Prevention of Aromatase Inhibitor–Induced Bone Loss Using Risedronate: The SABRE Trial

Abstract

PurposeTo investigate the management of bone health in women with early breast cancer (EBC) who were scheduled to receive anastrozole.Patients and MethodsPostmenopausal women with hormone receptor–positive EBC were assigned to one of three strata by risk of fragility fracture. Patients with the highest risk (H) received anastrozole 1 mg/d plus risedronate 35 mg/wk orally. Patients with moderate-risk (M) were randomly assigned in a double-blind manner to anastrozole and risedronate (A + R) or to anastrozole and placebo (A + P). Patients with lower-risk (L) received anastrozole (A) alone. Calcium and vitamin D were recommended for all patients. Lumbar spine and total hip bone mineral density (BMD) were assessed at baseline, 12 months, and 24 months.ResultsAt 24 months, in the M group, treatment with A + R resulted in a significant increase in lumbar spine and total hip BMD compared with A + P treatment (2.2% v −1.8%; treatment ratio, 1.04; P < .0001; and 1.8% v −1.1%; treatment ratio, 1.03; P < .0001, respectively). In the H stratum, lumbar spine and total hip BMD increased significantly (3.0%; P = .0006; and 2.0%; P = .0104, respectively). Patients in the L stratum showed a significant decrease in lumbar spine BMD (−2.1%; P = .0109) and a numerical decrease in total hip BMD (−0.4%; P = .5988). Safety profiles for anastrozole and risedronate were similar to those already established.ConclusionIn postmenopausal women at risk of fragility fracture who were receiving adjuvant anastrozole for EBC, the addition of risedronate at doses established for preventing and treating osteoporosis resulted in favorable effects in BMD during 24 months.