Wyeth’s Prempro, the hormone therapy linked to heart disease and cancer, increases the risk of breast cancer even with short-term use and may make detection of the cancer more difficult, a study showed.
Just one to three years of Prempro use can lead to abnormal mammograms in one in 25 women and raise the risk of breast cancer 24 percent within five years, according to a new analysis of last year’s research on the drug’s risks. Scientists had considered short-term use for menopause symptoms relatively harmless.
The findings published in the June 25 Journal of the American Medical Association may further hurt lagging prescriptions for Wyeth hormone treatments. The drugs were once the best-selling products at Madison, New Jersey-based Wyeth.
“This is another nail in the coffin of hormone replacement therapy as a treatment for menopause,” said Jim Lyon, who manages $400 million at Oakwood Capital Management LLC, said. “This is probably going to keep the stock under a little bit of a cloud.”
Oakwood Capital sold its Wyeth shares last year after initial study results indicated increased risks from hormone therapy.
Worldwide revenue from Prempro, a combination of estrogen and progestin, and the Premarin estrogen drug fell 40 percent in the first quarter to $402.7 million. Wyeth doesn’t separate the sales.
Lowest Dose, Shortest Use
Hormone therapy is the only treatment approved by the U.S. Food and Drug Administration to ease symptoms of menopause, including hot flashes, night sweats and vaginal atrophy.
“We continue to support the appropriate use of hormone therapy and recommend that it be used at the lowest dose for the shortest duration,” said Victoria Kusiak, vice president of global medical affairs for Wyeth. “This information is important to women and physicians, and should be considered by all women who are taking or contemplating hormone therapy.”
Shares of Wyeth fell 5 cents to $47.30 as of 4:18 p.m. in New York Stock Exchange composite trading. The study results were released after U.S. markets closed.
The study of 16,608 healthy women found that women taking Prempro had a 24 percent higher risk of getting breast cancer and developing invasive cancer, compared with women on a placebo. The tumors were larger and more advanced among women getting the hormones, the researchers said.
“It looks like estrogen plus progestin not only is stimulating breast-cancer growth but is hindering its diagnosis,” said lead researcher Rowan T. Chlebowski from Harbor-UCLA Research and Education Institute in California.
No. 2 Cancer
Breast cancer is the second most common type of cancer in women after skin cancer, with 211,000 people diagnosed each year, according to the National Cancer Institute. For every 10,000 women taking Prempro, eight more cases of invasive breast cancer will develop annually, Chlebowski said.
Even though most of the abnormal mammograms aren’t spotting cancer, women must still deal with the emotional, financial and psychological cost of confronting a potentially serious condition, Chlebowski said. The hormones are known to make breast tissue denser, which might be causing the diagnostic problem, he said.
There is also evidence that mammograms of women taking Prempro don’t always detect the cancer when it is present, Chlebowski said. As a result, the patients’ tumors were more advanced and probably more deadly when diagnosed, he said in an interview.
“The ability of combined hormone therapy to decrease mammographic sensitivity creates an almost unique situation in which an agent increases the risk of developing a disease while simultaneously delaying its detection,” wrote Peter H. Gann and Monica Morrow from the Feinberg School of Medicine at Northwestern University in an editorial.
The findings also refute a common assumption that the cancers triggered by hormone use come only after years of therapy, are less serious, and easier to treat, they wrote.
While scientists are often loath to describe any study as conclusive, the Prempro trial “is as close to definitive as can be expected,” the researchers said. The newly identified risks “provide further compelling evidence against the use of combination estrogen plus progestin hormone therapy,” they said.
There is a medical cost for even one year of combination hormone use and women may want to see if they can tolerate hot flashes or find another treatment, Chlebowski said.
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