Outcomes of children with T-cell acute lymphoblastic leukemia treated with the JACLS T-02 protocol.

Historically, patients with T-cell acute lymphoblastic leukemia (ALL) had poorer outcomes than those with B-cell ALL. However, with intensive chemotherapy regimens, outcomes for both groups have become similar. From 2002 to 2008, the Japan Association of Childhood Leukemia Study (JACLS) conducted the prospective ALL-02 study, using a unique protocol for T-ALL (T-02). All T-ALL patients received the same induction therapy, and those who had < 25% bone marrow blasts at day 15 and achieved complete remission (CR) after induction continued on the T-02 protocol. Of the 107 T-ALL patients enrolled, 98 (91.6%) achieved CR after induction. Among 79 patients continuing on the T-02 protocol, the 2-year event-free survival (EFS), the study's primary outcome, was 70.9%, with a cumulative incidence of relapse of 29.1% and no observed nonrelapse mortality. Univariate analysis identified female sex as a significant predictor of better EFS. This study suggests that excessive treatment reduction may lead to poorer outcomes, although female patients with a rapid early response could potentially benefit from less-intensive therapy, warranting further investigation in a larger study.