Intermittent IV Ibandronate May Overcome Problems with Oral Osteoporosis Therapy

Internal Medicine World Report, April 2006, Volume 0, Issue 0

San Diego?Quarterly intravenous (IV) ibandronate (Boniva) may circumvent some of the frequent compliance and tolerability problems associated with oral bisphosphonate therapy for osteoporosis and allow treatment for patients who would otherwise not be candidates. Several presentations at the annual meeting of the American College of Rheumatology highlighted the problem of poor compliance, showing that as many as 50% of patients with a new prescription for an oral bisphosphonate abandon it within the first year.

Ronald Emkey, MD, director of bone research, Radiant Research, Wyomissing, Pa, and associate professor of medicine, Temple University, Philadelphia, reported on 2-year results from the Dosing IntraVenous Administration (DIVA) study, which showed that an injection of IV ibandronate every 2 or 3 months more effectively increased bone mineral density (BMD) than daily oral drug treatment.

"The medication was more effective than the daily dosing that has already proven to reduce bone markers and ?fractures and increase bone density," Dr Emkey said. While the DIVA study was not powered to measure fracture rates, he noted that there were no disturbing trends.

This double-blind, double-dummy, phase 3, noninferiority trial included 1395 women (aged 55-80 years) who were ?5 years postmenopausal and who had osteoporosis documented at the lumbar spine. They were randomized to IV ibandronate 2 mg every 2 months, IV ibandronate 3 mg every 3 months, or oral ibandronate 2.5 mg daily, with appropriate IV or oral placebos for all groups. All the participants received daily oral calcium and vitamin D supplements.

Consistent with the 1-year results from the DIVA study, both IV regimens proved to be superior to oral dosing at 2 years in increasing BMD at the lumbar spine and the hip (Table). Tolerability remained good through 2 years, with 85.3% to 88.6% of patients in the IV or oral groups experiencing some adverse effect, but with only 9.8% to 11.7% of patients in any group experiencing a side effect that led to withdrawal.

Dr Emkey believes that intermittent IV ibandronate dosing is a good option for osteoporosis treatment and prevention and allows the physician to monitor whether the patient is taking the medication.

Also, older patients in a primary care practice often have multiple comorbidities, including dysphagia, that may preclude them from taking a pill, especially a bisphosphonate, which can irritate the upper gastrointestinal tract. "An every-3-month dosing would be simple to administer in the office setting and almost timed with some patients' visits every-3-months" for their various conditions, he said.

Dr Emkey predicted that some pa?tients may prefer a quarterly injection over a daily or even a monthly tablet.

Another IV bisphosphonate in development for osteoporosis, zoledronic acid (Novartis), has shown efficacy in increasing bone mass and reducing markers of bone turnover when given once a year.

"The use of an intravenous or parenteral form of medication allows us to open up treatment to a subset of patients who otherwise could not be treated," Dr Emkey advised. "That's an important thing because so many people are elderly, and so many people have dysphagia, esophageal strictures, or other problems, and in this situation they can now be treated safely and effectively on a 3-month basis."

Ibandronate was initially FDA ap?proved at an oral dose of 2.5 mg/day or 150 mg once monthly. In January it received additional approval for 3-mg IV dosing over 15 to 30 seconds once every 3 months.