Impact of GPR39 Inhibition on Tissue Oxygen Tension in Acute Myocardial Infarction: Modeling Using an Indirect Response Pharmacokinetics/Pharmacodynamics Approach

A groundbreaking study examined the impact of a novel GPR39 inhibitor, VC108, on tissue oxygen tension during acute myocardial infarction (AMI). Researchers developed a unique population PK/PD model using preclinical data from both healthy animals and those subject to AMI protocols. This model allowed them to simulate the temporal effects of VC108 on myocardial oxygen tension (mpO2) across various experimental scenarios.

The study revealed that VC108's pharmacokinetics (PK) data fit well within a two-compartment model, demonstrating that body weight, sex, and nominal dose significantly influenced clearance and central compartment volume. By employing indirect effect model principles, researchers constructed a structural population PK/PD model to capture mpO2 dynamics during different AMI phases, including before and during coronary occlusion and after reperfusion.

The model effectively captured the body's natural mpO2 homeostasis, the ischemic decline, and the reperfusion overshoot. It also quantified VC108's contribution to collateral blood flow and functional recovery. Researchers conducted dose response simulations to determine the effect of varying VC108 doses on permanent damage, defined as a reduction in mpO2 at steady state after AMI.

The findings indicated that the probability of remaining below predefined damage thresholds (5%-20% reduction in mpO2) increased with dose in both males and females. Interestingly, female subjects consistently experienced greater protection, with a plateau around 1 mg/kg of VC108 for higher permanent damage. This model marks a significant advancement in describing VC108's efficacy and pharmacokinetics, providing valuable insights into its impact on ischemia/reperfusion dynamics and its potential effects at untested dose levels.