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Long-term evaluation of M5049 for lupus patients

A Phase II, Double-blind, Dose-Ranging, Parallel, Long-term Extension Study to Evaluate the Safety and Efficacy of Enpatoran in Participants With Subacute Cutaneous Lupus Erythematosus, Discoid Lupus Erythematosus and/or Systemic Lupus Erythematosus Having Completed the WILLOW (MS200569_0003) Study Treatment (WILLOW LTE)

PHASE2 · Merck Healthcare KGaA, Darmstadt, Germany, an affiliate of Merck KGaA, Darmstadt, Germany · NCT05540327

This study is testing a new oral medication called M5049 to see if it is safe and effective for people with different types of lupus over a longer period of time.

Quick facts

PhasePHASE2
Study typeInterventional
Enrollment532 (estimated)
Ages18 Years to 76 Years
SexAll
SponsorMerck Healthcare KGaA, Darmstadt, Germany, an affiliate of Merck KGaA, Darmstadt, Germany (industry)
Locations123 sites (Torrance, California and 122 other locations)
Trial IDNCT05540327 on ClinicalTrials.gov

What this trial studies

This study evaluates the long-term safety and efficacy of M5049, an oral medication, in patients with subacute cutaneous lupus erythematosus (SCLE), discoid lupus erythematosus (DLE), and systemic lupus erythematosus (SLE) who have previously completed a 24-week treatment period. Participants will receive varying doses of M5049 or a placebo to assess its effects over an extended period. The study aims to gather data on how well the medication works and its safety profile in a real-world setting.

Who should consider this trial

Good fit: Ideal candidates are adults with active SCLE, DLE, or SLE who have completed the initial 24-week treatment of the Willow study.

Not a fit: Patients who experienced serious adverse events related to the study intervention during the previous Willow study may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could provide a new effective treatment option for patients suffering from lupus.

How similar studies have performed: Other studies have shown promise in evaluating treatments for lupus, but this specific long-term evaluation of M5049 is relatively novel.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

* Are active SCLE, DLE and/or SLE that have completed the 24 week Treatment of the Willow Study
* Have a Body Mass Index (BMI) within the \>= 40 kilograms per meter square (inclusive) at Screening
* Other protocol defined inclusion criteria could apply

Exclusion Criteria:

* Participants who experienced serious event(s) related to the study intervention during the WILLOW study
* Other severe acute or chronic medical or psychiatric condition or laboratory abnormality that may increase the risk associated with Long Term Extension (LTE) study participation
* Ongoing or active clinically significant viral (including Severe acute respiratory syndrome coronavirus 2 \[(SARS-CoV-2)\], bacterial or fungal infection, or any major episode of infection requiring hospitalization
* Received LTE prohibited medication during the WILLOW study or after the WILLOW study Week 24
* Participation in any other investigational drug study after the WILLOW study Week 24
* Other protocol defined exclusion criteria could apply

Where this trial is running

Torrance, California and 122 other locations

+73 more sites — see ClinicalTrials.gov for the full list.

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Systemic Lupus Erythematosus, Toll-like Receptor 7, Toll-like Receptor 8, WILLOW, Adults, SLE, CLE, Lupus

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.