New data from a study evaluating paired bone biopsies at the start of and after five years of risedronate (Actonel/Optinate) treatment in post-menopausal women with osteoporosis demonstrates that the new bone formed was normal and of good quality.

From the biopsies, a moderate suppression of bone remodeling was shown, which was in line with the estimated suppression of turnover assessed by serum bone turnover markers [ostase (-33 percent) and N-telepeptide/creatinine (-47 percent) markers (p =0.05)].

These unique data, presented at the annual meeting of the European Calcified Tissues Society (ECTS), came from a five-year placebo-controlled paired biopsy study of 86 postmenopausal women with osteoporosis who received either risedronate (44 patients) or placebo (42 patients). Bone tissue biopsies from 21 and 27 patients respectively were taken and histologically assessed at baseline and five years in both treatment groups. The biopsies showed that the new bone formed was normal and of good quality.

A significant moderate and sustained decrease in bone turnover was seen at five years in the risedronate group with no significant decrease in the placebo group. This finding is in line with the reduction in ostase and N-telepeptide/creatinine serum markers for bone turnover (-33 percent and -47 percent, respectively) (p =0.05). Cortical thickness decreased in both groups, but the risedronate group decrease was about 3-fold less than the placebo group. Lumbar spine BMD increased 9.2 percent relative to baseline in those patients treated with risedronate compared to no significant change in the placebo group. Bone formation and mineralization were normal as assessed by osteoid thickness, mineral apposition rate, mineralization lag time and wall thickness.

"Strong bones fracture less and getting the bone turnover right, well within the pre-menopausal range, is important because of its influence on bone strength," said Arkadi Chines, associate professor of Clinical Medicine, University of Cincinnati, and global medical director, Procter & Gamble Pharmaceuticals. "There is an emerging consensus that bone strength and the factors that influence it is what really matters in assessing treatments for osteoporosis. This study confirms that risedronate therapy reduces bone turnover to within normal premenopausal range while formation of good quality bone continues even after five years of treatment," he added.

Risedronate sodium is a bisphosphonate marketed by the Alliance for Better Bone Health (Procter & Gamble Pharmaceuticals and Aventis) and currently approved in 82 countries worldwide. Risedronate 35 mg Once a Week and risedronate 5 mg daily are indicated for the treatment of osteoporosis in postmenopausal women.

A disease characterized by low bone mass and micro-architectural deterioration of bone tissue, postmenopausal osteoporosis leads to reduced bone strength and a consequent increase in fracture risk.