Prevention of anastrozole induced bone loss with monthly oral ibandronate: Final 5 year results from the ARIBON trial

Abstract

PurposeThe ARIBON trial is a double blind, randomised, placebo controlled study designed to evaluate the impact of ibandronate on bone mineral density (BMD) in women taking anastrozole for adjuvant treatment of breast cancer.Methods131 postmenopausal women with early breast cancer were recruited to the study. Of these, 13 had osteoporosis, 50 osteopenia and 68 normal BMD. Patients with osteoporosis at baseline were treated with monthly oral ibandronate 150 mg for 5 years; osteopenic patients were randomised to receive either ibandronate or placebo for two years and offered open label ibandronate depending upon the results of their 2-year BMD result.ResultsOf the 20 patients with osteopenia who were randomised to ibandronate and evaluable at the 2 year visit, 17/20 were not offered a bisphosphonate and the improvements in BMD accrued during the first 2 years were lost both at the LS (−3.21%) and TH (−5.0%). Of the 16 patients randomised to placebo 8/16 with high rates of bone loss during years 0–2 received ibandronate over the next 3 years with improvements in BMD of +5.01 and +1.19 at the LS and TH respectively. The 8 patients who were not offered a bisphosphonate experienced relatively little change in BMD throughout the 5 years of the study (LS +0.15%, TH −2.72%). BMD increased steadily in the 9/13 patients initially identified as having osteoporosis (LS +9.65%, TH +2.72%).ConclusionsMonthly oral ibandronate provides an option to clinicians considering use of a bisphosphonate to prevent bone loss during aromatase inhibitor therapy.

Zoledronic acid for treatment of osteopenia and osteoporosis in women with primary breast cancer undergoing adjuvant aromatase inhibitor therapy: a 5-year follow-up

“…The improvement in BMD observed in this trial is consistent with data from prior studies evaluating use of oral bisphosphonates in a similar population [23,24]. In the SA-BRE trial, women with T-score <−2.0 who were treated with anastrozole and risedronate experienced a significant 3.0 % increase in LS and total hip BMD at 24-month follow-up [23].…”

“…In the SA-BRE trial, women with T-score <−2.0 who were treated with anastrozole and risedronate experienced a significant 3.0 % increase in LS and total hip BMD at 24-month follow-up [23]. In the 5-year follow-up of the ARIBON trial that treated osteoporotic postmenopausal women with early breast cancer with anastrozole and ibandronate, a 9.65 % increase in LS BMD was observed, along with a 2.72 % increase in total hip BMD [24]. This trial also randomized osteopenic patients to 2 years of anastrozole and ibandronate, or anastrozole and placebo.…”

Effects of adjuvant exemestane versus anastrozole on bone mineral density for women with early breast cancer (MA.27B): a companion analysis of a randomised controlled trial

“…12–14,24 Women who received oral bisphosphonates had either stabilised or increased bone mineral density at 2 years 12,14 and 3 years. 24 None of the trials of intravenous bisphosphonates included women with T-scores of less than –2·0 when starting aromatase inhibitor treatment.…”

“…MA.27 directly compared two aromatase inhibitors in postmenopausal patients with breast cancer, and reported fewer cases of osteopenia or osteoporosis for patients taking exemestane than those taking anastrozole. 16 We identified four trials 12–14,24 of oral bisphosphonates for women with baseline osteoporosis starting an aromatase inhibitor.…”

“…9,10 Bisphosphonates 11–14 and denosumab 15 can counteract bone loss of women treated with aromatase inhibitors; however, most breast cancer trials excluded women with osteoporosis at baseline. 11 …”