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Atara Biotherapeutics Inc (NASDAQ:ATRA)
Q4 2019 Earnings Call
Feb 27, 2020, 8:00 a.m. ET

Contents:

  • Prepared Remarks
  • Questions and Answers
  • Call Participants

Prepared Remarks:

Operator

Good morning, ladies and gentlemen and welcome to the Atara Biotherapeutics Q4 and Full Year 2019 Financial Results 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.

[Operator Instructions]. I would now like to turn the conference over to your host, Dr. John Craighead, Vice President of Investor Relations and Corporate Communications of Atara Biotherapeutics. Please go ahead.

John Craighead -- Vice President, Investor Relations & Corporate Communications

Thank you, operator. Good morning everyone and welcome to Atara's fourth quarter and full year 2019 conference call. On today's call, we will provide an update of our clinical, operational and strategic progress as well as review our upcoming milestones and key objectives for 2020. Earlier this morning, we issued a press release providing an overview of the company's fourth quarter and full year 2019 financial results. This press release and an updated investor presentation are available in the investor and 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; and Joe Newell, Chief Operations Officer; and Dr. AJ Joshi, Chief Medical Officer. We'll begin with prepared comments from Pascal and then open the call for your questions.

We'd 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'd like to turn the call over to Atara's President and Chief Executive Officer, Pascal Touchon.

Pascal Touchon -- President and Chief Executive Officer

Thank you, John. and thanks to all of you for joining us this morning. 2019 was a year of strategic prioritization and significant advancement of our T-cell immunotherapy programs. I would like to highlight that we've made important progress on our four strategic priorities. We have also extended our cash position into Q2 2021 and we continue to leverage our tab-cel experience to advance our innovative off-the-shelf T-cell immunotherapy platform.

Building on the significant progress and momentum, let me start by reviewing the recent highlights and anticipated milestones for tab-cel. We are currently conducting a Phase 3 clinical trial with tab-cel in patients with Epstein-Barr virus or EBV associated post-transplant lymphoproliferative disease or PTLD in the relapsed/refractory setting. Atara remains on track to initiate the tab-cel BLA submission to the FDA in the second half of 2020. We're currently at 38 sites in the United States and Australia actively enrolling patients and are preparing to open additional sites in the US, Canada and Europe. Toward this end, we submitted clinical trial application or CTA to several European countries in November and December of 2019 which will allow us to open clinical sites in Europe in 2020. We are excited as we recently received CTA approval in the UK, Austria and Spain. These additional sites are being added to support full enrollment of the Phase III study whether they are not necessary to meet the number of patients required for the planned Phase 3 interim analysis. Indeed as I just mentioned, we continue to be on track to initiate a tab-cel BLA submission for patient with EBV positive PTLD in the second half of 2020.

We plan to hold the pre-BLA meeting with the FDA prior to this submission, during which we will discuss the totality of tab-cel data we and our academic collaborators have generated including, the Phase 3 HCT and SOT cohorts, MSK Phase 2 studies and our expanded access program. As a reminder, we most recently presented data from this EAP in December 2019 at ASH Annual Meeting. These data comprised long-term clinical results for 61 patients with diverse EBV-associated disease, including efficacy and safety data for 26 patients with relapsed-refractory EBV positive PTLD and safety findings for 35 patients with other EBV-associated disease. The data demonstrated that tab-cel was generally well-tolerated in all patients participating to the study. Importantly, in the subgroup of 22 patients with EBV positive PTLD would have likely met eligibility criteria for the ongoing tab-cel Phase 3 study, the overall response rate for the HCT cohort was 55% with a two-year estimated overall survival of 79%.

