JACLS ALL-02 SR protocol reduced-intensity chemotherapy produces excellent outcomes in patients with low-risk...

Area of Science:

• Pediatric Oncology
• Hematology
• Clinical Trials

Background:

• Childhood acute lymphoblastic leukemia (ALL) is a significant pediatric cancer.
• Improved cure rates necessitate reduced treatment intensity for low-risk patients to minimize long-term side effects.
• The Japan Association of Childhood Leukemia Study (JACLS) ALL-02 study aimed to evaluate a standard-risk protocol.

Purpose of the Study:

• To report the outcomes of patients with newly diagnosed ALL treated under the JACLS ALL-02 standard-risk protocol.
• To assess the efficacy and safety of a reduced-intensity chemotherapy regimen in a specific ALL patient cohort.
• To compare outcomes with contemporary protocols and identify favorable prognostic factors.

Main Methods:

• Prospective study of 1138 patients with B-cell precursor ALL aged 1-18 years, conducted between 2002-2008.
• 388 patients were treated with the standard-risk JACLS ALL-02 protocol, characterized by low initial white blood cell count and good early response.
• The protocol involved reduced cumulative doses of chemotherapeutic agents while maintaining dose density.

Main Results:

• Excellent 4-year event-free survival (EFS) of 92.3% and overall survival (OS) of 98.2% were achieved.
• Patients with high hyperdiploidy (HHD) or ETV6-RUNX1 fusion gene showed superior outcomes (4-year EFS of 97.6% and 100%, respectively).
• The protocol demonstrated high efficacy despite lower overall treatment intensity compared to other contemporary regimens.

Conclusions:

• The JACLS ALL-02 standard-risk protocol offers an effective, less intensive treatment option for childhood ALL.
• Patient selection based on low WBC and early response, along with optimized chemotherapy, contributed to favorable outcomes.
• Ongoing research in Japan is exploring minimal residual disease (MRD) incorporation for further risk stratification.