In Miasa Barron, et al. v. Abbott Laboratories, Inc.,[1] the Missouri Court of Appeals recently affirmed a verdict by a St. Louis jury awarding $15 million in compensatory damages and $23 million punitive damages for birth defects caused by the antiepileptic drug Depakote. While there were other issues, the central liability question was whether Abbott adequately warned about the dangers of birth defects from using Depakote during pregnancy.

The parties agreed that Minnesota law governed the liability issues and that Minnesota follows the learned intermediary doctrine (i.e., that a physician acts as an intermediary between a drug manufacturer and the patient, and that warnings concerning prescription drugs given to the physician are deemed given to the patient). Abbott did not dispute that it had a duty to warn the prescribing physician concerning the risks of birth defects or that Depakote caused the plaintiff’s spina bifida, but contended that its warnings were adequate as a matter of law and should not have been submitted to the jury.

Under Minnesota law a warning must attract the attention of those to whom it is directed; explain the mechanism and mode of injury; and provide instructions on ways to safely use the product to avoid injury. Abbott contended that it adequately warned doctors about the potential for birth defects in a “black box” on the label prominently displaying the warnings in a fashion calculated to catch the eye. The plaintiff’s warnings expert agreed that a black box warning is the most serious type of warning mandated by the U.S. Food and Drug Administration, and is the most significant way to emphasize a warning or safety information about a drug.

The treating physician testified that he discussed the risks of birth defects with the patient, and that she understood that she should not get pregnant while taking the drug, but that the black box warning did not convey to him that the risk of birth defects from Depakote was greater than from other anti-epileptic drugs, and that he would not have prescribed Depakote had he known this. Abbot countered that it had no duty to warn about the relative risks of its own products compared to those of other products, and that it fully satisfied its duty to warn doctors about the risks of birth defects as a matter of law, leaving nothing for the jury to decide.

Barron illustrates an important question in product liability litigation: how is the adequacy of a warning determined? Abbot sought to present the issue as one of duty. The existence of a duty to warn is generally an issue of law to be determined by the judge rather than a jury. Abbot argued that the treating physician and the patient were aware that taking Depakote during pregnancy created a risk of birth defects, and that it had no duty to warn that other products allegedly presented a lesser risk. The plaintiff asserted that that Abbott’s duty to warn was not in question, but that the adequacy of the warning it gave was an issue of fact for the jury under Minnesota law, and that failing to disclose the allegedly greater risk of taking Depakote versus competitors made the warning inadequate.

The Missouri Court of Appeals agreed with plaintiff, saying, “Issues such as the adequacy of the warning, breach of duty and causation are for the jury’s resolution.” Pointing to the testimony of the treating physician and testimony of Abbott personnel that information relating to the risk of birth defects was regarded as an obstacle to sales and damaging to Depakote, it held that the jury had “significant evidence before it” to make a determination that Abbott’s black box warning was inadequate.

Barron illustrates the challenge faced by product sellers in defending warning claims against all types of products, not only pharmaceuticals: even where a clear warning is given and understood, its adequacy may still be determined by a lay jury weighing complex scientific issues and conflicting expert testimony.