Updated May 2026 · ClinicalTrials.gov
A 2-Part Study to Learn Whether Litifilimab (BIIB059) Injections Can Improve Symptoms of Adult Participants Who Have Active Cutaneous Lupus Erythematosus
A 2-Part Seamless Part A (Phase 2)/Part B (Phase 3) Randomized, Double-Blind, Placebo-Controlled, Multicenter Study to Evaluate the Efficacy and Safety of BIIB059 in Participants With Active Subacute Cutaneous Lupus Erythematosus and/or Chronic Cutaneous Lupus Erythematosus With or Without Systemic Manifestations and Refractory and/or Intolerant to Antimalarial Therapy (AMETHYST)
A 2-Part Study to Learn Whether Litifilimab (BIIB059) Injections Can Improve Symptoms of Adult Participants Who Have Active Cutaneous Lupus Erythematosus (NCT05531565) is a Phase 2 / Phase 3 interventional studying Subacute Cutaneous Lupus Erythematosus and Chronic Cutaneous Lupus Erythematosus, sponsored by Biogen. RECRUITING as of the most recent ClinicalTrials.gov update. Talk to your doctor before contacting the trial site.
About This Trial
In this study, researchers will learn more about a study drug called litifilimab (BIIB059) in participants with cutaneous lupus erythematosus (CLE). The study will focus on participants who have either active subacute CLE or chronic CLE, or both. They may also have systemic lupus erythematosus (SLE). The participants did not respond to antimalarial therapy or had problems with the treatment that made it hard to continue. The main objective of the study is to learn about the effect litifilimab has on lowering the activity of the skin disease. Researchers will measure symptoms and signs of CLE over time using a variety of scoring tools. These include the Cutaneous Lupus Erythematosus Disease Area and Severity Index (CLASI), the Cutaneous Lupus Activity of Investigator's Global Assessment-Revised (CLA-IGA-R), and the SELENA-SLEDAI Flare Index (SFI). The main questions researchers want to answer are: * How many participants have a score of 0 or 1 on the CLA-IGA-R looking at skin redness after treatment? * How many participants have their skin disease activity go down by at least 70% as measured by CLASI? Researchers will also learn more about the safety of litifilimab. They will study how participants' immune systems respond to litifilimab. Additionally, they will measure the effect litifilimab and CLE have on the quality of life of participants using a group of questionnaires. The study will be split into 2 parts - Part A and Part B. Both parts will be done as follows: * After screening, participants will be randomized to receive either litifilimab or placebo for the 1st treatment period. A placebo looks like the study drug but contains no real medicine. * Participants will receive either litifilimab or placebo as injections under the skin once every 4 weeks. * The 1st treatment period will be double blinded which means neither the researchers nor the participants will know if the participants are receiving litifilimab or placebo. * This double blinded treatment period will last 24 weeks, after which the 2nd treatment period will begin. * During the 2nd treatment period, all participants will receive litifilimab for 28 weeks. * After completing treatment in this study, participants that qualify will be given the choice to join the Long-Term Extension study, 230LE305. If they do not, they will move into a follow-up safety period that will last up to 24 weeks. * The total study duration for participants will be up to 80 weeks.
What Stage of Research Is This?
Phase 2 trials evaluate whether a treatment actually works against Subacute Cutaneous Lupus Erythematosus and continue monitoring side effects. Phase 2 enrolls larger groups (typically 100–300 patients) and produces the first real efficacy signal. A successful Phase 2 readout is what unlocks the much larger Phase 3 confirmatory trials needed for FDA approval.
This trial is currently recruiting participants. The sponsor has registered the study with ClinicalTrials.gov as actively enrolling, which means new applicants who meet the eligibility criteria can be considered for screening. Trial status can change between updates — confirm current recruiting status with the study contact before traveling for a screening visit.
A target enrollment of 450 participants makes this a sizable late-stage trial. Studies in this range typically have enough power to detect clinically meaningful differences from a comparator and to characterize less-common side effects.
Who May Be Eligible (Plain English)
These are translations of the protocol\'s inclusion and exclusion criteria, simplified for patients and caregivers. The original clinical text appears below. Eligibility is ultimately confirmed by the trial site\'s screening process — this summary is a starting point for a conversation with your doctor, not a final determination.
