Food for Thought: Moving Into the Clinic Without Animal Toxicity Tests

This month, MedNous provides an in-depth case study on an immune therapy developed by Immunocore Ltd. that won approval from the British and US regulators MHRA and FDA to start clinical trials on the basis of in-vitro safety studies only – without conducting any toxicity tests in animals.

The product in question, IMCgp100, is a monoclonal T cell receptor fused to an anti-CD3 single chain antibody fragment. The molecule is tricky in that both binding sites bind to human proteins and cells only. As a result, animal studies would have been without any predictive value. The company therefore had to design a reliable preclinical test for predicting the behavior of the drug in humans.

This has been a particular challenge as regulators still were digesting the shock from the TeGenero disaster in 2006, when six healthy volunteers almost died from cytokine storm in a Phase I clinical study of an immune therapy. Back then, the drug had been tested in animals and the volunteers received only a fraction of the dose that had been safely administered to monkeys.

After intense consultations with the regulators, Immunocore conducted a battery of tests on human cells to find out about potential cytokine release, cross-reactivity, etc. The company, too, tested whether hormones were able to shut done activity of the drug in case something would go wrong during the trials.

Trials are on the way already at three UK and two US sites in patients with metastatic melanoma and Immunocore hopes to have preliminary data, including some efficacy results, by 2012.