Bisphosphonates Can Cause Problems in Jaw

By Rachael Myers Lowe, cancerpage.com

(March 15, 2005) - Cancer patients given drugs called bisphosphonates to control hypercalcemia – too much calcium in the blood – or the growth of bone metastases can develop bone death in the jaw the FDA warns.

Makers of several bisphosphonates have added advisories to their drugs, warning doctors and patients of the increased risk of osteonecrosis of the jaw (ONJ), particularly in patients undergoing a dental procedure while taking an intravenous bisphosphonate such as Aredia or Zometa and other cancer treatments.

These drugs are often given to cancer patients with metastases to the bone as standard therapy.

Cancer that has spread to the bone upsets the delicate balance of healthy bone growth and regeneration so that often, bone is destroyed faster than it can be replaced.  Bisphosphonates slow down unnaturally speeded up bone destruction - called bone resorption.

Although researchers don’t know why,  a small number patients taking bisphosphonates develop osteonecrosis of the jaw, a condition in which the bone tissue in the jaw fails to heal after a minor trauma such as a tooth extraction causing the bone to be exposed.  Symptoms include jaw pain or inflammation, gums that don’t heal, loosening teeth, or a feeling of numbness or heaviness in the jaw.

The condition sometimes can be treated with antibiotics and mouth rinses. Because surgery can make the condition worse, it’s avoided although sometimes it’s necessary to remove dead tissue.

A background sheet from the FDA’s Oncologic Drugs Advisory Committee points out that the research suggests the risk is highest for people given bisphosphonates intravenously. Some patients take oral bisphosphonates, such as Fosamax, for osteoporosis.  The FDA acknowledges that there have been reports of ONJ in oral bisphosphonate users but writes: “There have been fewer reports [ …] and risk-benefit considerations are different for patients with malignant as opposed to benign disease.”

The new drug warning labels recommend patients delay invasive dental procedures such as tooth extraction.

SOURCES:

• FDA Oncologic Drugs Advisory Committee background sheet, March 4, 2005.
• Novartis "Dear Doctor" letter, September 24, 2004.