A Semi-Physiologically Based Pharmacokinetic Model Describing the Altered Metabolism of Midazolam Due to Inflammation in Mice

This is the author's accepted manuscript.Purpose To investigate influence of inflammation on metabolism and pharmacokinetics (PK) of midazolam (MDZ) and construct a semi-physiologically based pharmacokinetic (PBPK) model to predict PK in mice with inflammatory disease. Methods Glucose-6-phosphate isomerase (GPI)-mediated inflammation was used as a preclinical model of arthritis in DBA/1 mice. CYP3A substrate MDZ was selected to study changes in metabolism and PK during the inflammation. The semi-PBPK model was constructed using mouse physiological parameters, liver microsome metabolism, and healthy animal PK data. In addition, serum cytokine, and liver-CYP (cytochrome P450 enzymes) mRNA levels were examined. Results The in vitro metabolite formation rate was suppressed in liver microsomes prepared from the GPI-treated mice as compared to the healthy mice. Further, clearance of MDZ was reduced during inflammation as compared to the healthy group. Finally, the semi-PBPK model was used to predict PK of MDZ after GPI-mediated inflammation. IL-6 and TNF-α levels were elevated and liver-cyp3a11 mRNA was reduced after GPI treatment. Conclusion The semi-PBPK model successfully predicted PK parameters of MDZ in the disease state. The model may be applied to predict PK of other drugs under disease conditions using healthy animal PK and liver microsomal data as inputs

A Phase 1, Multicenter, Open-Label, First-in-Human, Dose-Escalation Study of the Oral Hedgehog Inhibitor Sonidegib (LDE225) in Patients With Advanced Solid Tumors

PURPOSE: This phase 1 trial was undertaken to determine the maximum tolerated dose (MTD), dose-limiting toxicities (DLTs), safety, tolerability, pharmacokinetics (PK), pharmacodynamics, and preliminary antitumor activity of the novel smoothened inhibitor sonidegib (LDE225), a potent inhibitor of hedgehog (Hh) signaling, in patients with advanced solid tumors. EXPERIMENTAL DESIGN: Oral sonidegib was administered to 103 patients with advanced solid tumors, including medulloblastoma (MB) and basal cell carcinoma (BCC), at doses ranging from 100 to 3000 mg daily and 250 to 750 mg twice daily, continuously, with a single-dose PK run-in period. Dose-escalations were guided by a Bayesian logistic regression model. Safety, tolerability, efficacy, PK, and biomarkers in skin and tumor biopsies were assessed. RESULTS: The MTDs of sonidegib were 800 mg daily and 250 mg twice daily. The main DLT of reversible grade 3/4 elevated serum creatine kinase (18% of patients) was observed at doses ≥ the MTD in an exposure-dependent manner. Common grade 1/2 adverse events included muscle spasm, myalgia, gastrointestinal toxicities, increased liver enzymes, fatigue, dysgeusia, and alopecia. Sonidegib exposure increased dose proportionally up to 400 mg daily, and displayed nonlinear PK at higher doses. Sonidegib exhibited exposure-dependent reduction in GLI1 mRNA expression. Tumor responses observed in patients with MB and BCC were associated with evidence of Hh pathway activation. CONCLUSIONS: Sonidegib has an acceptable safety profile in patients with advanced solid tumors and exhibits antitumor activity in advanced BCC and relapsed MB, which is strongly associated with activated Hh pathway, as determined by gene expression