Zoledronate for Treatment of Primary Osteoporosis

Dennis Black, PhD


June 25, 2004


I would like to know about use of zoledronic acid in osteoporosis. Have any studies evaluated its efficacy as treatment for primary osteoporosis?

Manuel Calipuy, MD

Response from Dennis Black, PhD

Zoledronic acid is a bisphosphonate that is being developed for prevention and treatment of osteoporosis. This drug is not approved for treatment or prevention of osteoporosis. Phase 3 testing is currently in progress. The dose that is being tested is 5 mg given as a once-per-year infusion. The main end points of the phase 3 trials will be occurrence of fractures.

A phase 2 study was performed and published in 2002[1] examining the effect of various doses and different times of administration of bone density and bone markers. This study was small and examined only about 60 patients per treatment group. Of most relevance to the clinical development was that 4 mg administered once per year increased spine bone mineral density by about 4.5% compared with placebo over 12 months. In this group, bone resorption decreased by about 50% to 60% over 12 months. More frequent (every 3 months and every 6 months) lower doses of zoledronic acid had similar effects.

However, current data for this drug are limited as there are no fracture data and no data at all beyond 12 months. The phase 3 trials that are currently in progress to determine fracture efficacy are long enough (2 to 3 years) and large enough to adequately assess the safety and fracture efficacy of this drug.


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