TPMT Genetic Variability and Its Association with Hematotoxicity in Indonesian Children with Acute Lymphoblastic Leukemia in Maintenance Therapy.

PURPOSE: Hematotoxicity monitoring in children with acute lymphoblastic leukemia (ALL) is critical to preventing life-threatening infections and drug discontinuation. The primary drug that causes hematotoxicity in ALL children is 6-mercaptopurine (6-MP). Genetic variability of the drug-metabolizing enzymes of 6-MP, thiopurine S-methyltransferase (TPMT), is one factor that might increase the susceptibility of children to hematotoxicity. The present study aimed to determine the variability in TPMT genotypes and phenotypes and its association with the occurrence of hematotoxicity in ALL children in maintenance therapy. PATIENTS AND METHODS: A cross-sectional study was conducted at Cipto Mangunkusumo and Dharmais National Cancer Hospital, Jakarta, Indonesia, from June 2017 to October 2018. We included ALL patients, 1-18 years, who were receiving at least one month of 6-MP during maintenance therapy according to the Indonesian protocol for ALL 2013. Direct sequencing was used to determine TPMT*3A, *3B, and *3C genotypes, and LC-MS/MS analysis was performed to measure the plasma concentrations of 6-MP and its metabolites. Association analysis between the TPMT genotype and hematotoxicity was evaluated using the unpaired t-test or Mann-Whitney's test. RESULTS: The prevalence of neutropenia, anemia, and thrombocytopenia in ALL children during maintenance therapy was 51.9%, 44.3%, and 6.6%, respectively. We found a low frequency of TPMT*3C, which is 0.95%. No association was found between hematotoxicity and TPMT genotypes or age, nutritional status, serum albumin levels, risk stratification, the daily dose of 6-MP, and cotrimoxazole co-administration. However, hematotoxicity was associated with 6-methylmercaptopurine (6-MeMP) plasma concentrations and the ratio 6-MeMP/6-thioguanine (6-TGN). We also found no association between TPMT genotypes and TPMT phenotypes. CONCLUSION: The 6-MeMP/6-TGN ratio is associated with hematotoxicity in ALL children during maintenance therapy but is not strong enough to predict hematotoxicity.

Association of CYP2D6*10 (c. 100 C>T) Genotype with Z-END Concentration in Patients with Breast Cancer Receiving Tamoxifen Therapy in Indonesian Population.

BACKGROUND: Tamoxifen (TAM) is a frequently used hormonal prodrug for patients with breast cancer that needs to be activated by cytochrome P450 2D6 (CYP2D6) into Zusammen-endoxifen (Z-END). OBJECTIVE: The purpose of the study was to determine the association between CYP2D6*10 (c.100C>T) genotype and attainment of the plasma steady-state Z-END minimal threshold concentration (MTC) in Indonesian women with breast cancer. METHODS: A cross-sectional study was performed in 125 ambulatory patients with breast cancer consuming TAM at 20 mg/day for at least 4 months. The frequency distribution of CYP2D6*10 (c.100C>T) genotypes (C/C: wild type; C/T: heterozygous mutant; T/T: homozygous mutant) was detected using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), the results of which were subsequently confirmed by sequencing. The genotypes were categorized into plasma Z- END concentrations of <5.9 ng/mL and ≥5.9 ng/mL, which were measured using ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). RESULTS: Percentages of C/C, CT, and T/T genotypes were 22.4%, 29.6%, and 48.8%, respectively. Median (25-75%) Z-END concentrations in C/C, C/T, and T/T genotypes were 9.58 (0.7-6.0), 9.86 (0.7-26.6), and 3.76 (0.9-26.6) ng/mL, respectively. Statistical analysis showed a significant difference in median Z-END concentration between patients with T/T genotype and those with C/C or C/T genotypes (p<0.001). There was a significant association between CYP2D6*10 (c.100C>T) genotypes and attainment of plasma steady-state Z-END MTC (p<0.001). CONCLUSION: There was a significant association between CYP2D6*10 (c.100C>T) and attainment of plasma steady-state Z-END MTC in Indonesian breast cancer patients receiving TAM at a dose of 20 mg/day.

Cost-effectiveness analysis of olanzapine-containing antiemetic therapy for managing highly emetogenic chemotherapy in Southeast Asia: a multinational study.

