CAG Regimen for Refractory or Relapsed Adult T-Cell Acute Lymphoblastic Leukemia: A Retrospective, Multicenter, Cohort Study

Abstract

Background: Adult patients with relapsed or refractory T cell acute lymphoblastic leukemia (R/R-T-ALL) have limited therapeutic options and extremely poor prognoses, representing an urgent unmet medical need. Finding an optimal salvage regimen to bridge to transplantation is a priority. The CAG regimen [cytarabine, aclarubicin and granulocyte colony-stimulating factor(G-CSF)], has been initially used from one group in China, showing unexpectedly promising results in 11 R/R-T-ALL patients. Here, we report the multi-center results from the Chinese Leukemia Cooperation Group. Methods: In this retrospective analysis, we included all patients aged ≥ 15 years old with R/R-T-ALL who received the CAG regimen as salvage therapy from September 2012 to June 2019 from the Chinese Leukemia Cooperation Group. Totally,41 adult R/R-T-ALL patients received the CAG regimen as salvage therapy. The CAG regimen consisted in cytarabine,10 mg/m2, q12h, d1-14; aclarubicin, 20 mg/d, d1-4; and G-CSF 200 mg/m2 from days 1 until neutrophil recovery. Outcomes were assessed in terms of complete remission rate, event-free survival, and overall survival. Findings: After one cycle of the CAG regimen among 41 patients, the complete and partial remission was achieved in 33 (80.5%) and 2(4.9%) patients, respectively. Failure to response was observed in 6 patients (14.6%). Early T-cell precursor (ETP) (n=26) and non-ETP (n=15) patients had a similar CR rate (80.8% vs 80.0%, p=0.95). Twenty-seven (66%) patients received allo-HSCT and 24 patients were still alive. With a median follow-up time of 12 months (range, 1-63 months), the estimated 2-year overall survival was 68.8% (95% CI, 47.3%-83.0%), and the event-free survival was 56.5% (95% CI, 37.1%-71.9%). The CAG regimen was well-tolerated, and no early death occurred. Interpretation: Our multicenter results show that the CAG regimen was highly effective and well-tolerated, representing a novel, optimal choice for adult patients with R/R-T-ALL and providing a better bridge to transplantation. Funding: Foundation for the National Natural Science Foundation of China. Declaration of Interest: We declare no competing interests. Ethical Approval: The study was conducted in accordance with the declaration of Helsinki, and approval was granted by the relevant ethics committees.