Question of the Week: Does Experimental Drug - LP533401 - Build New Bone?


Are you looking for a new treatment for bone loss that is nothing like the current drugs we have on the market now? There is a new drug under investigation that could be the answer to the treatment of osteoporosis and osteopenia. This drug is a serotonin-inhibitor that promotes new bone growth.

Dr. Gerard Karsenty, M.D., Ph.D. explains that "Bone growth is controlled in the gut through serotonin, the same naturally present chemical used by the brain to influence mood, appetite and sleep, according to a new discovery from researchers at Columbia University Medical Center. Until now, the skeleton was thought to control bone growth, and serotonin was primarily known as a neurotransmitter acting in the brain. This new insight could transform how osteoporosis is treated in the future by giving doctors a way to increase bone mass, not just slow its loss. Findings are reported in the Nov. 26, 2008 issue of Cell."

Researchers at Columbia University Medical Center administered a new drug to mice, either before or after they developed osteoporosis. At the end of the study the drug that turns off serotonins' production in the stomach, prevented and cured bone loss in these mice that had their ovaries removed to mimic menopause.

The drug that was used is called LP533401.

In humans, high serotonin production in the stomach results in severe bone loss, and inhibition of this chemical causes bone growth.

LP533401 has been used to treat irritable bowel syndrome (IBS) and was tested in humans at varying doses. Even at these varying doses, marginal toxicity occurred and the drug did not cross the blood-brain barrier and interfere with serotonins' ability to stabilize mood. Since LP533401 works on the serotonin found in the stomach, it does not affect serotonin in the brain.

In subsequent studies LP533401 was compared to the benefits of injected parathyroid hormone (Forteo ® ) for its bone building qualities. All other osteoporosis medications slow bone loss, but Forteo and this new LP533401 both work on osteoblast's (bone builders) instead of osteoclast's (bone removers) which only slow down bone loss.

It will take time for this new therapy to reach the market since human studies have not been completed for the treatment of osteoporosis, but it certainly looks very promising.


  • Would you be interested in taking this if it is approved?

  • Do you think this drug would be a safer option than the treatments we have on the market now?