PF221 MUTATIONAL PROFILE BY NGS COMBINED WITH EX VIVO DRUG SENSITIVITY PROFILE IMPROVE PREDICTION OF AML PATIENT OUTCOME
Authors: E. Onecha De La Fuente, Y. Ruiz Heredia, M. Linares Gomez, D. Martínez-Cuadrón, I. Rapado, P. Martinez Sanchez, A. Juarez Rufian, C. Sargas Simarro, B. Boluda, E. Acuña, I. Cano, P. Montesinos, E. Barragan, J.L. Rojas, J. Gorrochategui, J. Ballesteros, J. Martinez Lopez, R. Ayala Diaz
Journal: HemaSphere (2019)

Background: Cytogenetic and molecular alterations at diagnosis and response to treatment are the most useful criteria to predict prognosis in Acute myeloid Leukemia (AML). On the other hand, a precision medicine pharmacologic test (PM) based on an actionable native environment method is demonstrating to be able to uncover individual responses to treatment (Martinez-Cuadron D, et al. Leuk Res. 2019). Aims: To establish the clinical utility of the combination of the mutational profile and the ex vivo drug activity data to predict response to treatment, as well as establishing a patient risk stratification score. Methods: Bone marrow and peripheral blood from 190 newly diagnosed AML patients were included in the NGS study, of which 74 were also ex vivo PM tested. Informed consent participation and approval by the ethical committees were obtained. The ex vivo drug profiling was performed by PharmaFlow platform, which preserves bone marrow Native Environment (Bennett T, et al. Clin Lymphoma Myeloma Leuk. 2014). The mutational screening was performed using a custom NGS panel consisting of 32 recurrently mutated genes in myeloid diseases (Onecha E, et al. Haematologica,2019). Survival curves were calculated according to the Kaplan-Meier method and log-rank test. Multivariate analysis was performed by using Cox regression model. Results: A total of 264 non recurrent somatic variants were identified in 164 out of 190 patients. Shorter overall survival (OS) was observed in patients with EZH2, KMT2A, U2AF1 and/or TP53 mutations. High individual variability in sensitivity with the ex vivo assays for each drug tested was detected. A significant multi-resistant (MR) pattern, classifying samples that showed either resistance or sensitivity to most drugs tested, was identified by no-supervised hierarchical clustering test. Interestingly, patients with MR pattern were found to have significantly lower rates of OS.Significant differences were identified in the drug response depending on the mutational status of some genes (ie, FLT3-ITD mutated patients were more sensitive to DNR (p = 0.007) and Panobinostat (p = 0.013) than wt patients; TP53 mutated patients were found To be more resistant to FLU (p = 0.044) and MIT (p = 0.045), respectively; or patients with mutations in IDH2 (p = 0.049) genes showed lower sensitivity to CYT.Multivariable Cox regression model was used to evaluate the predictive value of all variables: clinical, molecular and pharmacodynamic. The multivariate test revealed 3 significant independent criteria to predict worse prognosis: MR pattern (HR:2.02,p = 0.034), mutated KMT2A status (HR:3.49,p = 0.026) and mutated TP53 status (HR:3.23,p = 0.008). This score improves prognosis AML patients with respect to the established risk classification (ELN-2010) which did not achieve statistical significance in survival analysis (p = 0.88). In this regard, a mixed score has been created by classifying patients based on the 4 possible levels (Figure 1): doubly negative, the presence of one or more mutations in these genes (HR:4.18;p = 0.0004), ex vivo MR pattern (HR:2.57;p = 0.0109) or doubly positive (HR:4.82;p = 0.002), a great prognostic patients classification was obtained, improving the stratification ability of each variable individually.Summary/Conclusion: The combination of pharmacological and mutational profiles represents a helpful approach towards precision medicine.