A toxicity risk index, an index for warning idiosyncratic drug toxicity

Area of Science:

• Pharmacology
• Drug Development
• Toxicology

Background:

• Drug toxicity poses a significant challenge in drug development and clinical application.
• Idiosyncratic drug toxicity (IDT) is a major concern, often leading to drug withdrawal.
• Predictive tools are needed to identify potential drug toxicity early in development.

Purpose of the Study:

• To propose and evaluate a Toxicity Risk Index (TRI) for predicting idiosyncratic drug toxicity (IDT).
• To assess the utility of TRI in categorizing drugs based on their safety profiles.
• To establish potential thresholds for classifying drugs as high-risk (BBW).

Main Methods:

• Defined TRI based on drug dose, pharmacokinetic parameters, and covalent binding toxicokinetic data.
• Analyzed 20 drugs categorized as BBW (black box warning), WNG (warning), or SAFE (no warning).
• Calculated and compared TRI values across the different drug safety categories.

Main Results:

• TRI values clearly differentiated SAFE drugs from BBW drugs.
• SAFE drugs exhibited TRI values below 0.456 (nmol/mg protein).
• BBW drugs showed TRI values above 1.10 (nmol/mg protein), suggesting a potential threshold.

Conclusions:

• The Toxicity Risk Index (TRI) shows promise in identifying drugs with potential idiosyncratic drug toxicity (IDT).
• A TRI value exceeding 1.0 nmol/mg protein may indicate a drug should be classified as BBW.
• Further research with larger datasets is warranted to establish a statistically significant cutoff value for TRI.