An appeals panel on Wednesday grappled with the breadth of California negligence law in a case that's attracted nationwide business and legal interests on both sides, including the U.S. Chamber of Commerce and the American Association for Justice.

More than 24,000 plaintiffs, in lawsuits coordinated in California state courts, alleged that Foster City, California-based Gilead Sciences Inc. delayed the release of an HIV medication that had fewer side effects than its first drug, which caused kidney or bone injuries. Gilead has insisted the new drug was still in development.