Denosumab is used in treatment of -

Ans. is 'a' i.e., Postmenopausal osteoporosis & 'b' i.e., Osteoclastoma' Denosumab* Denosumab is a monoclonal antibody, which inhibits osteoclast differentiation and function as well as promotes their apoptosis.* Osteoclast is a cell responsible for bone resorption.* Osteoclasts express RANK receptors on its surface (RANK receptor activator for nuclear factor).* When RANK receptor combine with their ligands (RANKL) osteoclastogenesis is initiated and bone resorption occurs.* Donesumab is a monoclonal antibody against RANK ligand. It prevents the activation of the osteoclasts by these ligand.* Osteoporosis is a disease characterized by decrease in the bone mass. In osteoporosis there is increase in the osteoclast activity and there is increased expression of RANK and RANKL.* Thus denosumab is the treatment option for osteoporosis when no other drug is appropriate.* Denosumab is also the only FDA approved drug for treatment of osteoclastoma.