Ladies and gentlemen, thank you for standing by, and welcome to the Atara Biotherapeutics First Quarter 2020 Financial Results Conference Call. Please be advised that today's call is being recorded. I would now like to hand the call over to Eric Hyllengren, Vice President of Investor Relations and Finance at Atara Biotherapeutics. Please go ahead, sir.

Thank you, Elaine. Good afternoon, everyone, and welcome to Atara's First Quarter 2020 Conference Call. On today's call, we will provide an update on our operational and strategic progress, review our upcoming key milestones and objectives for 2020, and discuss the potential impacts of the COVID-19 pandemic on our current and planned activities. Earlier today, we issued a press release providing an overview of the company's first quarter 2020 financial results and operational progress. This press release and an updated investor presentation are available in the Investor & Media section at atarabio.com. Joining me on today's call are Dr. Pascal Touchon, President and Chief Executive Officer; Utpal Koppikar, Chief Financial Officer; Joe Newell, Chief Operations Officer; and Dr. AJ Joshi, Chief Medical Officer. We will begin with prepared comments from Pascal and then open the call for your questions. We would like to remind listeners that during the call, 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 would like to turn the call over to Pascal.

Thank you, Eric, and thanks to all of you for joining us this afternoon. Let me open today's call by acknowledging the environment we are currently in. This global pandemic has impacted many lives across the globe, and our hearts go out to everyone who has been directly affected. Sharing the same vision as our frontline health care workers to serve patients, we at Atara would like to honor and thank the health care professionals who are here, especially during this time. This moment in time only reinforces our deep commitment to making a difference in patients' lives. It is with tremendous pride that I acknowledge the commitment and resiliency of our entire Atara team, who have remained focused on our mission to serve patients and implemented industry-leading practices to ensure safety while mitigating the impact of COVID-19 on our business. We have made significant progress in the first quarter of 2020 towards accomplishing our key objectives. Importantly, we remain on track to initiate the BLA submission for tab-cel in the second half of 2020 and to present key data from the Phase Ia study of ATA188 in patients with progressive multiple sclerosis in the second quarter. I want to take a moment to provide a brief update on the operational adjustments that we have made in response to the pandemic. First, prior to the COVID-19 outbreak, as part of our routine supply planning and operational risk management strategies, we had already manufactured significant inventories across tab-cel, ATA188, and our other programs including process intermediates and the required starting materials needed to maintain long-term product supply. Consequently, we continue to deliver product to patients from our inventory, which is a clear advantage of such off-the-shelf allogeneic EBV T cell therapy. In addition, our teams have been working closely with our clinical sites to ensure the safety of site staff and patients and to preserve data integrity and access to treatment as appropriate. Where needed, they have established remote study visits, leveraged telemedicine, home health care, and other methods to ensure continuity of care for patients and to preserve key endpoint data. We are closely monitoring the evolving COVID-19 pandemic and continue to assess its potential impact on our business and operations, including the timing and execution of clinical and preclinical studies. Regardless of the current pandemic, Atara Biotherapeutics remains a pioneer in allogeneic T-cell immunotherapy. With our lead program in Phase III clinical development, we are the most advanced allogeneic T-cell immunotherapy company, and we intend to rapidly deliver off-the-shelf treatments to patients with high unmet medical need. Our platform leverages the unique biology of EBV T-cells and has the capability to treat a wide range of EBV-associated diseases or other severe diseases including solid tumors and hematological cancers through the incorporation of engineered CARs or TCRs. A key step toward achieving this mission is initiating the BLA submission for tab-cel in EBV+ PTLD, which remains on track for the second half of 2020. We are very pleased to have enrolled a sufficient number of patients in our Phase III study to perform an interim analysis in Q3 2020 after the appropriate follow-up. We then plan to request a pre-BLA meeting with the FDA to discuss the totality of data from the tab-cel program, including the MSKCC Phase II studies and Atara's Expanded Access Program and single patient use. If the totality of clinical data are considered compelling enough by the FDA, we will initiate a BLA submission for tab-cel. With respect to site activity and patient enrollment for the ongoing Phase III tab-cel study, most of the 40 active clinical sites in the U.S. and Australia are available for enrollment, and we are continuing to prepare to open additional sites in the U.S., Canada, and Europe. As previously discussed, we submitted Clinical Trial Applications, or CTAs, to several European countries in November and December 2019 to enable the opening of European clinical sites in 2020. In addition to the previously reported approvals in the U.K., Austria, and Spain, I'm very pleased to report that the CTA in France was recently approved and that we have just activated our first European site in Spain. As I've noted before, these additional sites are being added to support full enrollment of the Phase III study and not an interim analysis for which we have already enrolled a sufficient number of patients. With respect to the tab-cel regulatory filing in Europe, in Q1 2020 we submitted a Pediatric Investigation Plan, or PIP, to the EMA as per the usual requirements. Following EMA approval of the PIP, we intend to submit a tab-cel EU marketing authorization application for patients with EBV+ PTLD in 2021. We continue to see strong tab-cel investigator, physician, and patient interest, even during this COVID-19 pandemic. And for cases in which patients are not able to enroll in the EBV+ PTLD Phase III clinical study, we are providing tab-cel to patients in need under our EAP and also SPU. Additionally, a growing body of data suggests that tab-cel may provide clinical benefit in additional EBV+ disease, and we are advancing clinical studies to further evaluate its potential. Toward this end, we continue to expect to initiate enrollment in the second half of 2020 in the tab-cel Phase II multi-cohort study that will include up to 6 additional ultra-rare EBV+ patient populations. I will now turn to ATA188, our allogeneic T-cell immunotherapy for