Two phase II single-group, multicentre studies examining the use of vemurafenib, an oral BRAF inhibitor, were undertaken in patients with hairy cell leukaemia who had either relapsed after receiving a purine analogue or who were refractory to purine analogues. One study was undertaken in Italy, the other in the USA. The primary end point in the Italian study was the complete response rate (CRR) and in the USA study, it was the overall response rate (ORR). The CRR in the Italian study was 35% (nine of 26 patients) and 42% (10 of 24 patients) in the USA study. In the Italian study, the ORR was 96% (25 of 26 patients) in the Italian study; in the USA study it was 100% (24 of 24 patients).
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