US regulator weighs up CRISPR cancer therapy trial

A US federal safety board is set to review an application for the first in-human use of CRISPR/Cas9 genome-editing technology to treat cancer.

The National Institutes of Health's (NIH) recombinant DNA advisory committee – established to review all human experiments that alter DNA – will consider a proposal to use CRISPR technology to treat cancer patients, in meetings on 21–22 June.

Proposed by scientists at the University of Pennsylvania, the experiment would first involve the removal of immune cells called T-cells from cancer patients. CRISPR would then be used to edit two genes in the T-cells so they express receptors allowing them to target melanoma, myeloma and sarcoma tumour cells, before being injected back into patients.

While the trial would represent a first-in-human use of CRISPR in the US or Europe, other immune-centred genetic engineering techniques are already being evaluated in cancer and other diseases. Last year a genome-editing technique called TALENs, transcription activator-like effector nucleases, was used to reverse advanced leukaemia in a one-year-old British girl (see BioNews 827). Scientists consider CRISPR, which was developed less than four years ago, to be more efficient and accurate than previous methods.

'Researchers in the field of gene transfer are excited by the potential of utilising CRISPR/Cas9 to repair or delete mutations that are involved in numerous human diseases in less time and at a lower cost than earlier gene-editing systems,' said Carrie Wolinetz, associate director of science policy at NIH, in a blog post.

Although CRISPR has been touted as carrying much potential to improve gene therapy-based treatments, safety concerns remain. The MIT Technology Review, which broke the news of the NIH evaluation, says that modified T-cells are potentially dangerous as they 'bypass the usual checks and balances that keep the immune system from attacking a person's own tissues'.

The committee meeting will be live-streamed on the NIH website.