Ladies and gentlemen, thank you for standing by, and welcome to the Atara Biotherapeutics conference call. At this time, all participant lines are in listen-only mode. If you require operator assistance, please press star then zero. After the speaker's presentation, there will be a question- and- answer session. To ask a question during the session you will need to press star then one. Please be advised that today's conference may be recorded. I'd now like to hand the conference over to your host today, Mr. Eric Hyllengren, Vice President of Investor Relations and Finance at Atara Biotherapeutics. Please go ahead.
Thank you, operator. Good morning, everyone, and welcome to Atara's Strategic Collaboration conference call. On today's call, members from the Atara executive team will discuss our recently announced strategic collaboration with Bayer, as well as recent data presented at the ASH annual meeting on our CAR T, ATA3219 and tabelecleucel. We recently issued a joint press release announcing that Atara and Bayer have entered into a strategic collaboration for mesothelin-targeted CAR T-cell therapies for solid tumors, as well as a press release on new data on our assets presented at ASH. These press releases and an updated investor presentation are now 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, Dr. Jakob Dupont, Executive Vice President and Global Head of Research and Development, Utpal Koppikar, Chief Financial Officer, and Joe Newell, Chief Operations Officer.
We will begin with prepared comments from Pascal, open up 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, the company undertakes no obligation to update these statements. Now I'd like to turn the call over to Pascal. Pascal?
Thank you, Eric, and thank you all for joining us this morning. I am very excited to announce that Atara and Bayer have entered into a worldwide strategic collaboration to develop Atara's novel allogeneic off-the-shelf mesothelin CAR T program, ATA3271, and autologous mesothelin CAR T program, ATA2271. This agreement recognizes Atara's leading technology platform in allogeneic cell therapy and is a fundamental element of Bayer's new Cell and Gene Therapy strategy. Our new partner, Bayer, brings significant oncology development and commercialization capabilities in solid tumors, as well as an expertise in targeting mesothelin. Partnering with Bayer allows us to accelerate and expand the development of ATA3271, which we believe maximizes the possibility to rapidly impact patients and create a significant opportunity for shareholder value. As a reminder, ATA3271 is a novel and unique allogeneic mesothelin-targeted CAR T with a PD-1 dominant negative receptor and the 1XX costimulatory domain.
It has the potential to be first in class with an optimized design for solid tumors. By leveraging Bayer's proven track record and clinical development capabilities, the development timeline of ATA3271 could be accelerated, together with the ability to conduct parallel studies in multiple tumor types such as mesothelioma, non-small cell lung cancer, and other tumors overexpressing mesothelin. Bayer, with its newly formed Cell and Gene Therapy unit, selected Atara, and our groundbreaking technology as very promising in the field of allogeneic CAR T. We believe that Bayer's investment in ATA3271 provides external validation of Atara's allogeneic EBV CAR T approach and platform, including endorsement of our allogeneic T-cell manufacturing process and capabilities. Going forward, Atara will lead IND-enabling study and process development for ATA3271, and Bayer will be responsible for submitting the IND, which is expected to occur in 2022, and then for subsequent clinical development and commercialization activities.
Atara and Bayer have aligned on preclinical CMC and clinical plans that we believe are leveraging the potential of ATA3271 across various solid tumors overexpressing mesothelin with significant unmet need and sizable patient population. Under the terms of the agreement, Atara will receive $60 million in cash upon signing and is eligible to receive up to $610 million in development, regulatory, and commercial milestone payment, plus tier royalties up to low double-digit percentage of net sales. As a result, our cash runway is expected to extend to mid-2022. Moving forward, we will be able to allocate even more resources to Atara's other proprietary programs such as tab-cel, ATA188, ATA3219, and a number of early-stage CAR T programs in hematological malignancy and solid tumors. As part of the transaction, Atara will also provide translational research and clinical manufacturing services to be reimbursed by Bayer.
In addition, and for a limited period of time, Bayer has a non-exclusive right to negotiate a license for additional Atara CAR T product candidates if Atara decide to out-license these. Just to be clear, tab-cel and ATA188 are not part of this consideration. Before opening for questions on this exciting deal, I'd like to provide a brief update on our key data presentation at the American Society of Hematology 2020 annual meeting. Today, we are presenting pre-clinical data for ATA3219 for off-the-shelf allogeneic CAR T targeting CD19 in B-cell malignancies. This program also utilized the 1XX costimulatory technology. The data presented at ASH showed potent anti-tumor activity, both in vitro and in vivo, with long-term allogeneic CAR T persistence and no evidence of allogeneic toxicity in vivo.
