Alendronate in the prevention of osteoporosis: 7-year follow-up

In a 3-year study followed by a 2-year open-label extension, alendronate sodium (ALN) maintained or increased bone mineral density (BMD) in 445 recently postmenopausal women with a spine BMD T-score >-2. In a second 2-year extension, 84 women previously treated with either 5 or 10 mg ALN daily during the first 3 years and 5 mg ALN during the first extension (group A) were randomized to either 5 mg ALN or placebo (PBO). Another group of 59 women (group B) received 20 mg ALN during the first 2 years, PBO during year 3, and were then followed up without treatment during years 4-7. In group A, continuous ALN treatment for 7 years increased spine and trochanter BMD by 2.7-4.1 and 3.3-4.2%, respectively, while femoral neck BMD was maintained. Patients initially receiving 10 mg ALN maintained total body BMD, whereas those treated with 5 mg ALN experienced a small but significant loss after 7 years. Among women who received ALN 5 mg during years 4-7, those who had been treated with ALN 10 mg in the first 3 years had slightly greater increases in BMD at most sites at the end of the study, compared with women who received ALN 5 mg during the first 3 years. During years 6-7, patients who switched to PBO during the previous 2 years showed a significant loss in femoral neck BMD, whereas changes at the other sites were not significant. Women in group B showed significant loss in BMD at all skeletal sites during years 4-7, when they received no treatment. In conclusion, ALN 5 or 10 mg daily for up to 7 years prevents bone loss in recently postmenopausal women. Patients started on ALN 10 mg appear to gain more BMD than those initially treated with 5 mg ALN. Early postmenopausal women who discontinue ALN after 2 years of treatment experience significant bone loss at all skeletal sites despite the higher (20 mg) initial dosing. The ALN was generally well tolerated during 7 years of treatment.