Ibandronate Stops Bone Loss in Breast Ca Patients


SAN ANTONIO — Monthly ibandronate appears to prevent, and perhaps even reverse, bone loss in women who are taking anastrozole for estrogen receptor-positive breast cancers, Dr. J.E. Lester reported in a poster presentation at the Sixth International Meeting on Cancer-Induced Bone Disease.

While she said that further follow-up is required, her randomized placebo-controlled trial showed that after 1 year, women taking the bisphosphonate showed a significant increase in bone mineral density (BMD) at both the hip and spine, while those taking the placebo experienced a significant decrease at both sites.

Dr. Lester, of the Cancer Research Centre of Weston Park Hospital, Sheffield, England, examined ibandronate's effects in 131 postmenopausal women who had estrogen receptor-positive breast cancer.

The women were grouped according to baseline BMD: 68 had normal BMD (mean age 63 years), 50 were osteopenic (mean age 67 years), and 13 were osteoporotic (mean age 71 years).

All patients were taking calcium and vitamin D supplements in addition to anastrozole. Those with normal BMD continued on the supplements.

Osteopenic patients were randomized to either 150 mg oral ibandronate every 28 days (25 patients) or placebo (25 patients). All osteoporotic women received the same monthly ibandronate treatment.

Ibandronate significantly increased BMD at the hip and spine in both treated groups. At 1 year, osteopenic women had a mean increase of 2.8% at the lumbar spine and 1.4% at the hip. After 1 year, five of the previously osteopenic women were found to have normal BMD.

Women in the placebo group had a decrease of BMD at both sites (mean -2.6% at the lumbar spine and −2.3% at the hip).

During the blinded period, two osteopenic patients lost more than 10% of their BMD at either the spine or hip. They were withdrawn from the study and unblinded; both had been taking the placebo and both were offered open-label ibandronate.

Among the osteoporotic women, the mean increase in BMD was 2.6% at the lumbar spine and 2.6% at the hip. Seven previously osteoporotic patients were found to be osteopenic at 1-year follow-up.

Of the 68 women with initially normal BMD who had not been treated with ibandronate, 20 were followed for 2 years.

Follow-up scans showed a mean decrease in BMD of −4% at the lumbar spine and −3% at the hip.

Despite these changes, however, none of the women who had not been treated with idandronate developed osteoporosis.


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