Cardiotoxicity, hepatotoxicity and neurotoxicity continue to underlie drug attrition at all stages of development. Often multiple mechanisms may be responsible, and thus any single, current approach is not likely to capture the complexity involved in cellular toxicity. High Content Screening (HCS) is one robust approach that overcomes the limitations of the existing single endpoint in vitro methods. It consists of a combination of biological samples, instruments and software to acquire, analyze, process, store and manage experimental data. HCS uses automated fluorescent imaging to simultaneously analyze multi-parametric indicators of cellular toxicity. In recent years the awareness of the potential value of HCS has increased and companies are beginning to leverage these tools to pick safer leads (DSEC 2011 Technology Survey).
Cyprotex offers two options for evaluating general cytotoxicity (and hepatotoxicity) using multiplexed cell-based assays. These include our cytotoxicity screening panel and our unique CellCiphr® Premier technology.
Cytotoxicity Screening Panel
Our cytotoxicity screening panel is an early stage, high content screening cell-based assay which evaluates general cell health in a single human hepatocellular carcinoma cell line (HepG2). It assesses key toxicity markers including cell number, nuclear condensation, total nuclear intensity, cell permeability, mitochondrial membrane potential and cytochrome c release. The assay offers greater sensitivity over cell viability assays such as MTT and LDH, and identifies potential mechanisms of toxicity.
CellCiphr® is a unique HCS system, which Cyprotex acquired from Cellumen in 2010. Cellumen invested substantial resources in developing the product, which Cyprotex has subsequently significantly improved. The system has been externally validated by a number of pharmaceutical companies and other organizations.
It is well-recognized that toxicological events can be organ-specific, time-dependent and concentration-dependent. The CellCiphr® system investigates up to 10 different toxicologically-relevant endpoints in two different cell types at several time points to represent early and late stage toxic responses. Dose-dependent effects are investigated by exposing cells to 10 different concentrations of the compound and incorporating predicted or actual Cmax to further understand exposure effects.
In 2012, we launched our most recent CellCiphr® service, named CellCiphr® Premier. This service offers superior predictive capability and replaces previous versions of CellCiphr®.
CellCiphr® Premier provides an extended screening program to provide a robust prediction of clinical toxicity. Advantages include:
Highly predictive for clinical hepatotoxicity (sensitivity of 70% and specificity of 100%)
Extended panel of toxicologically-relevant endpoints in both replicating (HepG2) and metabolically competent (rat primary hepatocytes) cells
Multiple time points investigated to identify early and late stage toxicities
Integration of actual or predicted Cmax data corrects for exposure-related effects
Common toxicity signatures can be assessed in SAR sets to pick out candidates with the lowest risk for further development