Whole exome sequencing and rare variant association study to identify genetic modifiers, KLF1 mutations, and a novel double mutation in Thai patients with hemoglobin E/beta-thalassemia.

OBJECTIVES: Clinical manifestations of patients with Hemoglobin E/beta-thalassemia vary from mild to severe phenotypes despite exhibiting the same genotype. Studies have partially identified genetic modifiers. We aimed to study the association between rare variants in protein-coding regions and clinical severity in Thai patients. METHODS: From April to November 2018, a case-control study was conducted based on clinical information and DNA samples collected from Thai patients with hemoglobin E/beta-thalassemia over the age of four years. Cases were patients with severe symptoms, while patients with mild symptoms acted as controls. Whole exome sequencing and rare variant association study were used to analyze the data. RESULTS: All 338 unrelated patients were classified into 165 severe and 173 mild cases. Genotypes comprised 81.4% of hemoglobin E/beta-thalassemia, 2.7% of homozygous or compound heterozygous beta-thalassemia, and 0.3% of (뫧)0 thalassemia Hb E while 15.7% of samples were not classified as beta-thalassemia. A novel cis heterozygotes of IVS I-7 (A > T) and codon 26 (G > A) was identified. Six genes (COL4A3, DLK1, FAM186A, PZP, THPO, and TRIM51) showed the strongest associations with severity (observed p-values of <0.05; significance lost after correction for multiplicity). Among known modifiers, KLF1 variants were found in four mild patients and one severe patient. CONCLUSION: No rare variants were identified as contributors to the clinical heterogeneity of hemoglobin E/beta-thalassemia. KLF1 mutations are potential genetic modifiers. Studies to identify genetic factors are still important and helpful for predicting severity and developing targeted therapy.

Adult aplastic anemia in Thailand: incidence and treatment outcome from a prospective nationwide population-based study.

The incidence and outcomes of aplastic anemia (AA) in Asia remain limited. This study aimed to explore the incidence and outcomes of patients with adult AA across the country of Thailand. This is a prospective multi-center nationwide population-based observational study of AA patients aged at least 15 years old, diagnosed from August 2014 to July 2016, with a longitudinal follow-up period over 2 years. There were 348 newly diagnosed adult AA patients during the enrollment period, giving an annual incidence of 4.6 per million. The incidence of severe (SAA) and very severe aplastic anemia (VSAA) (3.8 per million) was higher than non-severe AA (NSAA, 0.8 per million). The peak incidence was observed in the patients aged from 80 to 89 years old (14.4 per million). The 2-year overall survival (OS) in NSAA, SAA, and VSAA were 65.5%, 49.3%, and 20.1%, respectively (P < 0.001). With regard to the response to immunosuppressive therapy, the overall response rate (ORR) in SAA/VSAA treated with rabbit anti-thymocyte globulin with/without cyclosporin A (rATG ± CsA) were significantly superior to those treated with CsA alone, or anabolic steroids (44.4% vs 36.4% and 31.2%, respectively, P < 0.001). The 2-year OS in SAA/VSAA treated with rATG ± CsA, CsA, and anabolic steroids were 54.8%, 54.5%, and 37.6% (P = 0.037), respectively. The incidence of adult AA in Thailand is higher than those in Western countries, and the peak incidence is in the elderly. rATG ± CsA provided a better response than anabolic steroids, translating to the superior survival in SAA/VSAA treated with rATG ± CsA.

Efficacy and Safety of Metronomic Chemotherapy Versus Palliative Hydroxyurea in Unfit Acute Myeloid Leukemia Patients: A Multicenter, Open-Label Randomized Controlled Trial.

BACKGROUND: Management of unfit AML patients is a therapeutic challenge. Most hematologists tend to avoid aggressive treatment leaving patients with a choice of best supportive care. We hypothesized that metronomic chemotherapy could be an alternative treatment for unfit AML patients. METHODS: A multi-center randomized controlled trial was conducted in seven university-affiliated hospitals in Thailand. Unfit AML patients were recruited and followed up from December 2014 to December 2017. Patients were randomly assigned to receive either metronomic chemotherapy or palliative hydroxyurea. Overall survival rates were compared using Cox's proportional hazard survival analysis. RESULTS: A total of 81 eligible patients were randomly allocated and included for ITT analysis. The OS rate was higher in group receiving metronomic chemotherapy than in group receiving palliative treatment at 6 and 12 months with borderline significance (6 months HR 0.60; 95%CI 0.36, 1.02; p-value 0.060; 12 months: HR 0.66; 95%CI 0.41, 1.08; p-value 0.097). CONCLUSION: Metronomic chemotherapy could prolong survival time of unfit AML patients, especially in the first 12 months after diagnosis without increasing treatment-associated adverse events.