Study of KTE-X19 in Adult Japanese Participants With Relapsed/Refractory Mantle Cell Lymphoma or Relapsed/Refractory B-precursor Acute Lymphoblastic Leukemia (JKART-1)

A Phase 2 Multicenter Study Evaluating the Safety and the Efficacy of KTE-X19 in Adult Japanese Subjects With Relapsed/Refractory Mantle Cell Lymphoma or Relapsed/Refractory B-precursor Acute Lymphoblastic Leukemia

The goal of this clinical study is to learn more about KTE-X19, and how safe and effective it is in adult Japanese participants with relapsed/refractory (r/r) Mantle Cell Lymphoma (MCL) or r/r B-precursor Acute Lymphoblastic Leukemia (B-ALL).

The primary objectives of this study are to evaluate the efficacy of KTE-X19, as measured by:

• Objective response rate (ORR) per investigator assessment, in adult Japanese participants with r/r MCL
• Overall complete remission (OCR) defined as complete remission (CR) and complete remission with incomplete hematologic recovery (CRi) per investigator assessment, in adult Japanese participants with r/r ALL

Study Overview

• Status: Active, not recruiting
• Conditions: Relapsed/Refractory Mantle Cell Lymphoma; Relapsed/Refractory B-precursor Acute Lymphoblastic Leukemia
• Intervention / Treatment: Drug: Cyclophosphamide; Drug: Fludarabine; Drug: KTE-X19

Detailed Description

After completing at least 24 months in the study, all participants who received an infusion of KTE-X19 will be transitioned to a separate long-term follow-up (LTFU) study (KT-US-982-5968) to complete the remainder of the 15-year follow-up assessments.

• Study Type: Interventional
• Enrollment (Actual): 25
• Phase: Phase 2

Contacts and Locations

Study Locations

• Japan
  • Chiba, Japan, 260-8677
    • Chiba University Hospital
  • Fukuoka, Japan, 812-8582
    • Kyushu University Hospital
  • Hokkaido, Japan, 060-8648,
    • Hokkaido University Hospital
  • Kyoto, Japan, 606-8507
    • Kyoto University Hospital
  • Miyagi, Japan, 980-8574
    • Tohoku University Hospital
  • Okayama, Japan, 700-8558
    • Okayama University Hospital
  • Tokyo, Japan, 104-0045
    • National Cancer Center Hospital
  • Tokyo, Japan, 113-8431
    • Juntendo University Hospital
  • Tokyo, Japan, 113-8677
    • Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Key Inclusion Criteria:

MCL Cohort:

• Pathologically confirmed MCL, with documentation of either overexpression of cyclin D1 or presence of t(11;14)

• Up to 5 prior regimens for MCL. Prior therapy must have included:

  • Anthracycline-, bendamustine-, or high-dose cytarabine- containing chemotherapy, and
  • Anti-CD20 monoclonal antibody therapy, and
  • Bruton's tyrosine kinase inhibitor (BTKi)

• Relapsed or refractory disease, defined by the following:

  • Disease progression after last regimen, or
  • Refractory disease is defined failure to achieve partial response (PR) or complete remission (CR) to the last regimen

• At least 1 measurable lesion. Lesions that have been previously irradiated will be considered measurable only if progression has been documented following completion of radiation therapy

  • If the only measurable disease is lymph node disease, at least 1 lymph node should be ≥ 2 cm

ALL Cohort:

• Relapsed or refractory B-ALL defined as one of the following:

  • Relapsed or refractory disease after one line of systemic therapy;

    • Primary refractory, or
    • First relapse if first remission ≤ 12 months
  • Relapsed or refractory disease after two or more lines of systemic therapy
  • Relapsed or refractory disease after allogeneic transplant provided individuals is at least 100 days from SCT at the time of enrollment and off of immunosuppressive medications for at least 4 weeks prior to enrollment
• Morphological disease in the bone marrow (> 5% blasts)
• Individuals with Philadelphia-positive (Ph+) disease are eligible if they are intolerant to tyrosine kinase inhibitor (TKI) therapy, or if they have relapsed/refractory disease despite treatment with at least 2 different TKIs

Key Exclusion Criteria:

MCL Cohort:

• History of malignancy other than nonmelanomatous skin cancer or carcinoma in situ (eg, cervix, bladder, breast) unless disease-free for at least 3 years
• Autologous SCT (autoSCT) within 6 weeks of planned KTE-X19 infusion
• History of alloSCT with the exception of individuals with no donor cells detected on chimerism > 100 days after alloSCT
• Prior CD19 targeted therapy
• Prior CAR therapy or other genetically modified T-cell therapy
• History of hypersensitivity to any of the ingredients of KTE-X19 or to any of the animal-derived ingredients (bovine and rodent) used in the manufacturing process of KTE-X19

ALL Cohort:

• Diagnosis of Burkitt's leukemia/lymphoma according to World Health Organization (WHO) classification or chronic myelogenous leukemia lymphoid blast crisis
• History of malignancy other than non-melanoma skin cancer or carcinoma in situ (eg, cervix, bladder, breast) unless disease free for at least 3 years
• History of hypersensitivity to any of the ingredients of KTE-X19 or to any of the animal-derived ingredients (bovine and rodent) used in the manufacturing process of KTE-X19

