Solid Biosciences (NASDAQ:SLDB) used a presentation at the 2026 Emerging Outlook Biotech Summit to outline its gene therapy-focused pipeline and discuss recent regulatory interactions around its lead Duchenne muscular dystrophy (DMD) program, SGT-003, as well as early progress in Friedreich’s ataxia (FA).
Company overview and focus on delivery
President and CEO Bo Cumbo said the company has roughly 120 employees and describes itself as a precision genetic medicine company, with an emphasis on gene therapies. He highlighted three initial programs: SGT-003 for DMD, a dual-vector program for FA, and a program for catecholaminergic polymorphic ventricular tachycardia (CPVT). Cumbo also referenced additional work in dilated cardiomyopathy (TNNT2) and said Solid has built a capsid library and broader delivery platform.
FDA alignment and plans for a DMD registration study
Cumbo said Solid issued a press release “on Monday” describing alignment with the FDA on a registration study, calling it “a huge first step” given what he characterized as a complicated and shifting regulatory environment. He noted that Solid’s ongoing INSPIRE study is open-label, and said the company intends to seek accelerated approval in the U.S., with discussions with FDA expected “real soon.”
As part of its approach, Cumbo emphasized that Solid has not reviewed (“snooped”) functional data from the open-label cohort, which he suggested could help the company and FDA jointly determine appropriate statistical plans and the use of natural history or external controls. He also stressed the size of the safety database, stating the company had dosed 36 patients and expected to be above 40 by the time it meets with the FDA shortly.
On safety, Cumbo said that at the time of the presentation the company had not observed drug-induced liver injury, myocarditis, atypical hemolytic uremic syndrome (aHUS), or thrombotic microangiopathy (TMA) in the 36 dosed patients, while cautioning that he was not asserting such events could not occur later.
He also described plans to run a double-blind, placebo-controlled DMD study outside the U.S.—in Europe, Australia, and Canada—and said the FDA had reviewed the design, suggested changes including to secondary endpoints, and indicated the trial was reasonable. Cumbo said the first patient was originally expected to be dosed the following week, but that patient was ill and would not be dosed; the company was scheduling the next patient and anticipated dosing the first child in the double-blind study within roughly 90 days.
How Solid describes SGT-003’s differentiation
In discussing SGT-003, Cumbo said Solid designed the program “from day one” to improve upon first-generation DMD gene therapy approaches. He described several elements he believes differentiate SGT-003:
- Capsid and targeting: Cumbo said the company engineered a capsid (which he later referred to as SLB101) with RGD peptides intended to bind integrin receptors upregulated in skeletal and cardiac muscle. He said the capsid clears rapidly from blood in human subjects, claiming ~90% clearance by day four, which he believes could matter for safety.
- Cardiac expression and liver signals: He said the capsid reached human cardiomyocytes and expressed “about 20 times greater than AAV9.” He also asserted that animal findings suggested liver “retargeting,” and noted that in humans the company was tracking liver enzymes (ALT/AST) and GGT, which he said did not show the spikes seen with other approaches.
- Transgene/construct design: Cumbo said the construct aims to preserve flexibility in a shortened dystrophin protein and includes features intended to support nNOS creation. He discussed nitric oxide’s role in coronary perfusion and potential impacts on oxidative stress, fibrosis, and inflammation, and also mentioned incorporating alpha-syntrophin and caveolin-4 with a rationale related to ERK phosphorylation in the heart.
- Manufacturing and full-to-empty ratio: Cumbo said Solid’s manufacturing process yields approximately a 75% full-to-empty capsid ratio. He argued that a higher fraction of full capsids could support expression and reduce the need to increase vector genomes per kilogram, which he said could otherwise place pressure on complement and the liver.
He also argued that “ease of use” will ultimately drive adoption, suggesting physicians are constrained by time and monitoring demands. In that context, he contrasted Solid’s current regimen—described as using only steroids—with other approaches he said can involve higher rates of liver injury, hospitalizations, cardiomyopathy, and the use of additional immunomodulatory or complement-related therapies.
Protocol learning: steroid timing and infusion considerations
Cumbo said early dosing in the first 10 boys revealed variability that the company did not attribute solely to disease heterogeneity. He said Solid identified a marker (not disclosed during the session) and concluded that the first 24 to 48 hours are important for nuclear delivery and subsequent expression. He described a change in steroid strategy: instead of increasing steroids on the day of dosing, the company now starts the increased steroid regimen three days prior (day minus three). Cumbo said Solid filed method-of-use patents related to steroid use with the SLB101 capsid.
DMD trial design: endpoint and 18-month assessment
Asked about the planned final assessment at 18 months, Cumbo said he personally would have preferred 24 months but could not convince physicians and families to extend a placebo-controlled study that long. He described the study population as boys ages 7 to 11, stating they are “either plateauing or declining,” and said the FDA agreed to “time to rise” as the endpoint. He added that entry criteria would include a time-to-rise greater than five seconds and less than 10 seconds, which he characterized as a “sweet spot.” Cumbo said the trial is designed to allow about six months for adjustment to the new protein and another 12 months to assess benefit.
Friedreich’s ataxia: dual route administration and first patient dosed
Turning to FA, Cumbo said the program uses a dual route of administration designed to reach the dentate nucleus of the cerebellum while also targeting the spinal column and heart. He described MRI-guided stereotactic delivery into both sides of the dentate nucleus, led by neurosurgeon Dr. Lonser at Ohio State University, followed by intravenous dosing after a rest period.
Cumbo said Solid dosed its first FA patient, a 27-year-old who was “very, very sick,” and referenced an mFARS score of 93 (noting the patient had been in the high 80s). Roughly 40 days after dosing, he said the patient experienced a headache that resolved with Tylenol and that the company had not seen other issues. He added that the team was “already hearing things” suggestive of efficacy, but emphasized it did not yet have proof.
For planned data disclosure, Cumbo said Solid expects to dose three to six FA patients over the course of the year and anticipates reading out results from the first three patients in the second half of the year, while continuing dosing in a second cohort. On expectations for clinical benefit, he cited 2.14 as the mFARS bar associated with the regulatory approval of SKYCLARYS.
About Solid Biosciences (NASDAQ:SLDB)
Solid Biosciences Inc is a clinical‐stage biotechnology company focused on the development of therapies for Duchenne muscular dystrophy (DMD), a rare genetic disorder characterized by progressive muscle degeneration. The company’s primary approach centers on gene replacement and gene editing technologies designed to restore functional dystrophin protein in patients lacking this critical muscle‐stabilizing protein.
Solid’s lead investigational therapy, SGT‐001, is a micro‐dystrophin gene therapy candidate engineered to deliver a shortened but functional form of the dystrophin gene using an adeno‐associated virus (AAV) vector.
