ClinicalTrials.gov record NCT06371417
Phase 1b Trial of RAY121 in Immunological Diseases (RAINBOW Trial)
Phase 1b Open-label Basket Trial of RAY121 to Inhibit Classical Complement Pathway in Immunological Diseases (RAINBOW Trial)
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AI-written from the registry record, not the study's own wording. May contain errors or omissions. Check the registry text on this page and the original record ↗ before acting on it.
This is a Phase 1b, open-label trial giving multiple doses of RAY121 by injection to people with APS, BP, Behçet's syndrome, dermatomyositis, IMNM, or ITP. The study will collect information on safety and tolerability, how the drug behaves in the body, immune responses to the drug, and early signs of effect through Week 32. Participants receive RAY121 and have laboratory assessments (including serum drug levels, complement activity, and anti-drug antibodies) and clinical evaluations.
What it is studying. The study is testing RAY121 — an inhibitor of the classical complement pathway — to evaluate its safety and tolerability, measure drug levels and related immune markers, and look for preliminary signs of effectiveness in several immune-mediated diseases.
What the researchers hope to learn. To gather early safety and tolerability data for RAY121; to describe its pharmacokinetics (how the drug behaves in the body) and pharmacodynamics (its biological effects); to measure immunogenicity (antibodies to RAY121); and to collect preliminary information on clinical activity in the listed diseases.
What this study is about
The study's own summary, as published on ClinicalTrials.gov. Underlined terms have a short explanation.
This Phase 1b basket trial will investigate the safety, tolerability, pharmacokinetics, pharmacodynamics, immunogenicity and preliminary efficacy of RAY121, a inhibitor of classical complement pathway, after multiple dose administration in patients with immunological diseases such as antiphospholipid syndrome (APS), bullous pemphigoid (BP), Behçet's Syndrome (BS), dermatomyositis (DM), immune-mediated necrotizing myopathy (IMNM) and immune thrombocytopenia (ITP).
Interventions being studied
Being studied in this trial does not mean the treatment or procedure is approved or available for this condition.
- Drug
- RAY121
Eligibility
The criteria exactly as listed on ClinicalTrials.gov. Only the study team can say whether they apply to you.
Inclusion criteria
- Signed informed consent form
- Age ≥ 18 and ≤ 85 at the time of signing informed consent form with Karnofsky score ≥ 60 % at screening
- Ability to comply with the study protocol
- For women of childbearing potential: agreement to remain abstinent (refrain from heterosexual intercourse) or use highly effective contraceptive methods
- For men: agreement to remain abstinent (refrain from heterosexual intercourse) or use contraceptive measures, and agreement to refrain from donating sperm
- 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
- BP cohort:
- Predominant cutaneous lesions 2) Diagnosis with BP with following assessments positive:
- Positive direct immunofluorescence, and either
- Positive indirect immunofluorescence, or
- 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
- BS cohort:
- Diagnosed with BS
- Oral ulcers that occurred at least 3 times in the previous 12 month period
- Have at least 2 oral ulcers over the 4 weeks prior to screening
- Have at least 2 oral ulcers at Week 0
- Have prior treatment with at least 1 non-biologic BS therapy
- Patients who need systemic therapy as whose oral or mucocutaneous ulcers cannot be adequately controlled by topical therapy
- DM cohort:
- Diagnosed with definite or probable inflammatory myopathies and categorized as DM
- Patients with inadequate response to corticosteroids and/or immune-suppressants or intolerance to DM therapies
- 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
- Moderate to severe DM defined as CDASI activity score > 14
- IMNM cohort:
- Clinically Diagnosed with IMNM as anti-HMGCR myopathy or anti-SRP myopathy
- CK > 1,000 U/L
- Patients who have an inadequate response to corticosteroids and/or immunesuppressants or intolerance to IMNM therapies
- MMT-8 score < 142
- ITP cohort:
- 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
- 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
- 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
- History of anaphylaxis or hypersensitivity to a biologic agent
- Active infection requiring systemic antiviral, antibiotics or antifungal
- Planned surgery during the study
- Pregnant or breastfeeding, or intending to become pregnant
- Any serious medical condition or abnormality in clinical laboratory tests that precludes the patient's safe participation in and completion of the study
- Clinically significant ECG abnormalities
- Illicit drug or alcohol abuse
- Clinical diagnosis of autoimmune diseases other than the target disease (except for Sjögren's syndrome in DM and IMNM)
