A First-in-human Study of KT501 Administered Subcutaneously to Patients With Rheumatoid Arthritis (RA).

NCT07234773 | Recruiting Phase 1 DMC

• 1 other identifier: KT501-001
• Study Type: interventional
• Target: 24
• Locations: 1 country
• Sites: 1

Brief Summary

This is a Phase 1, open-label, first-in-human study to investigate the safety, tolerability, pharmacokinetics and pharmacodynamics of KT501 administered subcutaneously to participants with Rheumatoid Arthritis (RA).

Conditions

Rheumatoid Arthritis (RA)

Keywords

Rheumatoid Arthritis (RA); Autoimmune; T-cell Engagers (TCEs); B-cell Depletion

Outcome Measures

Primary Outcomes (10)

• Incidence of Adverse Events

  Incidence and severity of Adverse Events, with severity determined according to National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) v5.0.

  From Baseline Up to 12 weeks

• Incidence of Cytokine-release Syndrome (CRS)

  Incidence and severity of CRS with severity determined according to the 2019 American Society for Transplantation and Cellular Therapy (ASTCT) CRS Consensus grading criteria

  From Baseline Up to 12 Weeks

• Changes in Pulse Rate from Baseline

  Vital signs: Changes in Pulse Rate from Baseline

  From Baseline Up to 12 Weeks

• Changes in Respiratory Rate from Baseline

  Vital Signs: Changes in Respiratory Rate from Baseline

  From Baseline to 12 Weeks

• Changes in Blood Pressure from Baseline

  Vital Signs: Changes in Blood Pressure from Baseline

  From Baseline Up to Week 12

• Changes in Temperature from Baseline

  Vital Signs: Changes in Body Temperature from Baseline

  From Baseline to 12 Weeks

• Changes in Hematology Clinical Laboratory Results from Baseline

  Hematology: Changes in results from Baseline

  From Baseline Up to 12 Weeks

• Changes in Chemistry Clinical Laboratory Results from Baseline

  Chemistry: Changes in results from Baseline

  From Baseline Up to 12 Weeks

• Changes in Urinalysis Clinical Laboratory Results from Baseline

  Urinalysis: Changes in results from Baseline

  From Baseline Up to 12 Weeks

• Changes in Coagulation Clinical Laboratory Results from Baseline

  Coagulation: Changes in results from Baseline

  From Baseline Up to 12 Weeks

Secondary Outcomes (13)

• Serum Concentrations of KT501

  Pre-dose and 6 hours post-dose on Day 1; Day 2, 3, 4, 5, 8, 11, 15, 22, 29, 43, 57 and 85.

• Incidence of Treatment-induced Anti-Drug Antibodies (ADAs)

  Pre-dose and on Day 1; Day 8, 11, 15, 22, 29, 43, 57 and 85.

• To Determine Cmax

  Day 1 - Day 85

• To Determine Tmax, Derived from Serum Concentration of each Dose of KT501

  Day 1 - Day 85

• Area Under the Serum-concentration Time Curve (AUC) from Time Zero to the Last Timepoint with Measurable Analyte Concentration (AUC0-t)

  Day 1 - Day 85

Study Arms (5)

Dose Level 1

EXPERIMENTAL

KT501 Subcutaneous Injection Dose Level 1

Drug: KT501

Dose Level 2

EXPERIMENTAL

KT501 Subcutaneous Injection Dose Level 2

Drug: KT501

Dose Level 3

EXPERIMENTAL

KT501 Subcutaneous Injection Dose Level 3

Drug: KT501

Dose Level 4

EXPERIMENTAL

KT501 Subcutaneous Injection Dose Level 4

Drug: KT501

Dose Level 5

EXPERIMENTAL

KT501 Subcutaneous Injection Dose Level 5

Drug: KT501

Interventions

KT501 DRUG

KT501 is a monoclonal antibody that depletes B cells including plasma cells by targeting CD19, BCMA and CD3.

Dose Level 1; Dose Level 2; Dose Level 3; Dose Level 4; Dose Level 5

Eligibility Criteria

• Age: 18 Years - 75 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• to 75 years old
• Diagnosis of adult-onset RA for at least 6 months
• Moderately to severely active RA
• Inadequate treatment response as defined in the protocol
• RF + or ACPA+
• Stable use of traditional DMARDs is permitted
• Willing and able to comply with all study assessments and adhere to the protocol schedule and restrictions.

You may not qualify if:

• Functional class IV as defined by the ACR Classification of Functional Status in RA
• Presence of any concomitant autoimmune disease other than RA
• Active infection, history of serious recurrent or chronic infection
• History of progressive multifocal leukoencephalopathy
• Have a diagnosis or history of malignant disease within 5 years or breast cancer diagnosed within the previous 10 years.
• History of or planned organ transplant and/or autologous or allogeneic hematopoietic stem cell transplantation
• Receipt of live vaccine within 4 weeks
• Major surgery (including joint surgery) within 8 weeks prior to screening or planned major surgery within 6 months after study
• Women who are pregnant or breastfeeding
• Significant or uncontrolled medical disease that would preclude participant participation

Sponsors & Collaborators

• Kali Therapeutics, Inc.: lead

Study Sites (1)

Kali Study Site

Bayswater, Australia

RECRUITING

MeSH Terms

Conditions

Arthritis, Rheumatoid

Condition Hierarchy (Ancestors)

Arthritis; Joint Diseases; Musculoskeletal Diseases; Rheumatic Diseases; Connective Tissue Diseases; Skin and Connective Tissue Diseases; Autoimmune Diseases; Immune System Diseases

Central Study Contacts

Trial Information

CONTACT

1-858-888-3080; clinical@kalitherapeutics.com

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SEQUENTIAL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Model Details: Single Ascending Dose (SAD)

Study Record Dates

• First Submitted: November 13, 2025
• First Posted: November 18, 2025
• Study Start: March 6, 2026
• Primary Completion (Estimated): February 1, 2027
• Study Completion (Estimated): August 1, 2027
• Last Updated: March 10, 2026

Record last verified: 2026-03

Data Sharing

• IPD Sharing: Will not share

Locations

AU (1)