Solid Biosciences Inc. Common Stock Citigroup’s Biopharma Back to School Summit 2026

Yeah. Thank you, Yigal. Thank you, Citi, for the invitation. Great to be here. We are very excited. I think for those of you who do not know, Solid Biosciences is a precision genetic medicine company. We focus primarily with AAV at the moment. Two disease states we put almost all of our resources and personnel to is DMD and FA, Friedreich's ataxia and Duchenne muscular dystrophy. We are heading into a very interesting time over the next, let us call it, half a year for Solid Biosciences. We have multiple inflection points. The first one in the next couple of months is we are 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. We will be doing that in the fall with the FDA and talk to them about a pathway for Accelerated Approval. Then after we have that meeting with the FDA, which should happen in Q4, we will update the Street and provide them, the Street, not only our clinical data that we shared with the FDA, but also the sort of regulatory discussion on what is our path forward, if we have one, and how we are going to move based off the information that we have. We also have Friedreich's ataxia. We have already dosed our third patient. Planning patient number 4 in September, patient number 5 in October. That is 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.

Then you will have some extra safety data from a couple of patients as well, as long as we can dose patient 4 and 5. Very excited about that. I think it is an exciting couple of months for Solid.

Yeah. Let me backtrack and let us start with the end of 2025 so we can get here so you can figure out how we got here and then where we are going to go going forward. So at the end of 2025, the very end of 2025, we submitted a statistical plan, a SAP plan on basically the rules of how we were going to look at natural history data and do our data comparison for our INSPIRE trial when we actually had our clinical data. We also, at the end of 2025, early 2026, talked to the FDA about how we were going to set up our phase III clinical trial design, that is called the IMPACT trial, as well as our endpoints that we were going to look at.

I think that's critically important because 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 an AAV gene therapy that's got full approval, you need to make sure that the FDA acknowledges that Duchenne still has a high unmet need. They did, and they also acknowledged 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. Our drug, our proteins are novel. But during that meeting with the FDA, we started talking about a hypothetical situation of how we're going to look at our data, and also Duchenne videos.

We got back and forth with the FDA on that. They gave us a couple of ideas. We had to go back and modify our statistical plan, our SAP plan, based off that conversation. That means how we were thinking about 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 the SAP plan of how we are 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 were already listed in the IMPACT trial for the phase III, time to rise, Stride Velocity 95th Percentile, and then we have a couple of their endpoints like four-stair climb, 10-meter walk/run test, and we'll utilize those to create the data package. How many patients will we have? 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. Those patients are ongoing. We are only looking at patients that have at least hit 365 days, one year period of time. Basically, when you have the meeting with the FDA, you have to cut your data about 5 months ahead of time.

When we've 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 one year. A couple of patients will actually have up to 18 months. But at least 12 patients, slightly more, to discuss with the FDA. More data continues to roll in over the course of this year, but we won't be able to import that into the briefing book.

Is that correct? Yeah. What you want to do is you want to look for clinical benefit.

Remember, 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 Approval is based off a judgment call of 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 embryonic muscle, heavy chain, titin, 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 had biological correlate data.