Zometa is in the class of drugs known as bisphosphonates that are utilized for bone health. Currently not approved by FDA for cancer, but is approved by the FDA for preventing or delaying issues associated with hormone deprivation or from cancer itself, such as bone loss. Zometa and Xgeva can be used for patients with metastastic prostate cancer in order to prevent or delay an SRE.
Zometa is the most potent bisphosphonate and is only available in intravenous infusion. Infusions take 15-30 minutes. For the prevention of skeletal related events studies have shown that infusions every three weeks decreases the incidence of adverse events by 11% compared to placebo and an increase in bone mineral density a 5.6%. Intravenous zolendronic acid has proven to be superior than placebo in preventing SRE’s and delays onset of an abnormal SRE’s significantly at 2 years. No improvement in overall survival has been proven however. Other bisphosphonates have not been shown to be effective for prevention of disease-related skeletal complications.
A rare but serious complication is osteonecrosis of the jaw. Nephrotoxicity is also common and it is imperative to monitor renal function.
Comparison of agents for bone metastasis
Denosumab was compared to zoledronic acid in a randomized, double- blind,placebo-controlled study in men with CRPC. The absolute incidence of SREs was similar in the 2 groups; however, the median time to first SRE was delayed by 3.6 months by denosumab compared to zoledronic acid (20.7 vs. 17.1 months) The rates of important SREs with denosumab were similar to zoledronic acid and included spinal cord compression (3% vs. 4%), need for radiation (19% vs. 21%), and pathologic fracture (14% vs. 15%).
Treatment-related toxicities reported for zoledronic acid and denosumab were similar and included hypocalcemia (more common with denosumab 13% vs. 6%), arthralgias, and osteonecrosis of the jaw (ONJ, 1%–2% incidence). The most common side effects are minor flu-like symptoms and occasionally some mild Gastrointestinal problems constipation, nausea, vomiting or loss of appetite.
Care should be given to patients with kidney disease.
The most devastating adverse events is osteonecrosis of the jaw(ONJ). This problem occurs when an upper or lower area of the teeth or jaw becomes infected and this infection becomes difficult to cure while on these drugs. One way to decrease the risk of this problem is to get dental clearance prior to starting therapy.
The majority of cases of ONJ are in patients who have been treated for a longer duration and commonly have had a previous dental procedure. If you have any of the following symptoms be sure to mention it to your provider.
*Mouth or facial pain that resemble a toothache
*Chronic sinusitis (inflammation of the sinuses)
*Foul smelling drainage in the jaw area
*Numbness in either the upper or lower jaw
*An exposed bony area inside of the mouth seen on examination