the treatment of patients with multiple sclerosis. We previously reported encouraging early data at ECTRIMS 2019 from a Phase I multicenter open-label, dose-escalation study, evaluating the safety and efficacy of ATA188 in patients with the progressive form of MS. We are looking forward to presenting in the second quarter of 2020, in an appropriate form, the 6-month results for the dose-escalating cohorts 1 to 4, and very importantly, the 12-month results for the cohorts 1 to 3. We plan to present data on the clinical measures and in particular, the assessment of disability. We also expect to present 12-month cohort 4 data in the second half of 2020 when such data are available. We are still re-treating patients in the open-label extension of the Phase Ia study in an appropriate setting, given the constraint of the COVID-19 pandemic and as determined by the treating physician and patients. As previously announced, we have temporarily paused the screening and enrollment of patients in the Phase Ib randomized placebo-controlled study to ensure that the participating clinical sites can focus on meeting the needs of patients with COVID-19 and to protect the safety of study participants, investigators, and staff. This pause will also help preserve the study and data integrity as there are numerous assessments that require a specific clinical setting, and we want to have confidence that the clinical environment will allow these assessments to be conducted at the time period specified in the protocol. Based on our current assessment and information from the clinical sites, we expect this pause to be limited and to therefore initiate enrollment in this study in the second or third quarter of 2020. Throughout the first quarter of 2020, we also continue to make progress in advancing our CAR T pipeline. We expect that our collaborators at Memorial Sloan Kettering will submit an IND application to the FDA in the second or third quarter of 2020 for our next-generation mesothelin-targeted autologous CAR T immunotherapy, ATA2271. ATA2271 is designed to improve efficacy, persistence, and durability of response, using novel 1XX CAR co-stimulatory domain and cell-intrinsic checkpoint inhibition technology with a PD-1 dominant negative receptor. Preclinical data from ATA2271 IND-enabling studies have been accepted as a late-breaking e-poster at the AACR Virtual Annual Meeting in June, and the abstract will be released on May 15. We will also expect that MSK will present additional clinical data for the academic first-generation program in the second half of this year. We have also initiated preclinical IND-enabling studies for off-the-shelf allogeneic mesothelin-targeted CAR T, ATA3271, as well as for ATA3219 or CD19-targeted CAR T. Both of these programs utilize our next-generation CAR T technologies and EBV T cell platform. ATA3219, in particular, is supported by the initial proof of principle from an academic off-the-shelf allogeneic EBV CD19 CAR T clinical study presented at the 2020 TCT meetings, which to date show the longest duration of response for an allogeneic CD19 CAR T with 26.9 months median follow-up. As we advance multiple innovative programs and generate a growing body of promising clinical data, we are increasingly confident that our EBV T cell platform and technologies are strongly positioned to provide patients with meaningful clinical benefit and create tremendous value for shareholders. EBV T-cells offer numerous advantages as the basis of our allogeneic platform as they are potent cell killers that specifically target disease cells, are safe, traffic to the site of disease, expand and persist in patients. Beyond the therapeutic potential of our platform, we have also a robust and scalable manufacturing capability that is nearing commercial readiness. We are on track to complete commercial validation this year and have the ability to rapidly deliver products from inventory to patients in the U.S., Europe, and Australia in three days or less. We continue to innovate at our manufacturing facility in Southern California. Over time, we expect to further increase manufacturing yields to bring Atara off-the-shelf allogeneic T-cell therapy cost of goods manufactured in range with those of traditional biologics. In addition to the significant progress we achieved in the first quarter in our clinical, preclinical, and manufacturing activities, we also continue to attract highly talented individuals to the Atara team. I’m confident in the leadership team we are building out, including Ron Renaud, who has been appointed as our new non-Executive Board Chair; and Amar Murugan, who was named Senior Vice President and General Counsel. We are making tremendous progress on hiring a new head of R&D and currently expect to make this announcement in the very near future. We are on track to achieve our key 2020 objectives, and I strongly believe that we have the team, the technology, and the passion to succeed in our mission of innovating with transformative immunotherapies that have the potential to improve outcomes for patients with serious disease. Now turning to our financial results. We ended the first quarter of 2020 with $214.6 million in cash, cash equivalents, and short-term investments. This is a decrease of $44.5 million from the prior quarter and reflects cash used from operating activities of $67 million, offset by net proceeds from our at-the-market facility, or ATM, of $23.1 million. We believe our cash, cash equivalents, and short-term investments as of March 31, 2020, are sufficient to fund planned operations into the second quarter of 2021. In summary, despite operating in these unique and changing times, we remain committed to our mission and believe that we will be able to continue advancing our programs in the months ahead. I believe that this experience will only strengthen our resolve and commitment to our company and the patients we seek to serve. I know that many of you are experiencing disruption in your professional and personal lives, and I truly appreciate your time today. I also want to take this opportunity to thank our staff and our clinical collaborators for continuing to support our trials as they face their own challenges in caring for patients in an unprecedented environment. I also want to ensure that patients currently participating or interested in participating in our studies, that we remain committed to their safety and are positioned to continue dosing in our ongoing studies as they and their physicians deem appropriate. We understand that the pandemic is another significant obstacle in what is already a tremendously challenging patient journey, and we are doing everything in our power to minimize its impact on how we move forward. I hope that everyone on the call today is staying safe and healthy, and I look forward to sharing our progress with you in the weeks and months ahead. I will now turn the call back to the operator to begin the Q&A portion of the call.