Original Eligibility Criteria
View original clinical language
Treatments Being Tested
Litifilimab
Administered as specified in the treatment arm.
Placebo
Administered as specified in the treatment arm.
Locations (20)
Trial sites listed on ClinicalTrials.gov for this study. Site activation status can vary — confirm with the specific site before traveling for a screening visit.
How to Talk to Your Doctor About This Trial
Bring the printable summary of this trial — including the NCT ID (NCT05531565), the sponsor (Biogen), and the key eligibility criteria — to your next appointment. Your doctor can review the inclusion and exclusion criteria against your medical history, lab values, and current treatments to assess whether you are likely to qualify. They can also help you weigh whether trial participation makes sense alongside your existing care plan.
Useful questions to walk through together: What does the trial protocol require beyond standard care? How long is the active treatment phase, and how long is follow-up? Are there study visits at sites I can reach? Who pays for the trial-specific procedures, and who pays for standard-of-care portions? See our 25 questions to ask about clinical trials guide for a more complete checklist.
Authoritative Sources
The official record for this trial lives on ClinicalTrials.gov — the federal registry maintained by the National Library of Medicine at NIH. For background on how this trial fits into the FDA approval pathway, see the FDA drug approval process. For oncology-specific guidance for patients considering trials, the National Cancer Institute publishes patient-oriented overviews. International trial registries are aggregated by the WHO ICTRP.
Frequently Asked Questions
What is the NCT05531565 clinical trial studying?
In this study, researchers will learn more about a study drug called litifilimab (BIIB059) in participants with cutaneous lupus erythematosus (CLE). The study will focus on participants who have either active subacute CLE or chronic CLE, or both. They may also have systemic lupus erythematosus (SLE). The participants did not respond to antimalarial therapy or had problems with the treatment that made it hard to continue. The main objective of the study is to learn about the effect litifilimab has on lowering the activity of the skin disease. Researchers will measure symptoms and signs of CLE … The full protocol is registered on ClinicalTrials.gov and includes the primary outcome measures, eligibility criteria, and study endpoints.
Who can participate in NCT05531565?
Eligibility for this trial depends on the specific inclusion and exclusion criteria set by the sponsor. The plain-English summary above translates the most important criteria into accessible language; the official clinical text is preserved in the collapsible section underneath. Whether you fit any specific trial is a medical decision your doctor needs to confirm — bring the trial information to your treating physician for a full review against your medical history.
How do I contact the trial site for NCT05531565?
Contact information registered with ClinicalTrials.gov is shown in the sidebar of this page. Before reaching out, confirm with your treating physician that this trial is appropriate for your situation. The trial site will then walk you through the screening process to determine final eligibility.
Is participating in a clinical trial safe?
Clinical trials in the United States are regulated by the FDA and overseen by Institutional Review Boards (IRBs) that review the protocol for safety. Risk varies by trial — Phase 1 studies test new treatments in humans for the first time, while Phase 3 trials use treatments that have already passed earlier safety screening. The informed consent document for any specific trial details the known risks and what to expect. Discuss those risks with your physician before deciding whether to participate.
Where can I verify the data on this page?
Every detail on this page comes directly from the ClinicalTrials.gov API. Click "View on ClinicalTrials.gov" in the sidebar to see the official, unmodified record. The federal record is always authoritative; this page is a structured presentation with a plain-English eligibility translation. For background on how clinical trials are regulated, see the FDA drug approval process documentation.
How This Page Is Built
Every field on this page is pulled directly from the ClinicalTrials.gov API v2 — no estimates, no proxies. The plain-English eligibility translation is generated from the original protocol text and reviewed for fidelity to the underlying clinical criteria. The original clinical text remains visible in the collapsible section above so users and clinicians can verify the translation. Read the full methodology for the data pipeline and known limitations.
Source: ClinicalTrials.gov API v2 record for NCT05531565. Maintained by the National Library of Medicine at NIH. Public domain. Cite as: "TrialFinderData. NCT05531565. Data: ClinicalTrials.gov."
Medical disclaimer: This page is informational, not medical advice. Talk to your doctor about whether a clinical trial is right for you.
Last updated 2026-05-08 · Data from ClinicalTrials.gov.