Ibandronate May Have Fewer Gastrointestinal Side Effects


NASHVILLE, TENN. — Postmenopausal women with a history of gastrointestinal side effects on bisphosphonate therapy had a decline in GI symptoms after 6 months of either oral or intravenous ibandronate, although the decline was more pronounced with the intravenous drug, according to interim results presented at the annual meeting of the North American Menopause Society.

Dr. Mark Martens of the University of Oklahoma, Tulsa, reported 6-month data from the ongoing 12-month PRIOR study, which is assessing the tolerability of ibandronate (Boniva) in women with a history of daily or weekly bisphosphonate treatment for osteoporosis or osteopenia.

This trial is not randomized; the patients initially requested either 150-mg ibandronate orally once a month or quarterly intravenous 3-mg ibandronate, and they have the option of switching to the other arm if they experience side effects but may do so only once. The study initially enrolled 546 patients. Patients are assessed every 3 months.

Among 146 patients initially in the oral group, 11 (7.5%) switched to intravenous treatment, and 15 (3.8%) of 396 patients in the intravenous group chose to switch to the oral arm, Dr. Martens said.

Serious adverse events were reported by 4% of all patients—4% of the oral group and 3% of those on the intravenous treatment.

Dr. Martens reported that the total change from baseline in GI tolerance scores was 130 at month 1 for the oral group and 377 at month 1 for the intravenous group.

The primary diagnosis was osteoporosis for 85 patients in the oral group (58%) and 281 patients in the intravenous group (71%). Osteopenia was the primary diagnosis for 61 patients (42%) in the oral group and 115 patients (29%) in the intravenous group.

Dr. Martens disclosed that he has received financial support from GlaxoSmithKline, Procter and Gamble, Merck & Co., and Eli Lilly.

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