Population Pharmacokinetics of Ranibizumab Delivered via the Port Delivery System Implanted in the Eye in Patients with Neovascular Age-Related Macular Degeneration.

The port delivery system with ranibizumab (PDS) is designed to continuously deliver ranibizumab to maintain therapeutic drug concentrations in the vitreous of the eye for an extended duration. The PDS has been evaluated for the treatment of neovascular age-related macular degeneration in the Ladder (PDS 10, 40, and 100 mg/mL, with refill exchanges as needed, versus monthly intravitreal ranibizumab 0.5 mg), Archway (PDS 100 mg/mL with 24-week refill exchanges, versus monthly intravitreal ranibizumab 0.5 mg), and ongoing Portal (PDS 100 mg/mL with 24-week refill exchanges) clinical trials. Data from Ladder, Archway, and Portal were used to develop a population pharmacokinetics (PK) model to estimate the ranibizumab release rate from the PDS implant, describe ranibizumab PK in serum and aqueous humor, and predict the concentration in vitreous humor. A model was developed to adequately describe the serum and aqueous humor PK data, as suggested by goodness-of-fit plots as well as visual predictive checks. In the final model, the first-order implant release rate was estimated to be 0.00654 (1/day), corresponding to a half-life of 106 days, consistent with the implant release rate determined in vitro. The model-predicted vitreous concentrations achieved with PDS 100 mg/mL given every 24 weeks were below the intravitreal peak concentration and above the intravitreal trough concentration of ranibizumab over the entire 24-week refill interval. The results demonstrate a durable release of ranibizumab from the PDS with a half-life of 106 days, providing vitreous exposure to ranibizumab for at least 24 weeks that is within the range of exposure for monthly intravitreal treatment.

Population pharmacokinetics and exposure-response of anti-programmed cell death protein-1 monoclonal antibody dostarlimab in advanced solid tumours.

AIM: Develop a population pharmacokinetic (PopPK) model to characterise the pharmacokinetics (PK) of anti-programmed cell death protein-1 (PD-1) antibody dostarlimab, identify covariates of clinical relevance, and investigate efficacy/safety exposure-response (ER) relationships. METHODS: A PopPK model was developed using Phase 1 GARNET (NCT02715284) trial data for dostarlimab (1, 3 or 10 mg kg-1 every 2 wk; 500 mg every 3 wk or 1000 mg every 6 wk; 500 mg every 3 wk × 4 then 1000 mg every 6 wk [recommended regimen]) serum concentrations over time. Concentration-time data were analysed using nonlinear mixed effects modelling with standard stepwise covariate modelling. ER was explored for treatment-related adverse events and overall response rate (ORR) using logistic regression. RESULTS: PopPK model/adverse event ER analyses included 546 patients (ORR ER analysis n = 362). Dostarlimab PK was well described by a 2-compartment model with time-dependent linear elimination. Time-dependent clearance decreased over time to a maximum of 14.9%. At steady state, estimated dostarlimab geometric mean coefficient of variation % clearance was 0.179 (30.2%) L d-1 ; volume of distribution was 5.3 (14.2%) L; terminal elimination half-life was 23.5 (22.4%) days. Statistically significant covariates were age, body weight, sex, time-varying albumin and alanine aminotransferase for clearance; body weight, albumin and sex for volume of distribution of the central compartment. Hepatic or renal impairment did not affect PK. There were no clinically significant ER relationships. CONCLUSION: Dostarlimab PK parameters are similar to other anti-programmed cell death protein-1 antibodies. The clinical impact of covariates on exposure was limited-to-moderate, supporting recommended dostarlimab monotherapy therapeutic dosing.

Model-Based Interspecies Scaling of Glucose Homeostasis.

