The approved use of denosumab (Xgeva) has been expanded to include adults and some adolescents with giant cell tumor of the bone (GCTB).
GCTB, a rare tumor, usually is noncancerous. However, it destroys normal bone, which in turn leads to pain, limited range of motion, and bone fractures for the patient. GCTB typically strikes persons age 20 to 40 years.
Xgeva is a monoclonal antibody that binds to the RANKL protein, which is essential for the maintenance of healthy bone. (RANKL is also present in GCTB.) The drug was initially approved in 2010, for the prevention of fractures in persons with cancer whose disease metastasized to the bones. The expanded FDA approval now allows Xgeva to be used in persons who have unresectable GCTB or for whom surgery would result in loss of limbs, joint removal, or other severe morbidity, and in adolescents with GCTB whose bones have matured.
The FDA also approved lenalidomide capsules (Revlimid) for the treatment of persons with mantle cell lymphoma (MCL) whose disease has relapsed or progressed after two prior therapies, one of which included bortezomib.
Lenalidomide is a thalidomide analogue already used in combination with dexamethasone for the treatment of patients with multiple myeloma who have received at least one prior therapy, and for the treatment of transfusion-dependent anemia due to certain myelodysplastic syndromes. Because of the associated embryo-fetal risk, lenalidomide is available only through a restricted Risk Evaluation and Mitigation Strategy (REMS) program.
In 133 persons with MCL evaluated for efficacy of lenalidomide therapy (median age 67 years; 61% had MCL for at least 3 years), overall response rate (complete response, unconfirmed complete response, or partial response) was 26%. The majority of patients (25; 19%), achieved a partial response, with the remaining 9 (7%) achieving complete response or unconfirmed complete response.
The most common grade 3-4 adverse reactions seen among those patients were neutropenia, thrombocytopenia, anemia, pneumonia, leucopenia, fatigue, febrile neutropenia, dyspnea, and diarrhea.