Treatment Option Overview
Similarly, in a randomized, prospective study of 519 patients comparing dasatinib with imatinib, the rate of major molecular response at 12 months was 46% for dasatinib and 28% for imatinib (P < .0001). The rate of complete cytogenetic response at 12 months was 77% for dasatinib and 66% for imatinib (P = .007).[Level of evidence: 1iiDiv] Progression to accelerated-phase CML or blast crisis occurred in nine patients (3.5%) on imatinib and in five patients (1.9%) on dasatinib (not statistically different).
Although one of these two studies showed statistically significant decreased rates of progression to accelerated or blastic phase, which may ultimately translate into improved survival, the follow-up period with nilotinib and dasatinib has not been long enough to detect and confirm this prolonged survival with these agents. The preferred initial treatment for newly diagnosed patients with chronic-phase CML could be any of these specific inhibitors of the BCR/ABL tyrosine kinase.
The only consistently successful curative treatment of CML beyond 10 years' follow-up has been allogeneic bone marrow transplantation (BMT) or stem cell transplantation (SCT). Long-term data beyond 10 years of therapy are available, and most long-term survivors show no evidence of the BCR/ABL translocation by any available test (e.g., cytogenetics, RT–PCR, or fluorescent in situ hybridization [FISH]). Many patients, however, are not eligible for this approach because of age, comorbid conditions, or lack of a suitable donor. In addition, substantial morbidity and mortality result from allogeneic BMT or SCT; a 15% to 30% treatment-related mortality can be expected, depending on whether a donor is related and on the presence of mismatched antigens.
Long-term data are also available for patients treated with interferon alpha.[11,12,13] Approximately 10% to 20% of these patients have a complete cytogenetic response with no evidence of BCR/ABL translocation by any available test, and the majority of these patients are disease free beyond 10 years. Maintenance of therapy with interferon is required, however, and some patients experience side effects that preclude continued treatment.
Newly diagnosed patients with very high levels of circulating leukocytes (WBC >100,000/mm3) require immediate therapy with imatinib mesylate to avoid cerebrovascular events or death from leukostasis. Leukophoresis and plateletpheresis are sometimes required for an even more emergent reduction of counts.
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- Kantarjian HM, Talpaz M, O'Brien S, et al.: Survival benefit with imatinib mesylate versus interferon-alpha-based regimens in newly diagnosed chronic-phase chronic myelogenous leukemia. Blood 108 (6): 1835-40, 2006.
- Saglio G, Kim DW, Issaragrisil S, et al.: Nilotinib versus imatinib for newly diagnosed chronic myeloid leukemia. N Engl J Med 362 (24): 2251-9, 2010.
- Kantarjian H, Shah NP, Hochhaus A, et al.: Dasatinib versus imatinib in newly diagnosed chronic-phase chronic myeloid leukemia. N Engl J Med 362 (24): 2260-70, 2010.
- Wei G, Rafiyath S, Liu D: First-line treatment for chronic myeloid leukemia: dasatinib, nilotinib, or imatinib. J Hematol Oncol 3: 47, 2010.
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- Ozer H, George SL, Schiffer CA, et al.: Prolonged subcutaneous administration of recombinant alpha 2b interferon in patients with previously untreated Philadelphia chromosome-positive chronic-phase chronic myelogenous leukemia: effect on remission duration and survival: Cancer and Leukemia Group B study 8583. Blood 82 (10): 2975-84, 1993.
- Kantarjian HM, Smith TL, O'Brien S, et al.: Prolonged survival in chronic myelogenous leukemia after cytogenetic response to interferon-alpha therapy. The Leukemia Service. Ann Intern Med 122 (4): 254-61, 1995.
- Long-term follow-up of the Italian trial of interferon-alpha versus conventional chemotherapy in chronic myeloid leukemia. The Italian Cooperative Study Group on Chronic Myeloid Leukemia. Blood 92 (5): 1541-8, 1998.