For the SOT cohort, overall response rate was 82% and two year estimated overall survival was 81%. We also engaged in multiple activities designed to expand access to tab-cel for patients in Europe. Atara recently submitted a Pediatric Investigation Plan or PIP to EMA. Following EMA approval of the PIP, Atara plans to submit tab-cel EU marketing authorization applications for patient with EBV positive PTLD in 2021. The clinical data generated to-date with our EAP and SPU programs also support the potential of tab-cel as a transformative therapy in several other EBV-associated disease. In the second half of 2020, we expect to initiate enrollment of a tab-cel Phase 2 multi-cohort study including up to six additional ultra-rare EBV positive diseases. In addition, we have enrolled the final planned patients in the Phase 1b portion of the Phase 1b/2 clinical study of tab-cel in combination with anti-PD-1 therapy in patients with platinum-resistant or recurrent EBV-associated nasopharyngeal carcinoma, NPC. Prior to starting the Phase 2 portion of the study, we will evaluate the initial results of the Phase 1b as well as a relapsed/refractory NPC clinical landscape.

I will now turn to ATA188, our allogeneic T-cell immunotherapy for the treatment of patients with progressive multiple sclerosis. Recall that ECTRIMS 2019, we reported encouraging early data from Phase 1a multi-center open-label dose escalation study evaluating the safety and efficacy of ATA188 in patients with progressive form of MS. Safety results showed that a course of full dose of cohort, ATA188 was well-tolerated in patients with progressive MS. We reported at six months follow up in the lowest dose cohort, one of six patients with clinical improvement using the criteria we define at ECTRIMS. This improvement was also maintained at 12 months.

In cohort 2, two out of six patients, reached clinical improvement at six months. We recently selected the cohort 3 dose to initiate the randomized, double-blind, placebo-controlled Phase 1b part of this study. Our decision to initiate the Phase 1b was based on achieving in cohort 3 a predetermined criteria of an acceptable safety profile and three out of six patients achieving clinical improvement at six-months for more than one clinical study site.

Looking ahead, we expect to present updated clinical data at appropriate forms, including six month follow-up for all cohorts in Q2 2020 and 12-month follow-up for all cohorts in the second half of 2020. Additionally, we recently retreated the first patients in the open label extension portion of the phase 1a study, which is designed to allow patients to complete one year in a dose escalation portion of the study to be retreated annually using the cohort 3 dose for up to four years. We are also on track to initiate a whole month of the randomized, placebo-controlled Phase 1b ATA188 study in the second or third quarter of 2020. Site activation for this study is in process and we are expecting an increased number of leading MS centers to participate in the U.S. and Australia. In addition, Atara leading experts recently published review article in trends in molecular medicine regarding the mechanistic connection between EBV infection and MS.

Now, let's discuss our EBV CAR T platforms. At the 2020 Transplantation and Cellular Therapy Meeting last week, an academic team presented a clinical study in patients with relapsed/refractory B-cell malignancies treated with an off-the-shelf allogeneic CD 19 CAR T made from primary donor or partially HLA matched third-party donor EBV T cells. In this first in-human study with this EBV CD19 CAR T cells, investigators observed durable complete responses from five patients out of six patients who received partially HLA matched EBV CD19 CAR T cells manufactured from third-party donors. No cytokine release syndromes or neurotoxicity above Grade 2 and no dose limiting toxicities were observed post-infusion with multiple EBV CD19 CAR T doses. Also no confirmed GvHD was observed in patients who received third-party donor EBV CD19 CAR T cells. Importantly, investigators also observed durable complete responses with median follow-up of 26.9 months for 5 out of 6 patients who received partially HLA matched EBV CD19 CAR T cells, manufactured from third-party donors including four out of four responses in patients with NHL, one out of one response in patients with CLL, and 100% survival with NHL and CLL. Findings from the study provide initial clinical proof-of-principle that an EBV T-cell platform has the potential to generate off-the-shelf allogeneic CAR T immunotherapies with high and durable responses, low risk of toxicity and rapid delivery to patients. We continue to make progress in advancing of multiple CAR T therapy candidates. We expect that our collaborators at MSK will submit.