And your first question comes from the line of Marc Frahm from Cowen & Company.

Yes. Thanks for the extra clarity kind of around the BLA submission and the interim analysis. But I guess, what is the current plan on when we will see the data that is being generated in Q3? Should we - it would seem that the timing would be amenable to something like an ASH presentation. Should we expect to see that this year? Or is it likely not until 2021?

Thank you, Marc, for your question. As we said previously in the previous call, we will discuss with the FDA during the pre-BLA meeting the totality of that, including this interim analysis. And then we will also discuss with them regarding what will be needed for the completion of the submission as well as the possibility for us to communicate and how to communicate on this interim analysis data. So it all depends on the timing of this pre-BLA meeting. And then, of course, we will communicate with the agreement of the FDA at an appropriate congress after that pre-BLA meeting.

And your next question comes from the line of John Newman from Canaccord.

Thank you for the updates. So Pascal, I just wondered if you could comment a bit about what you expect to see in terms of enrollment from your European sites. You mentioned in your prepared remarks that you have the first site open for enrollment. Just curious if you can talk to us about, perhaps, the number of additional sites you will be looking to open in Europe and sort of what you would expect from enrollment there.

Thank you, John, for your question. AJ, do you want to answer?

Sure. Thanks, John. I think a couple of important points, right, just to reinforce Pascal's point earlier that our focus until now has been the 40 U.S. and Australian sites. And that has driven us to the enrollment points that Pascal has mentioned earlier. In terms of the European sites, we are not really going to specifically talk about the numbers of sites. The main point here is that the European sites are being opened now so that we can complete the study enrollment. And that gives us a much more expeditious path to complete it as rapidly as possible.

And your next question comes from the line of Salim Syed from Mizuho.

