Randomized crossover comparison of two teriparatide self-injection regimens for primary osteoporosis: final report of the Japanese Osteoporosis Intervention Trial 06 (JOINT-06).

Introduction: Although bone anabolic agents such as teriparatide are effective for osteoporosis, satisfaction and adherence may vary by regimen. This multicenter study assessed long-term satisfaction, persistence, efficacy, and safety in postmenopausal women with primary osteoporosis treated with alternating daily and twice-weekly teriparatide over 52 weeks, followed by a final free-choice treatment period.

Materials And Methods: In a randomized, open-label, crossover study, 358 postmenopausal women at high risk for fracture were assigned to receive once-daily (20 µg) or twice-weekly (28.2 µg) subcutaneous teriparatide for 26 weeks, then crossed over to the alternative regimen for another 26 weeks. Afterwards, 233 patients entered a 52-week free-choice period under their preferred regimen.

Results: Among the 233 patients entering the free-choice period, 162 chose twice-weekly and 71 chose daily teriparatide. Persistence at 104 weeks was 90.1% for twice-weekly and 88.7% for daily groups (p = 0.749). Overall and treatment satisfaction between groups did not differ significantly at 104 weeks (p > 0.05). Fracture incidence was low and similar (2.8% vs. 1.2%, p = 0.758). Patients in both groups showed significant increases in bone mineral density at L2-L4 and the femoral neck (p < 0.05). Adverse events were infrequent and non-severe.

Conclusions: Patient satisfaction and efficacy were maintained with both teriparatide regimens over 104 weeks, and persistence improved during the patient-choice phase. Supporting patient preference may improve adherence to osteoporosis medications.

Clinical Trial Registration: Japan Registry of Clinical Trials ID: jRCTs031210187.