Dasatinib and CAR T-Cell Therapy in Newly Diagnosed Philadelphia Chromosome–Positive Acute Lymphoblastic Leukemia

Importance A combination of tyrosine kinase inhibitors and chimeric antigen receptor (CAR) T cells has made a breakthrough in refractory or relapsed Philadelphia chromosome (Ph)–positive acute lymphoblastic leukemia (ALL). However, it remains unclear if this treatment in newly diagnosed Ph-positive ALL is associated with high rates of complete molecular remission (CMR) and leukemia-free survival. Objective To evaluate the efficacy and safety of dasatinib in combination with CAR T cells as frontline therapy in adults with newly diagnosed Ph-positive ALL. Design, Setting, and Participants This trial was conducted at a single center, the First Affiliated Hospital of Zhejiang University School of Medicine. Patients were enrolled in this phase 2, single-arm nonrandomized clinical trial between March 5, 2021, and April 13, 2024. The data cutoff date was February 10, 2025. The data analysis was conducted on February 11, 2025. The median duration of follow-up was 23.9 (range, 7.3-47.7) months. A total of 29 adults with newly diagnosed Ph-positive ALL and adequate organ function were screened for eligibility, and 1 patient who received a diagnosis of blast-phase chronic myeloid leukemia was excluded. Intervention Dasatinib was administered with a 2-week vindesine and dexamethasone regimen as induction, followed by sequential CD19 and CD22 CAR T-cell therapies and single-agent dasatinib maintenance. Main Outcomes and Measures The primary end point was CMR rate after CD19 CAR T-cell therapy. CMR was defined as undetectable BCR/ABL1 transcripts as measured by quantitative reverse transcription polymerase chain reaction with a sensitivity of 10 −4 in the bone marrow. Results Twenty-eight patients (median [range] age, 48.5 [18.0-69.0] years; 10 female individuals [36%]) were enrolled, and 1 patient withdrew after induction. The CMR rate was 25% (7 of 28) after induction and increased to 85% (23 of 27) after CD19 CAR T-cell therapy. Twenty-five patients (89.3%) received sequential CD22 CAR T-cell therapy, and the CMR rate was 76% (19 of 25). Of the 52 CAR T-cell therapies, only 21 cases of grade 1 cytokine release syndrome occurred. After a median follow-up of 23.9 (range, 7.3-47.7) months, the 2-year overall survival and leukemia-free survival were 92%. Conclusions and Relevance The results of this nonrandomized clinical trial suggest that the combination of dasatinib and CAR T-cell therapy showed encouraging efficacy in newly diagnosed Ph-positive ALL with acceptable toxic effects. Further studies with larger cohorts and longer follow-up durations are needed. Trial Registration ClinicalTrials.gov Identifier: NCT04788472