FDA expands use of denosumab for giant cell tumor of the bone

FDA approved the expanded use of denosumab (Xgeva, Amgen) to treat adults and some adolescents with giant cell tumor of the bone (GCTB), a rare and usually non-cancerous tumor.

Xgeva is the first FDA-approved treatment for this rare disease and was approved following a priority review. Xgeva is a monoclonal antibody that binds to RANKL (receptor activator of nuclear factor kappa B ligand), a protein essential for maintenance of healthy bone. RANKL is also present in GCTB.

Xgeva’s approval was based on positive results from 2 open-label trials that enrolled patients with GCTB that was either recurrent, unresectable, or for which planned surgery was likely to result in severe morbidity.

The cost of Xgeva treatment varies according to each patient's unique situation, according to Amgen spokesperson Christine Regan. “Patients with GCTB should discuss their treatment options with their physician to determine if this is an appropriate treatment for them,” she said.

“Advances in our understanding of the underlying biology of this rare disease have allowed [Amgen] to generate compelling clinical evidence to address the medical needs of patients and their healthcare providers,” Regan told Formulary. “With this new approval, providers can offer a much needed treatment option to patients who suffer from giant cell tumor of the bone that cannot be adequately treated with surgery.”

Common side effects include joint pain, headache, nausea, fatigue, back pain, and extremity pain. The most common serious side effects were osteonecrosis (areas of dead bone) of the jaw and osteomyelitis (inflammation or infection of the bone). Women of reproductive potential should use highly effective contraception while taking Xgeva because of potential fetal harm. Xgeva was approved in 2010 to prevent fractures when cancer has spread to the bones.