Thanks, Pascal, for all the clarity. I guess a few from me on multiple sclerosis on ATA188, if I can. One, can you just - I presume you submitted a late-breaker for EAN, and you are going to find out, at some point, whether that has been accepted or not. If we are going to get the data at EAN, can you tell us how you are - since it is so close now, how are you thinking about displaying that data? Not what the data is, but how are we going to get that data? Is it going to still be lumped like the ECTRIMS data? Or is it going to be more granular? That is the first question. And then the second question I had was just on the clinicaltrials.gov update, which looks like in March of this year you guys upped the trial for the Phase I ATA188 from 72 patients to 97 patients. And I'm wondering why you did that, and the implications coming out of that. And then lastly, how much data do you need based on your discussions with the regulators, perhaps, to file early on ATA188, if you show reversal on disability from baseline?

Thank you, Salim. A very detailed question, and thank you, I appreciate that. AJ, do you want to take this question? I will chime in if needed.

Sure. So thanks, Salim. I think - yes, so we have submitted to EAN for a late breaker, and we are waiting for a decision as everyone else is, quite frankly, for the late breakers. And in terms of the question on how we are going to be presenting there, we are certainly going to be giving more detailed information. Because as the data has matured, we are able to, now, actually provide that level of detail. And to kind of reinforce the notion, one of the biggest questions we continue to be asked is what were the - what do the disability assessments look like? And we will be providing detail on those, both by composite scales as well as by individual disability scales. In terms of the patient enrollment numbers, part of what we are doing here is we have set up the design of that study to allow us to have various elements of adaptive design, so that if we see any elements of clinical signal or biological signals in the course of that study, we are able to adapt the design and essentially target it towards potentially more meaningful statistical outcomes. So it is really an element of flexibility that you are seeing there as opposed to a specific need or driver that says we need to add more patients. It is meant to allow us the flexibility so that we can power the study along a variety of different measures, depending on how the cohort 4 data look, as well as how some of the blinded information looks like in the RCTs. And I guess the third question that you had was in terms of if we were to see reversal of disability, then does that give us some kind of accelerated pathway? I'm not going to comment on a specific - whether reverse or a specific endpoint at this point. What I would say is that if there is a - if we are able to show an efficacy signal that would be a transformational product profile when you prove it out in later studies, then I do think that creates significant opportunity for various conversations with the FDA on some form of accelerated pathway. But all of that obviously has to be proven out a bit more in a randomized setting to be able to say that there might be any kind of accelerated pathway there. But certainly, a transformational - potentially transformational profile would give us that opportunity.

Thank you, AJ. And it is really what is important for us, Salim, is really to aim at a transformative treatment of MS. And that is what we would like to bring to further development of that product in line with the need, the medical need that is immense in that population. Because as you know, no treatment today is really able to reverse decline, or they are just delaying the decline. I mean, talking about treatment approved in progressive MS. So there is really an unmet medical need, and we really aim at addressing that unmet medical need.

And your next question comes from the line of Yigal Nochomovitz from Citigroup.

Yes. Can you just explain a little bit more what exactly is going to happen at the interim analysis that you set for, what would be a success from the analysis? So understanding of what you need.

Yigal, we have some challenge to hear you, but I guess you have questions about the interim analysis in Q3 2020 and what will be considered a success. Isn't it?

Yes, you have outlined what needs to happen to feel confident with...

Okay. I think I understand the question. Thank you. AJ, do you want to answer? And then, Yigal, you will tell us whether it is answering your question because we still have some difficulty to hear you clearly.

Yes. I'm going to just take a crack at it, Yigal, and see if it ticks the point. I think the - as is the case in most ultra-rare conditions, the totality of data is what is most relevant here. We are not going to be specifically talking about exact numbers that are necessary for hitting an interim analysis. I think the key point here is that when you have the Phase III data and the totality of information that we have described here, it is that package that will drive the FDA view on things. And if you think about an ultra-rare condition, the package of information we have here is fairly significant when you look at the totality of information. So I think that is the main factor is how does that entire view look, of course, incorporating these major elements of the Phase III enrollment in study. Did that answer the question?

I was looking for specific numbers, but I understand you might not be able to provide them. I was hoping to gain more insight into the additional patients in the study. These patients are not part of the interim data and will be included later for approval once you have that data from the site you started at.

