Many news sources have reported on the results of a meeting held by the US FDA’s Drug Safety and Risk Management Committee and Advisory Committee for Reproductive Health Drugs, to discuss the safety of the bisphosphonate drug class and whether there should be a recommended ‘drug holiday’ or maximum duration of therapy.

Although the advisers voted in favour of increasing the cautionary language on the product labels, they did not recommend limiting use of the drugs to five years, as had been previously proposed.  The panel commented that the data are not sufficient to allow estimation of the balance of risks and benefits of taking these medicines for longer than three to five years, and to therefore make any specific recommendations on a maximum duration of therapy.  They suggested that more studies are needed to determine how exactly each of the bisphosphonates affects various subgroups of patients.

Earlier this year, bisphosphonate labels were modified in the US to include a recommendation that "continued therapy is re-evaluated on a periodic basis" to reflect the potential adverse reactions that can occur with prolonged exposure to the drugs.  While bisphosphonates have not been definitively proved as causing either atypical fractures or jaw osteonecrosis, epidemiological evidence suggests that risks may increase over time. The agency notes that epidemiological studies on oesophageal cancer associated with bisphosphonates have yielded conflicting results.

According to Reuters, the manufacturers have raised concerns that ‘a sweeping imposition of an interruption in treatment could leave patients vulnerable to more fractures’.