Pharmacokinetics of ranibizumab after intravitreal administration in patients with retinal vein occlusion or diabetic macular edema.
OBJECTIVE
To describe the systemic pharmacokinetics of ranibizumab after intravitreal administration in patients with retinal vein occlusion (RVO) or diabetic macular edema (DME).


DESIGN
A population approach of nonlinear mixed-effect pharmacokinetics modeling based on serum concentrations of ranibizumab measured at various times after intravitreal administration.


PARTICIPANTS
Patients with RVO (n = 441) and DME (n = 435) from 4 large, randomized, phase 3 clinical trials of monthly ranibizumab intravitreal administration.


METHODS
A 1-compartment pharmacokinetics model with first-order absorption and elimination rate constants previously developed in patients with age-related macular degeneration (AMD) was fitted separately to RVO and DME data. Population pharmacokinetic parameters and interindividual variability were estimated for each model. Baseline covariates were evaluated for potential effects on systemic pharmacokinetics. Model performance was validated using general diagnostic plots and a visual predictive check.


MAIN OUTCOME MEASURES
Ranibizumab disposition was determined in RVO and DME patients and compared with that previously seen in AMD patients.


RESULTS
The AMD pharmacokinetics model correctly predicted the measured serum ranibizumab concentration data for RVO and DME patients. Most observed data points were within the simulated 90% confidence interval, indicating that systemic ranibizumab concentrations were comparable among AMD, RVO, and DME patients. No disease-related covariates were identified by the population pharmacokinetics analysis.


CONCLUSIONS
The systemic pharmacokinetics of ranibizumab were similar among patients with AMD, RVO, or DME. Disease-related differences and patient demographics, measured in this study, did not lead to variability in ocular elimination or in systemic exposure of ranibizumab after intravitreal administration. In all disease processes tested, ranibizumab exits the eye slowly and then is eliminated rapidly from the circulation, thus minimizing systemic exposure.