Sex hormone drugs Premarin and Prempro of Wyeth lead to cancer in women

Common synthetic sex hormones like oestrogen and progesterone can lead to cancer in women who use it control menopause related complications.

About 13,000 women have sued the pharmaceutical company Wyeth — recently acquired by Pfizer — over the last seven years. The plaintiffs allege that Wyeth – the US company exaggerated the benefits of the drugs Premarin (conjugated estrogens) and Prempro (conjugated estrogens and medroxyprogesterone acetate) while downplaying the cancer risks.

A federally funded study documented an increased risk of breast cancer and heart attack for women taking Prempro, for instance, and no benefit in protecting against mild cognitive impairment in older women.

Women across the United States allege in lawsuits that they developed according to an investigative report, breast cancer and other problems after taking menopausal hormone drugs made by Wyeth,

Meanwhile, Pfizer has reportedy said the drugs are safe and that it will appeal the lawsuits.

Pfizer said that Wyeth acted responsibly by studying the risks and benefits of the drugs and that the drugs’ labels have warned about the risk of breast cancer for several years, with warnings about the risk of endometrial carcinoma appearing on the labeling for Premarin in the 1970s.

Premarin and Prempro are two drugs sold to replace estrogen lost due to menopause.

Premarin and Prempro medicines are prescribed mainly to relieve symptoms of menopause, such as hot flashes.

Wyeth overplayed some of the benefits and minimized risks.

However, Pfizer which acquired Wyeth, criticized reports saying it was “based on a misleading and selective reading of both the science and history of hormone therapy (HT) medicines.”

Premarin and Prempro medicines are among the most thoroughly studied drugs.

Wyeth conducted or supported more than 180 studies covering 180,000 women that examined the risks and benefits of hormone therapy (including the WHI), 19 of which expressly examined hormone therapy and breast cancer risk. The first such study was published in 1959, and these studies were published in peer-reviewed medical journals and were consistent with the then-current medical science.

The most definitive study on hormone therapy and breast cancer, the WHI, reaffirmed the increased relative risk of breast cancer that was already in the labeling for Premarin and Prempro.

Moreover, commenting on the Prempro labeling before the WHI, Janet Woodcock, then-director of FDA’s Center for Drug Evaluation and Research, told the NIH on October 24, 2002: “What was known at the time about benefits and risks was discussed within that label.”

Both Premarin (conjugated estrogens tablets USP), approved by the FDA in 1942, and Prempro (conjugated estrogens/medroxy-progesterone acetate tablets USP), approved by the FDA in 1994, treat moderate to severe symptoms of menopause and help reduce the chances of osteoporosis.