Good morning. We're happy to be hosting Cabaletta Bio. With us today, we have Dr. Steven Nichtberger, CEO, Dr. Arun Das, the Chief Business Officer, and Steve Gavel, Chief Commercial Officer. To start, could you guys provide a high-level overview of where rese-cel stands, the overall strategy post initiation of the pivotal myositis trial, and key catalysts we should be focusing on for the second half of 2026? Yeah, absolutely. Thanks for the opportunity. Rese-cel was the subject of multiple data presentations recently at EULAR. In London, we presented data on over 50 patients. I think the takeaway is that we can reliably reset the immune system and get immunomodulator-free responses that are durable to the vast majority of patients we treat. The second major point is that we're beginning to develop insights from the translational data in the first month or two that predict whether or not the patient is going to actually reset. In that vein, there was a very interesting poster presented on Friday out of EULAR, really giving insight into what we believe are the predictors of durability based on all of the evidence that we've seen so far with rese-cel. The third thing is, we're able to innovate as a result of these insights. Our preconditioning-free regimens are starting to be given to more and more patients. In pemphigus and in lupus, we're doing dose-ranging studies to identify the best dose to go forward with, without fludarabine and without cyclophosphamide in those indications, particularly in lupus, where the young women are the most sensitive to avoiding, most motivated by avoiding cyclophosphamide. Overall, rese-cel looks to have an excellent tolerability profile, a very effective, reliable ability to reset the immune system, and the ability to deliver real advances for patients. As we move into our myositis pivotal program now, we're excited to layer out the next year or so. Nice. Going down that vein, before we jump into the EULAR data, for rese-cel, it's an autologous 4-1BB CD19 CAR T. Given the breadth of approaches being investigated in autoimmunity, how is rese-cel differentiated from not just competitor autologous CAR Ts, but also allogeneics and bispecifics approaches, and where does rese-cel fit in the competitive landscape there? Yeah. Thanks for the question. Among autologous CAR T, let's start there. Nature Biotechnology had a review of all of the data that's previously been presented. It's about two months ago. In this paper, rese-cel looked to have a side effect profile, CRS risk, both the frequency and the magnitude, ICANS risk, and overall safety profile, tolerability profile of rese-cel looks like it will be second to none in the autologous space. A very excellent tolerability and safety profile with the vast majority, 97% of patients, no ICANS of any sort. 94% of patients, either no ICANS, which is about two-thirds of them, or if they have ICANS, it tends to be a fever and not much else. Really excellent safety and tolerability profile to start with. Among autologous products, we feel really good because they're all pretty much effective in comparable ways, the difference in autoimmune disease is going to be safety. That brings me to in vivo, I think I'm going to very quickly comment on bispecifics. Far better than rituximab. They will replace many of the chemotherapeutic or other agents that are currently used in these diseases. They'll be better therapy for many patients, chronic therapy. When added onto existing therapy, they'll be great. For all those patients, terrific. For patients who no longer want to be patients, who want to reset, that's what we believe we can do reliably and well. In vivo, really interesting data presented recently. Legend had some CD19 20 data that looks very promising for those patients that they treated, in the Kelonia data, BCMA targeting in vivo CAR, their data also looked very interesting. What neither of them has done yet is demonstrate safety over the long term. Any integrating product, I think is, I don't know if it's a non-starter in autoimmune disease, but it's got a very high hurdle to prove safety, both in the short term and in the long term. Remember how safe rese-cel is compared to whatever else you're looking at in the future. That's the bar for safety. The other thing that needs to be proven is durability. Durability of treatment effect, not the persistence of the cells. In the Legend data, they rightly highlighted that the durability of the CAR persistence was 116 days. They still had CAR T cells. By 116 days, our patients are regaining their normal B-cell population. It's just a fundamentally different approach, and over the next few years, we expect to launch rese-cel for myositis, for scleroderma, for PC-free containing regimens in other indications, and that will be the standard against which they will be judged in safety and in durability. By the time these drugs first develop the right product for autoimmune, then actually become developed For those diseases, we will have four, five, six years of durability data similar to the JAKs against the TNFs. You need to have durability data to compete. You need to have safety to compete. I think there's a very long road ahead for the in vivo autoimmune products, but it's thrilling what's happening in cancer. Yeah, no, I totally agree. I think it's a very interesting innovation, but it does take a long time to get these things optimized, so for in vivo CAR T. Now jumping to the EULAR data. Last