The recent law review article by the always interesting and extremely prolific Lars Noah, “‘Market Shift Liability’ for Generic Drugs: Market Share Theory’s Eccentric New Cousin,” 13 Tex. A&M L. Rev. 1415 (Spring 2026), warrants discussion. We usually agree with Prof. Noah, but we don’t buy the central premise of the article: that innovator liability – that the imposition of liability upon the original manufacturer to obtain FDA approval for a drug for injuries later caused by competing generic knock-offs – is similar to the now mostly passé market share liability theory from the 1980s.
The two theories have completely different origins, for one thing. Market share liability was a causation dodge, created by various pro-plaintiff courts when plaintiffs were unable to meet the basic substantive product liability element of product identification in DES litigation. DES was, in a sense the country’s first generic drug (no patent protection), with the result being the anybody with the necessary facilities could make it. But back then (from the 1940s until 1971), people didn’t keep good records, and the alleged injuries skipped to the next generation and were thus very delayed. So market share liability cut those plaintiffs a break by removing the but-for-causation requirement that they sue the actual manufacturer of the injurious product.
Innovator liability has nothing to do with causation, but-for, or proximate. It’s a preemption dodge, pure and simple. It didn’t gain any significant traction until after the Supreme Court, in PLIVA, Inc. v. Mensing, 564 U.S. 604 (2011), and Mutual Pharmaceutical Co. v. Bartlett, 570 U.S. 472 (2013), preempted virtually all product liability claims against generic drug manufacturers. So the theory wasn’t “a thing“ until after preemption required plaintiffs to look elsewhere for somebody to sue. Indeed, innovator liability creates, rather than solves, causation problems as warning causation depends on prescribing doctors supposedly relying on the inadequate labels of drugs that they never actually prescribed, and that may have been substituted after-the-fact by the actions of independent pharmacies. As we’ve discussed elsewhere, warning liability does not exist when the actor never read the allegedly defective warnings.
But while we find that aspect of “Market Shift Liability” a bit of a stretch, we wholeheartedly agree with Prof. Noah’s comprehensive critique of what we will continue to call “innovator liability” – since we are unapologetic defense hacks. See 13 Tex. A&M L. Rev. at 1416 n.2 (quoting pro-plaintiff article that called “innovator liability” a “catchy name” created by “lawyers who represent drug companies”). Cf. Id. at 1452 n.176 (we being the unnamed “bloggers” referred to in this footnote).
So, we’ll skip the article’s extended discussion (pp. 1421-52) of the development of both market share liability and innovator liability and go directly to that critique. Note: that’s not to say these origin stories aren’t interesting in their own right – Prof. Noah’s thorough and often wry exposition is quite readable – but it’s not what prompted us to find the article blogworthy.
So what does the esteemed Prof. Noah find objectionable about innovator liability? Like us, just about everything.
- “[V]iew[ing] the generic drug as a product of the brand-name manufacturer’s choices . . . seems only slightly less plausible than viewing NDA holders as pushers of prescription drugs sold by their competitors.” 13 Tex. A&M L. Rev. at 1453.
- Pro-innovator liability articles “mak[e] a series of indefensible assumptions that create[] a caricature far removed from the messy reality surrounding these tort claims,” and “entirely ignor[e] the far more important role of learned intermediaries.” Id. at 1454 (footnote omitted) & 1456 (footnote omitted).
- Innovator liability will “accelerate” abandonment of the market by “brand-name manufacturers.” Id. at 1458. “If exit occurs prior to the approval of any ANDAs, the first to apply may have to file a petition to confirm that the NDA’s withdrawal did not occur because of concerns about safety or effectiveness. Id. (footnote omitted). This would create a “regulatory void . . . , leaving the FDA alone to drive future revisions to the labeling.” Id
- To avoid potentially catastrophic “long tail” innovator liability, brand manufacturers could well seek to “persuade the FDA to withdraw the license in a way that would altogether prevent subsequent generic entry,” by engaging in liability reducing “product hopping.” Id. at 1461. What some view as “anticompetitive” behavior would gain the “legitimate business justification of “minimiz[ing] exposure to tort” liability. Id. at 1462-63.
- Treating drug labeling “as completely disembodied from the drug itself” is “visiting liability on purveyors of ideas and information that foreseeably might lead to physical injury,” which is recognized as having serious First Amendment implications. Id. at 1465.
- First Amendment implications “become[] more pointed . . . as misrepresentation claims threaten to penalize speech further removed from efforts to sell an allegedly injurious product.” Id. at 1467 (footnote omitted). There are “alarming free speech consequences of starting down this freewheeling path.” Id. (footnote omitted).
- Treating “the NDA sponsor as the ghost author for ANDA sponsors” might even (were it not for preemption) “allow plaintiffs injured by generic prescription drugs to assert design defect claims against brand-name manufacturers.” Id. at 1470-71 (footnote omitted).
- Innovator liability “seemingly would impose liability on the sponsor of an approved NDA that never came to market . . . because it could foresee that ANDA sponsors would mimic its never-used labeling.” Id. at 1472-73 (footnote omitted).
- “[P]redicating [innovator] liability on the supposed control exercised by the brand-name drug manufacturer hardly makes sense,” as “basing such claims instead on alleged misrepresentations arguably obviates any requirement of identity between the advertised product and the substitute product that caused an injury.” Id. at 1474. That could lead to liability based on warnings concerning “substitute product[s] posing somewhat different risks” such as “pharmacy-compounded versions.” Id.
Thus, Prof. Noah concluded that innovator liability was “counterintuitive” and the rationales offered by courts and commentators to justify it were “muddle-head[ed].”
Even with its limited uptake to date, however, market shift liability threatens to cause far greater disruption of the pharmaceutical sector (as well as tort doctrine) than market share liability ever did. For these and other reasons, innovative activity should not get singled out while imitative activity largely escapes any obligation to compensate patients injured because of alleged defects in prescription drugs. . . . [C]ourts in other jurisdictions need to resist the temptation to produce lazy knock-offs of [California innovator liability].
13 Tex. A&M L. Rev. at 1476.
Defense counsel (and their amici curiae) confronted with plaintiffs advocating innovator liability should consult this article and consider relying upon not only the arguments it makes, but also on the copious material that the footnotes we’ve omitted provide. In addition, feel free to utilize the Blog’s own material on innovator liability – our score card collecting all the cases that have addressed it in chronological order, and our 50-state survey. We keep both of these current.





