Facts
- Numerous plaintiffs filed consolidated actions alleging prenatal injuries from their mothers’ ingestion of diethylstilbestrol (DES), a prescription drug marketed by multiple manufacturers using a common formula.
- The cases were coordinated as complex litigation in San Francisco Superior Court, with pretrial legal rulings intended to apply across many individual actions.
- The trial court ruled that prescription-drug manufacturers could not be held strictly liable for design defects if the drug was properly manufactured and adequately warned, but could face liability for failure to warn and negligence.
- The trial court further ruled that DES plaintiffs proceeding under a market-share theory could not base claims on fraud or breach of warranty and that any liability would be several, limited to each manufacturer’s market share.
- Plaintiffs sought writ relief; the Court of Appeal largely upheld the trial court, and the California Supreme Court granted review to address the pretrial legal rulings.
Issues
- Whether a prescription-drug manufacturer may be held strictly liable for a design defect when the drug is properly prepared and accompanied by adequate warnings.
- Whether DES plaintiffs proceeding under market-share liability may assert fraud or breach of warranty theories.
- Whether liability under DES market-share liability is joint and several or several and proportional to each defendant’s share of the relevant DES market.
Decision
- The California Supreme Court largely affirmed the challenged pretrial rulings.
- It held that manufacturers of prescription drugs are not strictly liable for design defects when the drug is properly manufactured and accompanied by adequate warnings.
- It held that market-share DES actions may not be premised on fraud or breach of warranty.
- It held that, under market-share liability, each defendant’s liability is several and limited to its proportionate market share, not joint and several for the entire judgment.
Legal Principles
- Properly prepared prescription drugs accompanied by adequate warnings are exempt from strict products liability for design defect; manufacturers remain potentially liable for inadequate warnings and negligence.
- Market-share liability is confined to theories compatible with probabilistic causation; claims requiring defendant-specific proof such as reliance or individualized undertakings (e.g., fraud and warranty) are not permitted under that framework.
- In a market-share DES case, each defendant’s responsibility is several and corresponds to its share of the relevant market, consistent with allocating liability by the probability of causation.
Conclusion
The court limited prescription-drug design-defect strict liability to preserve access to beneficial but risk-bearing medications, while confirming that DES market-share liability remains a proportional, several-liability doctrine and cannot be expanded to fraud or warranty claims.