O’Melveny served as one of Merck’s national counsel in the Vioxx litigation, with responsibility for key aspects of the company’s defense at every stage, including the overall legal strategy, class certification briefing, trial briefing, appeals, and settlements. The Vioxx litigation involved thousands of individual claims and numerous class actions in state and federal courts all over the country. O’Melveny also played a key role in defending Merck against Vioxx-related claims outside the United States.