Stopping Tyrosine Kinase Inhibitors (TKI) to Assess Treatment-Free Remission (TFR) in Pediatric Chronic Myeloid Leukemia - Chronic Phase (CML-CP) A COG Groupwide Pilot Study

This is a non-randomized, prospective, longitudinal study in pediatric and young adult patients with chronic phase CML (CML-CP) who currently are on life-long tyrosine kinase inhibitors (TKIs). Pediatric patients with CML have long life spans with higher expected cumulative TKI exposure, especially during periods of growth and development, and hence are believed to be at a significantly increased risk for known and emerging side effects. The overall study objective is to determine the ability to achieve treatment free remission (TFR) in pediatric patients who discontinue their TKI and to describe the effect of TFR on QOL measure and long term effects. Patients with CML on treatment with any TKI ≥ 3 years and with confirmed molecular response results showing BCR-ABL1 < 0.01% by RQ-PCR of peripheral blood for at least 2 years will be eligible to stop their TKI. The study will closely monitor patients using standard RQ-PCR testing for molecular recurrence, testing them every 4 weeks for 1 year, then every 6 weeks until 24 months, followed by every 12 weeks until 36 months. Concurrently, the study will assess a wide range of patient reported outcomes (PROs), neurocognitive outcomes and late effects before stopping TKIs and after discontinuation in conjunction with PCR testing. Patients who have evidence of a significant molecular CML recurrence based on RQ-PCR testing will restart their TKI and be monitored for the ability to reachieve/maintain a molecular response.