Levormeloxifene prevents increased bone turnover and vertebral bone loss following ovariectomy in cynomolgus monkeys

Levormeloxifene, a nonsteroidal selective estrogen receptor modulator (SERM ), has been evaluated for its effects on bone in cynomolgus monkeys (Macaca fascicularis). Adult female monkeys were imported from Indonesia and rando mized into six groups of 25-28 animals each (n = 158). Animals in one group were sham ovariectomized (sham) and received vehicle. Animals in the remai ning five groups were ovariectomized and received either vehicle (ovx); 17 beta -estradiol at 0.016 mg/kg (est); or levormeloxifene at 0.5 (Ll), I (L2 ), or 5 (L3) mg/kg. Lumbar spine and whole body bone mass were measured by dual-energy X-ray absorptiometry (DXA) pretreatment and at 6 and 12 months following the initiation of treatment. Bone mass at the femoral neck was me asured by peripheral quantitative computed tomography (pQCT) at 0 and 12 mo nths. Serum markers of bone turnover, including bone-specific alkaline phos phatase (BSAP), osteocalcin (BGP), tartrate-resistant acid phosphatase (TRA P), and urinary collagen C-terminal extension peptides (CrossLaps), were me asured at 0, 6, and 12 months. Ovariectomy resulted in an increase in these markers; the increase was prevented by estradiol or levormeloxifene. Estra diol or levormeloxifene inhibited loss of lumbar spine bone mineral density (BMD) following ovariectomy compared with untreated monkeys (ovx -5.0%; sh am -0.4%; est +0.2%; Ll -3.6%, L2 -2.0%, L3 -2.5%). Estradiol, but not levo rmeloxifene, prevented loss of BMD at the femoral neck (ovx -7.4%; sham -3. 1%; est -3.6%; Ll -8.0%, L2 -6.5%, L3 -7.8%), and whole body bone mineral c ontent (BMC) (ovx -7.6%; sham -1.9%, est -2.9%; Ll -6.2%, L2 -6.1%, L3 -6.7 %). Bone loss at each site was correlated with bone turnover as measured by serum and urine biomarkers. There was no dose effect of levormeloxifene. ( C) 2001 by Elsevier Science Inc. All rights reserved.