In IND to the FDA in the second or third quarter of 2020 for ATA2271, an autologous mesothelin-targeted CAR T in patients with advanced mesothelioma. This program incorporates next-generation technologies, including a novel co-stimulatory domain 1XX that may offer greater persistence and more physiologic T cell signaling as well as a BD1-dominant negative receptor that is designed to provide intrinsic checkpoint inhibition and unlock the solid tumor microenvironment.

Furthermore, we have started pre-clinical IND enabling studies for ATA3271, an off-the-shelf allogeneic EBV mesothelin targeted CAR T with the same next gen CAR T technologies as ATA 2271. In addition, we have started pre-clinical IND enabling studies for ATA 3219 and EBV CD 19 targeted CAR T that incorporates 1XX. We believe Atara's off-the-shelf allogeneic EBV CAR T platform is differentiated and has tremendous potential as an engine for continued innovation, leveraging favorable EBV T cell safety expansion trafficking and persistence characteristics. Our dedicated facility in Thousand Oaks has the flexibility to produce multiple T-cell and CAR T immunotherapies and integrates preclinical and translational research, process science, quality control and regulatory CMC capabilities under one roof.

Such close integration enables a rapid development and scaleup of all those manufacturing processes to support our potential, current and future clinical and demand. The efficiency for manufacturing platform capabilities has recently been demonstrated with significant improvement in our manufacturing yield with tab-cel. Our commercial stage process is now enabling us to make over 400 doses from a single donor leukapheresis. Over time, we believe our commercial manufacturing process will allow for cost of goods profile similar to those of biologics. In addition, with lead program already in Phase 3 and T-cell manufacturing commercial validation activities progressing well, we are creating a significant competitive advantage for Atara in off-the-shelf allogeneic T cell immunotherapy. Not surprisingly, we are seeing a strong level of interest from potential partners to access off-the-shelf T cell platform and we also see opportunities for potential partnership with the current product portfolio.

On the operational front, earlier this month, we are pleased to welcome Kristin Yarema as our new Chief Commercial Officer. Dr. Yarema brings extensive hematology, oncology, neuroscience and autoimmune disease commercialization experience to Atara, which are very valuable as a company advances commercialization activities for tab-cel. We also created a Chief Operations Officer to continue to drive operational excellence across the company program and platform and I've appointed Joe Newell Atara current Chief Technical Operations Officer to this new role.

Turning to our financial positions, we extended our cash runway into the second quarter of 2021. We ended 2019 with cash, cash equivalents and short-term investments totaling $259.1 million as compared to $282.9 million as of September 30, 2019. Of note, pro forma cash and investments as of December 31, 2019 including ATM and option exercise proceeds from January 2020 was $282.7 million.

In closing, the progress we made in 2019 has positioned us well for tremendous success this year, delivering on key milestone for tab-cel, our lead pipeline candidate, and further advancing other promising programs with the hard work of all Atara's employees.

I'll no turn the call back to the operator to begin the Q&A portion of the call. Operator?

Questions and Answers:

Operator

[Operator Instructions] Your first question comes from the line of Phil Nadeau with Cowen & Company. You may ask your question.

Phil Nadeau -- Cowen & Company -- Analyst

Good morning. Thanks for taking my questions and congrats on the progress. Just a couple on tab-cel. First, since you're guiding to having a pre-BLA meeting in the second half of this year and starting the filing even later in the second half this year, it would seem that you've sufficiently enrolled enough patients for the interim analysis. Is that accurate?

Pascal Touchon -- President and Chief Executive Officer

Thank you, Phil, for your question. We are not making any comment on the enrollment at this stage and we are confirming our guidance that we plan to initiate filing of the BLA in the second half of 2020 following a PBLA meeting with the FDA, where we'll present the totality of data.

Phil Nadeau -- Cowen & Company -- Analyst

And what's your most recent thinking on when you'd publicly release the data from the interim analysis? Is that likely to happen with the filing or would it be sometime later?

