Monthly ibandronate suppresses serum CTX-I within 3days and maintains a monthly fluctuating pattern of suppression

• Published in: Osteoporosis international Vol. 20; no. 9; pp. 1595 - 1601
• Main Authors: Binkley, N, Silverman, S L, Simonelli, C, Santiago, N, Kohles, J D, Dasic, G, Sunyecz, JA
• Format: Journal Article
• Language: English
• Published: 01.09.2009
• ISSN: 0937-941X; 1433-2965
• DOI: 10.1007/s00198-008-0827-4

Bone turnover markers such as serum C-terminal cross-linking telopeptide of type I collagen (CTX-I) can be used to assess drug efficacy in osteoporosis. This study evaluated the pattern of CTX-I suppression in postmenopausal osteoporotic women receiving ibandronate. Ibandronate decreased serum CTX-I levels within 3days of therapy initiation. Over 6months, the levels remained suppressed below baseline. Introduction: This randomized, double-blind, placebo-controlled study evaluated the rapidity of onset and pattern of suppression of the bone resorption marker serum CTX-I in women with postmenopausal osteoporosis (PMO) who received once-monthly oral ibandronate. Methods: Women diagnosed with PMO received once-monthly oral ibandronate (150mg) or placebo for 6months. Serum CTX-I was measured at baseline and after study dose administration on day3 (month1 only) and days7, 14, 21, and 28 (months1-6). Bone-specific alkaline phosphatase was measured on days7 and 28 (months1-6). Results: This study enrolled 67 women: 49 received ibandronate, 17 received placebo, and one took no study drug. At day3, median reduction in serum CTX-I from baseline was 70.2% with ibandronate and 6.0% with placebo (difference, -64.2%; 95% confidence interval, -80.3% to -46.2%; p<0.0001). In women receiving ibandronate, serum CTX-I levels remained consistently below baseline, exhibiting a regular monthly fluctuating pattern of suppression over 6months. Ibandronate was well-tolerated. Conclusions: Monthly ibandronate decreased serum CTX-I within 3days. Over 6months, in women receiving once-monthly ibandronate, serum CTX-I remained suppressed below baseline. A monthly fluctuation, related to time from last dose, was observed.