Design of a randomized trial of teriparatide followed by alendronate: Japanese Osteoporosis Intervention Trial-05 (JOINT-05)

Introduction Despite advances in drug treatment, the optimal treatment strategy for severe osteoporosis remains uncertain. Materials and methods This article reports the design and rationale for the Japanese Osteoporosis Intervention Trial-05 (JOINT-05), a randomized, controlled trial that compares the efficacy and safety of teriparatide followed by alendronate with alendronate monotherapy for severe osteoporosis. Results Postmenopausal women aged at least 75 years were eligible for the study if they were at high risk of fracture. Patients were recruited from 113 institutions in Japan between October 2014 and December 2017. They were randomly assigned in a 1:1 ratio to the sequential therapy arm (once-weekly subcutaneous injections of teriparatide 56.5 μg for 72 weeks followed by alendronate for 48 weeks) or monotherapy arm (alendronate for 120 weeks). The regimens for alendronate are 5 mg (orally administered once daily), 35 mg (orally administered once weekly), or 900 μg (intravenously administered once every 4 weeks). The primary endpoint is the incidence of morphometric vertebral fracture at 72 weeks. The secondary endpoints include the incidence of morphometric vertebral fracture at 120 weeks; incidence of morphometric vertebral or non-vertebral fractures at 72 and 120 weeks; incidence of clinical vertebral fracture at 72 and 120 weeks; changes in bone mineral density, quality of life scores (EuroQol 5 Dimensions and the Japanese Osteoporosis Quality of Life Questionnaire short form), and a visual analog scale for back pain; and adverse events. Conclusion We reported the design and rationale for the JOINT-05. The trial is registered with the Japan Registry of Clinical Trials (jRCTs031180235) and the University Hospital Medical Information Network-Clinical Trials Registry (UMIN000015573).