A New Algorithm Integrating Molecular Response, Toxicity, and Plasma Level Measures for Ponatinib Dose Choice in Patients Affected by Chronic Myeloid Leukemia

Ponatinib may be effective in chronic myeloid leukemia (CML) patients after failure of first/second line therapies. Although its efficacy for minimum plasma concentrations (C-min) is >21.3 ng/mL (equal to 40 nM), ponatinib may cause adverse events (AE) that require dose optimization. The present study was aimed at investigating any possible correlations among ponatinib dose, plasma concentration, molecular response (MR), and tolerability in a real-world setting. Clinical and laboratory records (including MR and drug plasma concentrations) of 32 CML patients treated with ponatinib were harvested and analyzed. Twenty-seven patients (71%) had ponatinib C-min values > 21.3 ng/mL, but C-min values > 10.7 ng/mL (considered efficacious in BCR-Abl unmutated patients) were achieved by 80% of the patients receiving >= 30 mg/day and 45% of the subjects treated with 15 mg/day. No significant correlations were identified among clinical efficacy, tolerability, daily dose, and plasma concentration. Notably, patients who underwent dose tapering for tolerability or safety reasons did not experience treatment failure. In a real-world setting, adjustment of ponatinib daily doses lower than those registered may maintain therapeutic efficacy while reducing the risk of vascular events and improving tolerability. Further studies are warranted to confirm the present results in a larger cohort of patients.