New drug targets immune overdrive in six rare diseases

NCT ID NCT06371417

Disease control Sponsor: Chugai Pharmaceutical Source: ClinicalTrials.gov ↗

First seen Jun 27, 2026 · Last updated Jul 23, 2026 · Updated 2 times

Summary

This early-stage trial is testing a drug called RAY121 in 144 people with one of six immune diseases, including antiphospholipid syndrome and bullous pemphigoid. The drug works by blocking a specific part of the immune system (the complement pathway) that can cause tissue damage. The main goal is to check safety and how the body handles the drug, with a first look at whether it helps control the disease.

What this could mean

Our plain-language read of the trial. This is informational only, not medical advice or a prediction.

Active substance: RAY121 (a drug that blocks part of the immune system called the complement pathway)
What this could lead to: If successful, this could point toward a new treatment option for several rare immune diseases by calming overactive immune attacks.
What could go wrong: This is a very early Phase 1b trial, so it is primarily testing safety, not yet proving effectiveness. The drug may not work or could cause side effects, and results may not apply to all patients.

This is an AI summary of the original study and may miss details. Read our disclaimer.

Study facts

What this study's own registry entry says, in plain language.

Phase

Phase 1

The first testing in people. Mainly checks safety and dose, usually in a small group.

Participants

About 144 people

The number the study aims to enrol. It can still change while the study runs.

Started

Aug 2024

Expected to finish

Jun 2027

An estimate. End dates often move.

Lead sponsor

A company

The lead sponsor is a pharmaceutical, biotech, or medical-device company.

Who can take part

This study's own entry requirements. Only the study team can say for certain whether you qualify.

Ages

18 to 85 years

Sex

Anyone

Healthy volunteers

Not accepted

This study is not open to healthy volunteers. The entry requirements below say who it is open to.

