Evista: Help for Breast Cancer, Heart?
Researcher Says Study on Benefits for Osteoporosis Drug Are 'Disappointing'
No Heart Benefits continued...
The number of cardiac events experienced by the two groups was similar. But significantly fewer breast cancers were diagnosed in the Evista users than in those on placebo (40 vs. 70).
Deaths from any cause were also similar in both groups, and the two groups had roughly the same number of strokes. But Evista users had significantly more fatal strokes (59 vs. 39) and potentially dangerous blood clots (103 vs. 71 events) than women taking placebo.
Mosca points out that women taking the SERM also had a higher incidence of several nonlife- threatening, but troubling, side effects, including hot flashes and leg cramps.
The RUTH trial results may serve to dampen the optimism that surrounded Evista following the release of another study three months ago.
The Study of Tamoxifen and Raloxifene (STAR) trial -- one of the largest breast cancer prevention trials ever conducted -- found Evista to be as effective as tamoxifen for preventing breast cancers.
And unlike tamoxifen, Evista did not increase the risk of developing uterine cancers. There was also some suggestion that Evista was safer in terms of blood clot and cataract risk. The two treatment groups had roughly the same incidence of strokes, heart attacks, and bone fractures.
At the time, STAR researcher D. Lawrence Wickerham, MD, called Evista the clear "winner" of the head-to-head comparison trial.
But women's health researcher Marcia Stefanick, PhD, of Stanford University, says the STAR trial had no clear winner.
"I think that at best the findings represented a draw," she says. "The hope was that raloxifene would offer the benefits of tamoxifen without the risks, but that isn't what happened."
In an editorial examining the RUTH findings, Stefanick writes that identifying who should and should not take tamoxifen or Evista for breast cancer prevention remains problematic.
"For now, there is no magic bullet that can reduce the risks of major health problems related to estrogens and aging without introducing other potentially serious health concerns," she wrote.
She tells WebMD that drug makers are continuing the search for a better SERM for breast cancer prevention.
"If raloxifene is better [than tamoxifen], I believe it is just a little bit better," she says. "And you have to remember that far more women die from stroke than from breast cancer. More women die from heart disease than all cancers put together."