Pleural effusion (PE) represents the leading cause of dasatinib (DAS) discontinuation. However, the pathogenic mechanism of this adverse event (AE) is unknown and its management unclear. We investigated if a DAS dose reduction after the first PE would prevent the recurrence of this AE. We retrospectively collected data on all the cases of PE in CML-chronic phase (CP) DAS-treated patients from November 2005 to February 2017 in 21 Italian hematological centers. We identified 196 cases of PE in a series of 853 CML-CP DAS-treated patients (incidence 23.0%). DAS starting dose was 100 mg/day in 70.4% of patients, less than 100 mg/day in 14.3%, and more than 100 mg/day in the remaining cases. Median time from DAS start to PE was 16.6 months. At first PE development, 28.6% of patients were in MMR, and 37.8% in deep molecular response (DMR). DAS was temporary interrupted in 71.9% of cases, with a dose reduction in 59.2%. Recurrence was observed in 59.4% of the cases. Treatment was definitively discontinued due to PE in 29.1% of the cases. Interestingly, among patients whose DAS dosage was reduced, 59.5% experienced PE recurrence. DAS dose reduction after the first episode of PE did not prevent recurrence of this AE. Therefore, once a MMR or a DMR is achieved, different strategies of DAS dose management can be proposed prior to the development of PE, such as daily dose reduction or, as an alternative option, an on/off treatment with a weekend drug holiday.
Keywords: Chronic myeloid leukemia; Dasatinib; Dose reduction; Molecular response; Pleural effusion.