genuine issue of material fact as to this factor” and held that the defendant manufacture was therefore “entitled to summary judgment on Plaintiffs’ failure to warn claims” despite its conceded failure to warn.

Causation to the rescue!