Weekly treatment with oral alendronate maintains bone mineral increases gained after one year of romosozumab treatment, in women with chronic spinal cord injury

BACKGROUND: Bone loss following spinal cord injury (SCI) leads to an increased risk of fragility fractures, especially at the knee and hip. While research to date has primarily focused on mitigating bone loss in the acute phase, our recent publication demonstrated an improvement in bone mineral and strength at the lumbar spine and hip, but not the knee, in women with chronic SCI and osteoporosis after 12 months of romosozumab therapy. This paper presents 12 months of follow-up treatment with oral alendronate, which aimed to determine whether prior gains could be maintained with transition of therapy in the same sample. METHODS: Ten study participants completed the alendronate treatment. Dual-energy X-ray absorptiometry (DXA) and computed tomography (CT) scans were taken at the end of the treatment year to quantify changes to bone mineral density (BMD) and CT-based finite element (FE) estimations of fracture strength. Second year results were compared to the first year of romosozumab treatment data using non-parametric analyses. RESULTS: No significant changes between the month-12 and month-24 visits were observed for BMD at the lumbar spine (P = .432) or total hip (P = .432). Correspondingly, no significant change in FE-derived strength at the proximal femur (P = .695) was observed. There were no appreciable changes in BMD or bone strength at the knee following the alendronate intervention. CONCLUSIONS: Overall, one year of treatment with monthly romosozumab followed by one year of treatment with weekly alendronate, significantly increased and maintained bone mineral at the hip, but not the knee, in women with chronic SCI and secondary osteoporosis.