We are encouraged by these results as a support for plans to develop a potential best-in-class allogeneic CAR T for B-cell malignancies with high and durable responses in patients. We anticipate submission of an IND for ATA3219 in 2021. We are presenting several data sets related to tab-cel, including the first ever presentation of clinical data on patients with life-threatening complications associated with EBV viremia. In this heterogeneous group of patients, including some with hemophagocytic lymphohistiocytosis or HLH, a condition with poor prognosis for which treatment options are limited, 80% of patients in the EAP201 study with persistent EBV viremia were responders, and 50% of the patients in EAP901 with EBV viremia and HLH were responders. The overall survival OS rate at one year in patients with EBV viremia treated in the EAP201 study was 100% for a median follow-up of 14.6 months.
We are also presenting data on the substantial cost burden of PTLD, defining important aspect of the significant value that a transformative treatment such as tab-cel could provide to PTLD patients and healthcare systems. I now turn the call back to operator to begin the Q&A portion of the call. Operator?
Ladies and gentlemen, if you would like to ask the question at this time, please press the star then the number one key on your touch tone telephone. To withdraw your question, press the pound key. Our first question comes from John Newman with Canaccord. Your line is now open.
Hi, guys. Good morning, and congratulations on a very nice agreement here, which is very good. Pascal, I just had a question regarding the agreement. I'm wondering if the agreement allows Bayer to run future clinical studies for the autologous ATA2271 product. I see in the press release that you'll be responsible for the ongoing phase I study. I'm just wondering if it's fair to say that Bayer is prioritizing the allogeneic product at this point?
Yeah. It's fair to say that the collaboration with Bayer and Atara are prioritizing the allogeneic product, ATA3271, because we believe that's the one that could rapidly develop significant value for patients and our shareholders. At the same time, however, we are continuing this phase I study with our collaborators at Memorial for ATA2271. I would say data will tell that, at this stage, priority is ATA3271, but of course, if we, with Bayer, see a significant positive data coming from the autologous version of the product, certainly we will discuss and Bayer has a possibility to continue the development of the autologous version. Priority is the allogeneic, but we are continuing the development of the autologous.
Great. Thank you.
Our next question comes from Salim Syed with Mizuho. Your line is now open.
Great. Thanks for the question, guys. I'll add my congrats to the deal. Just a couple from me. Pascal, just one housekeeping on the milestones. Can you just give us the breakout between development, regulatory, and then also commercial? Two buckets or three buckets, however you want to do it. Just on the rationale here for me, I understand, the other CAR Ts here, can you just maybe outline for us how you're thinking about partnering those CAR Ts as well? I know Bayer has a non-exclusive right here for a limited period of time. What sort of time period are we talking about, is it your preference to partner those out, or would you like to retain those in-house? Thank you.
Thank you, Salim, for your question there. Answering the first question, we are not disclosing at this stage a particular detail of the different milestones. Let's just say that this is a very classical type of deal with milestones related to progress in development, in regulatory, and of course then commercial milestones. At this stage, we are not disclosing any detail there. Coming now to the second question. As you know, Atara is developing a large number of proprietary assets. In fact, all assets are proprietary assets at this stage. It is the first one that we are partnering out with someone, which we believe can accelerate and expand the development of this particular asset, I mean, Bayer. We are developing a number of CAR T, allogeneic CAR T. One of them is advanced. It should go to IND in 2021.
That's ATA3219, for which we are presenting today at ASH, very exciting preclinical data there that confirms our intent and possibility to become potentially a best in class in B-cell malignancies. That the most advanced one. We have done a number of CAR T that we are progressing at earlier stage with our collaborators at Moffitt Cancer Center and at Memorial Sloan Kettering. That's our portfolio of proprietary asset in the CAR T space.
What the agreement is saying is that due to the very high level of interest of Bayer in this allo CAR T technology and platform that we have, there is a possibility for us if we decide, and that's our decision, to partner out one of these CAR T, we will then, as part of the agreement, discuss and negotiate in a non-exclusive way with Bayer the possibility for them to become the partner of one of these CAR T. Again, it's only if we decide to do so, when we decide, of course, it, and it's a non-exclusive right to negotiate. Does it answer your question?
