Breakthrough Developments in Duchenne Muscular Dystrophy Treatment: New Candidates Show Promise for 2025

As the landscape for Duchenne muscular dystrophy (DMD) treatment continues to evolve, several pharmaceutical companies are making significant strides in developing innovative therapies. With eight drugs approved in the last eight years, including the first gene therapy, the industry is poised for another wave of progress. This article examines five promising DMD candidates that are expected to make headlines in 2025.

Next-Generation Exon Skippers Show Impressive Results

In the realm of exon skipping therapies, three companies are leading the charge with remarkable advancements. Dyne Therapeutics, Wave Life Sciences, and Avidity Biosciences are all reporting unprecedented levels of dystrophin expression in their clinical trials.

Dyne Therapeutics' Dyne-251, targeting exon 51, has demonstrated more than 10-fold higher dystrophin expression compared to the current standard of care. In a head-to-head comparison with Sarepta's Exondys 51, Dyne-251 achieved nearly 9% mean absolute dystrophin when adjusted for muscle content. The company is currently recruiting for a pivotal trial, with data expected by the end of 2025.

Wave Life Sciences' WVE-N531, an exon 53 skipper, showed consistent 9% dystrophin expression across patients in a Phase II study. This translated to reduced blood levels of creatine kinase, a biomarker for muscle damage. Full 48-week data, including impact on clinical measurements, is anticipated in the first quarter of 2025.

Perhaps most striking is Avidity Biosciences' delpacibart zotadirsen (del-zota), which targets exon 44 – an area currently without approved treatments. In Phase I/II trials, del-zota increased dystrophin production to 25% of normal function, some of the highest levels seen in any DMD drug trial. The FDA has already granted del-zota orphan drug designation and fast-track status.

Cell and Gene Therapies Target Cardiac Complications

While exon skippers continue to evolve, cell and gene therapies are making inroads in addressing the cardiac complications of DMD, a leading cause of mortality in patients.

Capricor Therapeutics' deramiocel, an allogeneic cell therapy derived from donor hearts, is under FDA review for DMD cardiomyopathy. If approved, it would be the first therapy specifically targeting this aspect of the disease. Phase II studies have shown deramiocel slowing disease progression in non-ambulatory patients by almost 50% in terms of upper limb performance loss. More critically, it has demonstrated a slowing of decline in cardiac function. Capricor anticipates a potential fourth-quarter launch, pending FDA approval.

In the gene therapy space, Regenxbio is advancing RGX-202 in a pivotal phase study. Early results from November 2024 showed improvements in strength and time function tests, along with a strong safety profile. The company is targeting a younger patient population than the currently approved gene therapy, with enrollment open to patients aged 1 year and older. Regenxbio expects to submit a Biologics License Application (BLA) in 2026.

As these candidates progress through clinical trials and regulatory reviews, 2025 is shaping up to be a pivotal year for DMD treatment. With potential approvals on the horizon, patients and families affected by this devastating disease may soon have access to a more comprehensive toolbox of treatment options, addressing multiple aspects of DMD from skeletal muscle function to cardiac health.