The Molecular Response at 3 Months, Measured Using a Genxpert Platform, Predicts Further Outcomes in Chronic Myeloid Patients, but the Cutoff Differs from the 10% Cutoff Commonly Used with the EUTOS Method

• Published in: Blood 2016-12, Vol.128 (22), p.1906-1906
• Main Authors: García Gutiérrez, Valentín, Gómez-Casares, María Teresa, Puerta, Jose Manuel, Alonso, Juan Manuel, Osorio, Santiago, Hernández-Boluda, Juan Carlos, Collado, Rosa, Ramirez, Maria Jose, Ibañez, Fatima, Martin, Maria Luisa, Rodriguez, Juan Diego, Martinez-Laperche, Carolina, Gomez, Montse, Fiallo, Viviana, Sara, Redondo, Rodriguez, Alicia, Ruiz, Concepcion, Steegmann, Juan Luis, Jiménez-Velasco, Antonio
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V128.22.1906.1906

Backgroung: In chronic myeloid leukemia (CML) patients, 3-month BCR-ABL1 levels ≤10% measured using conventional RQ-PCR (IS) have consistently been correlated with further outcomes. Monitoring molecular responses using the Xpert BCR-ABL1 MonitorTM PCR system has demonstrated an optimal correlation with standardized RT-qPCR (IS), however, it is not known whether both methods are also equivalent when measuring BCR-ABL1 levels higher than 10%. We previously showed how the cutoff of 10% was not correlate with subsequent responses when using Xpert BCR-ABL1 in a cohort of 125 consecutive CML patients treated with imatinib (58%) and second generation TKI (2GTKI) (42%) as frontline treatment. By contrast, by using a receiver operating characteristic curve, a new cutoff of 1.5% was correlated with probabilities to achieve complete cytogenetic response (CCR) and major molecular response (MMR. The aim of this study is to validate the new cutoff of 1.5% at 3 months in patients treated with second generation 2GTKI. Methods: We have studied 57 new consecutive CML-CP patients treated 2GTKI from from Andalusian CML Group Registry. BCR-ABL1 transcript quantification was performed using the automated method Xpert BCR-ABL1 Monitor™, Cepheid, aligned to the 0.1% BCR-ABL1 ratio according to the standards of the World Health Organization. The samples were not centrally collected. All analyses were performed on an intention-to-treat basis unless otherwise stated. The proportions of patients who achieved MMR and CCyR after first-line treatment for 1 year and the response at 3 months were compared by applying Pearson’s chi-square test or Fisher’s exact test The study was approved by the Ethics Committee. Results: The median age at diagnosed was 48 years (18-74). The ratio of men to women was 59/41, and the risk groups according to Sokal Score were 48%, 30% and 22% for low, intermediate and high risk, respectively. Median follow up was 38 months (3-56). First-line treatment consisted of nilotinib and dasatinib in 58% and 42% of patients, respectively. Overall, the probability of achieving CCyR and MMR at 12 months was 92% (48/52) and 82% (39/47), respectively. Ten patients (17%) required treatment changes as a result of resistance (n=3), not achieving MMR (n=3) or intolerance (n=4). No patients progressed to advanced phases, and only 1 patient died during follow-up (not CML related). The overall median value of BCR-ABL1 at 3 months was 0.16%. Consistent with the original cohort of