IDH1 and IDH2 Gene Mutations in Omani Patients with Acute Myeloid Leukemia: Prognostic Significance and Clinic-pathologic Features.

Objectives: We sought to define the prevalence of isocitrate dehydrogenase (IDH) mutations, evaluate the clinicopathologic impact of IDH mutations, assess the effect of IDH mutations on the response to the currently offered treatment for acute myeloid leukemia (AML) cases, and determine the impact of other common concurrent mutations with IDH.

Methods: A single-center retrospective cohort study was conducted at Sultan Qaboos University Hospital (SQUH) from October 2009 to October 2019. We included all Omani patients (pediatric and adult) treated at SQUH with the standard therapy, for whom DNA extraction was performed at diagnosis. The target mutations in both IDH1 and IDH2 genes were screened using the direct polymerase chain reaction product sequencing method. Statistical analysis was conducted using SPSS software. Survival differences were estimated using the log-rank test. Continuous variables were presented as median (IQRs), while categorical variables were presented as frequency.

Results: A total of 61 patients treated, for whom DNA extraction was performed at diagnosis were evaluated. The median age was 40 (range = 25.5-65.5). The prevalence of IDH1 R132, IDH2 R140, and IDH2 R172 mutations among the study group was 6.6%, 3.3%, and 1.6%, respectively. Clinicopathologic characteristics associated with IDH mutations at diagnosis included older age, lower white blood cell count, higher median platelet counts, normal karyotype AML, and cytogenetics intermediate-risk group. The overall survival (OS) in patients harboring IDH mutations was poor, with a median OS of nine months. This analysis confirms that the response rate and OS for both IDH-mutated and IDH wild-type AML patients were comparable. This will provide contemporary data to be used for comparison with the results of novel investigational (e.g., selective IDH inhibitor) strategies.

Conclusions: The current study results were consistent with the other international studies of IDH mutations in AML and demonstrate the poor prognosis associated with IDH mutations. Clinicopathologic features associated with IDH mutations included older age, lower white blood cell count, higher median platelet counts, normal karyotype AML, and cytogenetics intermediate-risk group.