Study participants
Between September 23, 2020, and November 29, 2021, 107 subjects who were eligible underwent randomization to receive different dosing regimens of SHR-1222 or matching placebo. Two subjects in the placebo group, who did not receive the assigned treatment, withdrew from the study. Of the 105 subjects, 21 received placebo and 84 received SHR-1222 (100 mg QM, n=4; 200 mg QM, 300 mg QM, 400 mg Q2M or 600 mg Q2M, n=20 each). Ninety-nine subjects completed the preplanned treatment period, and six stopped early (four due to subject withdrawal [200 mg QM, n=2; 300 mg QM, n=1; and 400 mg Q2M, n=1], one due to consent withdrawal in the 600 mg Q2M group, and one due to other reasons in the 300 mg Q2M group).The baseline demographics and clinical characteristics were similar between the placebo and SHR-1222 treatment groups (Demographics and baseline characteristics.eGFR was calculated using the modified MDRD formula for Chinese: eGFR (ml/min1.73mQM, once every month; Q2M, once every 2 months; SD, standard deviation; BMI, body-mass index; BMD, bone mineral density. P1NP, N-terminal propeptide of type 1 procollagen; BSAP, bone-specific alkaline phosphatase; OST, osteocalcin; β-CTx, β-C-telopeptide; Scr, serum creatinine; eGFR, estimated glomerular filtration rate; 25-OHD, 25-hydroxyvitamin D.