California Court Signals Limits on “Duty to Innovate” in Gilead HIV Case

California’s highest court is weighing a case that could reshape how far pharmaceutical companies are expected to go in developing improved medicines, with early signals suggesting caution around imposing a legal “duty to innovate.”

At the centre of the dispute is Gilead Sciences, which is facing negligence claims from around 24,000 HIV patients. The plaintiffs argue the company delayed bringing a newer drug with fewer side effects to market in order to maximise profits from an older treatment.

That older drug, based on tenofovir disoproxil fumarate (TDF), was approved in 2001 and is considered safe, despite known risks such as kidney and bone issues. Gilead later developed a similar drug, tenofovir alafenamide fumarate (TAF), which has fewer side effects, but halted its development in 2004 before eventually launching it years later.

The legal question now before the court is whether manufacturers can be held liable not just for unsafe products, but for failing to develop and commercialise potentially safer alternatives more quickly.

During oral arguments, several justices expressed concern that imposing such a duty could have wide-ranging consequences for the industry. There were suggestions that forcing companies to justify development decisions in hindsight could slow innovation or shift complex policy questions into the courtroom rather than the legislature.

From a market perspective, the stakes are significant. HIV treatments accounted for 70% of Gilead’s $29.4 billion revenue in 2025, and its shares rose modestly following the hearing, reflecting investor confidence that the court may avoid expanding liability.

A ruling against Gilead could redefine product liability standards and increase pressure on drugmakers to accelerate pipelines. For now, the court’s scepticism suggests a more cautious approach, with broader implications for R&D strategy and long-term investment across the sector.