Brittle bones Drug Bazedoxifene Stops Development Of Cancer Of The Breast Cells

Bazedoxifene, an osteoporosis medication which is approved in Europe, stops the growth of breast cancer cells, including those that are resistant to current medications, researchers from the Duke Cancer Institute reported at ENDO 2013 – The Endocrine Society’s Annual Meeting in San Francisco, California, June 15th, 2013.

They described that bazedoxifene not just blocks oestrogen in order that it cannot fuel cancer of the breast cell growth, it ensures the oestrogen receptor is wiped out off – it flags the oestrogen receptor for destruction.

The research was carried out by Suzanne Wardell, Jesse McDonnell, Erik Nelson and Christina Chao, all of them work on Duke College Med school.

Bazedoxifene undermines estrogen receptor and gets rid of it too

Donald McDonnell, PhD, chair of Duke’s Department of Pharmacology and Cancer Biology, said:

“We found bazedoxifene binds to the estrogen receptor and interferes with its activity, but the surprising thing we then found was that it also degrades the receptor; it gets rid of it.”


In cell cultures and animal studies, the researchers discovered that bazedoxifene:

  • halts the growth in estrogen-dependent cells
  • inhibits the growth of cells that have become resistant to tamoxifen and/or to the aromatase inhibitors, two of the most commonly used types of medications to prevent and treat estrogen-dependent breast cancer.

Current therapy for patients whose breast cancer cells have become resistant is to administer highly toxic chemotherapy agents which have considerable side effects.

Bazedoxifene, an orally-administered pill, belongs to a class of medications known as SERMS (specific estrogen receptor modulators). These medications can mimic estrogen in some tissues, while at the same time blocking estrogen’s action in other tissues. Tamoxifen is also an SERM. However, bazedoxifene also has some of the properties of SERDs (selective estrogen receptor degraders). SERDs can flag the estrogen receptor for destruction. Tamoxifen cannot do that.

Lead author Suzanne Wardell, PhD, said:

“Because the drug is removing the estrogen receptor as a target by degradation, it is less likely the cancer cell can develop a resistance mechanism because you are removing the target.”


McDonnell explained that most scientists had assumed that as soon as breast cancer cells became resistant to tamoxifen, they would also be resistant to SERDs.

McDonnell said “We discovered that the estrogen receptor is still a good target, even after it resistance to tamoxifen has developed.”

Bazedoxifene also inhibited the growth of lapatinib-resistance cancer cells

The researchers examined a variety of cancer of the breast cell types, including individuals which are responsive to tamoxifen but resistant against lapatinib, a medicine employed for patients with advanced cancer of the breast whose growths retain the mutated HER2 gene. Previous studies had proven these cells reactivate oestrogen signaling and therefore acquired drug resistance. Bazedoxifene also inhibited their growth.

Bazedoxifene behaves like oestrogen in navicular bone, thus safeguarding it from destruction. As bazedoxifene is definitely an existing Food and drug administration-approved medication, meaning it’s already gone through effectiveness and safety tests for brittle bones, maybe it’s a near-term choice for women with advanced cancer of the breast who haven’t taken care of immediately other treatments, Wardell authored.

Bazedoxifene was approved in April 2009 through the European Commission underneath the trade name Conbriza? to treat postmenopausal brittle bones in females at elevated chance of fracture.

The primary side-effect connected with bazedoxifene therapy was menopausal flashes.