Sigma-Aldrich Corporation's innovative biological products and services business, Sigma Life Science, will be launching the genetically-modified HepaRG human liver cell line, licensed from Biopredic, for hepatotoxicity and drug metabolism assays. Currently undergoing beta-testing by multiple contract research and pharmaceutical organizations, the assays will be publicly available later in Q1 2014 in a plated, live-cell format to support translational research in industry and academia. Through this license agreement with BioPredic International, Sigma-Aldrich will also offer high-quality wild-type HepaRG liver cells and supporting media.

In drug discovery and development, unforeseen toxicity issues, particularly in the liver, remain a major cause of late-stage drug failures that account for billions of dollars of lost pharmaceutical R&D investments. This has recently prompted regulators and pharmaceutical companies to issue guidance and develop robust studies to predict liver toxicity. However, current assays using animals or in vitro techniques—such as utilizing small molecule inhibitors, RNAi, or less than desirable cell lines—introduce biological ambiguity, off-target effects or limit the extent of acquirable data.

To generate novel, precision assays for early prediction of hepatic liabilities, Sigma-Aldrich will apply its exclusive CompoZr Zinc Finger Nuclease (ZFN) gene editing technology on the HepaRG human liver cells. Sigma-Aldrich plans to knock-out genes for critical xenobiotic sensors—such as PXR and CAR—and drug transporters—including BSEP, OATP1B1, and OATP1B3—that regulatory agencies have highlighted for possible analysis. The gene knock-out approach, only recently possible in human cells due to the advent of robust gene-editing tools such as CompoZr ZFNs, eliminates the ambiguities about a drug's interactions that would be introduced by conventional tools, such as small molecules or RNAi. Sigma-Aldrich will also knock-in fluorescence reporter tags to endogenous toxicity biomarkers, such as ALT and Cytochrome P450, to generate inexpensive, high-throughput live cell imaging or reporter-based assays that can reveal toxic drug effects and drug–drug interactions.

"Such precision assays currently do not exist. These gene-edited HepaRG cell-based assays represent a major improvement in the quality of data compared to the predominant way of studying liver drug metabolism and toxicity, which is through primary human hepatocytes recovered from donated cadavers. These primary cells suffer from sporadic availability, loss of in vivo functions, variable donor health, and genetic polymorphisms that can confound reproducible analyses," explained Paul Brooks, global market manager at Sigma-Aldrich.

The HepaRG immortalized cell lines from BioPredic International are unique in that they mirror the endogenous human hepatocyte functionality and metabolism providing a dependable supply of long-lifespan, isogenic cells that eliminate confounding sources of variation. Other immortalized liver cell lines exist, including Fa2N-4 and HepG2, but all of these cell lines lack important biological features, such as expression of the Cyp3A4 enzyme that metabolizes more than 50% of currently approved drugs.

The beta testing programme for the genetically-modified HepaRG cell lines is currently open to CRO, pharmaceutical, and academic partners.

Sigma-Aldrich currently offers several gene-edited human cell lines for ADME/Tox assays, including Caco-2 human liver cell lines with efflux transporter gene knock-outs for clear analysis of potential drug–drug interactions.

"The broad vision for Sigma-Aldrich's ADME/Tox R&D is to exploit gene-editing in human cell lines to provide  novel, isogenic assays that resolve fundamental shortfalls in current ADME/Tox methodologies.  By doing so, we can resolve a major hurdle in translational research,leading to safer drugs and more sustainable drug development programs," said Sean Muthian, Ph.D., Director of Strategic Marketing at Sigma-Aldrich.

Sigma-Aldrich, a leading Life Science and High Technology company focused on enhancing human health and safety, manufactures and distributes more than 200,000 chemicals, biochemicals and other essential products to more than 1.4 million customers globally in research and applied labs as well as in industrial and commercial markets.