Yes. I guess - it is still very difficult to hear you, Yigal. I guess your question is what is the objective of the patients - the additional patients to complete the enrollment of the study and how do we plan to discuss these with regulatory authorities. Is that right?

Yes. Can you hear me better now? Is that better?

Yes. Much, much better now. Yes. AJ, do you want to answer that question?

Yes. So typically when - if we were to - when you do an analysis like this, I think I got your question correctly, were those additional data that get generated after this analysis are information that you are definitely going to provide to the regulators. And oftentimes, in a situation like this, and I'm not going to predict which way things go, but there wouldn't necessarily be a prerequisite, for example, for moving forward. Most of the time, those are things that say the data that you provided at the time of the pre-BLA discussion, are the basis for the decision that they make to say, yes, let's - you can move forward with your BLA filings. Any data that you generate related to the Phase II program, they are always going to want to see when you finish generating those. But they will not be necessary for that decision that is made at the timing of the pre-BLA meeting.

Okay. But that is - the first submission for the BLA, that will be - I mean is it understood that that is going to be a conditional to - on further data? Or is this going to be a full approval? Or you don't know yet?

I think that is a review issue. That is going to be part of the discussion with the FDA at the pre-BLA meeting. But I wouldn't say priori, I would say that this is going to be conditional.

Not a priori, conditional. Okay. Got it. And then.

I don't think we can say definitively at this point. We've spoken with some experts in the United States, including a colleague at the Cleveland Clinic who is knowledgeable in EBV biology and MS. He indicated that the EBV hypothesis appears to be quite robust in cases of relapsed/refractory disease, although it's less certain in other areas.

Okay. We lost you again. But I guess you wanted to say in PMS. So probably your question is that on the EBV expert you mentioned - in the EBV hypothesis is - in MS, is stronger in relapse-remitting than it is in progressive. AJ, do you want to take that, and I will chime in?

Sure. The hypothesis, and I would love to maybe have some conversations because these are always good dialogues. But for that particular individual, the EBV hypothesis actually does not differentiate between whether it is relapsing-remitting or progressive MS. And to give you a little perspective, we had a recent advisory board with all our top advisers. And these are very well-established individuals within the MS space. And very consistently, there is no reason why it should impact one space versus the other. Their comment is, hey, if we start seeing something in PMS, you should be looking at all of them. And that has always been the plan. So there has not really been a differentiation. The hypothesis is MS, it is not just PMS. There should be really no difference between those two spaces in terms of EBV being a major element of the pathogenesis of the MS process.

And clearly, the reason we went into progressive MS, as I said earlier on, is because of the immense unmet medical need that exists there. And if we can show safety in this early study safety and a potential clinical efficacy signal that represent - would represent a transformational product profile in PMS, we will then go, of course, not only to pursue that in PMS, but also in other types of MS.

And your next question comes from the line of Ben Burnett from Stifel.

This is Kellie Breza on for Ben Burnett. My first question is just pertaining to tab-cel. And I know that you guys are looking to do a Phase II multi-cohort study that includes up to 6 additional ultra-rare EBV+ patients. I was wondering if you could provide any additional color pertaining to disease severity, patient population size relative to PTLD.

Yes. I think clearly, this study that we are doing is intending to expand the tab-cel label beyond second line PTLD and to address a serious unmet need in patients with EBV+ disease. This study is planned with up to 6 additional cohorts, creating the possibility for additional indications or even potentially to discuss a broader mechanistic label. And this is based on experience that we have both ourselves at Atara with our EAP and single patient use as well as our collaborators at Memorial in earlier studies, that we have some clinical data in this type of patients. So we are building upon this clinical data to move forward in this multi-cohort study. Each of these cohorts represents ultra-rare conditions. But collectively, they represent a potentially addressable EBV population - EBV+ population several times greater than the size of the second line EBV+ PTLD. And there are different types of disease that we are exploring there in the patient population; some are related to immunodeficiency lymphoproliferative disorders like primary immunodeficiency LPD and also acquired immunodeficiency LPD. We are also going to explore LMS, leiomyosarcoma, for which we had presented data in the past, as well as first-line EBV+ PTLD for patients where current first-line treatment is inappropriate and first or second line, CNS-PTLD. So as you can see, a range of different types of patient populations. And altogether, these represent significant commercial potential, if we are successful, and a population that is several times greater than the size of the second line EBV+ PTLD, which is the first indication that we are pursuing.

