Dianthus Therapeutics, Inc. Common Stock Citigroup’s Biopharma Back to School Summit 2026

Thank you, Sam, and thank you to Citi for allowing us to be here today and for hosting this webinar.

Sure. Thank you for that. Again, thanks for the opportunity to update everyone today. Over the last 12 months, with claseprubart, we have had two big moments in our development of claseprubart neuromuscular conditions. We had the very positive phase II MaGic results in myasthenia gravis from September or exactly about a year ago this week. Then the CIDP update, the early interim responder analysis we announced in March, and then the fulsome update on our first 40 patients and as part of the interim responder analysis in June. From our perspective, claseprubart is now pretty much de-risked as a very potent neuromuscular therapy and antibody. The next update is on the third indication. It's our phase II results, with MMN, which we are expecting to announce our top-line results in December of this year. That is a phase II study.

Originally, it was slated to have 12 patients per arm. We've over-enrolled, which is great. It shows a lot of enthusiasm for the program in the MMN community. So we'll have about 15 patients per arm. So relatively small phase II, mostly a safety study. That's the primary endpoint. Secondary endpoints are efficacy measures, mostly exploratory. The expectations there is, again, we'll report out if we see anything new on safety. I can tell you on a blinded basis to date, it looks very similar to MG, very similar to CIDP, so no new surprises. Of course, we're looking for just numerical trends. We're just looking for the numbers on the efficacy measure, the secondary efficacy endpoints to be moving in the right direction. Really, our goal is to get to a phase III start as fast as possible.

Back in 2024, when we met with the FDA to discuss the MMN program, we would've liked to have been able to go straight into a phase III the way we did with CIDP because it is an sBLA. But at that point, the FDA really did not know what our phase III should look like. They didn't have any direction to give us in terms of what the primary endpoint should be, so it made sense to do a phase II. Obviously, like CIDP, would've loved to have had a precedent and been able to go straight into phase III. So, we'll move as quickly as possible into phase III with MMN. In terms of DNTH212, our next program, our bifunctional fusion protein, that is in a phase I SAD study in healthy volunteers.

We'll provide an update on that by the end of the year and provide some visibility on when we'll start the MAD portion of the phase I and what our plans are over the next 12 months. We'll do that by the end of this year. Recently we announced DNTH312, that we are moving that into getting it phase I ready by the end of next year. Those are some of the big moments. On claseprubart, we will provide another update on CIDP. That'll be before the end of the year. Just provide guidance on when to expect top-line results for the phase III CAPTIVATE study. We'll also provide an update on what we truly think the end will look like in Part A.

Remember, the goal of the study is to recruit 128 patients into Part B, and those are patients who will have responded on Part A. Right now, we're saying we need up to 256 patients in Part A to get to that 128 in Part B. But if our responder rates look consistent with what we updated earlier this year, and to date they do look consistent, they're staying fairly consistent. If those responder rates continue to remain consistent throughout the end of the year, then we won't need anywhere close to 200 patients even in Part A. So I'll provide a bit of an update on that, and that should be an important catalyst. On MG, we've just initiated the EMERGE study where we're studying two different doses, once every two weeks and once every four weeks.

We are screening patients, and that is all on track, and we expect results from MG, top-line results from that phase III study in the second half of 2028.

Yeah. I will just add one element that you did not mention. In the market research we are doing with neurologists, one thing that came back very early on with some of the first neurologists we spoke to when we presented data to them is, "You guys should emphasize how fast this works." The stat sig separation on QMG and MG-ADL within 7 days is also really impressive and important for MG patients and neurologists, and a key differentiator. Excuse me. So, in terms of where we expect, if you can imagine the MG landscape when claseprubart is available. You will have FcRNs and different versions of FcRNs available. You will have UPLIZNA, and maybe you will have BAFF-APRIL. We will see what the data looks like from Vor BioPharma and Vertex, et cetera. And then you will have the complement class, which has been the class that is. It is a foundational class in MG.

It has been there forever, and it is still being used first-line. Obviously, efgartigimod has done a really good job of getting first-line use. C5s are being moved more and more to second-line. But within the complement class, you will have all sorts of different C5 inhibitors and only one C1s inhibitor, only one pure classical pathway inhibitor that will not have any boxed warning or REMS program, and that will be potentially a once-a-month subq autoinjector, like DUPIXENT. If you can imagine a label for a product like claseprubart, where you just take the safety and tolerability from ENJAYMO, sutimlimab, which is approved in the U.S. for cold agglutinin disease, just cut and paste that safety label, put it on ours. And then go to the dosing administration for DUPIXENT, but make it once a month. The exact same autoinjector. That is what we are going to be launching with.

Put that into our label. An efficacy that is at least as good as C5s, potentially better, and works within the first week. Literally, after your first dose, you see efficacy. You should respond if you do respond. I think if we price that intelligently and competitively, that should get a pretty nice share of first-line use. In terms of second line, if someone started on an FcRN, the claims database, if you look at it in the U.S. right now, at least 40% of patients are not on therapy 12 months later. Clearly, FcRNs do not work for everybody. Clearly, some patients are not going to be tolerating it or are not enjoying the dosing administration challenges with a high-volume therapy. I think the next logical step would be something like claseprubart.

I see it as being a major blockbuster, getting a fair share of first-line use, certainly getting a good chunk of second-line use. That easily with a large market like MG in the United States, where less than 20% of patients right now are on biologics. If you think about a healthier, younger, more active patient with a busy lifestyle, traveling, who wants something super easy, they can just travel with it, keep it at room temperature in their bag and give it to themselves wherever they are around the world when it is time to take their shot. I think claseprubart will be a very, very successful product in MG.