Continued Response Off Treatment After BRAF Inhibition in Refractory Hairy Cell Leukemia

Abstract

We treated a 51-year-old white man with classic hairy cell leukemia (HCL) who was-in contrast to most patients with HCL-refractory to multiple lines of conventional therapy. He was treated with a 5-day course of cladribine (0.14 mg/kg), which neither improved cytopenia nor reduced the degree of bone marrow infiltration. In December 2010 with disease progression, second-line therapy with pentostatin (7 4 mg/m 2 every 2 weeks) was initiated but no response was observed. Salvage treatment combining rituximab (8 375 mg/m2) and cladribine (0.14 mg/kg for 5 days) was given starting in May 2011. Again the patient failed to respond showing progressive and severe thrombocytopenia ( 30,000/L).