Show the full entry requirements

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

1. Signed informed consent form 2. Age ≥ 18 and ≤ 85 at the time of signing informed consent form with Karnofsky score ≥ 60 % at screening 3. Ability to comply with the study protocol 4. For women of childbearing potential: agreement to remain abstinent (refrain from heterosexual intercourse) or use highly effective contraceptive methods 5. For men: agreement to remain abstinent (refrain from heterosexual intercourse) or use contraceptive measures, and agreement to refrain from donating sperm 6. APS cohort: Established primary APS defined by the following criteria (at least one of the laboratory criteria and one of the clinical criteria must be met): * Laboratory criteria (aPL profile) * Persistently positive LA test * Persistently positive aCL IgG isotype * Persistently positive aβ2GPI IgG isotype * Clinical criteria * Livedoid vasculopathy and presence of skin ulcer * Acute/chronic aPL nephropathy 7. BP cohort: 1\) Predominant cutaneous lesions 2) Diagnosis with BP with following assessments positive: 1. Positive direct immunofluorescence, and either 2. Positive indirect immunofluorescence, or 3. Positive serology on ELISA for BP180 autoantibody 3) BPDAI score \>= 20 4) Weekly average of daily Peak Pruritus NRS \>=4 5) Accept to take photograph of bullous lesions 8\. BS cohort: 1. Diagnosed with BS 2. Oral ulcers that occurred at least 3 times in the previous 12 month period 3. Have at least 2 oral ulcers over the 4 weeks prior to screening 4. Have at least 2 oral ulcers at Week 0 5. Have prior treatment with at least 1 non-biologic BS therapy 6. Patients who need systemic therapy as whose oral or mucocutaneous ulcers cannot be adequately controlled by topical therapy 9\. DM cohort: 1. Diagnosed with definite or probable inflammatory myopathies and categorized as DM 2. Patients with inadequate response to corticosteroids and/or immune-suppressants or intolerance to DM therapies 3. MMT-8 score \< 142, with at least one abnormality in the following Core Set Measures: * PtGA-VAS \>= 2 cm * PhGA-VAS \>= 2 cm * Global extra-muscular activity \>= 2 cm * At least one muscle enzyme \> 1.5 times ULN * HAQ \>= 0.25 4. Moderate to severe DM defined as CDASI activity score \> 14 10\. IMNM cohort: 1. Clinically Diagnosed with IMNM as anti-HMGCR myopathy or anti-SRP myopathy 2. CK \> 1,000 U/L 3. Patients who have an inadequate response to corticosteroids and/or immunesuppressants or intolerance to IMNM therapies 4. MMT-8 score \< 142 11\. ITP cohort: 1. Confirmed diagnosis of persistent/chronic ITP based on the following criteria: * ITP defined per the current guidelines * Platelet count \<= 30 × 10\^9/L on 2 consecutive occasions 2. Lack of an sustained adequate platelet count response to a thrombopoietin receptor agonist and at least one other ITP treatment or a second TPO-RA 3. A history of response with an platelet counts increase more than 20 × 10\^9/L from baseline by at least one prior line of therapy Exclusion Criteria: 1. History of anaphylaxis or hypersensitivity to a biologic agent 2. Active infection requiring systemic antiviral, antibiotics or antifungal 3. Planned surgery during the study 4. Pregnant or breastfeeding, or intending to become pregnant 5. Any serious medical condition or abnormality in clinical laboratory tests that precludes the patient's safe participation in and completion of the study 6. Clinically significant ECG abnormalities 7. Illicit drug or alcohol abuse 8. Clinical diagnosis of autoimmune diseases other than the target disease (except for Sjögren's syndrome in DM and IMNM) 9. Positive for hepatitis B surface antigen 10. Positive for hepatitis C virus antibody 11. Positive for human immunodeficiency virus antibody 12. Evidence of current infection with tuberculosis 13. History of cancer within 5 years 14. Treatment with investigational therapy within 28 days or 5 half-lives 15. Previous and current treatment with anti-C1s antibody at any time 16. Other complement inhibitors within 3 months 17. Patients who receive any treatments which fall into the Prohibited Therapy Criteria 18. Patients with an elevated alanine aminotransferase or aspartate aminotransferase \> 1.5 × ULN in combination with an elevated total bilirubin \> 1.5 × ULN 19. APS cohort: * 1\) APS associated with other systemic autoimmune disease * 2\) Acute thrombosis (arterial or venous acute thrombosis diagnosis) within 30 days before screening * 3\) Patients with thrombotic APS without any anticoagulation treatment * 4\) Treatment with prohibited medications 20. BP cohort: ・ 1) Initiation of treatment with or increase in the dose of systemic or topical corticosteroid within 2 weeks * 2\) Current treatment with a drug that may cause or exacerbate BP unless the dose has been stable * 3\) Initiation of treatment with topical calcineurin inhibitor, or topical phosphodiesterase (PDE) 4 inhibitor within 7 days * 4\) Treatment with prohibited medications 21. BS cohort: ・ 1) BS-related active major organ involvement-ocular lesions requiring immunosuppressive therapy, pulmonary (e.g., pulmonary artery aneurysm), vascular (e.g., thrombophlebitis), gastrointestinal (e.g., ulcers along the gastrointestinal tract), and central nervous systems (e.g., meningoencephalitis) manifestations * 2\) History of venous or arterial thrombosis within 1 year * 3\) Treatment with prohibited medications 22. DM cohort: ・ 1) PhGA-VAS improvement \>= 3, or clinically relevant improvement between screening and baseline * 2\) Overlap myositis (except for overlap with Sjögren's syndrome), connective tissue disease associated DM, inclusion body myositis, polymyositis, IMNM, juvenile DM or drug-induced myopathy * 3\) Cancer-associated myositis * 4\) Significant muscle damage * 5\) Past history of severe Interstitial lung disease flare, severe non-infectious lung inflammation which required active intervention, or multiple episodes of lung disease * 6\) Severe respiratory muscle weakness * 7\) Severe bulbar palsy * 8\) Treatment with prohibited medications 23. IMNM cohort: ・ 1) PhGA-VAS improvement \>= 3, or clinically relevant improvement between screening and baseline ・ 2) Overlap myositis (except for overlap with Sjögren's syndrome), connective tissue disease associated DM, inclusion body myositis, polymyositis, juvenile DM or druginduced myopathy ・ 3) Cancer-associated myositis ・ 4) Significant muscle damage ・ 5) Past history of severe Interstitial lung disease (ILD) flare, severe non-infectious lung inflammation which required active intervention, or multiple episodes of lung disease ・ 6) Severe respiratory muscle weakness ・ 7) Severe bulbar palsy ・ 8) Treatment with prohibited medications 24. ITP cohort: ・ 1) Secondary ITP ・ 2) Clinical diagnosis or history of Myelodysplastic Syndrome or autoimmune hemolytic anemia ・ 3) History of venous or arterial thrombosis within 12 months ・ 4) Patients who experienced major bleeding within 4 weeks * 5\) Treatment with prohibited medications * 6\) Any laboratory test results meet either of the following criteria at screening: * Hemoglobin \<10 g/dL * Thyroid-stimulating hormone \>= 10 μIU/mL

