Merck & Co says that some 94% of eligible claimants in the USA have chosen to participate in its $4.85 billion proposed Vioxx settlement but has extended the deadline for others to join in.

The New Jersey-based drugs giant said that “the resolution programme is progressing in an appropriate manner” since last November when it announced a deal with lawyers who were suing over claims that the withdrawn COX-2 inhibitor Vioxx (rofecoxib) caused myocardial infarction and ischemic stroke. The firm said that because of the large number of enrollments received so far, it is confident that “all 85% thresholds will be met and exceeded” but has decided to extend the deadline by two months, to June 30.

To be eligible for the proposed settlement, patients or their survivors had to have filed a Vioxx product liability lawsuit in the USA by November 9, or officially expressed their intent to file a lawsuit. As of March 31, Merck said more than 28,250 eligible heart attack claimants had enrolled in the settlement, along with around 16,750 eligible stroke claimants.