Abstract
The efficacy and safety of RGB-10 and reference teriparatide were evaluated in a randomized 52-week study in 250 patients with osteoporosis at high risk of fracture. RGB-10 was equivalent to reference teriparatide in efficacy and had a comparable safety profile. INTRODUCTION: RGB-10 is the first biosimilar teriparatide authorized in the European Union. This multicenter, randomized, rater-blinded, parallel-group phase 3 study evaluated equivalence in efficacy and compared safety between RGB-10 and reference teriparatide in patients with osteoporosis at high risk of fracture for registration in Japan. METHODS: Ambulatory postmenopausal women and men (≥ 55 years of age) with osteoporosis at high risk of fracture were randomized 1:1 to receive either RGB-10 or reference teriparatide 20 μg once daily via subcutaneous self-injection for 52 weeks. The primary efficacy endpoint was the percent change from baseline to 52 weeks in lumbar spine (L2-L4) bone mineral density (BMD). Safety outcomes and immunogenicity were also assessed. RESULTS: In total, 250 patients (125 in each group) were randomized. The percent change from baseline to 52 weeks in lumbar spine (L2-L4) BMD (mean ± standard deviation) was 8.94% ± 6.19% in the RGB-10 group and 9.65% ± 6.22% in the reference teriparatide group. The estimated between-group difference (95% confidence interval) was - 0.65% (- 2.17% to - 0.87%) within the pre-specified equivalence margin (± 2.8%), which indicates equivalence in efficacy between the two groups. Changes in BMD at lumbar spine (L1-L4), femoral neck, and total hip and serum procollagen type I amino-terminal propeptide were also similar between the groups. Safety profiles, including immunogenicity, were comparable. CONCLUSIONS: The therapeutic equivalence of RGB-10 to reference teriparatide was demonstrated. RGB-10 had comparable safety profile to that of reference teriparatide.