Inhibition of periarticular bone loss is associated with clinical remission and ACR70-Response in rheumatoid arthritis

The aim of this study, based on a post hoc analysis of the data set used in the RAPID 1 trial, focuses on the associations between metacarpal bone mineral density, as estimated by digital X-ray radiogrammetry (DXR), and clinical remission as well as ACR70-Response in rheumatoid arthritis (RA) patients treated with certolizumab pegol (CZP). The trial evaluates a total of 345 RA patients treated with methotrexate versus CZP 200 mg versus CZP 400 mg. All patients underwent X-rays of the hand at baseline and week 52 as well as computerized calculations of bone mineral density (BMD) by DXR. Clinical remission was defined as DAS28 < 2.6. ACR70-Response was also evaluated. The radiological assessment of disease progression was estimated using the modified total Sharp Score. The mean difference for DAS28 was observed for patients treated with CZP 400 mg (median: − 3.53, minimum: − 6.77; maximum: + 0.48) and CZP 200 mg (median: − 3.13, minimum: − 6.37; maximum: − 0.52) compared to the methotrexate group (median − 2.41, minimum: − 4.76; maximum: + 0.31). The DXR-BMD showed a minor bone loss for the treatment groups undergoing therapy with CZP 200 mg (median: − 0.009 g/cm2, minimum: − 0.059 g/cm2; maximum: + 0.095 g/cm2) and CZP 400 mg (median: − 0.008 g/cm2, minimum: − 0.064 g/cm2; maximum: + 0.080 g/cm2). The methotrexate group presented an advanced periarticular metacarpal bone loss as measured by DXR-BMD (median: − 0.024 g/cm2, minimum: − 0.102 g/cm2; maximum: + 0.057 g/cm2). In the case of clinical remission and ACR70-Response, no significant change of the DXR-BMD was observed for both CZP groups. The study highlights that patients treated with CZP show a less accentuated periarticular bone loss as estimated by DXR in comparison to patients with methotrexate plus placebo. In addition, patients with clinical remission and ACR70-Response revealed no periarticular demineralisation.