Dianthus Therapeutics has announced the completion of patient enrollment in its Phase 2 MaGic trial evaluating DNTH103 for the treatment of generalized Myasthenia Gravis (gMG). The trial exceeded its target enrollment, with 65 patients successfully recruited versus the planned 60 participants. The company anticipates releasing top-line results from this study in September 2025.
The MaGic trial is a global, randomized, double-blind, placebo-controlled study specifically targeting patients with acetylcholine receptor (AChR) antibody-positive gMG. Following an initial loading dose, participants will receive DNTH103 via subcutaneous injection every two weeks for an initial treatment period of 12 weeks, followed by a 52-week open-label extension.
"We are pleased to have reached this important milestone in the development of DNTH103 for gMG, which is well understood to be a classical pathway-driven disease," said Marino Garcia, Chief Executive Officer of Dianthus Therapeutics. "Latest estimates indicate that the gMG market in the U.S. exceeds 100,000 patients, approximately 85% of whom have AChR autoantibody-driven disease, with growing first-line biologic use."
Trial Design and Endpoints
The primary endpoint of the MaGic trial focuses on safety and tolerability of DNTH103. Key secondary endpoints include changes in the Myasthenia Gravis Activities of Daily Living Scale (MG-ADL) and Quantitative Myasthenia Gravis (QMG) score assessments, which are validated measures of disease activity and symptom severity in gMG patients.
DNTH103 is designed as a potent monoclonal antibody that selectively targets the classical complement pathway by inhibiting only the active form of the C1s protein. This selective inhibition approach may provide advantages over broader complement inhibitors by preserving immune activity of the lectin and alternative pathways, potentially lowering patient risk of infection from encapsulated bacteria.
Addressing Unmet Needs in gMG Treatment
Generalized Myasthenia Gravis is a chronic autoimmune disorder that causes progressive muscle weakness, affecting over 100,000 people in the United States. Despite currently available treatment options, Garcia notes that "a significant unmet need exists for patients seeking continuous symptom control, lower risk for infections, and more convenient dosing and administration, which we believe DNTH103 has the potential to address as a first-line therapy."
The investigational therapy is enhanced with YTE half-life extension technology, designed to enable a more convenient subcutaneous, self-administered injection dosed as infrequently as once every two weeks. This represents a potential improvement over existing treatments that may require more frequent dosing or administration in clinical settings.
Building a Neuromuscular Franchise
DNTH103 is central to Dianthus Therapeutics' strategy of building a neuromuscular disease franchise. Beyond gMG, the company is evaluating the compound in two additional neuromuscular conditions:
- Phase 3 CAPTIVATE trial in Chronic Inflammatory Demyelinating Polyneuropathy (CIDP), with an interim responder analysis expected in the second half of 2026
- Phase 2 MoMeNtum trial in Multifocal Motor Neuropathy (MMN), with top-line data anticipated in the second half of 2026
"DNTH103 has the potential to be a best-in-class pipeline-in-a-product across a range of autoimmune disorders with high unmet need," according to company statements. The selective inhibition of the classical complement pathway represents a targeted approach to treating complement-mediated autoimmune diseases.
About Generalized Myasthenia Gravis
gMG is characterized by antibody-mediated autoimmune attacks on acetylcholine receptors at the neuromuscular junction, leading to muscle weakness that can affect multiple body systems. The disease can cause difficulties with basic functions such as speaking, swallowing, walking, and breathing in severe cases.
Approximately 85% of gMG patients have disease driven by acetylcholine receptor (AChR) autoantibodies. The classical complement pathway plays a significant role in the pathology of the disease, making it a logical target for therapeutic intervention.
DNTH103 remains an investigational agent that has not yet received regulatory approval for any indication in any jurisdiction worldwide. The results from the MaGic trial will provide important insights into its potential efficacy and safety profile in this patient population.
