Therapy adapted to molecular response in patients with chronic myelogenous leukaemia in first chronic phase: results of the Duesseldorf study

Abstract

This study evaluates response-adapted treatment of chronic myelogenous leukaemia (CML) in chronic phase using molecular response criteria. bcr-abl/G6PDH ratios were assessed by Light-Cycler quantitative real-time polymerase chain reaction (PCR( in 277 peripheral blood samples from 33 patients, before and every 3 months during therapy. Sixty-six per cent (22/33) of the patients fulfiled our molecular response criterion of > or = 1 log decrease in bcr-abl transcript after 6 or > or = 2 log decrease after 9 and every following 3 months. Dose escalation was necessary for 33% (11/33) of the patients. Of these, 54% (6/11) achieved a reduction of bcr-abl mRNA by > or = 2 log (n = 3) or > or = 3 log (n = 3) with 800 mg Imatinib. Forty-five per cent (5/11) showed insufficient molecular response with 800 mg Imatinib and received Nilotinib. In conclusion, the assessment of molecular response permits an individual patient-tailored treatment of CML in first chronic phase, resulting in the majority of patients achieving a major molecular response after 2 years of therapy.