To understand how bisphosphonates work, it helps to know a bit about normal bone activity.
Normal bone activity
Your bones are made of living tissue, and are constantly changing. In healthy bones, specialised bone cells constantly break down and replace bone tissue.
These specialised bone cells are:
- osteoclasts, these cells break down old bone
- osteoblasts which build new bone
This process is called bone remodelling. There is a very good balance between the rates of bone breakdown and growth, which keeps bones strong and healthy.
What bisphosphonates do
Bisphosphonates are drugs that target areas of higher bone turnover. The osteoclast cells, which break down old bone, absorb the bisphosphonate drug. Their activity is slowed down. This reduces bone breakdown.
There are several different types of bisphosphonates, and they each work slightly differently. Doctors are still learning more about the exact ways in which bisphosphonates work.
We know that bisphosphonates can:
- interfere with the formation of osteoclasts
- make osteoclasts self destruct or die early
- change the signalling between osteoclasts and osteoblasts
- form a barrier between the bone and the osteoclast
Researchers have found that some types of bone targeted treatments can:
- prevent or slow down the activity of bone disease and improve symptoms in people with myeloma
- prevent or reduce bone problems, including for pain relief, in some people with advanced prostate cancer
- help reduce the rate of early breast cancer coming back in the bone for some postmenopausal women
- help some postmenopausal women with early breast cancer live longer
- help to prevent complications from other cancers that have spread to the bones
Cancer cells seem to be attracted to an environment where bones are being broken down. Researchers hope that stopping this process could slow cancer growth and help people live longer, as well as reduce bone damage.