Alliance seeks animal test alternatives

Scottish biotech firm CXR biosciences and Edinburgh's Roslin Institute have entered into a collaboration with Geron to develop a new technique that promises to reduce the need to test drugs on animals.

The three partners plan to develop human embryonic stem cell (hESC)-derived hepatocytes developed by Geron for use in in vitro assays of drug metabolism and toxicity.

If they succeed, this will reduce the use of liver-damage tests on animals, thus putting an end to unnecessary deaths and giving a more accurate picture of liver damage earlier in the testing process.

Sourcing of human hepatocytes for in vitro assays has long been a problem in pharmaceutical drug development. They have traditionally been sourced from cadavers or cancer resections, but supply of these cells is limited and their characteristics vary widely among the sourced donors.

Moreover, hepatocytes cannot be sustained in culture without losing function, so they must be continually sourced. Hence, pharmaceutical companies have had to rely heavily on animal models for preclinical metabolism and toxicity testing, but even these are often not predictive for man.

The expensive and low-throughput nature of animal models has forced such testing to be reserved for compounds in late preclinical development, requiring pharmaceutical companies to invest significant resources in compounds before their metabolism and toxicity profiles are known, which contributes to their high failure rates in late preclinical testing.

CXR and Roslin have been working on animal testing alternatives since 2001, when they first started to collaborate on the area of gene reporter assays for toxicological stress.

'CXR's chief executive - Tom Shepherd, told the CORDIS news service that the current market for testing of this kind is about £100 million (€152 million) worldwide, but that demand would rise for an effective test of this type, potentially valuing the market at 'several hundred million pounds'.