Pharmacogenetic and clinical predictors of ondansetron failure in a diverse pediatric oncology population

Trial Sequential Analysis and Meta-Analysis of Olanzapine in Pediatric Patients for Chemotherapy-Induced Nausea and Vomiting (CINV)

Background and Objective: Olanzapine (OLZ) containing regimens are approved in adults for chemotherapy-induced nausea and vomiting (CINV) receiving highly emetogenic chemotherapy (HEC) or moderately emetogenic chemotherapy (MEC), and the same has not been approved in the pediatric population. In order to generate data regarding the efficacy and safety of OLZ as an adjunct to the standard of care (SoC) for CINV in pediatric patients receiving HEC/MEC, the review authors performed this systematic review and meta-analysis. Methods: A systematic literature search was performed through the databases Cochrane Library, Pub Med, and clinicaltrials.gov, from inception to September 2023, using keywords: "chemotherapy" and "olanzapine," "nausea" and "vomiting." Randomized clinical trials published in English that analyzed the efficacy and safety of olanzapine as an adjunct to SoC were included. The essential outcomes included in this study were the proportion of patients with no emesis in the acute and delayed phase, patients with no nausea in the acute and delayed phase, the proportion of patients requiring rescue medication, and the proportion of patients with reduced CNS arousal. Results: In the OLZ group, a greater number of patients had no emesis both in the acute and delayed phase (RR = 1.22; 95% CI = 1.09-1.37; P = .0004); and (RR = 1.23; 95% CI = 0.92-1.63; P = .16) respectively. Similarly, a higher number of patients showed no nausea both in the acute and delayed phase (RR = 1.08; 95% CI = 0.78-1.48; P = .66) and (RR = 1.12; 95% CI = 0.79-1.61; P = .52) respectively. The use of rescue medication was significantly less in the OLZ group (RR = 0.62; 95% CI = 0.42-0.91; P = .01). More patients experienced reduced CNS arousal in the OLZ group (RR = 2.97; 95% CI = 2.02-4.38; P < .0001). Conclusions: Olanzapine as an adjunct to the SoC may be effective in acute emesis, which may also reduce the use of rescue medication. Reduced CNS alertness was the significant adverse effect observed. For other endpoints, more studies are required to substantiate its role in CINV.

Factors Influencing Mortality in Children with Central Nervous System Tumors: A Cohort Study on Clinical Characteristics and Genetic Markers

Multidrug resistance (MDR) commonly leads to cancer treatment failure because cancer cells often expel chemotherapeutic drugs using ATP-binding cassette (ABC) transporters, which reduce drug levels within the cells. This study investigated the clinical characteristics and single nucleotide variant (SNV) in ABCB1, ABCC1, ABCC2, ABCC4, and ABCG2, and their association with mortality in pediatric patients with central nervous system tumors (CNST). Using TaqMan probes, a real-time polymerase chain reaction genotyped 15 SNPs in 111 samples. Patients were followed up until death or the last follow-up day using the Cox proportional hazards model. An association was found between the rs1045642 (ABCB1) in the recessive model (HR = 2.433, 95% CI 1.098-5.392, p = 0.029), and the ICE scheme in the codominant model (HR = 9.810, 95% CI 2.74-35.06, p ≤ 0.001), dominant model (HR = 6.807, 95% CI 2.87-16.103, p ≤ 0.001), and recessive model (HR = 6.903, 95% CI 2.915-16.544, p = 0.038) significantly increased mortality in this cohort of patients. An association was also observed between the variant rs3114020 (ABCG2) and mortality in the codominant model (HR = 5.35, 95% CI 1.83-15.39, p = 0.002) and the dominant model (HR = 4.421, 95% CI 1.747-11.185, p = 0.002). A significant association between the ICE treatment schedule and increased mortality risk in the codominant model (HR = 6.351, 95% CI 1.831-22.02, p = 0.004, HR = 9.571, 95% CI 2.856-32.07, p ≤ 0.001), dominant model (HR = 6.592, 95% CI 2.669-16.280, p ≤ 0.001), and recessive model (HR = 5.798, 95% CI 2.411-13.940, p ≤ 0.001). The genetic variants rs3114020 in the ABCG2 gene and rs1045642 in the ABCB1 gene and the ICE chemotherapy schedule were associated with an increased mortality risk in this cohort of pediatric patients with CNST.

Pediatric CYP2D6 metabolizer status and post-tonsillectomy nausea and vomiting after ondansetron

The goal of this study was to determine whether CYP2D6 metabolizer status within the ondansetron-treated pediatric tonsillectomy population is associated with risk of postoperative nausea and vomiting (PONV) in the post-anesthesia care unit. We conducted a retrospective cohort study of pediatric patients (<18 years) who underwent tonsillectomy and received ondansetron on the day of the procedure. Data were obtained from BioVU, an institutional biobank that links DNA to de-identified electronic health record data. Subjects were tested for 10 CYP2D6 allelic variants and copy number variation, and genotype data translated into CYP2D6 metabolizer status. The cohort included 652 individuals, 105 (16.1%) of whom had PONV. Rates of PONV were similar across groups: ultrarapid metabolizers (UMs), 1 of 9 (11.1%); normal metabolizers (NMs), 64 of 354 (18.1%); intermediate metabolizers (IMs), 33 of 234 (14.1%); poor metabolizers (PMs), 6 of 39 (15.4%); and ambiguous phenotypes, 1 of 16 (6.3%). In multivariable analysis adjusted for age, sex, and time under anesthesia, CYP2D6 metabolizer status was not associated with PONV, with an odds ratio of 1.37 (95% confidence interval 0.9, 2.1) when comparing PM/IM versus NM/UM. In this large pediatric population, no significant differences were detected for PONV based on CYP2D6 metabolizer status. Further investigation is needed to determine mechanisms for ondansetron inefficacy in children.

Optimizing antiemetic therapy for children undergoing chemotherapy

Chemotherapy-induced nausea and vomiting (CINV) is a common side effect of most chemotherapy agents. Suboptimal management of CINV impacts quality of life, nutrition, gastrointestinal (GI) integrity, and adherence to chemotherapy treatment plans. This article reviews the principles of CINV management, planning and implementation of antiemetic regimens, and pharmacology of the antiemetics currently available in the United States appropriate for pediatric use. With the advent of more targeted therapies, increased use of immunotherapy, and the effects of radiotherapy to the brain, spine, and abdomen, treatment of CINV now has a broader application than just for chemotherapeutics alone.