Pascal Touchon -- President and Chief Executive Officer

As we said, we plan to, of course, present these data on the study at an appropriate congress, but we do not intend to do that before the filing and we want to preserve the integrity of what is an open clinical study where we will start to initiate a filing with an interim analysis of the data. So, we will certainly discuss with the FDA during a pre-BLA meeting what is the best way to be able to communicate these data in due time, but at the same time, the initiation of the BLA filing by itself is a material event. So we will indeed communicate publicly that we have initiated the BLA filing.

Phil Nadeau -- Cowen & Company -- Analyst

Great. And last question for me is on the requirements for completing the filing and starting the PDUFA time clock. Do you think you'll be in a position to clarify what those requirements are at the time of the BLA filing, at the time of the initiation of the filing or we'll -- even more in subsequent discussions happening with the FDA once initial filings are made as to exactly what will be necessary to get the PDUFA time clock started?

Pascal Touchon -- President and Chief Executive Officer

When we will communicate about the initiation of the BLA filing, we will be hopefully able to give more details on that particular BLA filing and hence about what is the anticipated time of completion.

Phil Nadeau -- Cowen & Company -- Analyst

Got it. Perfect. Thanks for taking my questions.

Operator

Your next question comes from the line of John Newman with Canaccord. You may ask your question.

John Newman -- Canaccord -- Analyst

Hi guys, good morning. Thanks for taking my question. Just curious, it sounds like you have been adding additional trial sites for tab-cel. Just wondering if you have a target number in mind, the total number of sites that you would like to have open and actively enrolling patients.

Pascal Touchon -- President and Chief Executive Officer

Thank you, John, for your question. AJ, do you want to take that one?

Manher Joshi -- Senior Vice President, Chief Medical Officer

Sure. So I think, first off, we have as you know, we have 38 sites open in the US today and it's important to note that those 38 sites are the number that's necessary to achieve that interim analysis time point so that we can have the initiation of the BLA in the second half of 2020. In terms of Europe, Canada and other sites, I can give you a general sense that in Europe, we would enrolled probably up to about 24 sites.

John Newman -- Canaccord -- Analyst

Okay, great. And then, in terms of the data that are coming this year for ATA188 in MS, how should we be thinking about kind of the key points from that data? I know that you have sort of a different way of looking at the efficacy, based on a composite. Just curious as to how we should be thinking about the efficacy when you give us data with the six-month and 12-month follow-up there?

Manher Joshi -- Senior Vice President, Chief Medical Officer

Sure. So, in the first half of 2020, we should expect six months data on all four cohorts and then also 12 months data on the first three cohorts. We've talked about the types of analysis that we do in the initial -- the way we describe the initial data was really meant for signal seeking and making decisions about the trial and as you know, we've achieved our goal in the Phase 1 study which is safety and the decision to move forward with the cohort 3. We do expect to present some additional composite disability measures in that first half 2020 time frame as well as the second half.

John Newman -- Canaccord -- Analyst

Okay, great. Thank you.

Operator

Your next question comes from the line of Matt Phipps with William Blair. You may ask your question.

Matt Phipps -- William Blair -- Analyst

Good morning. Yeah, thanks for taking my questions. First, I guess, follow-up on Phil's question. So, really the next kind of material disclosure we get on tab-cel then would be the initiation of the rolling submission. Is that correct or could there be a material update ahead of that?

Pascal Touchon -- President and Chief Executive Officer

So, our current plan is, as I say, to communicate what we believe will be a material update, i.e. the initiation of the BLA filing in the second half of 2020.

Matt Phipps -- William Blair -- Analyst

Got it thanks. And then just two other questions on the pipeline. I guess, you mentioned the final patient was enrolled in the nasopharyngeal carcinoma study. Is it possible we see results later this year or is that something for early '21? And then, I realized this is an investigator-sponsored study, but do you anticipate MSK providing an update on the first-gen mesothelin CAR at some point this year? I know they've have been enrolling patients beyond mesothelioma as well. So, just curious if you've had any discussions with them on their plans there.

Pascal Touchon -- President and Chief Executive Officer

Thank you, Matt. First question, AJ?

