Solid Biosciences Inc. (SLDB) Earnings Call Transcript & Summary

Welcome back, everyone, on day 2 of Citi's Biopharma Back-to-School Summit. Yigal Nochomovitz, senior biotech analyst here at Citi. And so this is one of the final sessions of the day, but it's certainly a super important one for sure. My pleasure to have with me Solid Biosciences and the President and CEO, Bo Cumbo. So welcome, Bo. Thank you very much for doing this.

So you have a lot going on, obviously. Maybe just to set the scene, if you could kind of give us a high-level overview of the the pipeline, what you're doing in DMD, of course, Friedreich's Ataxia is super important as well. And you have a very important set of updates coming up in the fourth quarter, both both in terms of regulatory and data. So love to hear more about it.

Yes. Thank you, Yigal. Thank you, Citi, for the invitation. Great to be here. We're very excited. I think for those of you who don't know, Solid Biosciences is a precision genetic medicine company. We focused primarily with AB at the moment. Two disease states. We put most of our -- almost all of our resources and personnel to is D&D and FA, Friedreich's Ataxia and Duchenne muscular dystrophy. We are heading into a very interesting time over the next, let's call it, half a year for Solid Biosciences. We have multiple inflection points. The first one in the next couple of months is we're going to be holding a meeting with the FDA to talk about accelerated approval to actually show them some of our clinical data, it would be the first time that actually we have shared and actually looked at as well as analyzed and then shared our clinical data, and we'll be doing that in the fall with the FDA and talk to them about the pathway for accelerated approval. And then after we have that meeting with the FDA, which should happen in Q4, then we will update the Street and provide them the street, not only our clinical data that we shared with FDA, but also the sort of regulatory discussion on what is our path forward if we have one and how we're going to move based on the information that we have. We also have Friedreich's Ataxia where we've already dosed our third patient, in patient #4 in September, patient #5 in October, that's currently scheduled. That means you guys, the Street will have at least 3 patients of mFARS data in Q1 or really first half of next year, but most likely Q1 of next year. And then you'll have some of the extra safety data from a couple of patients as well as long as we can dose patient brand b. So very excited about that. I think it's exciting couple of months for some.

Okay. Well, I know you can't speak to too much detail in terms of the actual data, but can you give us a sense for the types of data and sort of the magnitude of data in terms of how many patients you might expect to learn about for DMD in the fourth quarter? And also, I know you still haven't had the conversation with the FDA, but what are the -- if you can kind of enumerate what you might see is like the differential scenarios there in terms of how things could go forward with the feedback from them?

Yes. Yes. Let me backtrack and give you -- let's start with the end of '25, so we can get here so you can figure out how we got here and then where we're going to go going forward. So in the end of 2025, at the very end of '25, we submitted a statistical [indiscernible] plan on how we were going to basically the rules of how we were going to look at natural history data and due to our data comparison for our INSPIRE trial when we actually had our clinical data. We also, at the end of '25, early '26, talk to the FDA about how we are going to set up our Phase III clinical trial design. That's called the IMPACT trial as well as our end points that we were going to look at. And I think that's critically important because that's what we're going to be -- those endpoints are going to be the ones that we're going to talk to the FDA about in the fall. In March, we had another meeting with the FDA. We established that there's still a high unmet need in Duchenne. This sounds trivial, but realistically, when there's a AB gene therapy that's got a full approval, you need to make sure that the FDA acknowledges that Duchenne still as a high unmet need they did. And they also acknowledge that our drug is novel. That's also important when you think about just making sure that they don't view all the gene therapies as a me too. And so our drug, our proteins are novel. During that meeting with the FDA, we talked -- we started talking about a hypothetical situation of how we're going to look at our data, our -- and also Duchenne videos. We've got back and forth with the FDA on that. They gave us a couple of ideas. So we had to go back and modify our statistical plan, our SAP plan. based off that conversation. And that means how we were thinking about taking the -- selecting the data and being able to analyze the data going forward. That SAP plan was submitted in late July. Now we are pulling all our natural history data in. We will be using how the SAP plan of how we going to analyze the data and select the data that's going to be used in the clinical analysis. We're pulling our clinical data in. We will be creating a dossier, a briefing book for the meeting. We'll be requesting the meeting very soon and then meeting with the FDA in the fall. What are we going to talk to them about the endpoints to your question. It's the ones that we're already listed in the impact trial for the Phase III, time to rise, stride velocity 95, and then we have a couple of other endpoints, like 4 stair climb, 10-meter run walk, and we'll utilize those to create the data package. How many patients will we have? Well, it's -- first, you have to understand, we dosed 53 patients, all safe all the way down to age 6 months all the way up to age 10. And those patients are ongoing. We are only looking at patients that have at least hit 365 days, 1 year period of time. And we have to -- basically, when you have the meeting with the FDA, you have to cut your data about 5 months ahead of time. So when you -- when we cut the data at day 365, we're going to have a little over 12 patients of data for the FDA to review that has at least 1 year. A couple of patients who actually have up to 18 months, but at least 12 patients, slightly more to discuss with the FDA. And that -- and then more data continues to roll in the course of -- over the course of this year. But it won't -- we won't be able to import that into the bridging build.

