STRUCTURE was a phase 3, open-label study evaluating the effect of romosozumab or TPTD for 12 months in women with postmenopausal osteoporosis transitioning from bisphosphonate therapy (NCT01796301). This study enrolled women with postmenopausal osteoporosis who had taken an oral bisphosphonate for ≥3 years prior to screening and alendronate in the year prior to screening; had a BMD T-score ≤−2.5 at the total hip (TH), lumbar spine (LS), or femoral neck (FN); and had a history of fracture. Subjects were randomized to receive subcutaneous romosozumab 210 mg QM or TPTD 20 μg QD. The primary endpoint was percent change from baseline in BMD by DXA at the TH through month 12. Secondary endpoints included percent change from baseline at months 6 and 12 in BMD by DXA at the TH, LS, and FN; hip integral and cortical BMD by quantitative computed tomography (QCT); and estimated hip strength by finite element analysis (FEA). The 436 women enrolled in the study had a mean age of 72 years and mean TH, LS, and FN T-scores of −2.2, −2.9, and −2.5, respectively. Through 12 months, the mean (95% CI) percent change from baseline in TH BMD by DXA was 2.6% (2.2, 3.0) with romosozumab and −0.6% (−1.0, −0.2) with TPTD (P<0.0001 between groups). Romosozumab also resulted in significantly larger BMD gains at the TH, LS, and FN at months 6 and 12 vs TPTD (P<0.0001). Significantly greater gains in integral and cortical hip BMD, and in estimated hip strength were observed with romosozumab vs TPTD at both time points (Table). The subject incidences of adverse events were generally balanced between treatment groups. In conclusion, in subjects transitioning from bisphosphonate therapy, romosozumab was well-tolerated and was associated with greater BMD gains and improved estimated hip strength compared with TPTD.
|Cortical BMD by QCT||Integral BMD by QCT||FEA Estimated Strength|
|Month 6||Month 12||Month 6||Month 12||Month 6||Month 12|
|Romo||0.7 (0.3, 1.1)*||1.1 (0.6, 1.6)*||2.3 (1.9, 2.7)*||3.4 (2.9, 3.8)*||2.1 (1.6, 2.5)*||2.5 (1.7, 3.2)*|
|TPTD||−2.7 (−3.1, −2.3)||−3.6 (−4.1, −3.1)||−0.8 (−1.1, −0.4)||−0.2 (− 0.7, 0.3)||−1.0 (−1.5, −0.6)||−0.7 (−1.5, 0.1)|
|Data are least squares means (95% CI). *P<0.0001 compared with TPTD.|
14 May 2016 - 17 May 2016