Study of twice-weekly injections of Teriparatide by comparing efficacy with once-weekly injections in osteoporosis patients: the TWICE study

A Summary A 48-week, multicenter, randomized, double-blind, double-dummy, active-controlled, non-inferiority trial (the TWICE study) conducted in Japanese primary osteoporosis patients with a high risk of fractures demonstrated that a 28.2-mu g twice-weekly regimen of teriparatide can provide comparable efficacy to a 56.5-mu g once-weekly regimen of teriparatide, while also improving safety. Introduction While a 56.5-mu g once-weekly regimen of teriparatide has high efficacy for osteoporosis, treatment continuation rates are low, with one of the major causes being adverse drug reactions such as nausea or vomiting. The TWICE study was therefore conducted to investigate whether a twice-weekly regimen with 28.2-mu g teriparatide can provide comparable efficacy to the 56.5-mu g once-weekly regimen while improving safety. Methods A 48-week, multicenter, randomized, double-blind, double-dummy, active-controlled, non-inferiority trial was conducted in Japan. Patients with primary osteoporosis aged >= 65 years at high risk of fractures (n = 553) were randomly allocated to the 28.2-mu g twice-weekly group (n = 277) or the 56.5-mu g once-weekly group (n = 276). The primary endpoint was the percentage change in lumbar spine (L2-L4) bone mineral density (BMD) at final follow-up. Results The percentage changes in lumbar spine (L2-L4) BMD at final follow-up in the 28.2-mu g twice-weekly and 56.5-mu g once-weekly groups were 7.3% and 5.9%, respectively; the difference (95% confidence interval [CI]) in percentage change was 1.3% (0.400-2.283%). Since the lower limit of the 95% CI was above the pre-specified non-inferiority margin (- 1.6%), non-inferiority of the 28.2-mu g twice-weekly group was demonstrated. Adverse drug reactions were significantly less frequent in the 28.2-mu g twice-weekly group (39.7% vs 56.2%; p < 0.01); the incidence of major adverse drug reactions was lower, and the number of subjects who discontinued due to adverse drug reactions was less in the 28.2-mu g twice-weekly group. Conclusions A 28.2-mu g twice-weekly regimen of teriparatide can provide comparable efficacy to a 56.5-mu g once-weekly regimen while improving safety.