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Conditions

The condition(s) this trial relates to.

antiphospholipid syndrome Behcet disease bullous pemphigoid dermatomyositis immune-mediated necrotizing myopathy Purpura, Thrombocytopenic, Idiopathic thrombocytopenia due to immune destruction

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

Antiphospholipid syndrome (APS) Behçet's syndrome (BS) Bullous pemphigoid (BP) Dermatomyositis (DM) Immune thrombocytopenia (ITP) Immune-mediated necrotizing myopathy (IMNM)

How to take part

Only the study team decides who joins. These are the ways to reach them.

The places running it

63 sites in 17 countries. The list below names each one and where it is.
The official record

ClinicalTrials.gov lists the study team's own contact details, including names and phone numbers. We don't republish those.

Open the record ↗
A doctor treating you

A doctor who knows your case can contact a study site on your behalf, and can tell you whether this study is worth pursuing at all.

Contacts and locations

Locations

"SHATHD" EAD Sofia
NOT_YET_RECRUITING

Sofia, Sofia City Province, 1756, Bulgaria
AKH - Medizinische Universitaet Wien, Abteilung fuer Klinische Pharmakologie
WITHDRAWN

Vienna, 1090, Austria
AP-HP Hôpital Universitaire Pitié Salpêtrière
RECRUITING

Paris, Île-de-France Region, 75013, France
Amarillo Center for Clinical Research
WITHDRAWN

Amarillo, Texas, 79124, United States
Austin Neuromuscular Center
RECRUITING

Austin, Texas, 78759, United States
Box Hill Hospital
RECRUITING

Melbourne, Victoria, 3128, Australia
Campbelltown Public Hospital
RECRUITING

Sydney, New South Wales, 2560, Australia
Centre de Rhumatologie de l'Est du Quebec
RECRUITING

Rimouski, Quebec, G5L 8W1, Canada
Centro Clinico Academico Braga
NOT_YET_RECRUITING

Braga, Braga District, 471-243, Portugal
Centro Hospitalar de Vila Nova de Gaia/Espinho, E.P.E.
NOT_YET_RECRUITING

Vila Nova de Gaia, Porto District, 4434-502, Portugal
Centrul Medical Monza SRL
RECRUITING

Bucharest, Bucharest Municipality, 400015, Romania
Clinica Universidad de Navarra
RECRUITING

Pamplona, Community of Madrid & Navarre, 28027, Spain
Clinical Hospital Center "Sestre Milosrdnice"
RECRUITING