Manher Joshi -- Senior Vice President, Chief Medical Officer

Sure. So Matt, regarding the NPC study, we've enrolled as you indicated, we enrolled the final patient in the Phase 1b portion of the study and our anticipation is we're going to evaluate the results and actually the entire NPC landscape, because as you know, that whole treatment landscape has been evolving. So, as the results mature and we assess the landscape, we'll then make decisions as to the appropriate forum to present those assessments.

Pascal Touchon -- President and Chief Executive Officer

And second question regarding the first generation mesothelin CAR T, as you say, this is an investigators initiated study. What we understand is that the investigator is continuing to follow up these patients and are also including additional patient in that study. It is, we understand, the intent of the investigator at the appropriate stage to communicate further results of that study in a congress. We cannot comment at this stage on which one or when exactly that will occur, but that's certainly the plan of the investigator.

Matt Phipps -- William Blair -- Analyst

Got it. Thanks for taking my questions.

Operator

[Operator Instructions]. Your next question comes from the line of Salim Syed with Mizuho Securities. You may ask your question.

Salim Syed -- Mizuho Securities -- Analyst

Hey, guys. Thanks so much for taking my questions and thanks for all the color as usual. Just a few from me on the multiple sclerosis program. AJ, did I hear you correctly in saying that we're going to be getting 12-month data either at AAN or EAN for the cohort 3?

Manher Joshi -- Senior Vice President, Chief Medical Officer

So, in terms of 12-month data in the first half of 2020, absolutely, we would be getting 12-month data through cohorts 1 through 3.

Salim Syed -- Mizuho Securities -- Analyst

Okay. For all six patients in that cohort?

Manher Joshi -- Senior Vice President, Chief Medical Officer

Yes.

Salim Syed -- Mizuho Securities -- Analyst

Okay. So when we're thinking about ATA188, I know this was something that came up at ECTRIMS last year. Are you guys still thinking here that we're going to need 12 months data for investors to really diligence the ATA188 efficacy profile or will six months data be enough when we're going into AN and EAN where we present the data? Will that be enough of a time duration to diligence this data set?

Manher Joshi -- Senior Vice President, Chief Medical Officer

I think when you take a look at -- certainly in all MS studies, you'd like to see some duration of response. So, like, everything else, 12 months is better than six months. When we talk about the ultimate proof of concept that certainly is going to come at the one-year end point of the Phase 1b randomized portion, but certainly the 12-month data off of this portion of the study would provide good additional support I think.

Salim Syed -- Mizuho Securities -- Analyst

Okay and lastly from me, on the redosing for multiple sclerosis, are you guys expecting upon redosing the one-year time point and the two-year time point further improvement in this ability or some sort of plateauing?

Manher Joshi -- Senior Vice President, Chief Medical Officer

Syed, we don't really have data to suggest one way or the other. Obviously, we'd love it if we have further improvement, but I think the most important thing is whatever improvement we achieve, if you're able to maintain that, that is already a major win in progressive MS. So, that should be our baseline that we work off of.

Salim Syed -- Mizuho Securities -- Analyst

Okay, excellent. Thanks so much.

Operator

Your next question comes from the line of Ben Burnett with Stifel. You may ask your question.

Ben Burnett -- Stifel -- Analyst

Hi, thanks for taking my question. So, this is a question regarding CAR T. So, how has the Memorial Sloan Kettering study impacted your thinking on lymphodepletion and whether or not this needs to be done and to what extent you think this could be done in the outpatient setting?

Pascal Touchon -- President and Chief Executive Officer

Thank you for your questions. I think, as you know, this study that was presented last week is an academic study in 10 patients and that study has gone for some time with different type of lymphodepleting regimen using these patients. So, we do not think we can draw a conclusion right now on what will be possible, if any need for depression regimen for ATA3219. This is something that we plan to study in a first-in-human study. One of the -- what we are going to do is to work with MSK on this particular offset of data that they have and more particularly on samples that they have of blood marrow and blood to be able to better understand the expansion and persistence of the EBV CAR T CD19 T cells in these patients and see whether there is any relationship whatsoever with the lymphodepleting regimen that they've had. So, that will be informative for us as we design the protocol of our first in-human study with ATA3219.

