Atara Biotherapeutics, Inc.

Good morning, ladies and gentlemen. Thank you for standing by, and welcome to the Atara Biotherapeutics First Quarter 2019 Financial Results and Corporate Update Conference Call. At this time, all participants are in a listen-only mode. Later, we will conduct a question and answer session, and instructions will follow at that time. As a reminder, this conference call will be recorded. I will now turn the call over to Dr. John Craighead, Vice President of Investor Relations and Corporate Communications of Atara Biotherapeutics. Please go ahead, sir.

Thank you, operator. Good morning, everyone, and welcome to the Atara first quarter 2019 financial results and corporate update conference call. Earlier this morning, we issued a press release providing an overview of the company's first quarter 2019 financial results and recent operational progress. Please note that this press release is available and a lot more. I'm joined on the call today by Dr. Isaac C. Hanover, President and Chief Executive Officer, Dr. Dietmar Berger, Global Head of R&D, and Upal Kopikar, Chief Financial Officer. We will begin with prepared comments from Isaac and Dietmar and then open the call for your questions. We would like to remind listeners that the company's management will be making forward-looking statements. Actual results could differ materially from those stated or implied by our forward-looking statements due to risks and uncertainties associated with the company's business. These forward-looking statements are qualified in their entirety by the cautionary statements contained in today's press release and the company's SEC filings. These statements are made as of today's date and the company undertakes no obligation to update these statements. Now, I'd like to turn the call over to ATARA's Chief Executive Officer and President, Dr. Isaac C. Hanover. Isaac?

Thank you, John, and thank you, everyone, for joining us this morning. We continue to make important progress advancing our T-cell immunotherapy programs across three major value drivers, tab cell, multiple sclerosis, and our next-generation CAR-T programs. On today's call, we will provide an update on our recent progress and upcoming milestones. In a moment, Dr. Dietmar Berger, our global head of R&D, and Alex Chao's PTLD. Enrollment in these studies is proceeding slower than anticipated. The factors that make this condition challenging to identify and enroll patients in clinical studies are similar to other ultra-rare and rapidly progressive diseases. We are aggressively implementing strategies to address these challenges that Dietmar will outline shortly and remain confident in our ability to successfully execute on our clinical development plan. and others. In addition to this, we are also working on a global regulatory strategy for TAB-Cell. The objective is to align on a TAB-Cell development plan for patients with EBV PTLD which may allow us to potentially expedite a U.S. regulatory submission. We are encouraged so far with our progress and we expect the outcomes of these ongoing regulatory discussions in the first half of 2019. We view our TAB cell pivotal development and regulatory progress to date as acknowledgement of the critical need to find new options to treat patients with this ultra-rare and often life-threatening disease. In parallel, we are continuing to advance our additional programs, including ATA-188 and ATA-190 for multiple sclerosis. We remain on track to present initial Phase I safety results for our off-the-shelf allogenic ATA-188 program at the Congress of the European Academy of Neurology, or EAN, in June of this year, with additional efficacy and safety results expected later this year. In addition, for our Next Generation CAR-T portfolio, our collaboration of MSK reported positive Phase I clinical results for their mesothelin-targeted CAR-T immunotherapy for patients with solid tumors at the 2019 AACR Annual Meeting. Efficacy and safety results presented for patients with malignant pleural mesothelioma who have also received a PD-1 checkpoint inhibitor and lymphodepleting chemotherapy exceeded our expectations. Following administration of a novel mesothelin-targeted CAR-T, MSK investigators observed a 72% response rate in a subset of these patients. These data are among the first proof-of-concept results for a CAR-T to treat cell and Alex Chapman. We are also excited for updated results from the MSK investigator-sponsored mesothelin-targeted CAR T study to be presented at ASCO in June. I would now like to turn the call over to Dietmar, who will provide a more detailed update on our clinical development programs.