MDR1 expression predicts outcome of Ph+ chronic phase CML patients on second-line nilotinib therapy after imatinib failure

M Agrawal1, B Hanfstein1, P Erben1, D Wolf2, T Ernst3, A Fabarius1, S Saussele1, D Purkayastha4, R C Woodman4, W-K Hofmann1, R Hehlmann1, A Hochhaus3 and M C Müller1 Nilotinib was able to impede proliferation of MDR1-overexpressing imatinib-resistant cells. High MDR1 gene expression might identify patients whose mode of imatinib resistance is essentially determined by increased efflux activity of MDR1 and therefore can be overcome by second-line nilotinib treatment.