ABSTRACT
Objectives: This study aimed to investigate the pharmacokinetic characteristics of siponimod in healthy volunteers and patients with MS based on aggregated data from published clinical trials, and to explore the factors influencing siponimod exposure. Methods: A total of 476 siponimod plasma concentrations aggregated from 28 dosage groups (corresponding to 294 healthy volunteers and 207 patients with MS) were collected from published clinical trials. Population pharmacokinetic (PPK) analysis was performed using a nonlinear, mixed-effect modeling approach. The pharmacokinetic properties of siponimod in healthy volunteers and patients with MS were compared, and the influence of covariates on siponimod exposure was evaluated using both PPK analysis and noncompartmental analysis (NCA). Results: A one-compartment model with first-order absorption and elimination adequately described siponimod pharmacokinetics. The typical population parameter estimates of clearance (CL/F), apparent volume of distribution (V/F), and absorption rate constant (ka) were 3.17 L/h, 112.70 L, and 0.38 h-1, respectively. An 11.85% lower siponimod clearance was estimated for patients with MS relative to healthy volunteers. Subgroup analyses using NCA assessments revealed that siponimod presented an accumulation index of approximately 2 after multiple administration. Compared with nonobese participants, obese participants had a relatively lower dose-corrected area under the concentration-time curve (AUC0-∞/D) (0.31 vs. 0.42 h/L) and V/F (120.95 vs. 133.75 L), and a relatively higher CL/F (3.25 vs. 3.21 L/h). Participants with CYP2C9*2/*3, *1/*3, and *3/*3 genotypes experienced an increased (1.3- and 3.4-fold, respectively) AUC0-∞/D and a decreased (0.7- and 0.3-fold, respectively) CL/F compared with those in participants with the CYP2C9*1/*1, *1*2, and *2*2 genotypes. Fluconazole combination led to a decrease in CL/F (approximately 0.5 times) and an increase in AUC0-∞/D (approximately 1.3 times). Conclusion: Siponimod pharmacokinetic properties in healthy volunteers and patients with MS were explored using complementary model-based meta-analysis (MBMA) and NCA approaches. A slightly lower siponimod clearance was observed in patients with MS than in healthy volunteers. The dosage regimen, body mass index, CYP2C9 genetic polymorphism and fluconazole combination may had influences on siponimod pharmacokinetics. Such model paves the road to more population-based analyses in different patient populations with MS to quantify the effect of any influencing factors on siponimod pharmacokinetics.
ABSTRACT
OBJECTIVE： To systematically evaluate the effects of MTHFR， RFC1 and MDR1 gene polymorphisms on high- dose methotrexate-induced ADR in osteosarcoma patients， and to provide evidence-based reference for individual medication of high-dose of methotrexate. METHODS： Retrieved from Medline， Embase， clinical trials.gov， CNKI， Wanfang database and CBM， cohort studies about the association of MTHFR C677T/A1298C， RFC1 G80A， MDR1 C3435T gene polymorphisms with high-dose methotrexate-induced ADR were collected. After data extraction of clinical studies met inclusion criteria， and quality evaluation with the Newcastle-Ottawa Scale， Meta-analysis and descriptive analysis were performed for outcome indexes as the incidence of high-dose methotrexate-induced ADR （hematotoxicity and myelosuppression， hepatotoxicity， nephrotoxicity， oral mucositis， digestive tract toxicity and overall adverse events） with Rev Man 5.3 and Microsoft Excel 2016 software. RESULTS： Totally 8 cohort studies involving 608 patients were included； 6， 5， 4 and 2 studies reported outcome indexes related to MTHFR C677T/A1298C， RFC1 G80A and MDR1 C3435T gene polymorphisms respectively. Meta-analysis and descriptive analysis showed that MTHFR C677T gene polymorphism was significantly associated with the risk of G3-4 renal toxicity [TT/CT vs. CC： OR＝12.35， 95％CI＝（3.28，46.42）， P＜0.001]， G3-4 oral mucositis [T vs. C： OR＝2.04， 95％CI＝（1.06，3.93）， P＝0.03]， oral mucositis [（TT vs. CT/CC： OR＝2.27， 95％CI＝（1.20，4.27）， P＝0.01] and renal toxicity （P＜0.05）； MTHFR A1298C gene polymorphism was associated with G3-4 hepatotoxicity， G3-4 nephrotoxicity and G3-4 oral mucositis， without statistical significance （P＞0.05）. There was no significant correlation between RFC1 G80A polymorphism and hemotoxicity， hepatotoxicity， nephrotoxicity and digestive tract toxicity （P＞0.05）. MDR1 C3435T polymorphism was significantly correlated with oral mucositis （P＜0.05）， but not with hematotoxicity and hepatotoxicity （P＞0.05）. CONCLUSIONS： MTHFR C677T mutation can increase the risk of high-dose methotrexate-induced ADR. There is no significant association between MTHFR A1298C polymorphism and high-dose methotrexate-induced ADR. There are few studies on RFC1 G80A or MDR1 C3435T polymorphism and high-dose methotrexate-induced ADR， and their association is unclear.