Okay. So the goal there, I gather, is with those 12 patients, as you point out, to be able to make a statement around a functional benefit that would support in your view, assuming you show that a pathway for accelerated approval. Is that a correct?

Yes, we want to do is you want to look for clinical benefit. Like remember, these -- what's the FDA have to do here? The FDA has to make a judgment call. They actually wrote that in our meeting minutes. The last time accelerated approvals based on the judgment call and the totality of all the data. And we have a whole bunch, as you know, a ton of biological correlate data looking at anything from Western blot, all the way down to muscle integrity biomarkers such as embryos, heavy chain, Titan, et cetera. But they want to see clinical data. And so now we need to show that the drug is actually doing something in the patients that have been -- had biological cool data. And so it's not just -- it can be western bought, it can be mass spec, but it also can be some of the biological or data or a whole host of data set looking at patients that are moving in a manner that's different than natural history. And you don't need to -- you just have to make a judgment call. It has to be directional in nature because one for one, our trial is 18 months. The INSPIRE trial in 18 months, but we're taking an interim look at 12 months, give the FDA some data. So directional in nature, clinical benefit based on biomarkers, including Western blot mass, et cetera. All of that data in totality, along with our Phase III that is up and running, that that is a double-blind placebo-controlled multi-foundry study. that should give the FDA a lot of confidence that they can make a good judgment call that maybe we can have a pathway for accelerated approval and that's we're hoping for as we move forward.

Okay. So it doesn't necessarily have to be -- since it's a small sample size to be statistically significantly different versus natural history necessarily just you have to be able to show some valuable, clinically valuable separation that sort of meets the like overall litmus test across all these different...

Yes, they have to make a judgment call and they have to have confidence in the data set that gives them enough data to make it to this judgment call. And it's also great, by the way, that the new steeper heads in place because I think when you're having to make a judgment call, you definitely want leadership in place so you can actually bounce ideas off them and sort of get their support. And having the severed now in place, I think it is beneficial for us as well as we head into the meeting.

And just so everyone understands, at the moment, you're in the active process of doing this analysis. So you don't necessarily have all the answers...

No, no. Yes. No, no, no. We were in the process, but we don't have all the answers yet. So we're pulling all the natural history data in. You have to run -- you have to see all the data for the natural history. You have to run through the statistical plan and sort of requirements because a lot of the natural history data won't be utilized because it doesn't meet the requirements that were placed in the SAP. Then you have to get your data to come into the in-house. You have to use the data, then you have to do the comparisons. You run a bunch of different comparisons. And then you put your briefing book together. So yes, we and we haven't even scheduled the meeting yet. We're getting to read, schedule the meeting in about a month. And then you have to make a briefing book, 45 days in advance of the meeting. So we still have a little bit of time to do this work.

I know I appreciate you're in the middle of it, but qualitatively, can you give sort of a sense as to, for example, with time to rise, like what might be a good result relative to natural history, is there a way to...

There's not a way for me to actually want to qualitatively or quantitative give you an answer on that because I don't know exactly what natural history is going to say.

You don't know that...

They're trying to beat natural history, and I don't know exactly what natural history is going to say for the subset of the patients as they're actually -- they're maybe 12 months. We've dosed anywhere from a just 6 months to 10 years of age. So there's a whole...

But you kind of do like age...

You are. And that's why it takes a little bit of time. That's why I don't give you an answer.

Understood. Understood. Okay. So that's obviously an important and that meeting with the FDA in the fourth quarter.