week you shared several important updates at EULAR. Let's start with the data in myositis as this is your lead indication. You shared that five out of six dermatomyositis patients and three out of four patients with anti-synthetase syndrome achieved immunomodulator-free remissions at week 16. Could you frame this result in the context of read-through to your ongoing pivotal RESET-Myositis study? Yeah, I'm happy to do that, Mark. Thank you for the question. I think a nice place to start is patients when they're coming on this study are discontinuing all of their immunomodulatory medicines prior to infusion of a single weight-based dose of rese-cel. That's where we start. That's where we started in the phase I/II study, and that's where the registrational study starts. Now, the way we designed the study, the registrational cohort being an extension of the phase I/II study, there is really quite a lot of overlap between the inclusion/exclusion criteria and the patient population in the phase I/II versus the registrational study. With the data that you just quoted that we reported last week at EULAR, 80% of those patients and five out of six dermatomyositis patients, adults, and the first juvenile dermatomyositis patient all were able to, at week 16, achieve either a moderate or a major TIS response while discontinuing and remaining off all immunomodulators for the duration of the follow-up. Not only that, but in those patients who achieve the primary endpoint, they all maintain their response through the latest follow-up, which we now are seeing in dermatomyositis as long as one and a half years. That's an opportunity to not only, in our minds, achieve a positive registrational study where if you assume very conservative assumptions on the control group, we need 50% of patients to achieve the primary endpoint. More importantly, and maybe I can turn it over to Steve for this point, as we start to see the emerging durability of rese-cel in dermatomyositis in particular, really shaping ourselves up to be favorable from a commercial and value perspective to generate the type of data that we need to have patients and the healthcare system overall benefit. Steve, maybe I'll turn it over to you for that piece. Yeah. It's an important piece, right? Steven talked about the Nature Biotechnology article. We're kind of clearing that first toxicity question around the program. Best in class, it appears to now. The second thing, and we just have to wait this out to see how long these patients continue to respond. Now you're starting to see that, right? A year and a half. The reason why the year and a half milestone is very important is in the private insurance side of the house, which is the overwhelming majority of payment for rese-cel. This is obviously a very different patient population than the ones I've been involved with in cancer, which is extremely important, and we could talk about that on the side. The fact that the commercial insurers have been very clear in terms of the milestone that they would like to be seeing a minimal of a year and a half, and two years plus. Obviously, they'd like to see multi years. We all would. In terms of that initial milestone, and the important part of this point, though, we've done the research around this because we knew going into EULAR what the data we were going to be presenting. We did some research with payers as well as U.S. providers, hospitals. What we did not present to them, which we will because we're building it right now, is the economic impact models that drug-free represent for them in this patient population. It's significant. It's very exciting now from a payment perspective, we're starting now clear that hurdle, that requirement around durability. As we get closer to them and closer to our launch of the program, we'll be able to demonstrate the economic impact, which is obviously going to have a lot of interest for them anyway. Mm-hmm. Got you. That makes a lot of sense. Yeah. On the line of durability, you guys mentioned that durability in dermatomyositis patients is 1.5 years, but in ASyS patients patients, durability was more variable. Yeah. I was wondering if there's any sort of mechanistic differences or disease etiology that could explain the result and how you're thinking about treatment and responses for the ASyS subgroup. Yeah, absolutely, Mark. Just a little bit of context. The way our registrational study is designed, it is a 17-patient study where the vast majority of the patients, 14 of them, will be adult dermatomyositis, the remaining three anti-synthetase syndrome patients. That is a reflection of the prevalence in the U.S., where probably 80%-85% of patients represent the adult dermatomyositis portion, let us say 60,000 patients in the U.S. roughly from a prevalence perspective. The remaining small piece of things represent the ASyS patients. I would say in those two different subtypes, what we are seeing, to your point, is divergence in what the durability appears to be. In the anti-synthetase syndrome patients, these patients have rapid responses, deep responses, and at least in the phase I/II data, most of them are achieving the primary endpoint. However, somewhere between month six and onwards, and this is the case in our data and in the academic data also presented by Charité at EULAR, actually this past week, it seems at some point in that journey, there is an emergence of disease activity that requires immunomodulatory medicines to help