Disappointing results with Precision Biosciences’ Arcus nuclease-edited allogeneic Car-T project have not stopped the company’s business development. Today a deal worth $100m up front, plus a $35m equity stake, was struck with Lilly; this appears to be the first tie-up focusing on in vivo application of Precision’s technology, and its initial focus will be Duchenne muscular dystrophy. The technology involves gene editing using Arcus nucleases, a method Precision argues is better suited to commercial use than Crispr/Cas9, claiming precise control, greater efficiency and ease of delivery thanks to a smaller enzyme size. However, ex vivo use of Arcus nuclease, in Precision’s CD19-directed Car-T project PBCAR0191, disappointed at last year’s Ash meeting: impressive early responses were seen in lymphoma patients, but some relapsed, and the stock crashed 52%. Precision’s $500m valuation puts is slightly behind its allogeneic Car-T peer Poseida, though two other competitors, Allogene and Crispr Therapeutics, have severalfold higher market caps. Precision signed its first Arcus nuclease deal, focused on Car-T applications, with Baxalta in 2016, and this was worth $105m up front. After Baxalta's takeover by Shire the Car-T licence was assigned to Servier.