Ben Burnett -- Stifel -- Analyst

Okay, perfect. And then just one more question on ATA2271. What's gating for the mesothelioma I and D submission and are there any plans to develop this in addition and solid tumors outside of mesothelioma?

Pascal Touchon -- President and Chief Executive Officer

So, thank you. There is no particular gating. It's just the time needed to put together all the data. Things are -- on site progressing well, and of course there will be the time then to submit that IND. As we said, it will be done by our collaborators at MSK in the second or third quarter of '20. Now, the first-in-human with these very innovative construct of CAR T is going to be in advanced mesothelioma, but we are already discussing with investigators about the possibility to use this construct, this new CAR T in other type of solid tumors that are over expecting mesothelin and particularly so ovarian cancer and pancreatic cancer.

Ben Burnett -- Stifel -- Analyst

Okay, perfect. That's all my questions. Thank you.

Operator

Your next question comes from the line of Anupam Rama with JP Morgan. You may ask your question.

Tessa Romero -- JPMorgan -- Analyst

Hi guys. Good morning. This is Tessa on the call today for Anupam. Thank you for taking my questions here. Perhaps, I could ask about your most up-to-date thoughts on the market size for the initial EBV positive relapsed/refractory PTLD indication in the US and then maybe ex-US as well in key geographies and then how are you thinking about sort of the size and scope of sales infrastructure to sort of address the patients globally. Thanks so much.

Pascal Touchon -- President and Chief Executive Officer

Thank you very much for your question. So, as we already indicated, we believe that in the US, the setting of our studies that could lead to a potential indication in relapsed/refractory PTLD is around -- it's an ultra-rare disease, which means that we believe there are several hundred patients in the US that could benefit potentially from tab-cel. We believe also that a similar number exists in Europe and also a similar type of number exists in the rest of the world beyond the United States and Europe. So, this is an ultra-rare indication. This is our first indication for tab-cel that we hope will be followed by several other indication.

As we confirme today, we are going to start in the second half of 2020 and holding the multi-cohort with up to six type of ultra-rare disease that could lead to up to six additional indications there that are going to increase the size, we believe, by at least a factor of 4 of population that could be treated efficiently by tab-cel. In terms of the commercial organization that is needed there, with this being an ultra-rare disease, and having no other treatment approved today for the disease, we believe that the commercial organization that will be needed to make sure that patient can access tab-cel is of limited size. It will be typical of an ultra-rare disease type of commercial organization.

Tessa Romero -- JPMorgan -- Analyst

Okay, great. Thank you so much for taking our questions.

Operator

Your next question comes from the line of Maury Raycroft with Jefferies. You may ask your question.

Dykin -- Jefferies -- Analyst

Hi, good morning. This is Dykin [Phonetic] on for Maury. So, the MSK data looked quite promising, especially on the overall survival aspects, but how confident are you that non-standard conditioning lymphodepletion contributed to the survival benefit?

Pascal Touchon -- President and Chief Executive Officer

So again, this study is, we believe, clinical proof of principle that the EBV-based CD19 CAR T allogeneic off-the-shelf as the six patients where the cells were coming from third parties donors are demonstrating is feasible, is safe and is effective. Now, there are a limited number of patients. We recognize that, as well as different type of disease, but altogether, the comprehensive nature of these data are clear clinical proof of principle that allogeneic off-the-shelf CD19 EBV CAR T again safe and effective, and we are particularly encouraged by the long-term durability of the response.

If you think about five patients out of six patients with CR and this CR being durable with in fact survival following the follow-up of 26.9 months survival of 100% in the patient with NHL and CLL. These are very encouraging data about the effect of this allogeneic off-the-shelf EBV CD19 CAR T.