continue to control disease. A lot of times these patients are significantly better off than when they originally started refractory to three, four, five, six medications, sometimes with severe active disease. However, what we are seeing is that the instance of autoantibodies in many of these cases in this particular population may point to a CD19 negative subset of cells that may be responsible for continuing to drive some emergence of disease, versus in dermatomyositis where it seems like when rese-cel is able to do its job completely but transiently deplete the B cell population, that is sufficient for maintaining those responses, at least in the patients we followed so far, through latest follow-up in as long as one and a half years, as Steve referenced. In ASyS, it seems like there is, from a physiologic perspective a difference in the mechanism of disease, which may allow for rapid and deep responses early and some emergence or breakthrough of disease as we continue to follow. It is still more to be learned, but those are some of the early findings. Understanding that finding, are there particular indications where you think rese-cel could be best applicable given, like you're saying, there are CD19 negative cells that are active in this particular subset? It's a really good question. It's exactly why we designed the studies across the portfolio- the way we did. Each of our studies evaluate a single weight-based dose in cohorts of patients in phase I, II settings. As we gather that data in that population, the ability to see how that data and make decisions as a company based on that data to determine, does this make sense to extend to registrational study? Does it make sense to continue evaluating? Does it make sense that this should not be an indication where CD19 CAR T should be developed? We came up with that design as a cross-functional team, this is now three or four years ago, so that we could efficiently develop rese-cel broadly across the portfolio, and by using that same weight-based dose, extend the learnings in one indication across more, but still able to make independent decisions across each indication based on the data that we get. A great example here is in our myositis registrational program, we are now prioritizing juvenile dermatomyositis in addition to adult dermatomyositis because not only does the data seem to show that there's the opportunity for durable responses to emerge, it also allows us to become potentially eligible for a priority review voucher. Those are learnings that we've been able to obtain and apply into that study directly that's been, I think, really beneficial for us. Got you. For the pivotal study design, you recently initiated the registrational study in myositis. If you can walk us through the recent myositis study design with any timelines for data, but also, given the recent changes in commentary from the FDA, could you provide any color on your FDA interactions regarding study alignment and endpoint selection and your overall confidence in the single arm study design? Yeah. A few highlights, and then I want to turn it over to Steve for an important feature here in terms of why the design is important for commercial uptake. Patient study is single arm evaluating a weight-based dose of rese-cel, primarily dermatomyositis, now prioritizing the juvenile dermatomyositis data, which we'll plan to submit when we submit the myositis BLA. Importantly in this study is the opportunity to evaluate outpatient dosing and with the safety profile that Steve and Steven talked about in terms of what is emerging for rese-cel, where in myositis we've had no ICANS observed. whatsoever in the patients that have been treated to date. We've seen all patients either have no CRS or Grade 1 CRS, a transient fever across the portfolio so far based on the data reported at EULAR. All of this has helped us enable the ability to enable outpatient dosing in the registrational setting and in the phase I, II expansion cohorts, actually. Maybe I can turn it over to Steve to talk about why outpatient dosing, there's no question from a patient and provider experience perspective can be really positive. Maybe, Steve, you can talk about what that means for the commercial opportunity and the reduction of burden on the healthcare system. Yeah, I mean, normally side of care, there's not a lot of conversation around that with a lot of product launches. However, with cell therapies in particular, it's been one of the biggest rate limiters for auto CAR T therapies for cancer. If you look at just the treated eligible patient population in cancer therapies, you see anywhere between 20%-25% of all eligible patients actually being treated. One of the challenges, the reason for that was that there was only so much inpatient capacity to treat these patients. Here you are, basically, you're launching into large patient populations, and the ecosystem cannot actually take those patients and treat them all as an inpatient administered product. One of the key strategies behind rese-cel, and the toxicity profile is what enables this to happen, is to safely treat these patients in the hospital outpatient setting first, and eventually to transition into the full outpatient setting. It's all predicated on this toxicity profile that was originally discussed by Steven upfront, is that you have now what appears to be the safest product in the class that's going to enable that to happen. Obviously, patients love being