A 30-year-old woman has a biopsy-proven giant cell tumour of the sacrum with extensive soft tissue extension. The tumour is deemed unresectable and she is not a candidate for embolisation or radiation. Which drug acts directly on the RANK-RANKL-OPG pathway and is used to control this tumour?
- A Pazopanib
- B Denosumab ✓
- C Teriparatide
- D Calcitonin
Explanation
Giant cell tumour stromal cells express RANKL, which drives the formation and activity of the osteoclast-like multinucleated giant cells responsible for bone destruction. Denosumab, a fully human monoclonal antibody against RANKL, blocks this axis and produces marked reduction in tumour-associated osteolysis, and is the established agent for unresectable or recurrent GCT, particularly in the axial skeleton. Teriparatide stimulates osteoblasts, calcitonin inhibits osteoclasts weakly but is not used here, and pazopanib is a tyrosine kinase inhibitor without RANKL action.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.