- Positive for hepatitis B surface antigen
- Positive for hepatitis C virus antibody
- Positive for human immunodeficiency virus antibody
- Evidence of current infection with tuberculosis
- History of cancer within 5 years
- Treatment with investigational therapy within 28 days or 5 half-lives
- Previous and current treatment with anti-C1s antibody at any time
- Other complement inhibitors within 3 months
- Patients who receive any treatments which fall into the Prohibited Therapy Criteria
- Patients with an elevated alanine aminotransferase or aspartate aminotransferase > 1.5 × ULN in combination with an elevated total bilirubin > 1.5 × ULN
- APS cohort:
- APS associated with other systemic autoimmune disease
- Acute thrombosis (arterial or venous acute thrombosis diagnosis) within 30 days before screening
- Patients with thrombotic APS without any anticoagulation treatment
- Treatment with prohibited medications
- BP cohort:
- ・ 1) Initiation of treatment with or increase in the dose of systemic or topical corticosteroid within 2 weeks
- Current treatment with a drug that may cause or exacerbate BP unless the dose has been stable
- Initiation of treatment with topical calcineurin inhibitor, or topical phosphodiesterase (PDE) 4 inhibitor within 7 days
- Treatment with prohibited medications
- 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
- History of venous or arterial thrombosis within 1 year
- Treatment with prohibited medications
- DM cohort:
- ・ 1) PhGA-VAS improvement >= 3, or clinically relevant improvement between screening and baseline
- 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
- Cancer-associated myositis
- Significant muscle damage
- Past history of severe Interstitial lung disease flare, severe non-infectious lung inflammation which required active intervention, or multiple episodes of lung disease
- Severe respiratory muscle weakness
- Severe bulbar palsy
- Treatment with prohibited medications
- 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
- 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
- Treatment with prohibited medications
- Any laboratory test results meet either of the following criteria at screening:
- Hemoglobin <10 g/dL
- Thyroid-stimulating hormone >= 10 μIU/mL
Study description and what participation involves
The registry record has no detailed description beyond the summary above.
AI summaryWhat participation may involve, in plain languageShow ▾Hide ▴
AI-written from the registry record, not the study's own wording. May contain errors or omissions. Check the registry text on this page and the original record ↗ before acting on it.
Participants receive multiple doses of RAY121 by injection. They attend study visits and are followed from baseline through Week 32 for safety monitoring while investigators record any adverse events. At visits they give blood samples to measure RAY121 concentrations, complement (classical pathway) activity, active and total C1s, and anti‑RAY121 antibodies. People in the bullous pemphigoid group must agree to have photographs taken of their skin lesions.
How the study is structured. Open-label, single-group Phase 1b trial: all enrolled participants receive multiple doses of RAY121 (injection). The study follows participants from baseline through Week 32 to record adverse events and to measure serum drug concentrations, complement activity, and anti-RAY121 antibodies, along with clinical assessments.
Questions you could ask
These questions are suggestions for a conversation with the study team or your own clinician, not advice.
- The registry lists this study under Antiphospholipid Syndrome (APS); Bullous Pemphigoid (BP); Behçet's Syndrome (BS); Dermatomyositis (DM); Immune-mediated Necrotizing Myopathy (IMNM); Immune Thrombocytopenia (ITP). Does it apply to my diagnosis?
- This is an early-phase study, mainly about safety and dose. What is already known about this treatment?
- The listed sites are in Australia, Austria, Bulgaria, Canada, Croatia, Czechia, France, Germany, Hungary, Italy, Japan, Netherlands, Norway, Poland, Portugal, Romania, Spain, Taiwan, Turkey, United States. Is any of them reachable for me, and does the study help with travel?
- Which of the eligibility criteria would need to be checked with tests before I could join?
More on polymyositis
This trial is also listed on this site under Behçet's disease, dermatomyositis and familial Mediterranean fever.
Important dates
- Study start
- Aug 19, 2024
- Primary completion
- Mar 31, 2027 (estimated)
- Study completion
- Jun 30, 2027 (estimated)
- Target enrollment
- 144 participants (estimated)
- Last updated on registry
- Jul 22, 2026
- Data verified
- Oct 10, 2026
Sponsor and research team
The lead sponsor funds and oversees the trial. A pharmaceutical or biotech company sponsor typically means the study is testing that company's drug or device; a hospital, university, or government agency usually indicates investigator-initiated or publicly funded research.
