Who may be eligible for the FT839 in Autoimmune Diseases trial?

Inclusion Criteria: * Age ≥18 to ≤70 years * Must have active B-cell mediated autoimmune disease (AAV, IIM, RA, SLE, or SSc) confirmed by standard criteria * Moderate to severe disease, requiring at least two prior treatments that were ineffective * Adequate organ function to tolerate treatment * Able to provide informed consent and comply with study procedures Exclusion Criteria: * Diagnosis of more than 1 disease under study (AAV, IIM, RA, SSc, or SLE) or overlap syndrome * Women must not be pregnant or nursing * Severe Organ Dysfunction: Significant heart, lung, liver, or kidney impairment. * Active or chronic infections * Active or recent malignancies * Prior CAR T-cell therapy or organ transplantation * Known allergies to study treatments * Body weight \<45 kg * Active central nervous system (CNS) symptoms attributable to autoimmune disease or nonmalignant CNS disease within 12 months prior to trial intervention * Receipt of any anti-CD19- or anti-CD20-directed therapy within 6 months prior to trial intervention

ClinicalTrials.gov record NCT07800871

FT839 in Autoimmune Diseases

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

An Open-Label, Multicenter, Phase 1/2 Dose-Escalation and Expansion Trial Evaluating the Safety and Efficacy of FT839 in Participants With Autoimmune Diseases

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.

StatusRecruitingThe study is currently enrolling participants. Only the study team can say whether a particular person can join.

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 1/2A study that combines safety and dose-finding (phase 1) with a first look at whether the treatment has an effect (phase 2).

Age18 years old to 70 years old

SexAll

LocationUnited States

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 open-label Phase 1/2 trial tests FT839, an allogeneic T‑cell therapy, in people with moderate-to-severe AAV, IIM, RA, SLE, or SSc. Participants may receive FT839 alone or with rituximab, with or without conditioning and/or stable background therapy; the trial starts with dose escalation and moves to disease-specific expansion cohorts. The study evaluates safety, dosing, and disease activity and includes follow-up up to 2 years and long-term safety follow-up up to 15 years.

What it is studying. The study is evaluating the safety, tolerability, dosing, pharmacokinetics, anti–B-cell activity, and clinical activity of FT839 in people with specified B‑cell–mediated autoimmune diseases. In Phase 1 it seeks the maximum tolerated dose (MTD) or a recommended Phase 2 dose and monitors adverse events; Phase 2 further evaluates activity within each disease cohort.

What the researchers hope to learn. Scientifically, the trial aims to determine the safe dose(s) of FT839, characterize its pharmacokinetics and anti–B-cell activity, document adverse events, and measure clinical activity within each listed autoimmune disease cohort to inform further development.

What this study is about

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

The primary objectives of this trial are to evaluate the safety and tolerability and to determine the maximum tolerated dose (MTD) or recommended Phase 2 dose of FT839 with or without rituximab and/or background therapy and/or conditioning therapy.

Interventions being studied

Being studied in this trial does not mean the treatment or procedure is approved or available for this condition.

Biological: FT839

Eligibility

The criteria exactly as listed on ClinicalTrials.gov. Only the study team can say whether they apply to you.

Inclusion criteria

Age ≥18 to ≤70 years
Must have active B-cell mediated autoimmune disease (AAV, IIM, RA, SLE, or SSc) confirmed by standard criteria
Moderate to severe disease, requiring at least two prior treatments that were ineffective
Adequate organ function to tolerate treatment
Able to provide informed consent and comply with study procedures

Exclusion criteria

Diagnosis of more than 1 disease under study (AAV, IIM, RA, SSc, or SLE) or overlap syndrome
Women must not be pregnant or nursing
Severe Organ Dysfunction: Significant heart, lung, liver, or kidney impairment.
Active or chronic infections
Active or recent malignancies
Prior CAR T-cell therapy or organ transplantation
Known allergies to study treatments
Body weight <45 kg
Active central nervous system (CNS) symptoms attributable to autoimmune disease or nonmalignant CNS disease within 12 months prior to trial intervention
Receipt of any anti-CD19- or anti-CD20-directed therapy within 6 months prior to trial intervention

Study description and what participation involves

The study's detailed description, as published on ClinicalTrials.gov.