Yeah. Sort of. I guess the other, is it your preference to partner these out? I mean, is the rationale here that it's not diluted financing, or is it just the acceleration or both?
No. At this stage, we want to create value with these assets. They are early-stage assets. ATA3219, we believe it's important to show some clinical data, hopefully demonstrating the positive for that asset to become a best in class in the B-cell malignancies field. Our intent is not to partner at this stage. We want to continue to progress with our own resources into clinical development and for the earlier stage asset into IND-enabling study and clinical development. We are not intending to partner at this stage.
Got it. Thanks so much. Thanks again.
Thank you.
Our next question. As a reminder, ladies and gentlemen, if you would like to ask a question at this time, please press the star then the number one key. Our next question comes from the line of Michael DiFiore with Evercore ISI. Your line is now open.
Hi. Hey, guys. Thanks so much for taking my question and congrats on a very good deal. Just have one clarifying question. Maybe I missed it, with regards to the, I guess, non-exclusive option to Bayer, I'm just trying to get a sense of how much flexibility Atara has. I realize that, since it is non-exclusive, Atara retains some optionality on these later CAR T technologies. Just if you could elaborate, if possible, on how much flexibility Atara has in this regard, that'd be helpful. Thank you.
No, thank you for your question. We have a lot of flexibility. In fact, what's happening there is that, first of all, it is at Atara's discretion to decide, of course, to partner or not to partner any CAR T program that we have. Say, take ATA 3219. If we decide by the time we get clinical data that it's a great potential best in class in that class that we want to commercialize by yourself and we don't want to partner, that's our choice. That's our strategic choice. This is full freedom of strategic choice for the decision to partner. Now, if we decide to partner, we will discuss with various companies, including Bayer, and that's what we call a non-exclusive right.
I think it makes sense for us to have that possibility to discuss with Bayer because we believe that they are a great partner and we're going to work efficiently with them to develop our mesothelin CAR T program as fast as possible. To us, it was extremely logical to be able to discuss with them if we decide to partner another type of CAR T program at certain stage. Does it answer your question?
Yes. Thank you very much.
Our next question comes from Ben Burnett with Stifel. Your line is now open.
Hey, thanks very much, and congrats on the partnership. I actually wanted to ask you a question regarding ATA3219 and the preclinical data that was described in the press release and coming out at the meeting. Basically, can you just talk about how you characterize persistence in vivo, and I guess how does that translate to what you expect for persistence in patients? Any color on that would be super helpful. Thank you.
Thank you, Ben, for your question. Jakob, do you want to take that one?
Certainly, Pascal, thank you, Ben. As we presented here at ASH, the first public presentation of the ATA3219 preclinical data, which is our allogeneic CD19 specific CAR. We showed in vivo and in vitro data, and persistence was really assessed according to the presence of these T cells in the mice over the passage of time. We were able to see with the 1XX costimulatory domain that's built into the ATA3219 cells, that we do see long persistence of these T cells in the animals as we assess them over time. Obviously, this comes with excellent efficacy and we also see really no evidence of alloreactivity, which portends well for the safety profile as we move towards the IND filing in 2021 next year.
I would add, Ben, that this is really in line with what we've seen from the academic construct, which was using a different costimulatory domain. The data that were presented at TCT Meetings in February this year. You maybe remember this clinical data on six patients treated with an allogeneic EBV CD19 CAR T made by Memorial Sloan Kettering. In these six patients with advanced B-cell malignancies, the response rate, the CR rate, complete remission rate, was over 83%, 83.6%. These patients were followed for a very long time, in fact, the longest follow-up ever of allogeneic CD19 CAR T in patients. The median follow-up was 26.9 months, so more than two years, and the patients were still responders at the time.
We have this initial proof of principle for that academic construct that building a CD19 CAR onto an EBV T-cell, an allogeneic EBV T-cell is indeed leading to high level of response and durable response with a very long follow-up. What we see right now in the animal models, in the preclinical data of ATA3219, is very much aligned from what Memorial has seen in the clinical study that they conducted.
Okay, that's very helpful. If I could just ask one follow-up question. Can you talk about your plan on how you plan on approaching lymphodepletion in clinical studies with ATA3219? I guess, is this a variable that you would focus on in terms of optimizing? Is there a scenario where you're thinking maybe you won't need chemo preconditioning?
