A Study of Injectable BLB101 and Blincyto® in Adult Participants With R/R CD19+ B-ALL

A Randomized, Double-Blind, Positive-Controlled, Multicenter Clinical Study to Compare the Similarities in Pharmacokinetics, Efficacy, Safety and Immunogenicity Between Injectable BLB101 and Blincyto® in Adult Participants with R/R CD19+ B-ALL. Provide evidence for the approval and marketing of the drug for its targeted indication. Primary Objectives： 1. To compare the pharmacokinetic similarity between Injectable BLB101 and Blincyto® in participants with R/R B-ALL. 2. To compare the efficacy similarity between Injectable BLB101 and Blincyto® in participants with R/R B-ALL. Primary Endpoints: 1. Css and area AUC0-24,d1 of Injectable BLB101 versus Blincyto® in participants with R/R B-ALL. 2. CR/CRh within the first two induction cycles of treatment with Injectable BLB101 and Blincyto® in participants with R/R B-ALL, as assessed by the IRC per the response criteria for ALL. This study plans to enroll approximately 212 participants, who will be randomized at a 1:1 ratio into the following two groups: Test group: BLB101 for injection Control group: Blinatumomab for injection (Blincyto®) A stratified block randomization method will be adopted. The randomization stratification factors are as follows:a) Creatinine clearance (≤90 mL/min vs \>90 mL/min);b) Baseline leukemic cell proportion (≤50% vs \>50%);c) Relapsed/refractory status (first relapse vs ≥2 relapses or refractory disease). For each participant, the overall study procedure is outlined as follows: Participants will receive treatment with either BLB101 for injection or Blincyto®. Each treatment cycle consists of 6 weeks, including 4 weeks of dosing followed by a 2-week treatment-free interval. Each participant is required to complete the first 2 induction treatment cycles (i.e., an induction treatment period of up to 12 weeks), after which the participant will be considered to have fulfilled the primary study objectives.