Table 3.

Major differences between denosumab and zoledronic acid.

	Denosumab	Zoledronic acid
Type of substance	Monoclonal antibody	Chemical agent
Mode of action	Inhibition of osteoclast differentiation	Induction of osteoclast apoptosis
Application	Subcutaneous	Intravenous
Direct antitumour effect	Possible, not yet observed	Suggested from preclinical and inconsistent clinical data
Inhibition of T-cell function	Suggested from in vitro data; increased infection rate not fully excluded	Not observed
Osteonecrosis of the jaw	Relevant side effect in patients receiving denosumab for bone metastases. Not observed in patients treated for osteoporosis	Relevant side effect in patients receiving zoledronic acide for bone metastases and osteoporosis
Renal toxicity	Not observed	Relevant side effects