Solid Biosciences Inc. has provided an update on the IGNITE DMD phase I/II microdystrophin gene therapy clinical program. As previously reported in late 2019, the IGNITE DMD clinical program was placed on hold. Today, they announced the biomarker data from the third patient dosed in the 2E14 vg/kg dose cohort of IGNITE DMD, including three-month biopsy data.

Letter to the Community

Thursday, March 12, 2020

Dear Duchenne Community,

This morning we issued a press release providing a business update, including new patient data from IGNITE DMD, Solid’s Phase I/II clinical trial of SGT-001. Our company is working with urgency and determination to address the IGNITE DMD clinical hold so we may continue to evaluate the ability of SGT-001 to help patients with Duchenne muscular dystrophy.

As you may recall, in December 2019, Solid announced biomarker data from two patients dosed in the 2E14 vg/kg dose cohort of IGNITE DMD. The data showed expression of SGT-001 microdystrophin and neuronal nitric oxide synthase (nNOS) function, providing further evidence of the therapeutic potential of SGT-001.

Today, we announced biomarker data from the third patient dosed in the 2E14 vg/kg dose cohort of IGNITE DMD, including three-month biopsy data. Using immunofluorescence assays, 50%-70% of the muscle fibers were determined to express SGT-001 microdystrophin. Immunofluorescence also showed stabilization and co-localization of nNOS and beta-sarcoglycan with SGT-001 microdystrophin. Inclusion of the dystrophin nNOS coding region in SGT-001 may result in unique activity, potentially providing important functional benefits such as diminished muscle fatigue and protection against muscle damage. Using western blot, expression was 8% of normal control samples. The levels of serum creatine kinase, a highly variable biochemical marker of muscle damage, declined from baseline.

We are encouraged by these data and continue to make progress on internal investigations and analyses to support the goal of resolving the IGNITE DMD clinical hold and advancing the SGT-001 program.

As always, we appreciate the continued support of the Duchenne community and we are looking forward to sharing our future progress.

Sincerely,

Your Solid Biosciences team

Link to letter

Recent Developments

• Today, Solid announced biomarker data from the third patient dosed in the 2E14 vg/kg dose cohort of IGNITE DMD, the company’s Phase I/II clinical trial of SGT-001, including three-month biopsy data. Using immunofluorescence assays, 50%-70% of the muscle fibers were determined to express SGT-001 microdystrophin. Immunofluorescence also showed stabilization and co-localization of nNOS and beta-sarcoglycan with SGT-001 microdystrophin. Inclusion of the dystrophin nNOS coding region in SGT-001 may result in unique activity, potentially providing important functional benefits such as diminished muscle fatigue and protection against ischemic muscle damage. Using western blot, expression was 8% of normal control samples. The levels of serum creatine kinase, a highly variable biochemical marker of muscle damage, declined from baseline.
• In January 2020, Solid announced changes to its organizational structure to create a leaner company focused on advancing SGT-001. The corporate changes implemented reduce the company’s planned corporate expenses and extend the expected cash runway.
• In December 2019, Solid announced biomarker data from two patients dosed in the 2E14 vg/kg dose cohort of IGNITE DMD. The data showed expression of SGT-001 microdystrophin and nNOS function that provides evidence SGT-001 could provide therapeutic benefit for patients with Duchenne.
• In November 2019, Solid reported that the U.S. Food and Drug Administration (FDA) placed IGNITE DMD on clinical hold following a serious adverse event in the sixth patient dosed. In December 2019, the company announced that the adverse event had fully resolved, and that the patient had resumed his normal activities. For all patients dosed in IGNITE DMD, any clinical or laboratory abnormalities observed following SGT-001 administration have fully resolved.

About Solid Biosciences

Solid Biosciences is a life science company focused solely on finding meaningful therapies for Duchenne muscular dystrophy (Duchenne). Founded by those touched by the disease, Solid is a center of excellence for Duchenne, bringing together experts in science, technology and care to bring forward meaningful therapies that have life-changing potential. For more information, please visit www.solidbio.com.