Detailed description from the registry

This is a multicenter, Phase 1/2, open-label trial designed to evaluate the safety, pharmacokinetics (PK), anti-B-cell activity, and clinical activity of FT839 in participants with moderate-to-severe ANCA-associated vasculitis (AAV), idiopathic inflammatory myositis (IIM), rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and systemic sclerosis (SSc). Participants will receive FT839 as monotherapy or in combination with rituximab, with or without conditioning therapy and/or stable background therapy. Participants will be enrolled in 2 stages during the Phase 1 portion of the trial: a dose-escalation stage and a dose-expansion stage. In the dose-escalation stage, safety and tolerability will be assessed to define the MTD (or through the maximum assessed dose [MAD] in the absence of dose-limiting toxicities [DLTs] defining the MTD). The DLT evaluation period will extend from Day 1 through Day 29. Participants will be followed during the post-treatment follow-up period for up to 2 years after the first dose of FT839, followed by long-term-follow-up for safety and survival for up to 15 years after the first dose of FT839. In the dose-expansion stage, participants will be enrolled into disease-specific cohorts to further evaluate the safety and activity of FT839. Following completion of the Phase 1 portion, the Phase 2 portion of the trial will further evaluate the efficacy of FT839 within each disease cohort.

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 FT839 by intravenous (IV) infusion on Day 1 and Day 4, given alone or with rituximab; some regimens may also include a conditioning treatment or continued stable background therapy. The trial begins with a dose-escalation stage (dose-limiting toxicity is assessed from Day 1 through Day 29) and then moves to disease-specific dose-expansion cohorts. Visits include blood draws for drug levels and safety testing, medical exams and disease-activity assessments; participants are followed for up to 2 years after the first dose and then for long-term safety and survival follow-up for up to 15 years. The registry does not list a full visit schedule or all tests in detail.

How the study is structured. Interventional, open-label, non-randomized Phase 1/2 trial with a single-group design. Phase 1 includes a dose-escalation stage (to define the MTD or maximum assessed dose, with a DLT evaluation period from Day 1 through Day 29) and a dose-expansion stage with disease-specific cohorts. Participants receive FT839 by intravenous infusion (described in the record as given on Day 1 and Day 4) either alone or combined with rituximab, with or without conditioning and/or stable background therapy. Participants are followed during a post-treatment period for up to 2 years and a long-term safety and survival follow-up for up to 15 years.

Questions you could ask

These questions are suggestions for a conversation with the study team or your own clinician, not advice.

This is an early-phase study, mainly about safety and dose. What is already known about this treatment?
The listed sites are in 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 dermatomyositis.

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: October 2026 (estimated)
Primary completion: October 2028 (estimated)
Study completion: October 2040 (estimated)
Target enrollment: 446 participants (estimated)
Last updated on registry: Sep 2, 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: Fate Therapeutics

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.

Fate Clinical Trials 📞 858-875-1800 ✉ clinicaltrials@fatetherapeutics.com
Natalie Shiff, MD

Participating sites (1)

Providence Medical FoundationRecruiting
Fullerton, California, 92835 · United States

Terms used on this page · explanations by MedicalUpdates.ai

maximum tolerated dose: The highest dose found in a dose-escalation study that can be given without too many dose-limiting side effects.
recommended Phase 2 dose: The dose chosen at the end of a phase 1 study for testing in later studies, based on safety and other measurements.
informed consent: 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.
CAR T: A treatment in which a person's own immune cells (T cells) are collected, modified in a laboratory to recognise a target, and returned to the body.
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.
open-label: No masking is used, so the assigned intervention is not deliberately hidden from participants or study staff.
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.
Phase 1: An 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.
dose-escalation: Groups of participants receive increasing doses of a treatment, one group after another, to find a dose that can be given safely.
dose-limiting toxicities: A side effect, defined in advance, that is severe enough to limit how far the dose can be raised in a dose-escalation study. How many such events stop escalation is set by the study's rules.
follow-up: The period after treatment or enrolment during which participants are observed or contacted, for example to record side effects or outcomes.
Phase 2: A study that tests whether a treatment has the intended effect and continues to check safety, usually in a larger group than phase 1.
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.

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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