A Phase 1 Study of Anitocabtagene Autoleucel for the Treatment of Subjects With Non-oncology Plasma Cell-related Diseases

February 24, 2026 updated by: Arcellx, Inc.
A Phase 1 dose-escalation study designed to evaluate the safety, tolerability, and preliminary efficacy of anito-cel in subjects with generalized myasthenia gravis (GMG). Anitocabtagene autoleucel (anito-cel) is a BCMA-directed CAR-T cell therapy.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

This is a Phase 1 open-label, multi-center safety and dose-escalation study of anito-cel* in adult subjects with GMG (MGFA Grade 2 to 4a), in whom immunosuppressive therapy is clinically indicated in the judgement of the treating neurologist. The primary objective of this study is to assess the safety profile, including any DLT and identification of a MTD (if applicable), to support selection of the RP2D of anito-cel when administered to subjects with GMG.

The study will have the following sequential phases: screening, enrollment (leukapheresis), pretreatment with lymphodepletion (LD) chemotherapy, treatment with anito-cel and follow-up. Optional bridging therapy is allowed at investigator discretion while anito-cel is being manufactured.

Following a single infusion of anito-cel both safety and efficacy data will be assessed. The DLTs will be assessed in the first 28 days following anito-cel administration, and safety data will be collected throughout the study.

*Anitocabtagene autoleucel (anito-cel) drug product consists of autologous T cells that have been genetically modified ex vivo to express a D-domain Chimeric Antigen Receptor (CAR), followed by a cluster of differentiation 8 (CD8) hinge and transmembrane region that is fused to the intracellular signaling domains for 4-1BB and CD3ξ, that specifically recognizes B-cell maturation antigen (BCMA). The active substance of anitocabtagene autoleucel is CAR+ CD3+ T cells that have undergone ex vivo T-cell activation, gene transfer by replication-deficient lentiviral vector, and expansion.

Study Type

Interventional

Enrollment (Estimated)

30

Phase

  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • United States
    • California
      • Los Angeles, California, United States, 90095
        • Recruiting
        • UCLA Medical Center
      • Orange, California, United States, 92602
        • Recruiting
        • University of California, Irvine
      • Palo Alto, California, United States, 94305
        • Recruiting
        • Stanford Hospital
    • Florida
      • Tampa, Florida, United States, 33612
        • Recruiting
        • University of South Florida - Carol and Frank Morsani Center of Advanced Healthcare
    • Michigan
      • Detroit, Michigan, United States, 48201
        • Recruiting
        • Karmanos Cancer Institute
    • Minnesota
      • Minneapolis, Minnesota, United States, 55414
        • Recruiting
        • University of Minnesota Delaware Clinical Research Unit
      • Rochester, Minnesota, United States, 55905
        • Recruiting
        • Mayo Clinic
    • New York
      • New York, New York, United States, 10032
        • Recruiting
        • Columbia University Irving Medical Center
    • Ohio
      • Columbus, Ohio, United States, 43221
        • Recruiting
        • Ohio State University
    • Oregon
      • Portland, Oregon, United States, 97239
        • Recruiting
        • Oregon Health & Science University (OHSU)
    • Pennsylvania
      • Philadelphia, Pennsylvania, United States, 19140
        • Recruiting
        • Temple University Hospital
    • Texas
      • Dallas, Texas, United States, 75390
        • Recruiting
        • UT Southwestern Medical Center
      • Houston, Texas, United States, 77030
        • Recruiting
        • Houston Methodist Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Subject must be 18 years of age or older
  • Must have MGFA clinical classification Grades 2-4A at time of screening
  • Subject must have clinically active disease and requiring ongoing therapy for GMG
  • MG-ADL score 6 and QMG score >10 at screening
  • GMG specific autoantibodies must be above the reference laboratory ULN

Exclusion Criteria:

  • Subject is pregnant or breastfeeding
  • Treatment with Anti-CD20 agents, calcineurin inhibitors, FcRN inhibitors, azathioprine, mycophenolate mofetil, methotrexate, or cyclophosphamide within the specified time frame prior to leukapheresis or prior to anito-cel infusion
  • Previous treatment with any gene therapy, chimeric antigen receptor therapy or T cell engager
  • Previous thymectomy within 6 months of screening
  • Major chronic illness that is not well managed at the time of study entry and in the opinion of the investigator

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: anito-cel
Single dose of anito-cel cells infused intravenously
Biological: anito-cel
Anitocabtagene autoleucel BCMA directed CAR T-cell therapy using a novel, synthetic binding domain, called a D-Domain
Other Names:
  • CART-ddBCMA
  • anitocabtagene autoleucel
Drug: Standard Lymphodepletion regimen
Standard lymphodepletion regimen subject receive 5 days prior to CAR T infusion
Other Names:
  • Cyclophosphamide
  • Fludarabine

