According to a media release from Amgen, issued late yesterday, the US Food & Drug Administration (FDA) has approved denosumab (to be known by the brand name Xgeva™) for “prevention of skeletal-related events (SREs) in patients with bone metastases from solid tumors.” This indication would include patients with prostate cancer and evident bone metastasis.
The initial indication granted by the FDA does not include the use of denosumab to prevent bone loss and fractures in patients before there is clear evidence of metastatic disease to bone (e.g., a positive bone scan). Full prescribing information for Xgeva is already available on line. Serious side effects known to be associated with discontinuation of the use of denosumab include hypercalcemia (high levels of calcium in the blood) and osteonecrosis of the jaw (a relatively rare form of deterioration of bone tissue in the jaw which is usually associated with other pre-existing dental conditions).
This approval is based on data from three large, Phase III randomized clinical trials that compared denosumab (given once every 4 weeks as a 120 mg subcutaneous injection) to zoledronic acid (Zometa®, also given once every 4 weeks but by intravenous infusion). In these Phase III trials, as far as patients with bone-specific metastatic prostate cancer were concerned, denosumab showed an improvement in the ability to prevent skeletal-rerlated events (SREs) — including fractures — by comparison with zoledronic acid.
Patients who need drugs like densosumab, zoledronic acid, or other bisphosphonates to prevent bone loss and fractures are usually encouraged to have a full dental check up and to have appropriate dental work completed before starting such treatment with these drugs so as to minimize risk for osteonecrosis of the jaw.