ClinicalTrials.gov record NCT06723106

Phase 1b Long-term Extension Trial of RAY121 in Immunological Diseases (RAINBOW-LTE Trial)

Record copied from ClinicalTrials.gov: Oct 10, 2026AI summaries generated: Sep 17, 2026

Phase 1b Open-label, Long-term Extension Basket Trial of RAY121 to Inhibit Classical Complement Pathway in Immunological Diseases (RAINBOW-LTE Trial)

About this page. This page shows the study's official ClinicalTrials.gov record ↗, with added help to make it easier to understand. We explain medical terms, highlight key details in plain language, and suggest questions you may want to ask the study team.

The record is periodically copied from ClinicalTrials.gov and may lag behind changes. AI summaries are checked by software, not a clinician.Read moreShow less

The official record is written by the study sponsor and published on ClinicalTrials.gov. It may not always reflect the latest changes. Before making any decisions, please confirm important information with the study team and your own healthcare team.

Where you see "AI summary", AI was used to create a plain-language explanation and software checked it against the source. It has not been reviewed by a clinician, so it may contain mistakes or leave out important details.

StatusEnrolling by invitationThe study enrols only people the study team invites, for example patients already at a particular clinic. It is not open to the public.

Study typeInterventionalA study in which researchers assign participants to one or more interventions, such as a drug, procedure, device, behavioural programme or other approach, to measure their effects.

PhasePhase 1An early-stage study, usually small, mainly to check safety, side effects and how much of a treatment can be given. Whether it works is not the main question yet.

Age18 years old to 85 years old

SexAll

LocationAustralia, Austria, Bulgaria, Canada, Croatia, Czechia, France, Germany, Hungary, Italy, Japan, Netherlands, Norway, Poland, Portugal, Romania, Spain, Taiwan, Turkey

AI summaryWhat this study is about, 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.

This is an open-label, single-group long-term extension trial of RAY121 for several immune diseases. It is for adults with antiphospholipid syndrome, bullous pemphigoid, Behçet's syndrome, dermatomyositis, immune-mediated necrotizing myopathy, or immune thrombocytopenia who completed prior RAY121 dosing and showed clinical responses. Participants receive repeated RAY121 injections and are followed with safety and blood tests through Week 52.

What it is studying. The study is testing the long-term safety and tolerability of repeated RAY121 injections, and measuring drug levels, markers of the classical complement pathway (active and total C1s, complement activity), and anti-RAY121 antibodies over time.

What the researchers hope to learn. Collect long-term safety data for RAY121; measure how much drug is in the blood over time; assess effects on classical complement pathway markers (active and total C1s and complement activity); and detect anti-RAY121 antibodies.

What this study is about

The study's own summary, as published on ClinicalTrials.gov. Underlined terms have a short explanation.

This is a long-term extension trial of RAY121 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
Have completed 4 doses of RAY121 administrations in RAY902CT trial and shown clinical responses
Ability to comply with the study protocol, in the investigator's judgment
For women of childbearing potential: agreement to remain abstinent (refrain from heterosexual intercourse) or use highly effective contraceptive methods during the treatment period and 20 weeks (140 days) after the last dose of RAY121
For men: agreement to remain abstinent (refrain from heterosexual intercourse) or use contraceptive measures, and agreement to refrain from donating sperm

Exclusion criteria

History of anaphylaxis or hypersensitivity to a biologic agent
Known active infection with encapsuled bacteria
History of Neisseria meningitidis infection
Planned surgery
Pregnant or breastfeeding, or intending to become pregnant
Clinically significant electrocardiogram abnormalities
Illicit drug or alcohol abuse
Known or suspected immune deficiency
Treatment with investigational therapy other than RAY121
Vaccination with a live vaccine within 4 weeks

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 will receive repeated injections of RAY121 and attend scheduled study visits with safety monitoring from baseline through Week 52. At visits, blood samples will be taken to measure RAY121 concentration, active and total C1s, classical complement pathway activity, and anti‑RAY121 antibodies. Study staff will record any adverse events and assess their severity and relationship to the drug. The registry record does not describe other procedures or participant services.

How the study is structured. Interventional, phase 1b, open-label, single-group long-term extension. All enrolled participants receive multiple doses of RAY121 by injection. The study records adverse events and measures serum RAY121 concentration, active and total C1s, classical complement activity, and anti-RAY121 antibody titers from baseline to Week 52.

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 registry says participants are enrolled by invitation. Who decides who is invited, and how?
The listed sites are in Australia, Austria, Bulgaria, Canada, Croatia, Czechia, France, Germany, Hungary, Italy, Japan, Netherlands, Norway, Poland, Portugal, Romania, Spain, Taiwan, Turkey. 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.

Clinical trials55 trials listed for polymyositisEvery trial the registry lists for polymyositis, with recruitment status, phase and sites, updated from ClinicalTrials.gov.See all trials →Research updatesWhat changed in polymyositis researchLatest monthly update: September 2026. Includes: CD4 count risk. New research summarized each month in plain language, with links to every source paper.Read the latest update →

Important dates

Study start: Dec 9, 2024
Primary completion: Feb 28, 2028 (estimated)
Study completion: Feb 28, 2028 (estimated)
Target enrollment: 144 participants (estimated)
Last updated on registry: Jul 17, 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

Participating sites (62)

Filter by country:

Royal Prince Alfred Hospital
Camperdown, New South Wales, 2050 · Australia
Westmead Hospital
Sydney, New South Wales, 2145 · Australia
Campbelltown Public Hospital
Sydney, New South Wales, 2560 · Australia
The Alfred Hospital
Melbourne, Victoria, 3004 · Australia
Box Hill Hospital
Melbourne, Victoria, 3128 · Australia
AKH - Medizinische Universitaet Wien, Abteilung fuer Klinische Pharmakologie
Vienna, 1090 · Austria
Diagnostic Consultation Center CONVEX EOOD
Sofia, Sofia City Province, 1202 · Bulgaria
"SHATHD" EAD Sofia
Sofia, Sofia City Province, 1756 · Bulgaria
UMHAT "Prof. Dr. St. Kirkovich", AD
Stara Zagora, Stara Zagora Province, 6003 · Bulgaria
DiIEX Recherche Sherbrooke, Inc
Sherbrooke, Quebec, J1L 0H8 · Canada

Terms used on this page · explanations by MedicalUpdates.ai

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.
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.
electrocardiogram: 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.
Inclusion Criteria: The conditions a person must meet to be considered for the study, for example a confirmed diagnosis, an age range or a test result.
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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