Bone turnover rate and bone formation/resorption balance during the early stage after switching from a bone resorption inhibitor to denosumab are predictive factors of bone mineral density change

OBJECTIVES: This study aimed to investigate the correlation between bone mineral density (BMD) and the turnover rate [√(MoMf²+ MoMr²), multiple of median formation (MoMf) was calculated as bone-specific alkaline phosphatase (BAP) value/18.6 and multiple of median resorption (MoMr) as tartrate-resistant acid phosphatase 5b (TRACP-5b) value/463] and the balance (MoMf/MoMr) and to compare differences in therapeutic effects evoked by differences in previous treatments. METHODS: In 51 osteoporotic women treated with bisphosphonates (BPs) or selective estrogen receptor modulators (SERMs), BMD was measured at 0, 24, and 48 weeks after denosumab administration. The values of BAP and TRACP-5b were measured at 0, 4, 12, 24, 36, and 48 weeks. RESULTS: The turnover rate decreased at week 4 and decreased further at week 12. The balance indicated a relative predominantly formative state at week 4. This balance became higher in the SERM group than in the BP group at week 4. A correlation was observed between the rate of BMD change and turnover rate at weeks 0 and 4. CONCLUSIONS: It is necessary to evaluate the turnover rate and balance to determine the therapeutic effect of denosumab, which induces dissociation between the trends in the bone turnover markers. Turnover rate and balance during the early stages of denosumab treatment may be predictive factors of BMD. When switching from bone resorption inhibitors to denosumab, it was necessary to consider the beginning values that were affected by the previous treatment. The state of relative anabolism is greater at 4 weeks when the previous treatment involved SERMs rather than BPs.

Effect and clinical significance of infliximab on tartrate-resistant acid phosphatase 5b in rheumatoid arthritis / 中华风湿病学杂志

Objective To detect the serum level of tartrate-resistant acid phosphatase 5b (TRACP5b) in patients with rheumatoid arthritis (RA) before and after infliximab treatment and analyze the relevance between TRACP-5b and activity indexes of RA.The effect of different medicines on bony erosion in RA and its possible mechanism were explored.Methods Patients were divided into two groups:16 patients were treated with inffiximab for 24 weeks (group 1 ),25 patients were treated with MTX for 24 weeks (group 2).The core indicators of RA activity were evaluated.Ranked test,grouped design and matched t test was used to examine the quantity data between groups,while numerate data was analyzed with qui-square test.Correlation between data was tested by Spearmen's and Pearson's tests.RestltsThe levels of TRACP-5b in patients with X-ray stagesⅠ ,Ⅱ ,Ⅲ ,Ⅳ were elevated at the baseline.The levels of TRACP-5b in phase Ⅲ and Ⅳ were [(3.34±1.07) U/L] and[(4.05±0.25) U/L] respectively,higher (P＜0.05) than those in phase Ⅰ[(1.69±0.48) U/L].At week 0,week 12,and week 24,the serum levels of TRACP-5b in group 1 were(3.07±1.32),(2.72±1.18),(2.16±1.09) U/L respectively,while the levels in week 12,and 24 were significantly lower than those of week 0(P＜0.05).A significant decrease of serum TRACP-5b level in group 1[(2.16±1.09 ) U/L]when compared to group two[ (3.05±0.93) U/L] after 24 weeks.TRACP=5b level was positively correlated with the course of disease (r=0.313,P=0.043 ),HAQ(r=0.443,P=0.007).Conclusion Infliximab can reduce TRACP-5b level in RA and inhibit inflammatory bone loss.TRACP-5b can be used to evaluate the efficacy of biological agents in treating RA.