Impact of prior teriparatide treatment on the effectiveness of romosozumab in patients with postmenopausal osteoporosis: A case-control study.

Purpose: To evaluate the impact of prior teriparatide (TPTD) treatment on the effectiveness of romosozumab (ROMO) in postmenopausal osteoporosis.

Methods: In this retrospective, case-controlled, multicenter study, 323 postmenopausal patients were initiated ROMO. Of these, 275 were treatment-naïve, and 48 were switched from TPTD, with uninterrupted ROMO treatment for 12 months. Propensity score matching was applied to ensure clinical comparability, yielding 44 patients in each group. Baseline characteristics included a mean age of 78.0 years, lumbar spine (LS) T-score of -3.6, and total hip (TH) T-score of -2.8. Bone mineral density (BMD) and serum bone turnover markers were evaluated over the 12-month period.

Results: The increasing rate in the bone formation marker PINP was significantly greater in the treatment-naïve group compared to the TPTD-switched group throughout the 1-12 month period. Conversely, the reduction in the bone resorption marker TRACP-5b was similar between the groups, indicating a diminished anabolic window in the TPTD-switched group. After 12 months, the TPTD-switched group showed lower BMD gains in the LS (10.3 % vs. 17.3 %; P = 0.002) and TH (3.1 % vs. 7.8 %; P = 0.002) compared to the treatment-naïve group. Multiple regression analysis revealed positive associations between the 12-month percentage BMD increases (LS; β = 0.30; 95 % CI = 0.85-11.61; P = 0.024 / TH; β = 0.32; 95 % CI = 0.51-8.56; P = 0.028) and being treatment-naïve compared to prior TPTD treatment.

Conclusions: Prior TPTD treatment may attenuate the effectiveness of ROMO, potentially due to diminished bone formation activation.