CD22-targeted immunotherapy for B-cell acute lymphoblastic leukemia progressing following CD19-targeted immunotherapy.

Patients progressing after CD19-targeted immunotherapy in r/r B-ALL experience poor outcomes. CD22-targeted therapies, including CD22 CAR-T cells and Inotuzumab Ozogamicin, show promise as alternatives, although data in those patients is limited. This study retrospectively analyzed 43 r/r B-ALL patients who had previously received CD19-targeted therapy at two centers in China. Among these patients, 27.9% received blinatumomab, 58.1% received CD19 CAR-T cells, and 14% received both. After CD19-targeted therapy, 34.9% of patients experienced CD19-negative relapse, while the remaining patients maintained CD19 expression. Subsequent treatments included CD22 CAR-T cells (55.8%) and InO (44.2%). The median age was 39 (24-56) years, with an overall CR/CRi rate of 54% and 35.1% achieving MRD negativity. Among the 22 patients achieving CR/CRi, 13 (59.1%) experienced relapse. The median relapse-free survival (RFS) was 236 days (95% CI: 132-unreached), and the median OS has not been reached. Multivariate analysis showed similar remission rates and survival for CD22 CAR-T and Inotuzumab Ozogamicin therapies. Patients with extramedullary disease had worse remission rates, and those previously resistant to CD19-targeted therapy had shorter RFS. CD22-targeted therapies offer a potential option for patients progressing after CD19-targeted immunotherapy, but high relapse rates highlight the need for better strategies for lasting remission.