Being able to scale preclinical pharmacodynamic response to clinical would be beneficial in drug development. In this work, the integrated glucose insulin (IGI) model, developed on clinical intravenous glucose tolerance test (IVGTT) data, describing dynamic glucose and insulin concentrations during glucose tolerance tests, was scaled to describe data from similar tests performed in healthy rats, mice, dogs, pigs, and humans. Several approaches to scaling the dynamic glucose and insulin were investigated. The theoretical allometric exponents of 0.75 and 1, for clearances and volumes, respectively, could describe the data well with some species-specific adaptations: dogs and pigs showed slower first phase insulin secretion than expected from the scaling, pigs also showed more rapid insulin dependent glucose elimination, and rodents showed differences in glucose effectiveness. The resulting scaled IGI model was shown to accurately predict external preclinical IVGTT data and may be useful in facilitating translations of preclinical research into the clinic.

Mathematical Modelling of Glucose-Dependent Insulinotropic Polypeptide and Glucagon-like Peptide-1 following Ingestion of Glucose.

The incretin hormones, glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1), play an important role in glucose homeostasis by potentiating glucose-induced insulin secretion. Furthermore, GLP-1 has been reported to play a role in glucose homeostasis by inhibiting glucagon secretion and delaying gastric emptying. As the insulinotropic effect of GLP-1 is preserved in patients with type 2 diabetes (T2D), therapies based on GLP-1 have been developed in recent years, and these have proven to be efficient in the treatment of T2D. The endogenous secretion of both GIP and GLP-1 is stimulated by glucose in the small intestine, and the release is dependent on the amount. In this work, we developed a semimechanistic model describing the release of GIP and GLP-1 after ingestion of various glucose doses in healthy volunteers and patients with T2D. In the model, the release of both hormones is stimulated by glucose in the proximal small intestine, and no differences in the secretion dynamics between healthy individuals and patients with T2D were identified after taking differences in glucose profiles into account.

Semimechanistic model describing gastric emptying and glucose absorption in healthy subjects and patients with type 2 diabetes.

The integrated glucose-insulin (IGI) model is a previously published semimechanistic model that describes plasma glucose and insulin concentrations after glucose challenges. The aim of this work was to use knowledge of physiology to improve the IGI model's description of glucose absorption and gastric emptying after tests with varying glucose doses. The developed model's performance was compared to empirical models. To develop our model, data from oral and intravenous glucose challenges in patients with type 2 diabetes and healthy control subjects were used together with present knowledge of small intestinal transit time, glucose inhibition of gastric emptying, and saturable absorption of glucose over the epithelium to improve the description of gastric emptying and glucose absorption in the IGI model. Duodenal glucose was found to inhibit gastric emptying. The performance of the saturable glucose absorption was superior to linear absorption regardless of the gastric emptying model applied. The semiphysiological model developed performed better than previously published empirical models and allows better understanding of the mechanisms underlying glucose absorption. In conclusion, our new model provides a better description and improves the understanding of dynamic glucose tests involving oral glucose.

A pharmacokinetic model for the glycation of albumin.

Glycated haemoglobin (HbA1c) concentrations can be falsely lowered in circumstances when red blood cell (RBC) survival is reduced, e.g. in patients with chronic kidney disease (CKD). Glycated albumin (GA) has been suggested as an alternative marker of glycaemic control in these patients since it is independent of the RBC life span. The primary aim of this work was to develop a pharmacokinetic model that describes the time course of GA. The secondary aim was to assess the performance of GA as marker for glycaemic control in comparison to HbA1c based on simulations. For the second aim, three different scenarios were considered in the simulations: 1) assessment of the effect of large intra-day fluctuations in mean blood glucose on GA concentrations, 2) initiation of antidiabetic treatment on the GA profile, and 3) a hypothetical phase II study for a new antidiabetic compound. The GA model, as well as a previously developed HbA1c model described literature data well. GA concentrations appear to be stable even in the presence of high intra-day fluctuations in mean blood glucose concentrations. Simulation of a decrease in mean blood glucose concentrations resulted in a faster change in GA compared to HbA1c. GA also provided a time to 90 % power of the effect of a hypothetical antidiabetic drug that was 16 days shorter than when using HbA1c. These results indicate that GA could be used as alternative marker to assess blood glucose control in diabetic patients with CKD and also to follow an individual patient over time.