Ibrutinib: A major breakthrough in the treatment of CLL and other lymphoproliferative disorders

The Bruton's tyrosine kinase protein is expressed in most hematopoietic cells with the exception of T cells and natural killer cells, but the selective effect of Bruton's tyrosine kinase mutations suggests that its primary functional role is in antigen receptor signalling in B cells. Ibrutinib (=PCI-32765) was designed as a selective and irreversible inhibitor of the Bruton's tyrosine kinase protein. In vitro, PCI-32765 arrested cell growth and induced apoptosis in human B-cell lymphoma cell lines, and inhibited tumour growth in vivo in xenograft models. A first analysis performed on 116 naïve chronic lymphocytic leukaemia patients with a median age of 71 (range: 65 - 84) shows an estimated 22-months progression-free survival rate of 96%; the median progression-free survival or overall survival had not been reached.[1] In 61 patients with relapsed/refractory chronic lymphocytic leukaemia/small lymphocytic lymphoma with a median age of 64 years (range: 40 - 81) and a high-risk cohort (24 patients), the estimated 22-months progression-free survival rate for the 85 relapse/refractory and high-risk patients was 76%. PCI-32765 (ibrutinib) has demonstrated promising activity in studies enrolling older patients with treatment-naïve or relapsed/refractory chronic lymphocytic leukaemia and older patients with small lymphocytic lymphoma. Randomised phase III studies in naïve chronic lymphocytic leukaemia/small lymphocytic lymphoma patients are currently on-going.http://www.ariez.nl/DownloadFile.lynkx?guid=4a3fd577-ff2a-4543-935f-92fe08777d26