Zagreb, City of Zagreb, 10000, Croatia
DIEX Recherche Sherbrooke Inc.
RECRUITING

Sherbrooke, Quebec, J1L 0H8, Canada
Diagnostic Consultation Center CONVEX EOOD
WITHDRAWN

Sofia, Sofia City Province, 1202, Bulgaria
Dr. Abdurrahman Yurtaslan Oncology Teaching and Research Hospital
WITHDRAWN

Ankara, Ankara, 06200, Turkey (Türkiye)
Hamamatsu University Hospital
RECRUITING

Hamamatsu, Shizuoka, 431-3192, Japan
Hokkaido University Hospital
RECRUITING

Sapporo, Hokkaido, 060-0808, Japan
Hopital Lapeyronie,Service d'Immuno Rhumatologie
RECRUITING

Montpellier, Occitanie, 34295, France
Hospital Universitari Vall d'Hebron, Internal Medicine Dept.
RECRUITING

Barcelona, Province of Barcelona and Catalonia, 08035, Spain
Hospital Universitari i Politecnic La Fe
WITHDRAWN

Valencia, Valencia, 46026, Spain
Hospital Universitario 12 de October
NOT_YET_RECRUITING

Madrid, Madrid, 28041, Spain
Hospital Universitario Ramon y Cajal, Servicio de Reumatologia
NOT_YET_RECRUITING

Madrid, Madrid, 28034, Spain
Hospital Universitario Reina Sofia
NOT_YET_RECRUITING

Córdoba, Province Of Córdoba, 14004, Spain
Hospital Universitario Virgen del Rocio
RECRUITING

Seville, Province Of Seville, 41013, Spain
Hospital for Special Surgery
WITHDRAWN

New York, New York, 10021, United States
Hyogo Prefectural Harima-Himeji General Medical Center
RECRUITING

Himeji, Hyōgo, 670-8560, Japan
IRCCS Istituto Scientifico Romagnolo Per Lo Studio Dei Tumori "Dino Amadori" - IRST
RECRUITING

Meldola, Forlì-Cesena Province, 47014, Italy
Immanuel Klinik Rudersdorf
RECRUITING

Rüdersdorf, Brandenburg, 15622, Germany
Institute Reumatologii I'm. Eleonory Reicher
RECRUITING

Warsaw, Masovian Voivodeship, 02-637, Poland
Institute of Science Tokyo Hospital
RECRUITING

Bunkyō-Ku, Tokyo, 113-8519, Japan
Istanbul University Istanbul Medical Faculty
WITHDRAWN

Istanbul, Istanbul, 34093, Turkey (Türkiye)
Istituto Clinico Humanitas
NOT_YET_RECRUITING

Milan, Milan Province, 20089, Italy
Johns Hopkins University
RECRUITING

Baltimore, Maryland, 21224, United States
Kindai University Hospital
RECRUITING

Sakai, Osaka, 590-0197, Japan
National Center of Neurology and Psychiatry
RECRUITING

Kodaira, Tokyo, 187-8551, Japan
National Taiwan University Hospital
RECRUITING

Taipei, 100229, Taiwan
Nerve and Muscle Center of Texas
RECRUITING

Houston, Texas, 77030, United States
Northwell Health, LLC PRIME
WITHDRAWN

Lake Success, New York, 11042, United States
Ohio State University
WITHDRAWN

Columbus, Ohio, 43203, United States
Okayama University Hospital
RECRUITING

Okayama, 700-8558, Japan
Oncology Institute Prof. Dr. Ion Chiricuta I.O.C.N.
RECRUITING

Cluj-Napoca, Cluj, 11658, Romania
Oregon Health & Science University
RECRUITING

Portland, Oregon, 97239, United States
Ospedale San Giovanni Bosco
WITHDRAWN

Torino, Turin Province, 10154, Italy
Royal Prince Alfred Hospital
RECRUITING

Camperdown, New South Wales, 2050, Australia
Sanatorium Profesora Arenbergera
WITHDRAWN

