A little over a year ago, we discussed one of the best decisions we had ever read on why comparative risk claims – premised on a manufacturer’s alleged failure to warn that a competing product was supposedly “safer” – are both statistically invalid and practically impossible.  That decision, Nelson v. C.R. Bard, Inc., 553 F. Supp.3d 343 (S.D. Miss. 2021), explained at length both how product “comparisons,” if based on the FDA’s voluntary “MAUDE” adverse event reporting system are inherently suspect due to “informational bias,” id. at 355, and, if based on non-public information, would require access to unavailable information about competitors’ products.  Id. at 354-55.

Plaintiffs’ “failure to disclose comparative risk” theory effectively charges manufacturers and sellers with having to know their competitors’ products’ failure rates, ignores the informational biases associated with the latency with which manufacturers or sellers receive complaints for new products as compared to established products, and creates new liability in every instance where one product is alleged to have higher risk of complication than another—regardless of whether any such difference has clinical significance.

Id. at 354.

Not too long ago we informed our readers that Nelson was affirmed.  Nelson v. C.R. Bard, Inc., 44 F.4th 277 (5th Cir. 2022).  Unfortunately, however, the appellate decision in Nelson avoided the comparative warning question, finding the risk discussion in the defendant’s labeling was adequate as a matter of law because it identified all of the relevant risks, and Mississippi law requires “failure to warn cases [to] be based upon the warning label itself − its text and language − rather than internal documents.”  Id. at 284 (following Johnson & Johnson v. Fortenberry, 234 So. 3d 381, 393 (Miss. 2017)).  As a result, the Fifth Circuit in Nelson did not reach the viability of comparative risk liability theories:

The district court noted the problematic policy concerns that would follow potential liability for failure to include comparative device risk information in warnings.  We do not address policy considerations, however perceptive; nor do we conclusively decide as a matter of Mississippi law whether a warning, using other language and in other circumstances, might be inadequate for failing to include undisclosed same-device “dangers.”

44 F.3d at 283-84.

Even though the Fifth Circuit, in Nelson, didn’t address the deficiencies of comparative warning liability theories, we’re not entirely empty handed.  As the opinion mentions, that issue was the focus of considerable briefing.  So we retrieved the defendant’s principal brief to see what else they had cited in urging rejection of such theories.  Here’s what we found:

Mississippi is not an outlier.  Courts across the country have similarly held that a manufacturer has no duty to warn of rates of adverse events generally or comparative rates related to other similar products.  See Yates v. Ortho-McNeil-Janssen Pharm., Inc., 808 F.3d 281, 291-92 (6th Cir. 2015) (applying New York law) (affirming summary judgment on failure-to-warn claim where manufacturer warned of risk of stroke, but did not warn risk was higher than in other birth control methods, and explaining “[w]arnings can always be made ‘better,’ . . . ‘better’ is not the standard New York law requires − adequacy is”); Ackley v. Wyeth Labs., Inc., 919 F.2d 397, 405 (6th Cir. 1990) (applying Ohio law) (“The manufacturer is obligated to make a reasonable disclosure of all the risks inherent in its own drug.  It is not obligated to provide a comparison of its drug with others.” (citation omitted)); Adamson v. Ortho-McNeil Pharm., Inc., 463 F. Supp.2d 496, 504 (D.N.J. 2006) (applying New Jersey law) (“Plaintiff does not cite a single case to suggest the existence of such a duty [to provide information comparing their product to another] and courts have routinely held that competitors have no duty to advertise or sell a competitor’s products.”); McDowell v. Eli Lilly & Co., 58 F. Supp.3d 391, 405 (S.D.N.Y. Nov. 7, 2014) (applying New York law) (“courts have refused to graft onto the adequacy standard a requirement that a package insert must include specific adverse event frequencies.”); Hurley v. Lederle Labs., 651 F. Supp. 993, 1002 (E.D. Tex. 1986), rev’d on other grounds, 863 F.2d 1173 (5th Cir. 1988) (applying Texas law) (“The plaintiff cites no authority for the proposition that a drug manufacturer has a duty to warn prescribing physicians of the rate of adverse reaction.”); Pluto v. Searle Lab., 690 N.E.2d 619, 621 (Ill. App. 1997) (holding warning adequate as a matter of law where label warned of risks and explaining manufacturer “is under no duty to provide information on other products in the marketplace.”).

Br. at 24-25.  Thus, the next time one of our readers is confronted with comparative warning claims, s/he can take advantage of a lot of research conducted by a top-of-the-line defense firm.

To that, we’ll add citations to our own prior related blogposts.  Our first post, on what we then called “comparative toxicity” warnings, is here, from 2007.  We discussed the McDowell decision, and the extent to which drug/device labels had to include statistics at all, here.  We then updated our research a bit, here, in 2015.  With this Nelson brief, we’re now reasonably confident that our research on this topic is up to date.