Thank you for that question. Jakob, do you want to take that one as well?
Yeah, absolutely. In terms of the clinical trial, we are obviously working towards the IND filing, as I mentioned, which will be submitted to the FDA next year. When we think about lymphodepletion, we would be planning for standard lymphodepletion with Cytoxan and fludarabine as well. That being said, with this study, we do want to obviously also assess the possibility potentially for decreasing the lymphodepletion over time because, again, the 1XX format and some of the potential for persistence as well. At this point in time, our idea is to proceed with standard Cy/Flu lymphodepletion in that study.
I will add that clearly, we don't need to add this kind of very aggressive long-term lymphodepletion to adding to Cy/Flu like an anti-CD52 monoclonal. We don't need that because we have this unique natural state of this EBV T-cell that are carrying the CAR, and in fact, we have this partial HLA matching that we believe is helping also the persistence of the cell. We know already that there is no need for this very heavy long-term lymphodepletion that some other are following.
Right. Okay. Thank you. I appreciate it. That's helpful.
Our next question comes from Phil Nadeau with Cowen and Company. Your line is now open.
Morning. Congratulations on the deal. A few questions from us. First, on ATA3219, now that you've had the pre-IND meeting with the FDA, what remains to be completed before you can file the IND and begin the clinical studies?
Yeah, thank you for your question. Jakob may want to chime in, but basically what's needed is really to work now on the CMC part and finalize the different batches, as well as to fine-tune a few of the additional studies there. Everything is on track, and we don't expect significant issue at this stage from that point of view. Jakob or Joe, do you want to add anything?
Yeah, I think Pascal, full agreement there. We're very much on track, very collaborative pre-IND meeting with the FDA as described, and Joe, any other comments on the manufacturing side?
Jakob, you characterized it beautifully. We're on track. Manufacturing is going well.
Great. Second question on ATA3219. Some of your potential competitors are looking at retreatment strategies in the CD19 allo space. Any thoughts on the need for retreatment with ATA3219, or do you think a single administration of the cells will be sufficient?
Yeah, thank you for the question. Maybe I'll start, before asking Jakob to chime in saying that we know already that there are two possibilities that are offered by our technology. One is multi-dosing, the other one is retreatment. Okay? Whether if retreatment is defined as the need to treat a patient that is not responding to the first treatment, and that is something that is possible with our technology, and we have significant experience, as you know, with that set of ATA188 there in patients there. If it's about multi-dosing, there is some experience from the Memorial clinical data that I was mentioning where on these six patients, they were treated with one to three dose. The median was two, and that's a possibility to do multiple dosing there. That's possible. Now, whether it will be required, really the first in human data will tell.
We believe that the persistence of the cells, and the ability for them to expand and really eradicate the tumor cells will be the key to see whether there is a need to do several dosing or whether there is the possibility to do retreatment if the patients are not responding to the first treatment. Jakob, anything to add?
Yeah, I agree with that, Pascal. I do think the key word here is flexibility. Obviously, with the profile of the ATA3219 cells, we do see between the EBV T-cell backbone and then also the 1XX costimulatory domain that we think we have the potential for having a best-in-class behavior for an allogeneic T-cell. Perhaps single administration is going to be sufficient. There's also potentially flexibility for multiple or retreatment, I should say. This will be a data-driven decision when we actually generate the data in the clinic. We think there's a chance that single administration could be potent and in and of itself, but again, there could also be the potential for retreatment if necessary.
That's very helpful. Maybe two last questions on the Bayer deal announced this morning. Specifically for ATA2271, I guess I'm still a little unclear how that's handled in the current collaboration. Just for argument's sake, if you move forward with ATA2271 instead of ATA3271, are the economics the same? At what point would Bayer start to run the trials for ATA2271?
Thank you for your question. We start the collaboration, in fact, with work with Bayer, but it's Atara leading the ATA2271 collaboration for the first human clinical study with Memorial. By the way, the first patient has been enrolled in that study, and that's very exciting. That's great news. That's Atara working with Memorial, but of course, in collaboration with Bayer as well there. We will have data, and we said in the past that we should start to see some data from this autologous program in the clinic in the second half of 2021. Second half of 2021, we start to see data, and we'll see how the data are playing out there. Depending on the data, there is a possibility for Bayer in that deal to then take over and develop further ATA2271. Again, the priority is ATA3271.
