Very short-term monitoring of Romosozumab longitudinal effects in a cohort of postmenopausal women by means of Radiofrequency Echographic Multi-Spectrometry (REMS) technology

Abstract Background Romosozumab/AMG785 (Evenity®, Amgen and UCB pharma, RMZ) is a sclerostin-neutralizing antibody that rapidly increases BMD, but very short-term monitoring in clinical routine is limited by specific issues of available ionizing techniques. Aims To assess the effectiveness of the radiation-free Radiofrequency Echographic Multi Spectrometry (REMS) for very short-term monitoring of RMZ in postmenopausal women. Methods Seventy-four postmenopausal women starting RMZ and 52 postmenopausal women not receiving anti-osteoporosis drugs underwent proximal femur REMS scans at baseline and after 6 months, assessing total hip (TH) and femoral neck (FN) BMD. Exploratory analyses were also performed in treatment-naïve patients and in women with ≥ 2 prior fragility fractures. Results After six months of RMZ, BMD significantly increased at both TH (+ 3.7%; 0.718 ± 0.103 g/cm 2 vs . 0.698 ± 0.116 g/cm 2 ; p  < 0.01) and FN (+ 4.1%, 0.572 ± 0.092 g/cm 2 vs . 0.556 ± 0.105 g/cm 2 ; p  ≤ 0.01). In treatment-naïve patients ( n  = 33), BMD gains were larger (TH + 4.7%; FN + 4.6%), as also in women with ≥ 2 prior fractures ( n  = 36), where TH BMD increased by 4.1% and FN BMD by 4.8%. In untreated controls, no significant changes were observed at either TH (-0.8%; p  > 0.05) or FN (-0.6%; p  > 0.05). Weight and BMI did not change significantly over the considered 6-month interval. Conclusions REMS detected clinically-relevant 6-month increases in femoral BMD during RMZ therapy, while BMD remained stable in untreated controls. These findings, together with anthropometric stability, support the feasibility of REMS for very short-term follow-up in real-world settings.