Note: Other protocols defined Inclusion/Exclusion criteria may apply.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: MCL Cohort- KTE-X19; Participants will receive cyclophosphamide 500 mg/m^2/day intravenously (IV) and fludarabine 30 mg/m^2/day IV lymphodepletion chemotherapy for 3 days followed by KTE-X19 administered intravenously at a target dose of 2 x 10^6 anti-cluster of differentiation (CD)19 chimeric antigen receptor (CAR) T cells/kg on Day 0. For participants weighing ≥ 100 kg, a maximum flat dose of 2 x 10^8 anti-CD19 CAR T cells will be administered.	Drug: Cyclophosphamide; Administered intravenously; Drug: Fludarabine; Administered intravenously; Drug: KTE-X19; A single infusion of chimeric antigen receptor (CAR) T cells; Other Names: Tecartus
Experimental: ALL Cohort- KTE-X19; Participants will receive cyclophosphamide 900 mg/m^2/day intravenously (IV) for 1 day and fludarabine 25 mg/m^2/day IV lymphodepletion chemotherapy for 3 days followed by KTE-X19 administered intravenously at a target dose of 1 x 10^6 19 CAR T cells/kg on Day 0. For participants weighing ≥ 100 kg, a maximum flat dose of 1 x 10^8 anti-CD19 CAR T cells will be administered.	Drug: Cyclophosphamide; Administered intravenously; Drug: Fludarabine; Administered intravenously; Drug: KTE-X19; A single infusion of chimeric antigen receptor (CAR) T cells; Other Names: Tecartus

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
MCL Cohort: Objective Response Rate (ORR) Per Investigator Assessment	ORR is defined as the incidence of a complete remission (CR) or a partial remission (PR) per the Lugano Classification.	Up to 24 months
ALL Cohort: Overall Complete Remission (OCR) Rate	OCR rate is defined as the percentage of participants achieving CR/complete remission with incomplete hematologic recovery (CRi) per investigator assessment.	Up to 24 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
MCL Cohort: Duration of Response (DOR)	DOR is defined as time from first objective response to disease progression per indication specific response criteria or death from any cause.	Up to 24 months
MCL Cohort: Best Objective Response (BOR)	BOR is defined as the incidence of CR, PR, Stable disease (SD) or progressive disease (PD) or unevaluable as best response to treatment.	Up to 24 months
MCL Cohort: Progression-Free Survival (PFS)	PFS is defined as time from enrollment or KTE-X19 infusion to disease progression per indication specific response criteria or death from any cause.	Up to 24 months
MCL Cohort: Levels of Cytokines in Serum		Up to Day 28
ALL Cohort: Minimal Residual Disease (MRD) Negativity Rate	The incidence of a minimal residual disease response (MRD-). MRD- is defined as MRD < 10^-6 per the standard assessment.	Up to 24 months
ALL Cohort: Allogeneic Stem Cell Transplant (alloSCT) rate	The percentage of participants receiving alloSCT as the 1st next therapy after KTE-X19 infusion.	Up to 24 months
ALL Cohort: Relapse-Free Survival (RFS)	RFS is defined as the time from enrollment or KTE-X19 infusion date to the date of disease relapse or death from any cause.	Up to 24 months
ALL Cohorts: DOR	DOR is defined as the time between their first complete remission (CR or CRi) to relapse or any death in the absence of documented relapse.	Up to 24 months
MCL and ALL Cohort: Levels of Anti-Cluster of Differentiation 19 (Anti-CD19) CAR T Cells in Blood		Up to 24 months
MCL and ALL Cohorts: Percentages of Participants Experiencing Treatment-emergent Adverse Event (TEAEs), Serious Adverse Event (SAEs) and Deaths		First infusion date up to 24 months
MCL and ALL Cohorts: Overall Survival (OS)	OS is defined as the time from enrollment or KTE-X19 infusion to death from any cause.	Up to 24 months
MCL and ALL Cohorts: Percentage of Participants Experiencing Clinically Significant Changes in Safety Laboratory Values		First infusion date up to 24 months

Collaborators and Investigators

• Sponsor: Kite, A Gilead Company
• Investigators: Study Director: Kite Study Director, Kite, A Gilead Company

Publications and helpful links

Helpful Links

• Gilead Clinical Trials Website

Study record dates

Study Major Dates

• Study Start (Actual): March 18, 2024
• Primary Completion (Actual): November 20, 2025
• Study Completion (Estimated): July 1, 2027

Study Registration Dates

• First Submitted: February 2, 2024
• First Submitted That Met QC Criteria: February 2, 2024
• First Posted (Actual): February 12, 2024

Study Record Updates

• Last Update Posted (Actual): December 16, 2025
• Last Update Submitted That Met QC Criteria: December 15, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pathologic Processes; Neoplasms; Disease Attributes; Immune System Diseases; Neoplasms by Histologic Type; Lymphatic Diseases; Lymphoproliferative Disorders; Immunoproliferative Disorders; Lymphoma, Non-Hodgkin; Lymphoma; Pathological Conditions, Signs and Symptoms; Hemic and Lymphatic Diseases; Recurrence; Lymphoma, Mantle-Cell; Organic Chemicals; Hydrocarbons; Phosphoramide Mustards; Nitrogen Mustard Compounds; Mustard Compounds; Hydrocarbons, Halogenated; Phosphoramides; Organophosphorus Compounds; Cyclophosphamide; fludarabine; brexucabtagene autoleucel
• Other Study ID Numbers: KT-US-472-0149

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: Yes