Genotoxicity Assessment of Drug Metabolites in the Context of MIST and Beyond

Abstract

While there are dedicated guidelines for industry regarding the assessment of the genotoxic potential of new pharmaceuticals and impurities, and the general safety assessment of major drug metabolites, only limited guidance exists on the assessment of potential genotoxic minor drug metabolites. In this Perspective, we discuss challenges associated with assessing the genotoxic potential of human metabolites and share five case studies within the context of an "aware−avoid−assess" paradigm. A special focus is on a class of potentially genotoxic carcinogens, aromatic amines (arylamines and anilines). This compound class is frequently used as building blocks and may show up as impurities, metabolites, or degradants in pharmaceuticals. We propose several recommendations that should help project teams at different stages of pharmaceutical development. In most cases, proactive interactions with the relevant health authority should be considered to endorse the proposed genotoxicity assessment strategy for minor drug metabolites.

Development and Validation for Quantification of 7-Nitroso Impurity in Sitagliptin by Ultraperformance Liquid Chromatography with Triple Quadrupole Mass Spectrometry

“…Since the molecular mass is specific for each compound and impurity, no interference was observed at the retention time of the impurity due to other drug substances or blanks. An advantage of this method is its ability to detect 7-nitroso impurity at ppm to ppb levels whereas the reported methods [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ] such as the SFC-MS/MS method, RP-HPLC method, HPTLC, HPLC method, HPLC-CD, LC-UV, LC-MS and FT-IR methods, and the UV spectrophotometric and UPLC-MS/MS methods are unable to determine the content of the 7-nitroso impurity. The developed method is simple and direct and no other derivatization process is required.…”

“…Therefore, the generation of these impurities must be controlled and monitored, which is typically attempted during the process of production [ 5 ]. However, the complete removal of these contaminants is often not assured, and thus the process must be carefully monitored to avoid unnecessary clinical holds or delays caused by regulatory agencies [ 6 ]. Therefore, the development of analytical techniques for the accurate analysis and detection of genotoxic impurities in pharmaceuticals is both imperative and challenging for analysts and scientists [ 7 ].…”

Metabolites in the regulatory risk assessment of pesticides in the EU

“…Because reactive metabolites may escape the identification due to their short presence in the in vitro assay, it should be considered to introduce the techniques available to identify them in order to identify early on the potential for hepatic injury. Zeller et al (2020) have presented interesting case studies illustrating how to assess the genotoxic potential of human metabolites whereby their special focus was on the compound class of aromatic amines, potentially genotoxic carcinogens, because of its use as building blocks of pharmaceuticals. The same group has described in their review (Schadt et al, 2018) that following the metabolites in safety testing (MIST) regulatory guidance (FDA, 2008) has influenced industries' approaches identifying drug metabolites and their potential contribution to safety, focusing on comparative metabolic profiles, human versus test animals, with specific emphasis on the metabolic profile in plasma.…”

A local QSAR model based on the stability of nitrenium ions to support the ICH M7 expert review on the mutagenicity of primary aromatic amines

“…Because aromatic amines are widely used as intermediates in pharmaceutical synthesis and can remain as impurities, their mutagenicity is a serious safety issue [ 4 , 5 ]. In addition, aromatic amines can be formed as metabolites, especially for drugs with amide bonds that may easily break down by enzymatic hydrolysis [ 6 , 7 ].…”