Dianthus clears CIDP interim GO gate; Part B relapse data due by year-end
The Phase 3 CAPTIVATE trial hit its Part A responder bar with 20 confirmed responders, and Dianthus now moves to the randomized-withdrawal Part B, the study that will decide the drug's regulatory path in CIDP.
Executive Summary
- Dianthus Therapeutics' Phase 3 CAPTIVATE trial in CIDP cleared its Part A interim bar, and the company moved directly into the randomized-withdrawal portion of the study that carries the primary endpoint.
- The company has said this single trial is intended to support a Biologics License Application, which means the upcoming relapse data, not the interim result already reported, decides the regulatory path.
- DNTH103 shares its complement-pathway target with a Sanofi program also in Phase 3 CIDP testing, and neither has posted a resolved randomized relapse result, leaving the mechanism unbenchmarked in this indication.
- Passing the interim bar cleanly reduces near-term operational risk to the program, but it does not substitute for the withdrawal-design relapse data that will actually test efficacy.
The interim result
Dianthus Therapeutics announced on March 9, 2026 that the Part A interim responder analysis of the Phase 3 CAPTIVATE trial (NCT06858579) reached its prespecified target of 20 confirmed responders, achieved with fewer than 40 participants enrolled in the open-label lead-in. An independent Data Safety Monitoring Board confirmed the go-decision, and the company reported no related serious infections, autoimmune activation symptoms, or discontinuations. That result triggered automatic progression into Part B, the randomized, placebo-controlled withdrawal phase that carries the trial's registered primary endpoint: time from first dose to relapse, assessed by the adjusted Inflammatory Neuropathy Cause and Treatment (INCAT) disability scale. NCT06858579+1A Study to Evaluate the Efficacy and Safety of DNTH103 in Adults With Chronic Inflammatory Demyelinating Polyneuropathy (CAPTIVATE)NCT06858579Dianthus Therapeutics Highlights Recent Business Achievements and Reports Q4 and FY 2024 ...Mar 11, 2025
Probability of SuccessBased on the AppliedXL Probability of Success model. For more information about the methodology, read the research here.
What Part B will test
CAPTIVATE is designed as a single, global, two-part randomized-withdrawal Phase 3 trial, meaning patients who respond in the open-label lead-in are then randomized to continued DNTH103 or placebo to see who relapses first. Dianthus said in its March 11, 2025 disclosure that it believes this single pivotal trial can support a Biologics License Application filing in adult CIDP patients, and in its most recent guidance the company said it expects to provide CAPTIVATE Part B top-line results by the end of 2026. The trial's registered primary completion date remains December 31, 2028, but the interim readout schedule is the near-term catalyst investors are tracking. DianthusDianthus Therapeutics Highlights Recent Business Achievements and Reports Q4 and FY 2024 ...Mar 11, 2025
Enrollment target reset
The trial's anticipated enrollment target was revised from 480 to 256 participants on April 21, 2026, a change the operational model characterizes as a routine Part A-to-Part B resizing rather than a deviation from plan, since Dianthus had already disclosed intent to enroll up to 256 in Part A to randomize 128 into Part B once the interim bar was met. The registry marks the trial Recruiting, with three eligibility-criteria amendments and two endpoint amendments recorded to date, a change cadence the protocol-stability tool labels Stable at roughly one change event per year. NCT06858579A Study to Evaluate the Efficacy and Safety of DNTH103 in Adults With Chronic Inflammatory Demyelinating Polyneuropathy (CAPTIVATE)NCT06858579
The competitive frame
DNTH103 targets the active form of the C1s protein in the classical complement pathway. The nearest mechanism neighbor in CIDP is Sanofi's riliprubart, also a C1s-targeting monoclonal antibody, currently in a Phase 3 long-term safety and efficacy study in the same indication (NCT06859099). Neither program has posted a resolved randomized relapse result in CIDP, so the mechanism carries no completed same-target precedent in this indication to benchmark against. The broader CIDP trial field remains built mostly on immunoglobulin and FcRn-pathway approaches such as efgartigimod and rozanolixizumab, which work through different mechanisms and do not directly compete on target.
This analysis was produced using AI-assisted reporting systems, AppliedXL data, and official public records. These systems undergo editorial review, quality checks, and regular audits by human experts. Errors may still occur, as with any automated system. Always consult the linked primary sources. Read our AI Editorial Policy.