Mutational analysis in chronic myeloid leukemia: when and what to do?
OBJECTIVE
Imatinib, which was the first targeted therapy for patients with chronic myeloid leukemia (CML), has led to the significant prolongation of life for most patients. However, approximately 30% fail therapy. The major mechanism of acquired resistance is somatic mutation within the BCR-ABL1 kinase domain, which affects imatinib binding. Recently, more potent inhibitors have been approved that retain activity against most of the more than 100 mutations. However, some mutations remain problematic for one or more of the new inhibitors. The most frequently detected mutation, T315I, remains resistant to all of the currently approved inhibitors. More sensitive mutation techniques that focus on the detection of a limited number of specific mutations may be beneficial, but are yet to prove their clinical utility for the early detection of relapse in routine practice.


RESULTS
Inhibitors with alternate binding modes that may overcome T315I-associated resistance are at the preclinical stage or are undergoing clinical trial.


CONCLUSIONS
Each of the new, more potent kinase inhibitor drugs appear to have a partially overlapping set of mutations that confer a degree of resistance. Mutation detection techniques may need to adapt to provide clinicians with a more timely indication of mutation acquisition and pending relapse.
Department of Molecular Pathology, SA Pathology, University of Adelaide, Adelaide, South Australia, Australia. susan.branford@health.sa.gov.au
Susan
S
Branford
Timothy P
TP
Hughes
D001549:Benzamides; D004252:DNA Mutational Analysis / Q000379:methods; D004305:Dose-Response Relationship, Drug; D016044:Fusion Proteins, bcr-abl / Q000037:antagonists & inhibitors / Q000235:genetics*; D006801:Humans; D000068877:Imatinib Mesylate; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000175:diagnosis / Q000188:drug therapy / Q000235:genetics*; D009154:Mutation; D010879:Piperazines / Q000627:therapeutic use; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics*; D011743:Pyrimidines / Q000627:therapeutic use; D013997:Time Factors
D001549:Benzamides; D010879:Piperazines; D047428:Protein Kinase Inhibitors; D011743:Pyrimidines; D000068877:Imatinib Mesylate; D011505:Protein-Tyrosine Kinases; D016044:Fusion Proteins, bcr-abl