PURPOSE: Recent studies suggested that olanzapine, together with dexamethasone and serotonin-3 receptor antagonist (5HT3RA), is effective in preventing chemotherapy-induced nausea and vomiting (CINV) following highly emetogenic chemotherapy (HEC). This regimen is particularly useful in Southeast Asia (SEA) countries where resources are limited. We aimed to evaluate the cost-effectiveness of incorporating olanzapine into standard antiemetic regimens for the prevention of CINV in patients receiving HEC among SEA countries. METHODS: Using a decision tree model, clinical and economic outcomes associated with olanzapine-containing regimen and standard antiemetic regimen (doublet antiemetic regimen: dexamethasone+first generation 5HT3RA) in most SEA countries except in Singapore (triplet antiemetic regimen: dexamethasone+first generation 5HT3RA + aprepitant) for CINV prevention following HEC were evaluated. This analysis was performed in Thailand, Malaysia, Indonesia, and Singapore, using societal perspective method with 5-day time horizon. Input parameters were derived from literature, network meta-analysis, government documents, and hospital databases. Outcomes were incremental cost-effectiveness ratio (ICER) in USD/quality-adjusted life year (QALY) gained. A series of sensitivity analyses including probabilistic sensitivity analysis were also performed. RESULTS: Compared to doublet antiemetic regimen, addition of olanzapine resulted in incremental QALY of 0.0022-0.0026 with cost saving of USD 2.98, USD 27.71, and USD 52.20 in Thailand, Malaysia, and Indonesia, respectively. Compared to triplet antiemetic regimen, switching aprepitant to olanzapine yields additional 0.0005 QALY with cost saving of USD 60.91 in Singapore. The probability of being cost-effective at a cost-effectiveness threshold of 1 GDP/capita varies from 14.7 to 85.2% across countries. CONCLUSION: The use of olanzapine as part of standard antiemetic regimen is cost-effective for the prevention of CINV in patients receiving HEC in multiple SEA countries.

Quantification of 6-Mercaptopurine and Its Metabolites in Patients with Acute Lympoblastic Leukemia Using Dried Blood Spots and UPLC-MS/MS.

This research aimed to quantitatively bioanalyze 6-mercaptopurine (6-MP), 6-methylmercaptopurine (6-MMP), and 6-thioguanosine-5′-monophosphate (6-TGMP) in dried blood spots (DBS) prepared from a small volume of acute lymphoblastic leukemia (ALL) patients. Analytes on the DBS card were extracted using 90% methanol with 5-fluorouracil (5-FU) as an internal standard. Analytical separation was performed on a Waters Acquity® UPLC BEH AMIDA column of 1.7 μm (2.1 × 100 mm) with a mobile phase mixture of 0.2% formic acid in water and 0.1% formic acid in acetonitrile-methanol, with gradient elution and a flow rate of 0.2 mL/min. Mass detection of 6-MP, 6-MMP, 6-TGMP, and 5-FU showed m/z values of 153.09 > 119.09, 167.17 > 126.03, 380.16 > 168.00, and 129.09 > 42.05, respectively. This DBS method had a run time of 5 min and yielded a linear calibration curve over a range of 25.5⁻1020 ng/mL for 6-MP, 6-MMP, and 6-TGMP. Analyte analysis in 22 of 24 ALL patients showed that the measured value of 6-TGMP as an active metabolite was in the range of 29⁻429 pmol/8 × 108 erythrocytes. Five of 22 patients had concentrations in a therapeutic range, which indicates that the treatment is effective, while 17 of 24 patients had concentrations below the therapeutic range, which indicates that a treatment dose adjustment is needed. The measured value of 6-MMP, an inactive metabolite, was in the range of 28⁻499 pmol/8 × 108 erythrocytes, which includes concentrations below the hepatotoxic range. The method employed here can thus be effectively utilized to support therapeutic drug monitoring.

Evaluation of Antibiotic Use Among Sepsis Patients in an Intensive Care Unit: A cross-sectional study at a referral hospital in Indonesia.

OBJECTIVES: This study aimed to evaluate the appropriateness of antibiotic use and factors associated with outcomes among sepsis patients in an intensive care unit (ICU). METHODS: This cross-sectional study was carried out from February to May 2017 and included all adult patients with sepsis or septic shock admitted to the ICU of Dharmais Cancer Hospital, Jakarta, Indonesia. Data were collected from the patients' medical records. RESULTS: A total of 60 patients with sepsis or septic shock were admitted to the ICU during the study period. The most common source of infection was hospital-acquired pneumonia (61.7%) and the majority had two or more comorbidities (93.3%). There were 115 antibiotic regimens prescribed. Overall, 33.3% of patients were prescribed inappropriate types of antibiotics and 51.7% were given an inappropriate dosage. The mortality rate was 68.3%. There was a statistically significant association between patient outcome and inappropriate doses of antibiotics (P = 0.034), although not inappropriate types of antibiotics (P = 0.050). A multivariate analysis indicated that the main factors influencing patient outcome were septic shock and the presence of at least two comorbidities (P <0.050 each). CONCLUSION: Inappropriate doses of antibiotics, a diagnosis of septic shock and the presence of at least two comorbidities were found to significantly increase the mortality rate of sepsis patients admitted to an ICU in Indonesia.