Why is it a priority? Because if you think about it, the IND is coming in 2022, so it's not too distant from the first clinical data with ATA2271. One way to really accelerate the development of ATA3271 is really to leverage the information, the data, the know-how that we as collaboration, we get from the clinical study with ATA2271 to be able to further accelerate ATA3271 clinical development. Again, both products, both assets, ATA2271 and ATA3271 are part of the deal and moving forward, the data will be the key to decide what we do. Clearly, the emphasis on that deal and our collaboration is on the allogeneic EBV mesothelin CAR T because we believe that will offer much more flexibility and benefit for patients.
Also, as you know very well, we are moving forward with new manufacturing technologies, new manufacturing process into bioreactor and the possibility to have a low cost of goods manufactured for this type of allogeneic EBV CAR Ts. We believe with our partner Bayer that is also something very important to consider moving forward to develop a successful and profitable product.
That's right. Then just the last question is on the timing of the collaboration. I'm curious why now? Why do you think this is the time to maximize the value for shareholders? It does seem like there's a decent number of milestones for ATA2271 and ATA3271 over the next 12-18 months. Why now and why not wait to get some data and maybe a bit more progress on ATA3271?
Yeah. We think that it was the right time to do a deal now for two good reasons. One is that with a partner like Bayer, we can accelerate and expand our development of ATA3271 because this particular allogeneic EBV CAR T could really address several type of tumors, from mesothelioma to non-small cell lung cancer, and then to a number of other tumors that are also overexpressing mesothelin like ovarian cancer, pancreatic cancer. If you think about the broad type of tumors that could benefit from that type of product, having the possibility to do a parallel type of development is very important, because then you can really accelerate and broaden the possibility to create value there.
The idea to go fast and to go broad was really what was behind the deal with a partner like Bayer that not only is very enthusiastic, is very committed. We agreed with them on the development plan there, and it's a very exciting development plan that really is maximizing the value of the asset there. The second aspect is that from a resource point of view and allocation of resource at Atara and financial and other resources, we believe it was important to partner some assets at this stage because that allows us to then dedicate a lot of our resources to other proprietary programs, especially tab-cel, ATA188, where we are waiting now for the response from the FDA by the end of the year on the immunized control trial. We're very excited about this program.
We have also to accelerate the development of ATA3219 and this early-stage CAR T program that we were mentioning earlier on. These two aspects, one is how can we maximize the value of that asset, make sure that we have very large potential ahead of us if we go fast and we go in parallel in multiple development, and then at the same time, having the possibility to allocate a resource in a way that could allow us to develop to their true potential tab-cel, ATA188 and other allogeneic CAR-Ts.
That's very helpful. Thank you for taking my questions, and congratulations again on the deal.
Thanks, Phil. Appreciate it.
Our next question comes from Matt Phipps with William Blair. Your line is now open.
Morning, thanks. Congrats, obviously. Kind of following up on Phil's question there, it seems like this trial just started with the ATA2271. I guess, how much data was available from that for the deal? It seems like if you could have gotten some real proof of concept with that, the deal could have been more attractive for you all. Just again, with the timing for doing it now, and I guess specifically, was there data available for the deal negotiations?
Yeah. No data was available, apart, of course, from the IND package. No data relating to the clinical results because, as I said, the first patient has just been on November 7th. It's nothing to do with that. Certainly, the IND package and the fact that the FDA cleared that IND, all that played a role in the deal and was discussed with Bayer there, but not any clinical data on ATA2271. Again, one thing that is very important to keep in mind that, as any biotech company, you could wait for all your proprietary program to come to different type of value inflection point. Here, in that particular case, we thought that the best way to create value for shareholders and for patients was to accelerate this program right now, right here.
Not to wait a year, a year and a half to have data and then to consider partnering that particular asset or that potential asset. Going fast now is the best way to be competitive and other programs that are targeting mesothelin, but also to be able to, as I say, run in parallel several developments for ATA3271, several clinical studies in development across different tumor site. That requires significant investment, not only to go to the IND, but then also to move forward, build the inventory to do various clinical studies and so on and so forth.