- Lead sponsor
- Chugai Pharmaceutical
Central study contact
If you're interested in participating, the central contact can answer general questions about the study — including eligibility requirements and how to find a recruiting site near you. Actual eligibility is determined by the site's medical team.
- Clinical trials information 📞 only use Email ✉ clinical-trials@chugai-pharm.co.jp
Participating sites (77)
- University of California-IrvineRecruiting
Orange, California, 92868 · United States
- Johns Hopkins UniversityRecruiting
Baltimore, Maryland, 21224 · United States
- Northwell Health, LLC PRIMEWithdrawn
Lake Success, New York, 11042 · United States
- Hospital for Special SurgeryWithdrawn
New York, New York, 10021 · United States
- Universtity of North Carolina at Chapel HillRecruiting
Chapel Hill, North Carolina, 27599 · United States
- Ohio State UniversityWithdrawn
Columbus, Ohio, 43203 · United States
- Oregon Health & Science UniversityRecruiting
Portland, Oregon, 97239 · United States
- University of Pennsylvania, Perelman Center for Advanced MedicineRecruiting
Philadelphia, Pennsylvania, 19104 · United States
- Amarillo Center for Clinical ResearchWithdrawn
Amarillo, Texas, 79124 · United States
- Austin Neuromuscular CenterRecruiting
Austin, Texas, 78759 · United States
Terms used on this page · explanations by MedicalUpdates.ai
- pharmacokinetics
- How the body absorbs, distributes, breaks down and removes a drug. It is studied by measuring drug levels or related substances at set times after a dose.
- pharmacodynamics
- What a drug does to the body, for example how it changes a blood marker or a symptom, and how that relates to the dose.
- informed consent form
- The process of explaining a study, including its risks and what participation involves, so that a person can decide freely whether to take part. Consent is usually documented in writing, and a participant can choose to leave the study later.
- Karnofsky
- A scale from 100 (no complaints) down to 0 that describes how well a person can carry out daily activities. Studies often require a minimum score.
- at screening
- The checks done before enrolment to see whether a person qualifies, such as tests, scans or a review of medical history.
- women of childbearing potential
- Studies often ask participants who could become pregnant, or could father a child, to use contraception during the study and for a period afterwards, because the effect of the treatment on a pregnancy is unknown.
- cohort
- A group of people who share a characteristic, such as a diagnosis, and are studied together. 'Prospective' means they are followed forward from enrolment; 'retrospective' means existing records are reviewed.
- prior treatment
- Treatment a person has already had for the condition. A 'line of therapy' is one course of treatment; studies often require, or limit, the number of prior lines.
- corticosteroids
- Steroid medicines, such as prednisone, that reduce inflammation. Studies often require a stable dose at entry or measure whether the study treatment allows the dose to be reduced.
- ULN
- The highest value of a blood test that a laboratory considers normal. Criteria such as '≤ 3 × ULN' mean the result must be no more than three times that value.
- baseline
- Measurements taken at the start of the study, before any study treatment, so that later results can be compared with them.
- ECG
- A recording of the heart's electrical activity. QTc is one measurement from it; some drugs are avoided if it is prolonged.
- investigational
- A treatment that is being tested and has not been approved for this use. It may be approved for a different condition. Being studied does not mean it works or is available outside the study.
- 5 half-lives
- The time it takes for the amount of a drug in the body to fall by half. 'Five half-lives' is often used as the point at which a previous drug has essentially left the body.
- Prohibited Therapy
- A medicine that participants may not use during the study, usually because it could interfere with the study treatment or its measurement.
- immunosuppressive
- A medicine that reduces the activity of the immune system. Studies of autoimmune conditions often require a stable dose, a prior failure, or a washout of such medicines.
- Exclusion Criteria
- The conditions that rule a person out even if they meet the inclusion criteria, for example other illnesses, certain medicines or pregnancy.
The study record on this page is reproduced from ClinicalTrials.gov, a database of the U.S. National Library of Medicine, where it was submitted by the study sponsor. MedicalUpdates.ai does not own this content, is not affiliated with or endorsed by ClinicalTrials.gov, NIH, or the U.S. Government, and does not verify the record. Plain-language notes, the glossary and the questions above are added by this site; text in the boxes marked "AI summary" was written by an AI model and may contain errors. Registry records change over time. Check the original record for the current version and discuss eligibility or participation with a qualified healthcare professional.
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