able to take it as an outpatient, right? Of course. The hospitals love it because payment's much better for them. That's been also a rate limiter for them. The payers love this because now you're able to treat these patients and totally reduce total cost of inpatient admissions, and you're looking at taking from a $1 million-plus patient administered in the inpatient setting and significantly reducing that cost point for a payer. It's an exciting part of the launch, and it's a key focus for us as we move forward. For sure. Keeping hospital beds open is great for everyone. Absolutely. What safety parameters are you monitoring, or what specific criteria are you tracking in the study to support an outpatient label, and what proportion of patients do you expect will be treated in the community outpatient setting upon rese-cel launch? Yeah. You take piece, and I'll take doctor to community. That's great. Let's do it. Yeah, sure. From a safety profile or parameters perspective, what are we looking at? It's really in the peri-infusion period, how is the patient being Is this something that is suitable for the outpatient setting? One of the things that we've been able to leverage, and this is thanks to the guy on my right here, Steve, who led the effort at Legend with CARVYKTI, is there's already a significant outpatient infrastructure developed in the oncology setting for CAR T, and that's with a safety profile across the products that is substantially more significant, more severe CRS and ICANS, where cell therapists are now accustomed to understanding what the protocol is to manage CRS, what the protocol is to manage ICANS. Already in the CARVYKTI setting, nearly half of new patients starts were happening in the outpatient setting. With rese-cel, we're seeing with a significantly more favorable safety profile in terms of lower CRS frequency, lower CRS severity, lower ICANS frequency in particular, a real opportunity to move much earlier in the line of therapy, not the line of therapy, but in terms of how rese-cel can move early to launch in the outpatient setting. It's why we incorporated the option in our outpatient study to begin with, and maybe Steve, you can walk through how we see the transition to outpatient happening and how quickly. Yeah pace will look like. Yeah, that's a key point. Arun was talking about my old program with CARVYKTI. It took us about three years to get to that point of about 50% or so new starts in the clinic for these hospitals. The rate limiter, again, that you start to run into is these patients are still extremely ill, these end-stage and even mid-stage cancer patients that many of these programs are treating historically. I keep coming back to this, the beauty of this program, these folks are ambulatory, they're younger, and they're working class, right? They want to continue on with their lives. The adoption sequence in outpatient here that we're starting to see in the research that we're performing based upon the profile that we have been demonstrating at EULAR, that data, is way faster than the three-year point that I referenced in terms of my old program. You're going to, like I said earlier, you're going to see a very rapid adoption on the back of the infrastructure that's been created with CARVYKTI. Many of the sites are the same, and again, all the data that we're seeing, that we are fielding right now is suggesting a rapid uptake there, so fast that we are looking at how do we safely now move this, to your point about really community practice. Community practice, it's limited right now. You see it a little bit, it's spotty with CARVYKTI. The proof of concept's been established in really sick patients, okay? Like I said, it's our intention to follow the model that we created before, but really start to open it up. You have to do it. In order to reclassify these CAR T therapies to really treat the patient populations to fulfill the potential of them, you have to do that. It's the first time ever that a product like this has had a profile to enable you to actually get there. Got you. You touched on the inclusion of juvenile dermatomyositis patients, given you have rare pediatric disease designation for rese-cel in JDM, how many JDM patients will the pivotal study enroll? Could you talk about the significance here for both review timelines and capital infusions? Yeah. We were fortunate enough to actually have, I know one of your questions, Mark, was talk about the FDA kind of discussions. Yeah How those are going. Don't think we forgot it, we can fold it into this question. Sounds great. I think the nature of the RMAT designation that we received long ago in myositis leverage or provided us, afforded us the opportunity to have frequent interactions with the agency, really over the last several years now. One of those interactions was actually a Type C meeting back in April of 2025. There was a point where in those discussions with the agency, what was determined was that at the time of submission of the myositis BLA, they encouraged us to submit the available pediatric data in the population on the basis that if the PK/PD looks similar in the pediatric population and the adult population, then that may provide the grounds for potential inclusion of the pediatric data, pediatric indication into the adult indication, into the overall myositis BLA. This is really only possible because unlike every other CAR T player in the field, we are advancing a weight-based dosing regimen. That