Effects of Romosozumab on Bone Density in Women With Anorexia Nervosa

This protocol is a randomized, double-blind, placebo-controlled clinical trial which aims to investigate the effect of romosozumab on BMD in women with anorexia nervosa. The investigators will also investigate the safety of romosozumab in women with anorexia nervosa. The investigators hypothesize that 12 months of romosozumab administration will result in an increase in bone mineral density, increase in markers of bone formation and decrease in markers of bone resorption, and improvement in bone microarchitecture in osteopenic women with anorexia nervosa compared with placebo. In Phase 2, participants will receive a single infusion of open-label zoledronic acid (an intravenous bisphosphonate) 5 mg after the initial 12-month administration of romosozumab or placebo. The investigators hypothesize that 12 months of romosozumab followed by a single intravenous infusion of open-label zoledronic acid will result in a greater increase in BMD compared to 12 months of placebo followed by a single intravenous infusion of open-label zoledronic acid. Within the group of women who receive sequential therapy with 12 months of romosozumab followed by a single intravenous infusion of zoledronic acid, the investigators hypothesize BMD will be maintained between 12 and 24 months following administration of zoledronic acid.