Abstract
The BCR-ABL1 tyrosine kinase inhibitor dasatinib is effective in chronic myeloid leukemia (CML) treatment. The major known adverse effects of dasatinib include pleural effusion and pulmonary arterial hypertension (PAH); however, the underlying mechanisms remain unclear. This case report describes a two-step dasatinib dose reduction decided by multi-disciplinary collaboration between cardiologists and hematologists for the management of PAH that led to treatment-free remission (TFR), suggesting an important improvement in the field. Herein, a 43-year-old woman with CML was administered 100 mg of dasatinib daily as a first-line therapy from May 2014. There were no evident abnormalities on her electrocardiogram and transthoracic echocardiography (TTE) charts before she started taking dasatinib. She developed leg edema in June 2015, and the TTE showed a high transtricuspid pressure gradient value. Based on these findings, we diagnosed PAH and right-sided heart failure due to dasatinib. However, since it was confirmed that the molecular response (MR(4.5)) (International Scale: BCR-ABL1(IS) ≤ 0.0032%) was sustained, the hematologist decided to reduce the dasatinib dose to 70 mg after thorough deliberations with the cardiologists. After the dose reduction, the PAH improved immediately; however, it was observed again in 2017, which improved with a second dose reduction to 50 mg. Additionally, cardiovascular drug therapy was initiated. The PAH was exacerbated again in 2018 with sustained MR(4.5). Hence, we decided to discontinue dasatinib as the MR(4.5) had been sustained over 4 years. After the discontinuation of dasatinib, PAH improved again, and near MR(4.0) (BCR-ABL1(IS) ≤ 0.01%) level has been sustained for several years now. Thereafter, no apparent deterioration in PAH was observed. We present a case of reversible dasatinib-induced PAH. Successful management of recurrent PAH was possible with several dose reductions, and TFR was achieved. This was partly due to effective collaboration between the hematologists and cardiologists. If needed, dose reduction as a treatment strategy may be considered before discontinuing dasatinib.