Cabaletta Bio, Inc. Common Stock Morgan Stanley 24th Annual Global Healthcare Conference

Yeah. Thanks, Mike, for having us, and thanks for investing the time with us today. Listen, patients who have autoimmune disease simply want to get rid of their symptoms, get rid of their medicines, and just be normal people. They don't want to have the patient label. There's really only one category of treatment that has delivered on that promise to date, despite a lot of people trying. That category is the autologous CAR T category of treatments. Within that category, rese-cel, we believe is the only product that was designed specifically for patients with autoimmune disease. By that, I mean that it uses a standard 9-day manufacturing process. It is using a 4-1BB costimulatory domain and is weight-based in its dosing, which we think is a unique constellation for any product being developed for these patients.

Using the approach of a standard, well-characterized 9-day manufacturing process and weight-adjusted dosing with our product design, we've been able to deliver on the promise with differentiating safety. The majority of the nearly 100 patients that we have now dosed, the vast majority are demonstrating compelling clinical outcomes on the efficacy side, largely delivering on the aspiration of these patients. On safety, you'll hear more about it from our Chief Medical Officer, but there we are differentiating in a highly meaningful way from the other autologous CAR T products. What that has allowed us to do is begin to use rese-cel for dosing patients in an outpatient setting. From our Chief Commercial Officer, you'll hear a bit about why that is not only exciting but really important. It all is based upon the emerging differentiation on our safety profile.

It also allows us to think about rese-cel as a portfolio in a product. Specifically, in the next 12 months, we'll have the initiation of our second pivotal program for scleroderma this time, added to the ongoing study in myositis for adult and juvenile patients. We're really excited about both of these programs, but in the near term, the myositis program has the promise and the potential of delivering not only a really transformative product for patients, adult and children, but for delivering a PRV, a priority review voucher, for Cabaletta. We expect to report out in the second or third quarter next year, the middle of next year, something we've been saying for quite a long time, the clinical data from our pivotal myositis program, and by the end of the year to file our initial BLA for rese-cel in adult and juvenile myositis.

Then finally, on the innovation side, because we are safe enough with our side effect profile when added to a preconditioning regimen, it opened the door for us to evaluate rese-cel without preconditioning. Here it's only possible because you're killing so many more B cells when you don't use preconditioning. You have to be very safe with preconditioning to even begin to think about using your drug without preconditioning. That's true for other autologous products, that's true for allogeneic products, and that's true for in vivo products. If you don't have a very safe and clean profile in the preconditioned patient, there's no way that you're going to safely get to a great outcome in patients without preconditioning. Really excited about that program, its prospects, and we'll be revealing data as warranted over the coming months and years from that program.

Yeah. Really excited about the overall constellation that we're working on.

Yeah, I could take that one. Fate Therapeutics is a company that's been developing a CAR T-like therapy with their stem cell light product. I think there's this limited amount of data that we're seeing from phase I, right?

They present that EULAR, and only a handful of patients beyond six months' worth of data regarding their lupus patients they treated either with lupus nephritis or those without lupus nephritis. I think it's too early to say whether that type of technology is something that would be of a challenge to Cabaletta, but I think we have to wait and see what the data is.

Yeah. So for overall efficacy, I think we've seen across the entire RESET program, remarkable responses without continued use of immunomodulatory agents and on a low dose or off of steroids altogether. So these are patients who have severe refractory disease, who are now stopping all their medications and replacing it with a one-time dose of a weight-based rese-cel, and they're still getting remarkable responses. Responses very similar to what Chet had seen- with his patients in Germany.

These are remarkable responses. Some are going to remission, some are going to major responses, and we would say characterize that over 80%, 85% of our patients are achieving these types of endpoints off of therapy on a low dose of steroids. I think from an efficacy perspective, we are replicating the type of data that has been seen by University of Erlangen-Nuremberg.

Can you talk about this idea of this immune RESET and what it means and how that sort of plays out in the- Yeah, I think that's really the key here, is that I know that we've talked about, people talk about how long is the B cell depleted, or how high is your level of persistence, or how long does it persist?