Treatment for sublesional bone loss (osteoporosis) in persons with chronic, motor-complete spinal cord injury (SCI) has been limited and unsuccessful to date. Romosozumab, a sclerostin antagonist, has potential to increase bone formation (anabolic) and decrease bone resorption (anti-catabolic) in persons with chronic SCI. Conventional anti-resorptive therapy alone would not be anticipated to reverse sublesional bone loss in a timely manner because the skeleton below the level of lesion in chronic SCI is assumed to be in a low turnover state. However, because there is a high likelihood that the bone accrued while on romosozumab will be lost once discontinued, denosumab, an anti-resorptive agent, will be administered after treatment with romosozumab, to maintain or, possibly, to continue to increase, bone mineral density (BMD).

The purpose of this study is to address the gap in the treatment of osteoporosis in individuals with chronic SCI by partially restoring BMD with romosozumab treatment for 12 months and then to maintain, or further increase, BMD with denosumab treatment for 12 months. A two group, randomized, double-blind, placebo-controlled clinical trial will be conducted in 39 participants who have chronic (\>3 years), motor-complete or incomplete SCI and areal BMD (aBMD) values at the distal femur of at the distal femur \<1.0 g/cm2 measured by dual photon X-ray absorptiometry (DXA). The intervention group will receive 12 months of romosozumab followed by 12 months of denosumab, and the control group will receive 12 months of placebo followed by 12 months denosumab.