Experimental and virus-specific drivers of EC50 variability in antiviral assays evaluated using mathematical modeling
Year: 2026
Type: article
Abstract: • Mathematical mechanism-based modeling quantified assay‑driven EC 50 variability across experimental design and virus properties. • Viral infection rate and production rate are the main virus-specific properties that affect apparent EC 50 estimates. • Experimental design choices such as initial cell densities and sampling time markedly influence apparent EC 50 estimates. • The results from this study may guide the design of experiments evaluating antiviral pharmacological activity in vitro . The half-maximal effective concentrations (EC 50 ) reported for specific antiviral agents often vary widely across in vitro studies. The cause for this may be due to differences in viral strains, cell types, and experimental design choices. Variability in EC 50 estimates complicates potency interpretation and cross-study comparison. Here, we applied a mechanism-based mathematical target cell-limited model to examine the impact of virus-specific parameters and different experimental design choices on EC 50 estimation. Empirical EC 50 values were estimated from simulated concentration–response experiments for different virus-specific properties and experimental conditions. Among viral parameters, EC 50 changed more than 20-fold across the range of infection rate (β) and over 50-fold across viral production rate (ρ), whereas clearance rate had only minor effects. Among experimental factors, higher initial cell number (T₀) and later sampling time changed EC 50 by more than 15-fold, while delayed time of adding drug increased EC 50 by approximately 50%. When both β and ρ were high, EC 50 changed nearly 900-fold. Overall, our findings demonstrate that EC 50 is highly sensitive to several virus-specific parameters and experimental design choices, and provides quantitative directions which may guide the design and interpretation of antiviral in vitro assays evaluating pharmacological activity.
Institution: Leiden University
Language: English
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $3,070
OpenAlex ID: W7130516541