Real-life Experience With Ponatinib in Chronic Myeloid Leukemia: A Multicenter Observational Study

Abstract

BackgroundThe strict recruitment criteria of patients for clinical trials often lead to reduced generalizability of the findings. We studied how ponatinib is used outside clinical trials in patients with chronic myeloid leukemia (CML). Patients and MethodsThe present retrospective study included all patients with a diagnosis of CML who had received ponatinib in 7 medical centers in Israel. ResultsFrom 2011 to 2016, we identified 37 patients with CML who had received ponatinib, 21 in the chronic phase and 16 in the advanced phase. Only 9 patients (26%) harbored the T315I (threonine to isoleucine mutation at position 315) mutation. All patients had received ≥ 1 previous tyrosine kinase inhibitor. The median age in our cohort was 43 years (range, 9-82 years), significantly younger than expected for patients with relapsed or refractory CML and 20 years younger than the median age of patients who participated in the PACE (ponatinib Philadelphia-positive acute lymphoblastic leukemia and CML evaluation) trial. During a median follow-up of 14 months (range, 1-51 months), the overall response rate was 85%. Of 34 patients, 16 (47%) experienced at least a major molecular response. Of the 37 total patients, another 16 patients (43%) discontinued treatment because of disease progression (n = 6), vascular complications (n = 1), severe cytopenia (n = 2), or for other reasons (n = 7). ConclusionIn real life, ponatinib is a “niche-drug” reserved for a unique population of exceptionally young patients with CML with or without the T315I mutation. In this highly selected group, very different from the PACE cohort, ponatinib achieved high overall response rates.