Philadelphia chromosome-positive acute lymphoblastic leukemia: 8 years′ experience from a tertiary care center in India

Abstract

Introduction: The Philadelphia chromosome (Ph) is the most common cytogenetic abnormality associated with adult acute lymphoblastic leukemia (ALL) occurring in 20% to 40% of patients. It is also detected in 2% to 5% of children with ALL. Historically, patients with Ph-positive ALL carried a dismal prognosis, with poor response to most chemotherapy combinations, short remission durations, and long-term disease-free survival rates of 10% to 20%. The advent of tyrosine kinase inhibitors (TKIs) has revolutionized therapy of Ph-positive ALL. Materials and Methods: This retrospective and descriptive single center study was carried out based on data retrieved of 508 patients treated for ALL from 2007 to 2014. Of these thirty patients were Ph-positive ALL and were available for analysis, and these patients were included in the study. Ph-positive ALL was defined as ALL carrying the t(9;22) translocation on standard karyotype and/or fluorescent in situ hybridization analysis and/or positivity for BCR-ABL fusion transcript detection by real-time quantitative polymerase chain reaction (RQ-PCR) analysis. Patients were treated with combination chemotherapy and oral TKIs and responses were classified as either CR defined by the absence of circulating blasts and <5% marrow blasts on a bone marrow examination done at the end of induction chemotherapy or failure, including persistent disease and early death. Results: There were 30 (5.9%) cases of Ph-positive ALL out of a total of 508 cases of ALL with a median age of 27.5 years (range: 7-55). The choice of first line TKI was Imatinib in 25 (83.3 %) patients and Dasatinib in 1 (3.3 %) patient. Fourteen patients (46.6 %) had a CR, 3 (10 %) had a partial response (PR), 8 (26.6 %) had persistence of disease at the end of induction chemotherapy. The overall survival in those who received sequential chemotherapy followed by TKI (n = 4) was 28.5 months (95% CI 10.78 to 46.21 months) compared with 13.98 months (95% CI 6.04 to 21.97 months) for patients who received concurrent chemotherapy and TKI (n = 20); log rank (Mantel Cox) X 2 = 8.33, P = 0.040), however limited sample precluded meaningful subgroup analysis. Conclusion: The results of our study showed that we still have a long way to go to match outcomes of western published series, even when the same treatment protocol is used, probably due to the underutilization of Allogeneic SCT as an option in first CR.

Keywords

• Acute lymphoblastic leukemia
• chemotherapy
• overall survival
• Philadelphia chromosome