From that point of view, we thought that the best way to create value is to accelerate and expand the value potential of this asset in doing a deal right now with a partner that is very committed, very knowledgeable, and is going really to support this program moving forward in collaboration with Atara.
Okay. Thanks, Pascal. What is owed to MSK now? Does Bayer take responsibility for any royalties paid to MSK, or does that have to come from you all?
We are not disclosing any particular aspect of that. The specifics of the deal are what we put on the 8-K. Of course, there will be the redacted version of the agreement next year in our filings there. At this stage, we're not disclosing anything. Suffice to say that we believe that this deal is creating a significant value for Atara. That's very exciting to be able, as I said, not only to have the possibility to accelerate and expand the program, but also to have resources that we can dedicate to, particularly financial resources, that we can dedicate to other proprietary programs to advance them rapidly.
Okay. Thanks, Pascal. One question, if I may, on ATA3219, just bigger picture question. Based on what we've seen from both autologous and other allogeneic programs, where specifically the allogeneic having persistence problems, how do you think about this for ATA3219, particularly going into maybe the leukemias versus lymphomas? Some data with the autologous program showing that persistence might be more important actually in the leukemias than lymphomas. Does that influence your thinking for ATA3219 as far as where to initially try it out?
Thank you for your question there. We certainly are aimed at B-cell malignancies in general. Lymphoma and leukemia with that program. We don't have any focus on only one type of hematological malignancies linked with B-cells there. This being said, we believe that persistence of the cells, and what I would call functional persistence, which we believe is very important, is key in both disease. The idea is that when you think about the best-in-class in lymphoma, it's a mix of higher response rate than what is existing today. Better safety than what is existing today, and longer durability of response than what is existing today. If you look at the kinetics of response in the autologous setting right now, you have this initial peak in response, but then with time, this is progressively decreasing.
You have a plateau, which is probably around the 40%-50% CR long-term there. That means that 50%-60% of the patients are not benefited. There is a significant unmet medical need right there from that point of view. Of course, safety is still an area where there is a need to progress compared to the current approved autologous. All these aspects are very important to keep in mind. We believe that the way we've constructed ATA3219 with 1XX as a costimulatory domain, which is helping that functional persistence, and we have this clinical data from ATA3219, and by the way, also from ATA3271, showing this functional persistence, the cells are persisting longer and are not exhausted. They are able to continuously address the antigen challenge there. It's important.
In leukemia, it's like that the persistence of the cells seems to be even more important there, but we believe that this will be an additional element of creating value for ATA3219 moving forward.
All right. Thanks, Pascal. Congrats again.
Thank you.
Our next question comes from Anupam Rama with JP Morgan. Your line is now open.
Hi, guys. Thanks so much for taking the question and congrats on the Bayer collaboration. Just a quick question on the collaboration. It seems like for a time period here, Bayer will have the potential to negotiate additional licenses for CAR T programs. What is that time period? I guess this is non-exclusive, should we be taking that as you guys strategically open to additional partnerships outside of Bayer as well? How should we be thinking about that? Thanks so much.
No, thank you, Anupam, for your question. Here, clearly, first it's Atara's decision. We decide in the future whether we want to partner on some other CAR T programs. Take ATA3219, which is the most advanced. Okay? If we decide in the next two to three years to develop that program, we will go to discuss with different companies, including Bayer. To us, it makes sense, if we decide to partner that program, to connect with Bayer as well. Then it will be a competitive process to extract as much value as possible for our shareholders there. Again, it's our decision.
If we decide not to partner in the next few years this program, we just continue as a proprietary program, and it continues to create value internally for our shareholders, and we might decide to commercialize by ourselves or to get a partner at a later stage for commercialization and not for development. There are many options. We have the flexibility in option, and I think that's what is very important in that type of deal. I think Bayer interest in other CAR T, I believe, is something linked with the keen interest that they have in cellular therapy in oncology and in our technology. I see that as a tribute paid to the amazing work that's been done by my team in R&D, in manufacturing, and technical operation process science. That's good. That's great.
We were not ready to partner anything else at this stage because we think we have to first create value and then decide whether we want to partner or not some of this asset at a later stage. Does this answer your question, Anupam?
Yep. Thanks so much.
Okay. You're welcome.
Our next question comes from Salveen Richter with Goldman Sachs. Your line is now open.
Thanks for taking the question. This is Andrea on for Salveen. Maybe as the first one, if you could speak on what we could expect from the regulatory update from ATA188, and then just remind us on the 12-month catalyst path. Thanks so much.