Prague, Prague, 11000, Czechia
Semmelweis Egyetem
RECRUITING

Budapest, 1083, Hungary
Sorlandet sykehus Kristiansand
RECRUITING

Kristiansand, Agder County, 4604, Norway
Specialty Hospital Medico
WITHDRAWN

Rijeka, Primorje-Gorski Kotar County, 51000, Croatia
Stavanger Universitetssjukehus
RECRUITING

Stavanger, Rogaland County, 4011, Norway
Sykehuset Ostfold Fredrikstad
NOT_YET_RECRUITING

Fredrikstad, Østfold fylke, 1603, Norway
Szegedi Tudomanyegyetem Szent-Gyorgyi Albert Klinikai Kozpont
NOT_YET_RECRUITING

Szeged, Csongrád-Csanád County, 6720, Hungary
Taichung Veterans General Hospital
RECRUITING

Taipei, 407219, Taiwan
The Alfred Hospital
RECRUITING

Melbourne, Victoria, 3004, Australia
The Royal Institution for the Advancement of Learning/McGill University
RECRUITING

Montreal, Quebec, H3A 0G4, Canada
The University of Osaka Hospital
RECRUITING

Suita, Osaka, 565-0871, Japan
Toho University Omori Medical Center
RECRUITING

Ōta-ku, Tokyo, 143-8540, Japan
Tohoku Medical and Pharmaceutical University Hospital
RECRUITING

Sendai, Miyagi, ９８３-８５１２, Japan
Tohoku University Hospital
RECRUITING

Sendai, Miyagi, 980-8574, Japan
Tokai University Hospital
RECRUITING

Isehara, Kanagawa, 259-1193, Japan
Toyama University Hospital
NOT_YET_RECRUITING

Toyama, 930-0194, Japan
UMC Utrecht
RECRUITING

Utrecht, Utrecht Province, 3584 CX, Netherlands
UMHAT "Prof. Dr. St. Kirkovich", AD
NOT_YET_RECRUITING

Stara Zagora, Stara Zagora Province, 6003, Bulgaria
UMHAT Sv Ivan Rilski EAD
RECRUITING

Sofia, Sofia City Province, 1612, Bulgaria
Universitaetsklinikum Carl Gustav Carus TU Dresden, Klinik und Poliklinik f. Dermatologie
NOT_YET_RECRUITING

Sachsen, Bundesländer, 1307, Germany
Universitaetsklinikum Erlangen
NOT_YET_RECRUITING

Erlangen, Bavaria, 91054, Germany
Universitaetsklinikum Schleswig Holstein - Campus Luebeck, Klinik f Dermatologie, Allergologie u Venerologie
WITHDRAWN

Lübeck, Schleswig-Holstein, 23538, Germany
Universitaetsklinikum Tuebingen
NOT_YET_RECRUITING

Tübingen, Baden-Wurttemberg, 72076, Germany
Universitaetsmedizin Goettingen
WITHDRAWN

Göttingen, Göttingen District, 3075, Germany
University Medical Centre Groningen UMCG
RECRUITING

Groningen, Groningen Province, 9713 GZ, Netherlands
University hospital centre Zagreb
NOT_YET_RECRUITING

Zagreb, City of Zagreb, 10000, Croatia
University of Alberta Hospital - Department of Anesthesiology and Pain Medicine
RECRUITING

Edmonton, Alberta, T6G 2B7, Canada
University of Alberta Hospital - Dermatology
RECRUITING

Edmonton, Alberta, T6G 2G3, Canada
University of California-Irvine
RECRUITING

Orange, California, 92868, United States
University of Pennsylvania, Perelman Center for Advanced Medicine
RECRUITING

Philadelphia, Pennsylvania, 19104, United States
Universtity of North Carolina at Chapel Hill
RECRUITING

Chapel Hill, North Carolina, 27599, United States
Westmead Hospital
RECRUITING

Sydney, New South Wales, 2145, Australia

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