Dykin -- Jefferies -- Analyst

Thank you. And have you considered like what conditioning regimen and variables you are going to do in your ATA run study and which ones you should focus on?

Operator

First of all, what we're going to bring to the clinic is a different product. This is a ATA3219 which is also based on EBV T-cells, but using Atara on process and especially using a new co-stimulatory domain 1XX, which is there to bring potentially increased persistence of the cells and less exertion of the T-cells. So that's a different product, but of course we'll be informed in our first-in-human study protocol and follow-up by the experience that these academic team has obtained with this construct, which is again a different product from ATA3219, but that's why we say that this is a clinical proof of principle, but ATA3219 is really the product we are supporting the development of. We have started as we say, pre-clinical IND enabling studies for that product to bring it the clinic as soon as possible and to be able to prove the concept of our EBV T cell CAR T platform and the ability to treat patients safely, effectively with another off-the-shelf treatment that could be available within days to patients.

Dykin -- Jefferies -- Analyst

Thank you.

Operator

Your next question comes from the line of Tony Butler with Roth Capital. You may ask your question.

Tash Hasan -- Roth Capital -- Analyst

Hey, good morning. This is Tash dialing in for Tony here. Just quick question on 3219 in continuation of your latest comment. Based on the learnings from the TCT Congress data, do you have any specific plan as to what kind of population that you will be targeting, let's say, CLL, NHL versus ALL?

Pascal Touchon -- President and Chief Executive Officer

We are not communicating at this stage what will be the protocol and the type of patients we'll address first-in-human, but we'll do so at the appropriate time. Clearly, we believe that there is a medical need today that still exists in the population of NHL patients, CLL patients, ALL patients. We will have ourselves to decide at the time we enter the clinic where we want to focus, but we believe that ATA3219 has a potential to bring significant benefits to patients.

Tash Hasan -- Roth Capital -- Analyst

Thank you. That helps.

Operator

Your next question comes from the line of Yigal Nochomovitz with Citi. You may ask your question.

Samantha Semenkow -- Citi -- Analyst

Hi, this is Samantha on for Yigal. Thanks for taking our questions. I wanted to sort of build on a prior question on the EBV CAR T study presented at TCT. Can you talk about any other differences outside of the 1XX stimulatory domain that AT319 will have versus the CAR Ts used in that study and with these differences between the two products what should we think about the read-through in terms of the data that was presented there and the differences you think might show up in your clinical program?

Pascal Touchon -- President and Chief Executive Officer

So a few things. First of all, what we're doing with ATA3219 is to develop a product through a proper manufacturing process and development phase. So, this will not be an academic type of study. It will be Atara study developing that particular product. And the difference is that we anticipate at this time is mainly the difference in co-stimulatory domain, as well as in the manufacturing process to have a product that not only allows us to prove in the clinic potentially, safety, efficacy and persistence and durability there, but also this is helping to build a platform of AlloCAR T. As you know ATA3219 is just one of the allogeneic EBV based CAR T that we are developing and advancing that through pre-IND enabling studies, IND first-in-human is going to help us to continue to progress with our platform. We've made significant progress about it and we're going to leverage that progress. So, two key differences will be 1XX and manufacturing process, and we believe that in particular 1XX is going to bring some significant potential advantage in preclinical studies, this particular co-stimulatory domain as shown that is indeed inducing less exertion of the T-cells and more persistence. So, that's something that is certainly going to bring some potential benefits and at the same time, the fact that we built a robust manufacturing process, allowing us not only to make allogeneic CD19 CAR T based on EBV T cells, but other type of allogeneic CAR T based on the EBV T cells will be something very important there.