Yeah. Okay. Jakob, do you want to take the ATA188 question first?
Yes, certainly, Pascal. Andrea, thanks for the question. As you know, with the ATA188 program, we have been presenting data most recently at ECTRIMS for the phase I-A part of the study in progressive MS patients. What we did in the fall is we submitted a data package to the FDA, along with the randomized control trial protocol, and we asked the agency a series of questions. Number one, in terms of the protocol, what about the patient population, the primary endpoint, and the timing of the primary endpoint? We expect to get feedback from the agency in the short term, and I'll describe the timing of that in a moment. We also asked them about the randomized control trial, if that could actually be part of a registration intent package with another phase III study conceivably.
Our base case currently is that we would do this randomized control trial and then follow that with two phase III studies in progressive MS, but we want to be opportunistic and see if the agency is open to letting us use this current randomized control trial as part of a registrational package. The final series of questions was really related to expedited development of the ATA188 program, namely pathways such as breakthrough therapy designation, RMAT or fast track designation. We asked the agency whether or not the data in the package that we submitted was sufficient for us to proceed to apply for some of these designations, and if not, if they could give us guidance on what else they would like to see.
We do expect to receive feedback from the agency here between now and the end of the year, and we do intend to communicate the outcome of that feedback by the early part of next year.
Regarding the cash situation, Utpal? Utpal? Okay, maybe I'll answer for that. As you know, at the end of September, we had $327 million of cash. This particular deal is really helping us now with the cash at signing to extend our cash burn rate into mid-2022. Does it answer your question, though? Hello?
Yeah, I can hear you, Pascal. This is Jakob.
Sorry, our next question comes from Jonathan Miller with Evercore ISI. Your line is now open.
Hi, guys. Thanks for squeezing me in here. I guess we've had a lot of questions on the other programs. I'd love to ask one on tab-cel. You had some expanded access data in AID and LPDs at ASH. How good should we think of this ASH data as a proxy for behavior in these indications in the multi-cohort study? Is this the sort of response rate and behavior you'd expect to see as we move forward in that indication? Is there some reason to think that those populations would be different? Thanks.
Yeah, no, thank you for your question, Jon. Before handing over to Jakob, clarification that we have, as you know, six cohorts in our medical study that we have initiated recently. Now we have shown clinical data in most, if not all of these cohorts, the most recent being what we're presenting at ASH on people with life-threatening situation of EBV viremia there with this high level of response there. Jakob, do you want to comment on the response rate per cohort that we've seen so far in previous clinical data and what's our expectation for the medical study?
Yes, absolutely. Thank you for the question. At the ASH meeting, which is currently ongoing, we did present data from our expanded access and phase II experience of tab-cel and the academic one as well. We did describe that for this population of patients that have severe EBV viremia, that we do see response rates depending on the study on the order of 50% - 80%, which is obviously a very high response rates. We also see overall survival at one year of 100% with a median follow-up of 14.6 months. This is obviously quite strong and profound data.
If you look now at the six populations that are included in the multi-cohort study, whether it's the PID, LPD, AID, LPD, the CNS PTLD, the frontline PTLD patients, or the leiomyosarcoma patients, and now most recently, the EBV viremia patients, we have now publicly disclosed historical data from our clinical experience of tab-cel in all six populations. I think it's fair to say that we are seeing response rates and durability of response across all of those six populations that are meaningful, where these are patients with really no significant treatment options, and we are seeing high response rates and durability that we believe are meaningful here for these patients. That's obviously why we are also initiating the multi-cohort study. The study is open and enrolling, and we're seeking that first patient enrolled before the end of the year.
We do think that this multi-cohort study does allow us to expand the reach of tab-cel in terms of treating patient populations. Obviously, PTLD is where we're attempting to get our regulatory approval first. Again, we feel quite confident on that based on the interim analysis of the pivotal study, as well as the interactions that we've had with the Food and Drug Administration and EMA for that matter. The multi-cohort study really does represent a significant opportunity to expand the reach of tab-cel and to help more patients and certainly enhance the commercial opportunity.
Sure thing.
That concludes today's question- and- answer session. Ladies and gentlemen, thank you for participating in today's conference. This concludes the program, and you may now disconnect. Everyone, have a great day.