Atara Biotherapeutics announced this morning an update to its development plan for the open-label phase III "Tab-cel" program in patients with Epstein Barr virus associated post-transplant proliferative disease. The update is a slight change to what had been expected and creates a delay in timing of regulatory authority submissions, Roth Capital analyst Tony Butler tells investors in a research note. The biologics license application filing in the U.S. will be in the second half of 2020, and will be before the submission in Europe. The analyst had expected the opposite. Further, he believes the timing of the EU submission is now unclear. Butler, however, reiterates a Buy rating on Atara Biotherapeutics with a $30 price target. The stock in morning trading is down 11% to $16.10.