Pulmonary Vasculopathy Under Second-line Therapy of Chronic Myeloid Leukemia

Chronic myelogenous leukemia (CML) is a chronic myeloproliferative disorder characterized by a translocation between chromosome 9 and 22, leading to a pathogenic tyrosine kinase signal transduction protein. CML can be treated with tyrosine kinase inhibitors (TKIs), which inhibit BCR/ABL kinase, such as imatinib. In about 20% of CML patients who are treated by imatinib, a complete cytogenetic response cannot be achieved. The other two novel TKIs (dasatinib and nilotinib), achieve higher rates of complete cytogenetic response and they are proposed as second-line therapy for imatinib-resistant patients or for those who do not tolerate imatinib. Dasatinib inhibits BCR/ABL kinase in about >300 times in vitro in more than imatinib and also inhibits several other kinases, including the Src family. Src tyrosine kinase is crucial for potassium channel function in human pulmonary arteries. Imatinib and nilotinib do not inhibit the Src.

Incident cases of precapillary PH have been reported in patients who have CML treated with the dasatinib. Improvements were usually observed after withdrawal of dasatinib.

This study is designed to identify incident cases of dasatinib-associated PH and describe pulmonary vascular changes induced by dasatinib. As comparison population will be patients who receive another second-line TKI (nilotinib).