Merck & Co has suffered a major blow in its legal defence of Vioxx after a US judge rejected the company’s efforts to throw out two lawsuits concerning its withdrawn painkiller.

The New Jersey-based drugs giant had sought a summary judgment in two cases in Louisiana on federal pre-emption grounds, but US District Court Judge Eldon Fallon said that “because the court finds that the plaintiffs' claims are not expressly nor impliedly pre-empted by virtue of the federal regulation of prescription drugs, Merck's motion is denied". The pre-emption defence basically hangs on the notion that pharmaceutical firms have a level of immunity against product liability claims, because the US Food and Drug Administration has already deemed a treatment to be safe before it is marketed.

This argument cut little ice with Judge Fallon who, in a 21-page ruling, noted that “the Food, Drug and Cosmetic Act does not contain an express statement that Congress intended to displace state-law claims in the prescription drug context….Congress has never spoken on preemption with respect to prescription drugs”. He added that “because there are no federal remedies for individuals harmed by prescription drugs, a finding of implied pre-emption in these cases would abolish state-law remedies and, in effect, render legally impotent those who sustain injuries from defective prescription drugs.”

One case involved in this latest ruling was brought by Lene Arnold, who claims she used Vioxx (rofecoxib) from July 2003 to October 2004 and suffered a heart attack in December 2003. The other suit was brought by the family of Joseph Gomez, who suffered a fatal heart attack in January 2003 after taking the drug for nearly 14 months.

Unsurprisingly Merck disagreed with the ruling and the firm’s outside counsel, Ted Mayer, issued a statement saying “we believed that these two cases should have been dismissed because the FDA approved the product label that was included with the medicine, and that label reflected the cardiovascular risks known at the time these plaintiffs started taking Vioxx”. He added that the two cases “specifically involved patients who began using Vioxx after the FDA approved label was revised to include the cardiovascular data from the VIGOR study," a large clinical trial in which results released in 2000 showed signs of increased heart risk to patients taking Vioxx. Merck is expected to appeal the Louisiana ruling.

Merck’s risk claim time-scale for Vioxx is disputed

Meantime Merck faces more problems on the Vioxx front following a report from The Wall Street Journal online edition which claims that heart risks associated with the drug began almost immediately after patients started taking the painkiller. This suggestion goes very much against the firm’s assertion that the drug may cause serious cardiovascular events only after 18 months of use.

The WSJ’s claims are based on a new study that has been approved for publication in the New England Journal of Medicine. The study, called Victor, which was conducted by researchers at Oxford University and has not been published yet, involved over 2,400 patients who were followed for two years and the WSJ reports that 16 of the 23 cardiovascular events occurred in the Vioxx patients (as opposed to placebo), and half of those happened within 12 months of taking the drug. The authors of the study wrote that “it would appear…that patients do not need to take rofecoxib for 18 months to be at increased risk of a cardiovascular thrombotic event,” and suggested that 14 days after patients stopped taking Vioxx, the risk of heart and stroke subsided.

Mr Mayer issued another statement saying that Merck “will wait until publication of the study before going into detail about what the data show or do not show”. He added that the data have been previously presented last year at a scientific meeting, and at that time "it was noted that there were limitations in it related to the premature termination of the study, together with the fact that events were collected after patients had been unblended”.