Study of Alendronate to Prevent and Treat Osteoporosis in Cystic Fibrosis Patients

The primary objective of this study is to determine efficacy of 70 mg alendronate once weekly compared to placebo. This will be measured by percent changes in lumbar spine(LS) bone mineral density(BMD) in adult cystic fibrosis(CF)patients after one year of treatment. The investigators hypothesize that in adult CF patients with osteopenia or osteoporosis, alendronate 70 mg once weekly will produce a mean increase from baseline in lumbar spine BMD that is greater than that observed with placebo at 12 months.

Randomized controled trial have begun to establish the efficacy and safety of bisphosphonates in CF patients with decreased BMD. The development of a once weekly dosing regimen of alendronate and the low prevalence of esophageal adverse events may be an advantageous therapeutic option for this high-risk population. This is a one-year randomized, double-blind, placebo-controlled, multicentre study in 55 CF patients with osteopenia or osteoporosis. Six Canadian centres are participating in this study. Patients randomized to treatment will receive 70 mg oral alendronate once weekly, while controls will receive identical placebo once weekly. All medication dispensed will be concealed. There will be no dose modification during the course of the trial. All patients will receive a total of 1000 mg calcium, 500 through supplementation and 500 through diet. All patients will continue to take vitamin D supplementation ( 2 tablets per day, 400 IU vitamin D/tablet).