A California Court of Appeal decision recognizing an unusual and potentially far-reaching negligence duty for product manufacturers is now before the California Supreme Court. In the 
Gilead Tenofovir Cases, the Court held that, in “appropriate circumstances,” a manufacturer’s duty of reasonable care to users of its product can extend beyond the traditional obligation not to place a defective product into the stream of commerce. The decision may have wide implications for all manufacturers as the newly articulated duty is grounded in general negligence principles, not limited to drug manufacturers.

The Court of Appeal’s New Duty

The approximately 24,000 plaintiffs in the
Gilead Tenofovir Cases are users of HIV medicines containing tenofovir disoproxil fumarate (TDF). Critically, they do not contend TDF is defective in design, manufacturing, or warnings, and they do not seek to remove it from the market. Instead, they allege the manufacturer should have developed and commercialized a different compound, tenofovir alafenamide fumarate (TAF), sooner.

The Court of Appeal framed the duty question as:

“whether a drug manufacturer, having invented what it knows is a safer, and at least equally effective, alternative to a prescription drug that it is currently selling and that is not shown to be defective, has a duty of reasonable care to users of the current drug when making decisions about the commercialization of the alternative drug.” Gilead Tenofovir Cases, 98 Cal.App.5th 911, 922 (2024).

The Court generally found that there was such a duty and refused to adopt a categorical no-duty rule under Rowland v. Christian that would foreclose the negligence claim, allowing plaintiffs’ negligence theory to proceed.¹ Plaintiffs’ theory focuses on “commercialization” decisions for alternative products: even where the product on the market has not been “shown to be defective,” a manufacturer may face negligence exposure based on how it handled the timing and path of bringing an alternative product to market.

The decision also raises questions about what “knowledge” means in this context. The court spoke in terms of what a manufacturer “knows,” but noted that plaintiffs often plead “knew or should have known,” leaving unclear whether constructive-knowledge theories are in play. That ambiguity could expand disputes (and discovery) over what companies should have inferred from evolving data during development.

Why This Is Significant: Liability Without a Defect

Traditionally, product-liability doctrine has been anchored in a defect concept: design, manufacturing, or warning defect. Here, however, the plaintiffs’ theory proceeds without attempting to prove any defect in the product they used.

Therein lies the problem. If a plaintiff can recover for “injuries” from a concededly non-defective product based on the argument that the manufacturer should have moved faster to make a different product available, the defect requirement risks becoming optional in certain claims.

The Court of Appeal’s reasoning reflects a broader and more elastic view of duty for negligence claims. The court concluded that negligence can provide a remedy “even when there is no showing that the injury resulted from a product defect.”² For defendants, this shift in liability framework will be tested by plaintiffs well beyond the pharmaceutical sector.

The Precedent and Possibilities in Practice

Even if the duty is described as “narrow,” it is difficult to administer and harder to confine to the fact pattern the Court of Appeal described.

1. A duty focused on products not the market

Products cases typically regulate the safety of what is sold: whether the marketed product was reasonably safe and adequately warned. Gilead instead pushes courts toward regulating development and commercialization timing for products not yet available, turning R&D and pipeline decisions into potential tort disputes. In practice, it invites discovery and expert battles over internal prioritization decisions, such as why one design path was pursued over another; budget and staffing allocations; and what manufacturers believed various studies indicated. Plaintiffs can be expected to frame this in a “profits over people” narrative.

2. Hindsight-driven decision making

The articulated duty invites juries to evaluate complex product-development timelines with the benefit of hindsight about what later proved safer or better for a subset of users. This is different from evaluating whether a marketed product was defectively designed when sold, and it raises the risk that development decisions become litigated as “unreasonable” simply because a later alternative succeeded.

The rule also creates negative incentives for manufacturers, including (i) pressure to stop early-stage investigations before generating “knowledge” that later becomes actionable in litigation;
(ii) delays launching beneficial products until additional alternatives are fully vetted; or
(iii) hesitation to introduce improved next-generation products. In addition to the litigation risk, this decision may systematically distort product-development behavior toward legally defensive choices rather than maximizing innovation, affordability, and overall consumer safety.

Potential Expansion: From Drugs to Medical Devices and Beyond

Although Gilead arises in the drug context, plaintiffs and courts may attempt to extend the duty’s logic to other regulated (and non-regulated) product categories.

1. Medical Devices

Device manufacturers often have iterative product lines: next-generation implants, revised components, software updates, new coatings, alternative materials, and modified instructions for use. In many device areas, an “alternative” may be:

• Safer for one cohort but not others,
• Safer for one failure mode but worse for another, or
• Safer but not yet validated to the same evidentiary standard.

A negligence theory targeting “commercialization decisions” could be used to argue that a manufacturer should have accelerated a new design, a software update, an accessory, a revised labeling approach, or a different version of the product—while conceding the existing device is not defective and should remain available for many patients.

2. Products Nationwide

Once separated from defect, the theory can migrate to any industry with product development pipelines. Plaintiffs could recast injuries from a concededly non-defective product into a claim that the manufacturer unreasonably delayed a safer alternative or feature. The Court of Appeal grounded its analysis in general negligence principles (Civil Code section 1714), making it easier for plaintiffs to argue the duty is not limited to drugs.

Conclusion: Moving Beyond Defect, and What the California Supreme Court May Do

Because the Court of Appeal’s opinion remains controlling, it signals how California intermediate courts may define duty and the limits of products liability, especially in coordinated proceedings. It also shows a willingness to entertain negligence claims untethered from defect, shifting from “defect as the gateway” to a broader inquiry into the reasonableness of a manufacturer’s conduct apart from the product’s condition.

That shift creates two practical problems. First, it reduces predictability: defect doctrine provides workable, designable standards (risk-benefit, consumer expectations, warning adequacy), while an open-ended reasonableness review of development and commercialization decisions is harder to apply in real time. Second, it expands litigation: plaintiffs may plead around defect and reach costly discovery into internal R&D, prioritization, and pipeline decisions—areas usually outside core defect litigation.

The California Supreme Court’s decision will likely determine whether it (1) rejects the new duty and reaffirms a defect-centered framework; (2) adopts limiting principles the Court of Appeal did not supply (for example, confining any duty to later-stage development supported by stronger evidence); or (3) affirms the duty in a way that encourages broader use, potentially extending beyond pharmaceuticals to devices and then other products. During the May 6 hearing, the justices’ questioned the suggested skepticism about expanding tort law into product-development and commercialization timing, particularly where plaintiffs allege no defect and where courts would struggle to define “reasonable” R&D prioritization without hindsight. Although the Court’s determination remains uncertain, initial observations note that the dialogue and argument potentially appear more favorable to manufacturers than the Court of Appeal’s interpretation.

We will continue to monitor the case and provide updates on what the Supreme Court’s decision means for manufacturers.

1. Id. at 934–948; see also Rowland v. Christian, 69 Cal.2d 108 (1968) (establishing the “Rowland factors” framework for duty analysis, which provides that under California law, courts may recognize or limit duty by weighing policy factors—including foreseeability, closeness of connection, moral blame, burden, and insurance). ↩︎
2. Gilead Tenofovir Cases, 98 Cal.App.5th at 925. ↩︎