Data Readout

Dianthus keeps Q4 2026 target for DNTH103 trial in rare nerve disease

The Phase 2 MoMeNtum trial pits claseprubart against placebo in multifocal motor neuropathy, a setting with no approved complement-targeted therapy and where IVIg remains the standard of care.

By AppliedXLJuly 13, 2026Trial NCT06537999

Executive Summary

Dianthus is running a randomized, placebo-controlled Phase 2 trial testing whether selectively blocking the active form of C1s can help patients with multifocal motor neuropathy, a nerve disease currently managed with chronic immunoglobulin infusions.
The company has consistently guided to a second-half 2026 readout across multiple disclosures, and its most recent update narrowed that guidance to the fourth quarter without any registry sign of delay.
The trial's protocol and enrollment profile show no destabilizing changes heading into the readout, which shifts the open question from execution risk to what the data itself will show.
No therapy sharing this mechanism has been approved in this indication, and the nearest late-stage rival is testing a different complement target against immunoglobulin rather than placebo, leaving this readout to stand largely on its own evidence.

The catalyst

Dianthus Therapeutics reported in a May 5, 2026 business update that the Phase 2 MoMeNtum trial of claseprubart in multifocal motor neuropathy (MMN) remains ongoing, with top-line results on track for the fourth quarter of 2026. The trial, registered as NCT06537999, is a randomized study with two active-treatment arms and one placebo comparator arm, enrolling adults age 18 to 75 who have documented responsiveness to immunoglobulin (Ig) therapy and are on a stable Ig regimen. Chief Executive Officer Marino Garcia said the quarter was "a pivotal period for Dianthus," pointing to progress across the company's complement-targeting franchise, though that comment referred to a related CIDP program rather than the MMN trial itself. Dianthus+1

Probability of Success

Endpoint Met33%

Completes61%

Clinical Significance10%

Regulatory24%

What the trial tests

Claseprubart is a monoclonal antibody engineered to selectively inhibit only the active form of C1s, a protein in the classical complement pathway, and is designed for subcutaneous, self-administered dosing as infrequently as once every two or four weeks. The MoMeNtum trial's registered secondary endpoints include treatment-emergent adverse events, grip strength, the 9-Hole Peg Test, the MRC sum score and the Multifocal Motor Neuropathy Rasch-Built Overall Disability Scale, alongside patient-reported measures such as the Patient Global Impression of Change and time to retreatment with immunoglobulin. The design targets 36 patients, a size set at trial initiation on September 17, 2024, that has not changed since. Dianthus+1

Timing discipline

Dianthus has repeated the same second-half or fourth-quarter 2026 guidance across multiple disclosures dating back to June 2024, and the trial's registered primary completion date of June 30, 2026 has not shifted since it was first set. No enrollment change, no primary-completion-date amendment and no post-completion endpoint change have been recorded on the trial. That protocol stability, paired with a trial that has been actively recruiting across sites in the United States, Poland, Spain, the United Kingdom, France, Denmark, Canada, Italy, South Korea, China, Malaysia and several other countries, points to routine execution rather than any operational strain heading into the readout. NCT06537999

The competitive frame

No therapy sharing claseprubart's mechanism, selective inhibition of active C1s, has been approved in multifocal motor neuropathy. The nearest late-stage precedent in the indication is argenx's empasiprubart, a Phase 3 program that targets a different complement protein, C2, and is being tested head-to-head against intravenous immunoglobulin rather than placebo, with completion guided for September 2026. argenx also runs a Phase 2 study of ARGX-117 in the same indication. Standard care for multifocal motor neuropathy remains chronic immunoglobulin infusion, and no complement-targeted mechanism has yet established an approved alternative in this setting. A result from claseprubart that shows a treatment effect against placebo, on a validated functional measure such as grip strength or the MRC sum score, sustained through the trial's follow-up, would be the type of finding that distinguishes it in a field where immunoglobulin remains the only approved option. Dianthus

Franchise readthrough

Claseprubart is Dianthus's lead asset across three neuromuscular indications. The company said in the same update that its Phase 3 EMERGE trial in generalized myasthenia gravis is on track to start in mid-2026 following an end-of-Phase 2 FDA meeting, with results expected in the second half of 2028, and that an early GO decision was reached in March 2026 for the CAPTIVATE trial in chronic inflammatory demyelinating polyradiculoneuropathy after 20 confirmed responders were identified among fewer than the 40 participants planned to complete Part A. Claseprubart also holds FDA Orphan Drug Designation for myasthenia gravis. The MoMeNtum result in MMN will add a third data point on whether selective active-C1s inhibition produces a consistent clinical effect across this neuromuscular portfolio. Dianthus

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