The Food and Drug Administration is to allow Intellia Therapeutics Inc to include the US in its global trial of a genome editing therapy for hereditary angioedema (HAE), a rare protein deficiency that can cause swelling in multiple parts of the body. To date, the Phase 1/2 study has been taking place at sites in the Netherlands, New Zealand and the UK. The addition of sites in the US will increase the geographical reach of the programme, as well as the number of patients receiving the experimental therapy. Intellia is based in Cambridge, US.