Effect of chronic treatment with ipriflavone in postmenopausal women with low bone mass

We present the results of two multicenter, double-blind, placebo-controlled, 2-year studies to evaluate the efficacy and tolerability of ipriflavone in postmenopausal women (PMW) with low bone mass. 453 PMW (aged 50-65 years) with a vertebral (VMD) or radial (RMD) mineral density value 1 SD lower compared with age-matched controls, were randomly selected to receive oral ipriflavone (200 mg T.I.D. at meals) or matching placebo, plus 1 g oral calcium daily. Vertebral (study A, by dual X-ray absorptiometry-DXA) and radial (study B, by dual photon absorptiometry-DPA) bone density, serum bone Gla-protein (BGP), and urinary hydroxyproline/creatinine (HOP/Cr) were measured every 6 months. In both studies, the Valid Completers (VC) analysis showed a maintenance of bone mass in ipriflavone-treated women, whereas in the placebo group, bone mineral density (BMD) was significantly decreased. The final outcome was a bone-sparing effect of 1.6% in study A, and of 3.5% in study B after 2 years. The Intention to Treat (ITT) analysis confirmed the decrease in the placebo group, with no changes in ipriflavone-treated women. A significant (P < 0.05) between-treatment difference was found in both studies. Biochemical markers of bone turnover decreased in patients treated with ipriflavone, thus suggesting a reduction of bone turnover rate. Twenty-six women treated with ipriflavone and 28 receiving the placebo dropped out because of side effects, mainly gastrointestinal. The compliance to the oral long-term treatment was good. The results of these studies show that ipriflavone is able to prevent both axial and peripheral bone loss in PMW with low bone mass, and is well tolerated.