And there was some particular details in the presentation of the academic team last week. Just to give you an example, the level of CAR T cells transfixion that we had at 20.5% is something that we believe can and is to be improved by our manufacturing process, as well as the yield, the possibility to make significant number of doses from one leukopak. As you know, recently we've announced that the tab-cel, which is at the beginning, the same type of process where we harvest cells from healthy donors, we select and activate these cells. We are now able to make 400 doses from one leukopak. So this type of efficiency of a manufacturing process is what we want to see in the manufacturing of ATA3219 and the preclinical stage, we are at right now is indicative that we are on the right track in terms of making not only rapidly bringing the product to the clinic, but also making manufacturing this product in a very efficient way.

Samantha Semenkow -- Citi -- Analyst

Got it. Thank you for all that detail. Very helpful. But that's sort of leads into my other question, when we think about your CAR T pipeline long term, should we anticipate using the EBV CAR T platform that you mentioned you're building out here? And you had a comment about partnering potential. Is it this platform that you're thinking about versus say like the partnership with MSK for the ATA2271?

Pascal Touchon -- President and Chief Executive Officer

Thank you for your question. So, clearly our current pipeline in CAR T in terms of strategic priorities is having two allogeneic CAR T-based on EBV T cells ATA3219 that is in preclinical IND enabling studies and ATA 3271 the mesothelin targeted allogenic CAR T that is also in preclinical IND-enabling studies. So these are the two that are the most advanced. We have also activities with our collaborators at Memorial Sloan Kettering as well as at Moffitt Cancer Center in Tampa where at the earlier stage, we have some exciting type of CAR T that are being developed and these are developed first by these academy collaborators as autologous CAR T and once we are moving into a full development, we are going to, as usual, develop an allogeneic version, based on EBV T cells. What we've built is a true allogeneic CAR T platform, based on these EBV T cells, and this is an allogeneic CAR T platform that benefits from the work we've done on tab-cel as well as the work we're doing on ATA188.

So, there is a clear correlation between these. We have the most advanced allogeneic T cell immunotherapy with tab-cel as it is now in Phase 3 and we don't know any others that is in Phase 3 at this stage right now. We have a robust manufacturing process there. We're going to leverage that and that's what we're doing every day. Our team is doing every day and our manufacturing unit, leveraging that experience to make robust and efficient process for allogeneic CAR T, based on EBV T cells.

Getting your question on partnering, as we said, we have a very advanced platform for allogeneic CAR T. So, that's why there is strong interest regarding the possibility to partner with around this platform to be able to develop, create, develop and make allogeneic CAR Ts and the same time, we also open to discussion on partnering other assets of our pipeline.

Samantha Semenkow -- Citi -- Analyst

Got it. Thanks very much for taking the question.

Operator

I'm showing no further question at this time. I would now like to turn the conference back to Pascal Touchon.

Pascal Touchon -- President and Chief Executive Officer

Thank you very much, operator. So, thank you very much for being there today for conference. Clearly, we are making significant progress. This is an exciting time for all of us at Atara and I'm very pleased to have had the opportunity to review recent accomplishments and discuss our upcoming milestone for 2020. We have a great deal of momentum coming into 2020 and I look forward to updating you on our continued progress in the months ahead. We aim at transforming the lives of many patients in need across various serious disease and this is possible only through the contribution of many individuals to whom we are very thankful including our shareholders, our committed employees, our clinical investigators, our academy collaborators, and of course, all the patients that are participating in our studies. Thank you very much.

Operator

[Operator Closing Remarks]

Duration: 45 minutes

Call participants:

John Craighead -- Vice President, Investor Relations & Corporate Communications

Pascal Touchon -- President and Chief Executive Officer

Manher Joshi -- Senior Vice President, Chief Medical Officer

Phil Nadeau -- Cowen & Company -- Analyst

John Newman -- Canaccord -- Analyst

Matt Phipps -- William Blair -- Analyst

Salim Syed -- Mizuho Securities -- Analyst

Ben Burnett -- Stifel -- Analyst

Tessa Romero -- JPMorgan -- Analyst

Dykin -- Jefferies -- Analyst

Tash Hasan -- Roth Capital -- Analyst

Samantha Semenkow -- Citi -- Analyst

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