Great. And then if I can have one more question. I had a question regarding ATA2271. What is gating for the mesothelioma IND? And are there any plans to develop this in additional solid tumors outside of mesothelioma?

Thank you for your question. So as we said, there will be the presentation of some preclinical data from the IND-enabling studies that will have been accepted as the late-breaking poster at AACR, and the abstract will be released on May 15. And these are part of the package that we need our collaborators, who are going to - at MSK, we are going to submit that IND needs to submit the IND. All the data and all the studies have been done now, so it is just more of moving into the preparation of the submission. And that is why we are confident that this IND submission should be able to be done in Q2 or Q3 2020. Now in terms of this first study, it will be addressing advanced mesothelioma. But we have the plan to go in other types of solid tumors, where you have high expression of mesothelin, in particular, ovarian cancer and pancreatic cancer.

And your next question comes from the line of Tony Butler from Roth Capital.

Really three very brief questions. Number one is when you think about the 188 Ia study, they are - in the open-label portion, there is retreatment. And I'm curious if, potentially, there will be some retreatment data that will also be presented at EAN. That is question one, and I will finish the other two very quickly, if I may. The second is with respect to the Ib study of 188. I think currently, you have nine sites open. Because you have paused the Ib study, will you then decide to create a greater number of sites in order to speed up that enrollment opportunity? And then finally, on the CAR programs on 7119, your programs, do you think - or is it a goal to file INDs for those in this calendar year? Or is that more a 2021 event?

Thank you, Tony. AJ, do you want to take the first two questions? I will take the last one.

Sure. So with respect to the Ia long-term extension patients, just a quick reminder, we chose the dose for that long-term extension based on the cohort three data. So if you recall, once we achieve the pre-specified endpoints of the Phase Ia to move into the RCT, we did that based on the Phase III cohort dose. So that became the dose that we used for the open-label extension. So it may - so because of that, we have treated several patients actually, and we have begun to treat them in the open-label extension. But they are not far enough along to present at the EAN. So we will ultimately present those data, but they are not going to be available for the EAN discussion. And in terms of your question on adding additional sites to try to catch up on the RCT, the good news for us is although we paused the actual enrollment, we were able to continue the pre-screening activities. So we do have several patients lined up for those studies once we are able to resume full enrollment activities. So I don't really anticipate needing to add additional sites.

We lost you. So if you can start, you are explaining what is happening in the current time where we paused, but we are still active in preparing the site. I guess that is what you wanted to say.

Yes, I apologize for the connection issue. We have been actively pre-screening patients for the studies and have several lined up so that once we resume enrollment activities, we can put them through the full screening process. Because of this, I don't expect to need to add more sites. We anticipate resuming enrollment activity soon in this study. Given the variability caused by COVID-19, we have maintained strong relationships with the sites. Our plan is to work on a site-by-site basis to get them started up again quickly. We have a checklist to ensure that the sites can perform all the necessary assessments and that they have the required staff, facilities, and equipment. As long as we can meet that checklist, we will be able to resume enrollment at those sites soon.

Team, we have initiated the IND-enabling study and are making steady progress toward bringing this exciting asset into the clinic. We are not currently disclosing the timing of the IND filing, but we will share that information soon.

And your next question comes from the line of Maury Raycroft from Jefferies.

This is Brice on for Maury. I guess a couple of quick questions. For the IND-enabling studies on the ATA2271, do you expect to include like nonhuman primates later? Or if you can provide some more perspective into what to expect.

I think his line is disconnected, and he's dialing back in now, one moment.

This is AJ Joshi. Sorry for the technical issues. I think I've just been able to get back in. Eric, are you on?

It looks like they have him, and about to put him in.

Okay. I was going to say maybe what we can do is, moderator, do you know where we got lost? Was it in the middle of my response on the MS, so I can continue that while we wait for others to join back in?

I think it might be, AJ. I think it was when I was starting to answer on ATA3219. So maybe you can start there. Can I start, operator?

Yes, go ahead.

