Background: The study was to evaluate the equivalence of LY01011 to the reference product denosumab in terms of reduction of bone metabolism markers. Methods: Eligible patients were randomized at 1:1 ratio to receive 120 mg LY01011 injection or 120 mg denosumab every four weeks subcutaneously. Following the completion of three doses of 120 mg LY01011 or denosumab in a 12-week double-blind treatment period (DBTP), all enrolled patients would continue to receive LY01011 administration until the week 53 of follow-up period. The primary end point was the natural logarithm change at week 13 from baseline in urinary cross-linked N terminal telopeptide of type I collagen, corrected for urine creatinine (uNTx/uCr). The equivalence between LY01011 and denosumab would be concluded if the 90% CI was completely inside the pre-defined equivalence boundary between -0.135 and 0.135. A formal blinded sample-size re-estimation (BSSR) was planned to take place once 60% of the planned participants had completed the Week 13 assessments. After BSSR, the sample size increased from 560 to 850 according to prespecified procedure based on pooled standard deviationfrom the blinded data, which was set as a cap to ensure a feasible sample size for the study and no need to do any multiplicity adjustment. Results: All eligible 850 patients, included in the full analysis set, were randomized into the LY01011 group (n = 424) and denosumab group (n = 426). The samples from the 12-week DBTP were collected for analysis in both groups. The least square mean (LSM) (SE) of the natural logarithm change of uNTX/uCr at week 13 from baseline was -1.740 (0.0420) in the LY01011 group and -1.745 (0.0421) in denosumab group. The LSM difference was 0.005 between LY01011 and denosumab groups with 90% CI of [-0.088, 0.097] (p > 0.05). Skeletal related events occurring in the LY01011 and denosumab groups were 3.5% and 2.8%, respectively. The mean (SD) percentage changes of serum bone-specific alkaline phosphatase (s-BALP) from baseline to week 13 were -31.154% (39.6790) and -33.021% (37.3826) in the LY01011 and denosumab groups, respectively. The median was -36.866% and -37.457% (p > 0.05). The incidence of treatment-emergent adverse events (TEAEs) of any grade was 91.7% and 90.8% in LY01011 and denosumab groups(p > 0.05). Both groups had 38.4% of Grade ≥3 TEAEs, of which 5.4% (LY01011) and 4.5% (denosumab) were judged to be related to the study drug. Immunogenicity analysis showed that no participant (0/399) had a positive ADA test in denosumab group and only one participant (0.2%, 1/401) was tested ADA positive in LY01011 group. Conclusions: The study demonstrated the equivalent efficacy of LY01011 in the reduction of bone metabolism biomarker NTX to reference product, denosumab, which met the primary endpoint. It had a good safety profile with no unexpected adverse reactions in the study. Clinical trial information: NCT04859569.