A Study of CLN-978, a Subcutaneously Administered CD19-directed T Cell Engager, in Subjects With Rheumatoid Arthritis

A Phase I, Open-Label Study of CLN-978 in Patients With Treatment-Refractory Rheumatoid Arthritis (RA)

A Study of CLN-978, a Subcutaneously Administered CD19-directed T Cell Engager, in Subjects With Rheumatoid Arthritis (NCT06994143) is a Phase 1 interventional studying Rheumatoid Arthritis (RA, sponsored by Cullinan Therapeutics Inc.. RECRUITING as of the most recent ClinicalTrials.gov update. Talk to your doctor before contacting the trial site.

About This Trial

A Phase I, open-label study of CLN-978 in patients with treatment-refractory rheumatoid arthritis.

What Stage of Research Is This?

Phase 1 trials test a new treatment for the first time in humans, focusing on safety, dosing, and how the body processes the drug. For Rheumatoid Arthritis (RA, a Phase 1 study typically enrolls a small number of participants — often healthy volunteers or patients who have exhausted standard treatment options. Phase 1 results determine whether a treatment moves into larger Phase 2 efficacy studies.

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.

With a target enrollment of 37 participants, this is a small study — typical of early-phase research, rare-disease trials, or pilot studies designed to generate preliminary signal before a larger study is launched.

Who May Be Eligible (Plain English)

Who May Qualify: - Documented diagnosis of RA which fulfills the 2010 American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) Classification Criteria ≥12 weeks prior to screening. - Evidence of B-cell-driven disease at Screening or previous medical documentation, defined as either (i) seropositivity for RF and/or any AMPA and/or (ii) a synovial biopsy showing B-cell infiltration - Active RA disease, as demonstrated by a DAS28 - ESR ≥3.2 and at least one swollen joint at screening. - Inadequate response to at least 2 targeted treatments with different mechanisms. These can include tsDMARD and/or bDMARD, after failing conventional synthetic DMARD (unless contraindicated). - Local laboratory assessments must meet the following criteria: - Absolute lymphocyte count (ALC) ≥0.5 x 10\^9/L - Peripheral CD19+ B cell count ≥25 cells/μL - Absolute neutrophil count (ANC) ≥1.0 x 10\^9/L - Hemoglobin (Hgb) ≥8 g/dL - Platelet count ≥75 x 10\^9/L - Estimated glomerular filtration rate (eGFR) (based on the Chronic Kidney Disease Epidemiology Collaboration \[CKD-EPI\] formula) ≥30 mL/min/1.73m\^2 - Total bilirubin ≤1.5 × ULN, except patients with confirmed Gilbert's Syndrome - Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤2.5 × ULN - Concurrent corticosteroids is permitted if the dose is ≤10 mg/day prednisone equivalent in the 2 weeks prior to initiation of study treatment. Hydroxychloroquine ≤400 mg/d or chloroquine ≤ 250 mg/d is allowed. Who Should NOT Join This Trial: - Active inflammatory disease other than RA within 12 months prior to screening or during screening that may interfere with the study assessments. Thyroiditis or secondary Sjogren's syndrome is allowed. - Clinical evidence of any other significant unstable or uncontrolled acute or chronic disease not due to RA which, in the opinion of the Investigator could put the patient at undue risk or confound study results. - Prior treatment with the following: ...See full criteria on ClinicalTrials.gov Always talk to your doctor about whether this trial is right for you.

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

Inclusion Criteria: * Documented diagnosis of RA which fulfills the 2010 American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) Classification Criteria ≥12 weeks prior to screening. * Evidence of B-cell-driven disease at Screening or previous medical documentation, defined as either (i) seropositivity for RF and/or any AMPA and/or (ii) a synovial biopsy showing B-cell infiltration * Active RA disease, as demonstrated by a DAS28 - ESR ≥3.2 and at least one swollen joint at screening. * Inadequate response to at least 2 targeted treatments with different mechanisms. These can include tsDMARD and/or bDMARD, after failing conventional synthetic DMARD (unless contraindicated). * Local laboratory assessments must meet the following criteria: * Absolute lymphocyte count (ALC) ≥0.5 x 10\^9/L * Peripheral CD19+ B cell count ≥25 cells/μL * Absolute neutrophil count (ANC) ≥1.0 x 10\^9/L * Hemoglobin (Hgb) ≥8 g/dL * Platelet count ≥75 x 10\^9/L * Estimated glomerular filtration rate (eGFR) (based on the Chronic Kidney Disease Epidemiology Collaboration \[CKD-EPI\] formula) ≥30 mL/min/1.73m\^2 * Total bilirubin ≤1.5 × ULN, except patients with confirmed Gilbert's Syndrome * Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤2.5 × ULN * Concurrent corticosteroids is permitted if the dose is ≤10 mg/day prednisone equivalent in the 2 weeks prior to initiation of study treatment. Hydroxychloroquine ≤400 mg/d or chloroquine ≤ 250 mg/d is allowed. Exclusion Criteria: * Active inflammatory disease other than RA within 12 months prior to screening or during screening that may interfere with the study assessments. Thyroiditis or secondary Sjogren's syndrome is allowed. * Clinical evidence of any other significant unstable or uncontrolled acute or chronic disease not due to RA which, in the opinion of the Investigator could put the patient at undue risk or confound study results. * Prior treatment with the following: * Cellular therapy (e.g., chimeric antigen receptor T-cell (CAR-T) or gene therapy product directed at any target. * Receipt of an investigational therapy within 30 days or 5 drug-elimination half-lives (whichever is longer) prior to Day 1 and during the study. * Received any anti-CD19 or anti-CD20 therapy such as blinatumomab, obinutuzumab, rituximab, ocrelizumab, or ofatumumab within 3 months prior to Day 1. * Non-biologic DMARD within 14 days prior to Day 1. * Cyclophosphamide or a biologic immunomodulating therapy within 2 months of Day 1. * Live or live-attenuated vaccines within the 4 weeks prior to the Screening visit or during the Screening Period * Active or latent tuberculosis (TB) evidenced by a positive or indeterminant Interferon Gamma Release Assay (IGRA), unless the patient has documented previous completion of TB treatment and no current clinical indication of TB.

Treatments Being Tested

DRUG

CLN-978

Specified dose on specified days

Locations (2)

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.

Cullinan Investigative Site

Erlangen, Germany

Cullinan Investigative Site

Rome, Italy

How to Talk to Your Doctor About This Trial

Bring the printable summary of this trial — including the NCT ID (NCT06994143), the sponsor (Cullinan Therapeutics Inc.), 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 NCT06994143 clinical trial studying?

A Phase I, open-label study of CLN-978 in patients with treatment-refractory rheumatoid arthritis. The full protocol is registered on ClinicalTrials.gov and includes the primary outcome measures, eligibility criteria, and study endpoints.

Who can participate in NCT06994143?

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 NCT06994143?

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 NCT06994143. Maintained by the National Library of Medicine at NIH. Public domain. Cite as: "TrialFinderData. NCT06994143. 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.