I’m very, very sorry. I really apologize for this technical issue. So I'm going to go back to the questions from Tony on 3219. As I said, at this stage, we are working actively on the IND-enabling studies, but we are not going to say when is that going to be filed. We will do that at the appropriate time. However, I would like to say that this program, we believe, is very exciting because this field of CD19 CAR T is well-known in terms of the level of safety and efficacy achieved by autologous CAR T at this stage. And we believe that we, in going as fast as we can in the clinic, can really deliver a proof-of-concept of our platform in terms of its ability to deliver safe and effective allo CAR-T. But at the same time, if due to the specificity of the allo platform, particularly. So the EBV T cell and 1XX have a unique co-stimulatory domain that impacts the persistence and efficacy of the T-cells having less exhaustion of the T-cells, this might lead to superior activity in patients. And in that case, of course, that will create a very significant value for that product. Does it answer your question, Tony?

And your next question comes from the line of Brice from Jefferies.

This is Brice on for Maury. So the first question is for the ATA2271 program. Are you going to have nonhuman primates data included there as well that you are going to present?

For ATA2271, the mesothelin autologous CAR T, that is the one you are asking about?

Yes.

Okay. So the IND-enabling studies are mostly in vitro and in vivo studies that are needed as well, of course, CMC package that is needed for the FDA to review through the IND process. So the data that will be presented are related to in vivo preclinical studies. And I'm not going to give any more detail at this stage as the abstract is going to be released very soon.

Okay. That is fine. For the MSK data previously, the off-the-shelf EBV CD19 data, so it lacked many specifics on the CAR-T expansion persistence area. So did you get a chance to evaluate the peripheral and the marrow samples from the 10 patients?

So this is, as you know, an academic study. And the data they presented at the TCT meetings with - by the way, on the 6 patients that were treated with these third-party donor cells modified with CD19 CAR, have been quite clear in terms not only of the level of response with 5 out of 6 in CR but the durability of response for a median follow-up of 26.9 months, so the longest ever for an allo CAR T. Now we don't have a - need MSK data at this stage on the kinetics of the cells. These are the type of data analysis that hopefully they will be able to do in the future based on the samples they have. But we don't have these data available at this stage.

Okay. That is fine. The other question is for the ATA188. Can you recap the redosing plan strategy and insight about how the redosing is going?

Yes. Thank you for your question. AJ, do you want to answer this one?

Sure. So the redosing plan is when patients come due for redosing. That is essentially we have left a relatively open window, but it is after the 12-months' time point, so it usually hit anywhere between 12 and - I think we leave a window of about 12-months to 24-months because that allows some of the earlier cohort patients to be re-treated. But the goal was to re-treat as close to that 12-month time frame as we can. And it is basically a 1-cycle treatment at that point. So it would be day one, day eight, day 15, you get doses of ATA188. And the goal is going to be that we are going to continue annual treatments on these patients all the way through to five years of follow-up from the initial study entry.

And your next question - and your last question is from Salveen Richter from Goldman Sachs.

This is Andrea on for Salveen. Maybe just one question on tab-cel. As you have seen an increasing number of clinical sites come online, particularly in Europe, has this provided any additional insights into the potential market size opportunity?

Thank you for your question. As you know, we are working on opening new sites in Europe in various countries. And we do so once we have obtained, of course, the CTA approval. And this has been obtained in four countries right now, the U.K., Austria, Spain, and France. So we are working in these four countries on active opening and activating sites. And as we said earlier on, we have just activated the first European site in Spain very recently. So things are progressing there, but I guess your question is about the medical need and the patient population. And when we discussed with European experts, they clearly told us that there is a medical need. They have patients that don't have options for treatment today, and they are very eager to get access to tab-cel. So we see that in terms of the clinical trials, but also we plan to open, as we have done in Australia and the U.S. in parallel to our clinical trials, a compassionate use program, which is a different system than the EAP but similar in different European countries, which is to be able to address the need of patients that, for whatever reason, cannot be enrolled in the study. So we clearly see strong demand there from these sites in terms of having access to tab-cel and we are getting ready to be able to deliver tab-cel to them either through the clinical pivotal study or for compassionate use, because they have many patients waiting for transformative treatment for their very severe and rapidly progressing disease. No further question?

That concludes our question and answer session for today. Thank you for joining the Atara Biotherapeutics First Quarter 2020 Financial Results Conference Call. You may now disconnect your line.