Yes, it will be in the fourth quarter. And we plan on hitting that time line.

And then so somewhere together, like...

30 days later, we'll get the meeting minutes, as soon as we get the meeting minutes, I go to the Board of Directors, make sure that they're cool with it. And then we're going to release all the data at sort of the regulatory update to the Street.

Okay. So it sounds like back half of 4Q, '26 is a more likely time. Is that...

I would say, back half of '26 to very, very early '27.

Okay. Okay. Got it. All right. Very good. And then as far as the study -- the confirmational study, confirmatory trial, the IMPACT trial, where does that stand in terms of its rollout today?

Yes. So we're still waiting on Europe. We don't have Europe up and running yet. Right now, the only 2 sites that we have, Australia and Canada. And so enrollment really won't pick up until we have all the European sites. We had -- so we have Belgium, Italy, I think, France, U.K., Spain. There's a whole host of countries that need to get up and running. That should happen at the end of the year to early next year. And then we have a couple of sites in the United States for kids that are traveling from abroad. They do this sort of health care tourism. They obviously cannot get reimbursed for [indiscernible]. And so -- because they're from overseas, but they would like to participate in clinical trials. They come to the United States for health care. And so these tend to be a sort of kids coming from families that can afford it. And so we'll set up some side to the United States. We'll say that that will happen at the end of the year to early next year. We'll set all the European sites and then the enrollment really enhances after that. It's also important that we're going to be with FDA in Q4. And if something comes out of that, then we can also modify the trial if needed, based off the discussion with the FDA.

And there, Rob, as you said many times before, they're already aware that you've initiated that study in...

So we've met with them, as I said, like December-ish last year, '25, talked to them about the Phase III. We sent them in the press release when we enrolled the first patient and that was somewhere like May of this year or something like that. So they're aware.

Yes. Any -- do you want to offer any thoughts in terms of what happened with Capricor and how that shook out with the FDA? Does that -- what lessons did you learn or not learn there in terms of what the FDA is looking for in a DMD package?

Well, one, I find -- I found it great that they're actually continuing to communicate and review the data. I think that shows a lot of flexibility. Obviously, you had the AdCom, you had all the debate around it. Yet the FDA is still communicating and working with the FDA. I actually think that as a good sign, not just for capital actually just for a rare disease and having the flexibility or having the willingness to actually communicate and talk through the data because some of these rare disease packages are very challenging, especially in kids, young kids, Duchenne kids, cardiomyopathy or young looking at pull. I think these are very hard diseases and it takes a good communication. I'm actually pleased to see that they're still talking. I think we did learn some lessons on how you think about setting up your Phase III, how you think about -- and we didn't just smart it from [indiscernible] we actually watch all the trials, all the trials that are ongoing and the lessons burn, not just in Duchenne, but all the rare disease trials and how the FDA communicates around them as well. So we try to always do the best thing we can. We know that this is an open-label study. We know that the FDA doesn't like some of these endpoints because they can be effort based in the open-label study, and you worry about bias or coaching or training and anything, all this stuff. By the way, that's one of the reasons we love STRIVE Velocity 95. It gets away from all of that. StriveVelocity95 is a great endpoint. When you want to tie it back to another endpoint like a functional endpoint and say, hey, look, here's 2 endpoints, 1 functional in nature, 1 effort-based in nature, 1 that has no human touch whatsoever, in STRIVE Velocity 95, and you can show sort of comparison. If you have those 2 approach, I think that really helps with the FDA. And hopefully, we're going to try to do that all of this and create the best package we can, knowing there are limitations to the data.

Okay. So presuming you get good feedback and they say, we agree, we think you should file for accelerated approval, how quickly can you get that filing together?

Yes. So all right, in that scenario, and that's the A scenario, right? So in that scenario where the high 5 of us and they say, you're good to go, which the FDA never does that. But if they do say that, then we're in the middle of our peak BQ, probably CMC, that's the last to file. We're in the middle of our PPQs. We've found our PP Q1, PQ 2 is done. PPQ3 is underway. We'll probably have all that data in by end of the year. That means we need to meet with CMC part of the FDA early next year to go over that data with them. And then we -- and then once the FDA is good with our 3 PPQs and everything looks good, then we'll start making the CMC module. And we could potentially have the CMC module completed over mid-summer. And then once we do that, that would be the time that we could follow the modules.