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British Hormone Study Stopped

In a new blow to the prospects of long-term hormone treatment, the U.K. Medical Research Council (MRC) today put an end to a large British study that had planned to enroll as many as 20,000 women. The decision is a direct result of the halting of a similar trial in the United States 3 months ago, which found that the benefits of the same hormone combination did not outweigh the increased risks.

Researchers have long debated the pros and cons of "replacing" postmenopausal women's waning hormones with pills. To the surprise of many, the National Institutes of Health recently decided to stop a major part of the Women's Health Initiative (WHI), which tested a popular hormone combination called Prempro. An interim analysis had shown that the hormones increased the risk of heart disease and breast cancer more than they reduced chances of osteoporosis, bone fractures, and colorectal cancer (ScienceNOW, 9 July).

Initially, the leaders of the Women's International Study of Long Duration Oestrogen after Menopause (WISDOM), which started in the United Kingdom in 1999, said their trial could continue. The WHI results left enough room for scientific doubt, they argued, to continue enrolling women (ScienceNOW, 23 July). But 2 weeks later, MRC's Council overruled that decision and asked an independent panel to take a closer look. Now, that group has concluded that WISDOM should stop as well. The $32 million study was already years behind schedule, because enrolling women had proved much harder than researchers had thought, says the panel's chair, Ray Fitzpatrick of Oxford University. Moreover, the results, not expected until 2016, were unlikely to differ much from those of WHI, he says.

WISDOM researchers are "very disappointed," Janet Derbyshire, director of the MRC Clinical Trials Unit, wrote in a press statement. Richard Gray, who chaired WISDOM's Data Monitoring and Ethics Committee, calls the decision "premature." It's very unlikely that anybody will fund a similar randomized trial of hormone treatments in the future, he says, which means that questions about its efficacy will linger.

But continuing WISDOM would have been ethically questionable, given the results of previous trials, says Elizabeth Barrett-Connor of the University of California, San Diego--and the heightened risks would have made recruiting participants even more difficult. "There just isn't a glimmer of light."

Related sites
MRC press release about the decision, with additional information about WISDOM
More about the halted Women's Health Initiative trial
Paper in the Journal of the American Medical Association with the results of the WHI study