ICH S2(R1) - Genotoxicity Testing and Data Interpretation for Pharmaceuticals

What it says

S2(R1) provides guidance on genotoxicity testing of pharmaceuticals intended for human use. It describes two standard test batteries, one beginning with a bacterial gene mutation test and one adding a mammalian cell test and an in vivo test, along with advice on follow-up of positive results and the interpretation of data.

Paraphrased for plain-language clarity. Always verify against the current published regulation text.

What it means in practice

• Genotoxicity is assessed before first clinical use, and the package is completed before later phases.
• A positive in vitro result does not always mean a hazard, so follow-up testing and interpretation matter.
• Testing of impurities is handled in other guidelines such as ICH M7.

What inspectors look for

• Whether the studies follow the recommended battery.
• Whether studies were conducted under GLP.
• Whether positive findings were followed up.

Related regulations