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Assess safety profile, including any DLT and MTD (if applicable)
Time Frame: 24 months
Type, incidence, and severity of treatment-emergent adverse events (TEAEs), including DLT(s) and laboratory abnormalities
24 months
Selection of RP2D
Time Frame: 24 months
Evaluate the MTD and establish the RP2D
24 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Quantify Clinical Effect of Anito-cel in the Myasthenia Gravis Activities of Daily Living (MG ADL) score
Time Frame: 24 months
The proportion of subjects achieving a ≥2-point change in the MG ADL score from Baseline at any timepoint after treatment. The MG-ADL is an 8-item patient-reported outcome measure assessing GMG symptoms and functional activities related to activities of daily living and producing a total score ranging from 0 to 24, where higher scores indicate greater severity of disease symptoms.
24 months
Quantify Clinical Effect of Anito-cel in the Quantitative Myasthenia Gravis (QMG) score
Time Frame: 24 months
The proportion of subjects achieving a ≥3-point change in the QMG from Baseline at any timepoint after treatment. The QMG score is a 13-item direct physician assessment scoring system that quantifies disease severity, based on impairments of body functions and structures. The total QMG score ranges from 0 to 39, where higher scores indicate greater disease severity.
24 months
Quantify Clinical Effect of Anito-cel in the Myasthenia Gravis Composite (MGC) scale.
Time Frame: 24 months
The proportion of subjects achieving a ≥3-point change in the MGC score from Baseline at any timepoint after treatment. The MGC is a 10-item assessment that measures signs and symptoms of GMG based on physical examination findings and patient history. The total score ranges from 0 to 50, where higher scores indicate more severe impairment.
24 months
Mean change in QMG score
Time Frame: 24 months
The mean change in the QMG score from Baseline at any timepoint after treatment. The QMG score is a 13-item direct physician assessment scoring system that quantifies disease severity, based on impairments of body functions and structures. The total QMG score ranges from 0 to 39, where higher scores indicate greater disease severity.
24 months
Mean change in MG-ADL score
Time Frame: 24 months
The mean change in the MG-ADLscore from Baseline at any timepoint after treatment. The MG-ADL is an 8-item patient-reported outcome measure assessing GMG symptoms and functional activities related to activities of daily living and producing a total score ranging from 0 to 24, where higher scores indicate greater severity of disease symptoms.
24 months
Mean change in MCG score
Time Frame: 24 months
The mean change in the MGC score from Baseline at any timepoint after treatment. The MGC is a 10-item assessment that measures signs and symptoms of GMG based on physical examination findings and patient history. The total score ranges from 0 to 50, where higher scores indicate more severe impairment.
24 months
Mean change in MG-QoL15R score
Time Frame: 24 months
The mean change in the MG QoL15R score from Baseline at any timepoint after treatment. The MG-QoL15 is a 15-item questionnaire that allows clinicians to estimate a patient's quality of life relevant to GMG. The cumulative scores range from 0 to 60, with higher scores representing decreased quality of life.
24 months
Change in titer of myasthenia specific autoantibodies
Time Frame: 24 months
The proportion of subjects achieving ≥50% reduction in myasthenia-specific autoantibody titers from Baseline at any timepoint after treatment
24 months
PK Parameter for anito-cel: Cmax
Time Frame: Day 1 up to 24 months
Cmax is defined as the maximum observed concentration of anitocel measured/quantified using vector copy number (VCN) on peripheral blood mononuclear cells
Day 1 up to 24 months
PK Parameter for anito-cel: Tmax
Time Frame: Day 1 up to 24 months
Tmax is defined as the time (observed time point) of Cmax of anitocel measured/quantified using vector copy number (VCN) on peripheral blood mononuclear cells
Day 1 up to 24 months
PK Parameter for anito-cel: Area under the curve (AUC)
Time Frame: Day 1 up to 24 months
AUC is a measure of the anitocel concentration in the blood measured/quantified using VCN on peripheral blood mononuclear cells over time.
Day 1 up to 24 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Arcellx, Inc.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

April 30, 2025

Primary Completion (Estimated)

March 1, 2027

Study Completion (Estimated)

April 1, 2028

Study Registration Dates

First Submitted

September 19, 2024

First Submitted That Met QC Criteria

October 2, 2024

First Posted (Actual)

October 4, 2024

Study Record Updates

Last Update Posted (Actual)

February 25, 2026

Last Update Submitted That Met QC Criteria

February 24, 2026

Last Verified

February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • ARC-311

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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