Second Look at U.K. Hormone Trial

The U.K. Medical Research Council (MRC), one of the main sponsors of a large trial of hormone replacement therapy in the United Kingdom, Australia, and New Zealand, has postponed the decision whether or not to continue the trial in the face of evidence from a similar U.S. study that ended 2 weeks ago. The MRC today announced that it will convene an international panel to study the issue.

The U.S. study testing the long-term benefits and risks of hormone replacement therapy (HRT) was halted after an interim analysis found that the drugs--a combination of estrogen and progestin--increased the risk of breast cancer, stroke, and heart disease, and that those risks outweighed reduced risks of colorectal cancer and bone fractures (ScienceNOW, 9 July).

Despite those findings, leaders of the Women's International Study of long Duration Oestrogen after Menopause (WISDOM) saw no compelling reason to halt their trial. Both WISDOM's steering committee and an independent safety panel concluded that the U.S. study, part of the Women's Health Initiative (WHI), had not conclusively demonstrated an increased risk of heart disease. That meant the balance of risk and harm from HRT was still uncertain, they said, and it was ethical to keep enrolling women provided they were fully informed about the risks.

But in a council meeting today, MRC decided not to follow the recommendation; instead, it wants an international group of experts to study the matter and issue a recommendation by October. "The MRC has a duty to safeguard the well-being of the women who have volunteered for the WISDOM study," MRC's chief George Radda said in a press statement. "We must be absolutely satisfied that it is right to press ahead ... with the study." In the meantime, WISDOM will continue.

"It sounds like a very reasonable approach to me," says Marcia Stefanick of Stanford University, principal investigator in the WHI study. Stefanick says that unlike the WISDOM panels, she has no doubts about her own results--but researchers differ in what they regard as convincing evidence, she says, and a careful examination may help inform the difficult decision whether or not to halt WISDOM.

Related sites
Press release about the WISDOM steering committee's recommendation to continue the study
The Medical Research Council
More information about the WHI study and the reasons it was stopped
JAMA paper describing the results from WISDOM