A medical journal has asked the authors of a pivotal study of Merck & Co’s withdrawn painkiller Vioxx (rofecoxib) to correct a published article on the trial, saying they failed to disclose three cases of heart attack in the data.

An editorial published on The New England Journal of Medicine’s website yesterday alleges that the authors of the article also deleted other pertinent data shortly before submitting the manuscript for publication. Details of the missing data only emerged after they were made public by the US Food and Drug Administration (FDA), say the senior editors at the journal, including editor-in-chief Jeffrey Drazan.

Drazan and colleagues maintain that: “Taken together, these inaccuracies and deletions call into question the integrity of the data on adverse cardiovascular events in this article.”

But Merck insists that the excluded heart attack cases do not materially affect the conclusions of the study - called VIGOR – and were reported after the pre-specified cut-off date for the article. The cases were disclosed to the FDA in 2000, presented publicly at the FDA's Advisory Committee in February 2001, and included in numerous press releases subsequently issued by Merck, said the company.

VIGOR was used to secure labeling for the drug that it had fewer gastrointestinal side effects than traditional non-steroidal anti-inflammatory drugs (NSAIDs), and was published a year before Vioxx’ approval in the USA.

The timing of the allegations is terrible for Merck, which is in the latter stages of a federal lawsuit in which the widow of a man who died of a heart attack is claiming that Vioxx was responsible. This case - the third drug liability lawsuit involving Vioxx - went to jury yesterday.

Merck has so far won one case and lost another, in which it was ordered to pay damages of $253 million, subsequently capped at $26 million by state rules. 7,000 cases are still outstanding, leading to speculation that the firm could face liabilities of $50 billion.

Late last month Merck announced swingeing job cuts in a bid to save $4 billion in costs by 2008, to help it ride out this difficult period. The firm is also facing patent expiries on key products, notably cholesterol-lowering drug Zocor (simvartatin) that will cut into 2006 profits.

The editorial can be read online here and will be published in the December 29 printed edition of the NEJM.