weight-based dosing regimen allows us to transition seamlessly into the pediatric population. It's why we opened up the study to juvenile dermatomyositis to begin with years ago. As we stand today, what our plans are to submit the available juvenile dermatomyositis data at the time of submission of the myositis BLA overall. It's one of the reasons why we narrowed in our guidance into 2H 2027 for the BLA submission for myositis because we want to ensure that we have robust 16-week and 52-week outcomes in that patient population to enable the maximum chance of inclusion of the pediatric indication into the initial BLA approval, because that's what affords us the opportunity to have the priority review voucher. What we can say from our early canvassing of the sites in juvenile dermatomyositis is that the physician urgency to treat and the patient and advocacy strength with which they advocate for something like rese-cel to provide immunomodulator-free outcomes for their patients, for kids who can go back to school, kids who can resume normal daily activities of life, is so strong that it was really a clear opportunity for us to be able to deliver for these patients and this population as a whole, an opportunity to get rese-cel in the context of this initial registrational study and hopefully initial approval. On the capital infusion point? Say that again. On the capital infusion point. Yeah. The pediatric review. Oh, from the primary. Those priority review vouchers, if you look in the last three to six months, have sold anywhere from, let's say, $180 million-$200 million. Now, this is multiple sales. I think for us as an emerging biotech company, why that's important is if we are able to obtain the priority review voucher at the time of approval, that's now immediate non-dilutive capital that comes in and allows us to fund the business, to fund the launch in a way that's really differentiated because most companies don't have that opportunity. When we think about doing all the things that can help Steve enable an excellent launch, when we can think about funding the business within myositis and within the broader portfolio, that type of capital infusion really can come in handy. Yeah, for sure. Yeah. That's really meaningful. Yeah. In the last few minutes, I know we have several other programs to touch on, we're going to pivot to RESET-SSc. Yeah. You additionally announced plans to initiate the single-arm registrational study in systemic sclerosis in the fourth quarter, and you showed strong data at EULAR demonstrating durable responses through week 36 for that indication. Could you walk us through the key findings at EULAR and the decision to pursue SSc as the second rese-cel registrational study? Absolutely. SSc is one of the highest burden in terms of mortality and morbidity of autoimmune diseases that exist in the landscape. I think you summarized it nicely, actually, in terms of what the key findings were. The one point I would add on is that in systemic sclerosis, what we saw pretty consistently is that the responses actually seem to increase in magnitude over time as patients remain off all their disease-specific medications. The data we saw at week 12 versus the data we saw at week 24 versus the data we saw at week 36, and then even if you extend it out a little further to week 52, those responses seem to be increasing in magnitude over time. For us, that was an interesting finding consistent with the academic standard of care is with 52-week endpoints for the two approved drugs in the is, let's say, at week 36, an average or a median 7.5% improvement in SSc. That can be hard to contextualize, just looks like numbers on a paper. The two approved medications at week 52 in their registrational studies actually had SSc worsening in one at 52 weeks, and the other had SSc stabilization, which means from time zero to week 52, there was either no change in SSc or the worsening was simply less than the worsening that you would have if you were not on that medication. Again, in contrast with rese-cel, what we're seeing is an improvement of 7.5% at week 36 across the patients that were identified, and that type of really unprecedented data across the field in terms of CAR T enabling these sorts of outcomes is really what guided us, one of the main things that guided us to enable the registrational design that you just mentioned briefly. For us, it's a 25-patient single-arm study with a 52-week SSc-based endpoint in patients with ILD. We think based on the phase I, II data that's emerged, that really sets us up really favorably for what the registrational study could be, which we expect to initiate in the fourth quarter of this year. Got you. Just to repeat, all of that is after you discontinue all of your immunomodulators. Yeah. There's not, I think, enough light shed on the outcomes that we are discussing about rese-cel in those 50-some-odd patients. They're all in patients who, frankly, are no longer patients. They're just not taking any medicines anymore. The vast majority of patients are no longer on any medication. When we talk about other modalities or other categories of drug, remember, those are all on top of existing therapy with chronic administration of the new and probably very expensive therapy, right? When you put it all together, the proposition for rese-cel in autoimmune disease, I think compares quite favorably on the safety and tolerability to, frankly, any alternative modality, any alternative