The second trial over injury claims from Merck's withdrawn pain drug Vioxx headed to the jury yesterday. The verdict could be influential in how the US drugmaker defends thousands of future cases.

The trial jury in Atlantic City will also send a signal on Merck's new, more aggressive defence strategy. The company has sharpened its defence, questioning the credibility of the plaintiff, Frederick Humeston, a 60-year-old postal worker who is claiming that taking Vioxx for two months caused his 2001 heart attack.