Impact of Baseline BCR-ABL Mutations on Response to Nilotinib in Patients With Chronic Myeloid Leukemia in Chronic Phase

• Published in: Journal of clinical oncology Vol. 27; no. 25; pp. 4204 - 4210
• Main Authors: HUGHES, Timothy, SAGLIO, Giuseppe, KIM, Dongho, ERBEN, Philip, YAPING SHOU, HAQUE, Ariful, GALLAGHER, Neil, RADICH, Jerald, HOCHHAUS, Andreas, BRANFORD, Susan, SOVERINI, Simona, KIM, Dong- Wook, MÜLLER, Martin C, MARTINELLI, Giovanni, CORTES, Jorge, BEPPU, Lan, GOTTARDI, Enrico
• Format: Journal Article
• Language: English
• Published: Alexandria, VA American Society of Clinical Oncology 01.09.2009
• Subjects: Antineoplastic Agents - therapeutic use; Australia; Benzamides; Biological and medical sciences; Chromosome aberrations; Drug Resistance, Neoplasm - genetics; Europe; Fusion Proteins, bcr-abl - antagonists & inhibitors; Fusion Proteins, bcr-abl - genetics; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Leukemic; Humans; Imatinib Mesylate; Korea; Leukemia, Myelogenous, Chronic, BCR-ABL Positive - drug therapy; Leukemia, Myelogenous, Chronic, BCR-ABL Positive - enzymology; Leukemia, Myelogenous, Chronic, BCR-ABL Positive - genetics; Medical genetics; Medical sciences; Mutation; ORIGINAL REPORTS; Piperazines - therapeutic use; Protein Kinase Inhibitors - therapeutic use; Pyrimidines - therapeutic use; Time Factors; Treatment Outcome; Tumors; United States; Australia; United States; Europe; Korea; Chromosomal aberration; Human; Nilotinib; Enzyme; Tyrosine kinase inhibitor; Transferases; Non-specific serine/threonine protein kinase; Chronic myelogenous leukemia; Malignant hemopathy; Philadelphia chromosome; Myeloproliferative syndrome; Abnormal chromosome C9; Cancerology; bcr gene; C-Onc gene; Abnormal chromosome G22; Abnormal chromosome; Genetics; Mutation; Hybrid gene; Cancer; Chromosome translocation
• ISSN: 0732-183X; 1527-7755
• DOI: 10.1200/JCO.2009.21.8230

Nilotinib is a second-generation tyrosine kinase inhibitor indicated for the treatment of patients with chronic myeloid leukemia (CML) in chronic phase (CP; CML-CP) and accelerated phase (AP; CML-AP) who are resistant to or intolerant of prior imatinib therapy. In this subanalysis of a phase II study of nilotinib in patients with imatinib-resistant or imatinib-intolerant CML-CP, the occurrence and impact of baseline and newly detectable BCR-ABL mutations were assessed. Baseline mutation data were assessed in 281 (88%) of 321 patients with CML-CP in the phase II nilotinib registration trial. Among imatinib-resistant patients, the frequency of mutations at baseline was 55%. After 12 months of therapy, major cytogenetic response (MCyR) was achieved in 60%, complete cytogenetic response (CCyR) in 40%, and major molecular response (MMR) in 29% of patients without baseline mutations versus 49% (P = .145), 32% (P = .285), and 22% (P = .366), respectively, of patients with mutations. Responses in patients who harbored mutations with high in vitro sensitivity to nilotinib (50% inhibitory concentration [IC(50)] <or= 150 nM) or mutations with unknown nilotinib sensitivity were equivalent to those responses for patients without mutations (not significant). Patients with mutations that were less sensitive to nilotinib in vitro (IC(50) > 150 nM; Y253H, E255V/K, F359V/C) had less favorable responses, as 13%, 43%, and 9% of patients with each of these mutations, respectively, achieved MCyR; none achieved CCyR. For most patients with imatinib resistance and with mutations, nilotinib offers a substantial probability of response. However, mutational status at baseline may influence response. Less sensitive mutations that occurred at three residues defined in this study, as well as the T315I mutation, may be associated with less favorable responses to nilotinib.