therapeutic opportunity that you may have for these patients if they want to go off their medicines and they want to no longer be a patient. This is the one way you can get there, and if I tell you that the primary side effect of rese-cel is safety related to a fever that occurs day seven to day 12, in that range, in about a third of patients. Last time we saw an ICANS was about 14 or 15 months ago. Now, we may have one tomorrow, and we'll have them from time to time, but the risk of ICANS is we've dosed 50 or 60 patients in that period of time. This is not autologous CAR T of the past when it comes to the safety profile or when it comes to the value proposition. The flip side that we're not talking about today, but is our ability to industrialize and automate manufacturing and lower the cost of goods to among the lowest in the industry at launch. It's just something nobody's ever seen before. I think it takes diving in to really explore each of these in order to understand the value proposition that is rese-cel. Yeah. Another, I think, key value proposition and data you showed at EULAR was around the no preconditioning program. Yeah. For those unfamiliar, maybe could you explain why eliminating preconditioning could be such a key value proposition for patients? Yeah, absolutely. What we've established with rese-cel with preconditioning to start with, and this is in the 50+ patients that Steven just referenced that we've presented, is an ability to reliably see an immune system reset. We actually, in the translational poster on Saturday, defined what the immune system reset was, both from a B-cell depletion perspective and a B-cell repopulation perspective. I know we don't have enough time to go into it, but it really is a poster worth looking into because those parameters are going to be key as we look forward to evaluate how other modalities do or don't achieve immune system reset and for us, guiding our own efforts in the PC-free regimen. What did we share in PC-free? In the first two patients with lupus who were treated with the lowest dose of rese-cel without preconditioning. We saw in one of those patients, they achieved essentially the hallmark of immune system reset from a depletion perspective. We saw the second patient achieve a 90% decrease in peripheral B-cell depletion. Overall, to us, what that demonstrated was similar to the patients that we reported in pemphigus at that same lowest dose. We appear to be at a threshold dose where some patients respond, some patients may respond, but not completely. For us, with the safety profile that we've talked about throughout this discussion, we believe really strongly that the opportunity to dose explore and find the optimal dose to achieve immune system reset and the subsequent clinical outcome for sufficient number of patients to receive a PC-free regimen is there in front of us, and we're already enrolling at the next higher dose cohort in both pemphigus and in lupus. Really encouraged by that data, really encouraged for the opportunity it can provide patients. Here I do think it depends based on the indication or the disease. In lupus, I think what we can say is that the urgency to remove preconditioning is at an order higher than it may be in some of the other indications because of the demographics of patients that are affected. By that I mean most patients with lupus that are enrolled in our studies and across the field are women of childbearing potential. When you can eliminate preconditioning from the regimen and ideally achieve similar sorts of outcomes, especially from a translational perspective, that then can lead to clinical outcomes that are similar. We now have the opportunity to differentiate ourselves from every other player that's in the field of lupus, and again, really excited for that opportunity. Likewise, I agree. I think the potential to get rid of preconditioning is huge for the field. Sort of in the last couple of minutes, could you just remind us of your cash runway and how you're thinking about cash burn in the context of pivotal study expansion, expanding your programs and also commercial build-out as you potentially get ready for the first rese-cel launch? For those who aren't familiar, we recently completed a $150 million financing, which included many of our current investors, a number of new large mutual funds, sovereign wealth funds, and Eli Lilly among the investors from a corporate perspective. With that cash, in addition to the cash on hand, brought us to about a quarter of a billion dollars of cash. That will take us well into 2027, and we expect that we'll be able to have, in 2027, the delivery of our pivotal data on myositis. We'll begin to see enrollment in scleroderma. We are not committing to specific timelines for presenting the preconditioning-free data, the PC-free data in lupus or in any other indication, partly because we recognize that this is incredibly important information, and we are clearly leading the field. Frankly, from a competitive standpoint, we don't want to educate the world on what's going to work well in terms of dosing. The opportunity to break away from the field with regard to PC-free is paramount. The timeline and nature of disclosure there is going to be more thoughtfully kind of created over time. That makes sense. I think that's a good place to end it. Thank you so much to the team. Really appreciate your time. Thank you. Thanks, Mark. Appreciate it. Thanks, bud. Great. Good stuff.