According to a commentary published on Wednesday in the New England Journal of Medicine, Pfizer’s experimental osteoporosis drug lasofoxifene, which is awaiting U.S. regulatory approval, works about as well as currently approved drugs, but not much better.
Overall, lasofoxifene looks good, according to lead study author Dr. Steven Cummings, professor and director of the San Francisco Coordinating Centre at the University of California San Francisco, but raises the risks of blood clots, like other anti-osteoporosis drugs already on the market.
The new drug is in a class of medications known as selective oestrogen-receptor modulators (SERM), which act like oestrogen in some tissues but anti-oestrogen in other. The study recruited 8,556 women who were aged 59 to 80 and had osteoporosis to take a daily dose of the drug (either 0.25 or 0.5 milligrams a day) or a placebo for five years.
The results showed that the drug not only improved bone mineral density and reduces the risk of all fractures (spinal and elsewhere but also cut the risk of breast cancer by more than half, heart disease and stroke by a quarter to a third. The results are all for the higher dose, 0.5 milligrams a day, when compared to placebo and is the dose planned for clinical use.
But Dr. Carolyn Becker of Brigham and Women’s Hospital in Boston expressed scepticism regarding lasofoxifene’s efficacy and said: “Given the plethora of drugs currently available for osteoporosis, studies of new agents should show clear benefits over existing agents. A study of the drug published in the same issue suggests lasofoxifene offers no major clinically important benefits over raloxifene for the skeleton, breast, heart, or reproductive tract.”
Dr. Becker suggests a ‘wait and watch’ approach for the use of the drug in clinical practice.
Written by Snigdha Taduri