A recent study showed poor outcomes in a long-term analysis of patients with B-cell acute lymphoblastic leukemia (B-ALL) who experienced relapse after CD19-directed chimeric antigen receptor T-cell (CART19) therapy. Study findings were presented at the 2023 ASPHO Annual Meeting by Barbara D. Friedes, MD, of the Children’s Hospital of Philadelphia and colleagues.
In their poster, Dr Friedes and colleagues explained that approximately 50% of children treated with CART19 therapy for relapsed/refractory B-ALL will undergo relapse. However, information regarding long-term outcomes following relapse is limited.
Dr Friedes and colleagues evaluated outcomes for patients below 30 years of age who participated in any of 5 clinical trials with CART19 during the years of 2012 through 2019. Patients included in analyses had reached complete remission but later experienced relapse. Overall survival (OS) after post-CART19 relapse was the primary study outcome.
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There were 195 patients evaluated in the study, among whom 185 had reached complete remission. Of these patients, 85 went on to experience relapse, which occurred at a median of 8.8 months. These patients had a median age of 10.6 years at the time of relapse after CART19 therapy. Over half (55.3%) had previously undergone hematopoietic stem cell transplantation (HSCT). Relapse most commonly occurred in bone marrow (79%).
The median OS duration was 15.3 months (95% CI, 9-27), with a median follow-up time after relapse following CART19 therapy of 51 months. The OS rate at 24 months was 43% (95% CI, 32-53).
OS was significantly worse in patients who had experienced relapse within the first 6 months after receiving CART19 therapy than it was for those with relapse after this time point (P <.0001). In patients who received salvage therapy, event-free survival rates did not appear to differ based on the type of salvage therapy received (P =.116).
In 37 patients who underwent HSCT after CART19 relapse, OS differences did not significantly differ after HSCT based on whether patients had had prior HSCT or were HSCT naïve (P =.160). Among patients who underwent HSCT, 43.2% were alive in remission, 46.0% had a subsequent relapse, and 10.8% (4 patients) died of transplant-related complications.
Dr Friedes and colleagues concluded that in this long-term analysis, outcomes after CART19 relapse in children were poor. However, they considered novel immunotherapies to have potential for improving outcomes and they noted a need for innovative therapies for this patient population.
Reference
Friedes B, DiNofia A, Li Y, et al. Salvage therapies and outcomes of patients with relapse of B-ALL after CD19 CAR T-cell therapy. ASPHO 2023; May 10-13, 2023. Abstract 121.
