One-year consolidation with Ponatinib 15 mg in chronic myeloid leukaemia on deep molecular response with Imatinib

Tyrosine kinase inhibitors (TKIs) discontinuation is the standard option for patients with chronic myeloid leukaemia (CML) in deep molecular response (MR) with imatinib. This study aimed to evaluate the efficacy and safety of one year consolidation with ponatinib on treatment-free remission (TFR) rate. This was a multicenter open-label, single-arm, phase II, exploratory clinical trial including patients with CML treated ≥4 years with imatinib therapy, and MR4.0 ≥12 months. Patients entered the TFR phase after receiving ponatinib at 15 mg/day for one year. Twenty three patients received ponatinib and 19 completed consolidation. Among the patients with detectable BCR::ABL1, 70% deepened response. The 48-weeks MR4.0 rate was 68.4% (95%CI: 43.4-87.4). The 48-week TFR rate as classically defined was 73.7% (95% CI: 8 56.3-96.4). Five restarted TKIs and all regained MR. The most frequent adverse events (AEs) were constipation (34.8%), asthenia (30.4%) and myalgia (21.7%). Patients who remained relapse-free one year after ponatinib discontinuation exhibited higher levels of NK and NKT-like cells with degranulation capacity. Consolidation with ponatinib showed a high TFR rate and adequate safety, granting further research.