Romosozumab (formerly AMG 785/CDP7851) is a monoclonal antibody that blocks 
sclerostin from inhibiting osteoblast maturation and function. This 
double-blind, placebo-controlled, randomized, ascending multiple-dose study 
enrolled 32 postmenopausal women and 16 healthy men with low bone mass. Women 
received six doses of 1 or 2 mg/kg once every 2 weeks (Q2W) or three doses of 2 
or 3 mg/kg once every 4 weeks (Q4W) or placebo; and men received 1 mg/kg Q2W or 
3 mg/kg Q4W or placebo. Mean serum romosozumab exposures increased approximately 
dose-proportionally. Romosozumab increased serum type 1 aminoterminal propeptide 
(PINP) by 66-147%, decreased serum C-telopeptide (sCTX) by 15-50%, and increased 
lumbar spine bone mineral density by 4-7%. Two subjects developed neutralizing 
antibodies without discernable effects on pharmacokinetics, pharmacodynamics, or 
safety. Adverse event rates were balanced between groups without any significant 
safety findings. These data support continued investigation of sclerostin 
inhibition in disorders that could benefit from increased bone formation.