Denosumab is designed to target RANKL (RANK ligand), a protein that acts as the primary signal to promote bone removal/resorption. In many bone loss conditions, RANKL overwhelms the body's natural defense against bone destruction. Denosumab prevents RANKL from activating its receptor, RANK, on the surface of osteoclasts and their precursors. Prevention of the RANKL/RANK interaction inhibits osteoclast formation, function, and survival, thereby decreasing bone resorption and increasing bone mass and strength in both cortical and trabecular bone.
In clinical studies, treatment with 60 mg of Prolia resulted in reduction in the bone resorption marker serum type 1 C-telopeptide (CTX) by approximately 85% by 3 days. Consistent with the physiological coupling of bone formation and resorption in skeletal remodeling, subsequent reductions in bone formation markers (i.e. osteocalcin and procollagen type 1 N-terminal peptide [PlNP]) were observed starting 1 month after the first dose of Prolia.
In patients with postmenopausal osteoporosis, the most common adverse reactions (> 5% and more common than placebo) were: back pain, pain in extremity, hypercholesterolemia, musculoskeletal pain, and cystitis. Pancreatitis has been reported in clinical trials. In male patients with osteoporosis, the most common adverse reactions (> 5% and more common than placebo) were: back pain, arthralgia, and nasopharyngitis. In patients experiencing bone loss due to hormone ablation for cancer, the most common adverse reactions (≥ 10% and more common than placebo) were: arthralgia and back pain. Pain in extremity and musculoskeletal pain have also been reported in clinical trials