Shares of Solid Biosciences SLDB have rallied 59.9% in the past month. The stock price increase was mainly due to positive initial data, announced in mid-Feb, from the early to mid-stage study of its next-generation gene therapy product candidate, SGT-003, for treating Duchenne muscular dystrophy (DMD).

Interim biopsy data reported in the first three participants at day 90 showed an average microdystrophin expression of 110%, as measured by western blot, along with improvements in multiple biomarkers that are indicators of muscle health and resilience.

In the past three months, shares of Solid Biosciences have gained 7.6% against the industry’s 1% decline.

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More on SLDB’s Phase I/II DMD Study for SGT-003

The phase I/II INSPIRE DUCHENNE study is evaluating the safety, tolerability and efficacy of SGT-003, administered as a one-time intravenous infusion in pediatric DMD patients. As of Feb. 11, 2025, six participants have received SGT-003 doses in the INSPIRE DUCHENNE study. Enrollment is currently ongoing, with at least 10 participants expected to be dosed by early in the second quarter of 2025 and around 20 by fourth-quarter 2025.

The initial data readout also showed encouraging early signals of potential cardiac benefit. SGT-003 was well-tolerated in the first six DMD patients dosed. Adverse events were mostly mild to moderate in severity and consistent with those typically observed in AAV gene therapy.

SLDB plans to request an FDA meeting in mid-2025 to discuss a potential accelerated approval pathway for SGT-003 for DMD treatment.

DMD is a progressive and degenerative disorder that leads to weakness and wasting of the body’s muscles. The candidate is being developed using SLDB’s proprietary and rationally designed capsid (AAV-SLB101). The investigational gene therapy already enjoys the FDA’s Fast Track, Rare Pediatric Disease and Orphan Drug designations in the United States for the treatment of DMD.

SLDB’s Other Clinical-Stage Pipeline Candidate

Apart from SGT-003, Solid Biosciences’ clinical-stage pipeline comprises another novel AAV-based gene therapy candidate, SGT-212, which is being developed for the treatment of Friedreich’s ataxia (FA). In January 2025, the FDA cleared SLDB’s investigational new drug (IND) application to begin clinical studies on SGT-212 for the FA indication.

Per the company, SGT-212 is the only full-length frataxin replacement gene therapy candidate that targets the cardiac manifestations of FA. The candidate is being developed to treat the neurologic and systemic clinical manifestations of FA to address the full spectrum of disease progression.

Solid Biosciences plans to initiate a phase Ib study of SGT-212 for treating FA in the second half of 2025.

Solid Biosciences Inc. Price and Consensus

Solid Biosciences Inc. price-consensus-chart | Solid Biosciences Inc. Quote

Currently, Sarepta Therapeutics SRPT markets Elevidys as the only approved one-shot gene therapy drug for DMD in the United States. The drug initially received accelerated approval in 2023 to treat ambulatory patients aged four through five years with DMD, which was converted to full approval, last year. Additionally, in June 2024, the FDA granted accelerated approval to Elevidys for treating non-ambulatory DMD patients. 

Elevidys has been developed by Sarepta in collaboration with Roche RHHBY. Sarepta and Roche entered into a licensing agreement in 2019 to jointly develop and commercialize Elevidys. Per the agreement, RHHBY has exclusive rights to launch and commercialize the gene therapy in ex-U.S. markets. We remind the investors that, apart from Elevidys, Sarepta has three other therapies in its commercial portfolio targeting the DMD patient population — Exondys 51, Vyondys 53 and Amondys 45.

On the other hand, drug giant Biogen BIIB currently markets Skyclarys, which is the first approved treatment for FA. The FDA approved the drug in 2023, while it was approved in Europe in February 2024. The acquisition of Reata Pharmaceuticals in September 2023 added this rare disease drug to Biogen’s portfolio. BIIB’s Skyclarys recorded sales of $382.5 million in 2024.

SLDB's Zacks Rank

Solid Biosciences currently carries a Zacks Rank #2 (Buy). You can see the complete list of today’s Zacks #1 Rank (Strong Buy) stocks here.

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This article originally published on Zacks Investment Research (zacks.com).

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