A Phase 1b/2a Study of Budoprutug in Systemic Lupus Erythematosus (SLE)

A Phase 1b/2a Open-Label, Dose-Escalation and Dose-Expansion Study to Evaluate Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of Budoprutug (TNT119) in Adult Subjects With Systemic Lupus Erythematosus (SLE)

Budoprutug is a humanized, immunoglobulin (Ig) G1 monoclonal antibody that selectively binds to CD19 and is projected to deplete targeted cells through antibody-dependent cellular cytotoxicity. This Phase 1b/2a, open-label study will evaluate budoprutug in ascending dose cohorts of patients aged 18 years and above with active, seropositive SLE and inadequate response to standard therapy. The study will also assess the pharmacokinetics, pharmacodynamics and early indications of efficacy of budoprutug in SLE, where pharmacodynamics will be evaluated as the change in the number of B cells and immunoglobulins (antibodies) in the blood over time. Budoprutug will be administered as two (2) IV infusions 14 days apart in ascending dose cohorts.

Study Overview

• Status: Not yet recruiting
• Conditions: Systemic Lupus Erthematosus
• Intervention / Treatment: Drug: Budoprutug

• Study Type: Interventional
• Enrollment (Estimated): 30
• Phase: Phase 2; Phase 1

Contacts and Locations

• Study Contact: Name: Climb Bio Study Director; Phone Number: +1 8668572596; Email: clinicaltrials@climbbio.com

Study Locations

• China
  • Beijing, China
    • Peking University People's Hospital
    • Contact: Climb Bio Investigative Site; Email: clinicaltrials@climbbio.com

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

1. Aged 18 to 65 years at the time of consent.
2. Diagnosis of SLE according to the 2019 European League Against. Rheumatism and the American College of Rheumatology (ACR) classification criteria.
3. Active, seropositive disease, with SLEDAI 2K >=6 at screening
4. Inadequate response to at least one therapeutic intervention

Exclusion Criteria:

1. Active neuropsychiatric SLE.
2. Active lupus nephritis type III or IV that is expected to require induction therapy during the study or recently treated with induction therapy within 12 weeks.
3. Prior diagnosis of, or fulfills diagnostic criteria for, other autoimmune or inflammatory disease that may confound clinical assessments or increase subject risk in the study
4. Active systemic infection or history of chronic, recurrent, latent, or recent serious infections.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Cohort 1: Dose Level A; Single IV dose at Day 1 and Day 15	Drug: Budoprutug; Single IV dose of study product on Day 1 and Day 15; Other Names: TNT119
Experimental: Cohort 2: Dose Level B; Single IV dose at Day 1 and Day 15	Drug: Budoprutug; Single IV dose of study product on Day 1 and Day 15; Other Names: TNT119
Experimental: Cohort 3: Dose Level C; Single IV dose at Day 1 and Day 15	Drug: Budoprutug; Single IV dose of study product on Day 1 and Day 15; Other Names: TNT119
Experimental: Dose Expansion Cohort; Single IV dose at Day 1 and Day 15	Drug: Budoprutug; Single IV dose of study product on Day 1 and Day 15; Other Names: TNT119

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of Treatment-Emergent Adverse Events (TEAEs)	Number of participants experiencing TEAEs, graded per NCI CTCAE v6.0.	Up to week 28
Incidence of Clinical Laboratory Abnormalities	Number of participants with clinically significant laboratory abnomalities.	Up to week 28
Incidence of dose-limiting toxicities (DLTs)	Number of incidences of dose-limiting toxicities (DLTs)	up to 28 weeks
Change from Baseline in Systolic Blood Pressure	Mean change from baseline in diastolic blood pressure (mmHg).	Up to week 28
Change from Baseline in Diastolic Blood Pressure	Mean change from baseline in systolic blood pressure (mmHg).	up to 28 weeks
Change from Baseline in Heart Rate	Mean change from baseline in heart rate (bpm).	up to 28 weeks
Change from Baseline in Respiratory Rate	Mean change from baseline in respiratory rate	up to 28 weeks
Change from Baseline in Body Temperature	Mean change from baseline in body temperature (°C)	up to 28 weeks
Change from Baseline in PR Interval	Mean change from baseline in PR interval (ms)	up to 28 weeks
Change from Baseline in QRS Duration	Mean change from baseline in QRS duration (ms)	up to 28 weeks
Change from Baseline in QT Interval	Mean change from baseline in QT interval (ms)	up to 28 weeks
Change from Baseline in QTc Interval	Mean change from baseline in corrected QT interval (QTc)	up to 28 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Area Under the Curve (AUC)	Measurement of the area under the drug concentration-time curve	Up to week 28
Terminal Half-Life (T1/2)	Measurement of the terminal half-life in days	Up to week 28
Incidence of Anti-Drug Antibodies (ADAs)	Number of participants with detectable ADAs.	Up to week 28
ADA Titer Over Time	Measurement of ADA titer over time	Up to week 28
Change from Baseline in CD20+ B-cell Count	Change in absolute peripheral B-cell count	Up to week 28
Change from Baseline in SLEDAI-2K Score	Measurement of change in SLEDAI-2K score from baseline	up to 28 weeks
Change from Baseline in Urine Protein Creatinine Ratio (UPCR)	Measurement of change in UPCR from baseline	up to 28 weeks

Collaborators and Investigators

• Sponsor: Climb Bio, Inc.
• Investigators: Study Director: Study Director, Climb Bio, Inc.

Study record dates

Study Major Dates

• Study Start (Estimated): June 1, 2026
• Primary Completion (Estimated): September 1, 2027
• Study Completion (Estimated): September 1, 2027

Study Registration Dates

• First Submitted: April 27, 2026
• First Submitted That Met QC Criteria: April 27, 2026
• First Posted (Actual): May 4, 2026

Study Record Updates

• Last Update Posted (Actual): May 4, 2026
• Last Update Submitted That Met QC Criteria: April 27, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Lupus; Open-label; SLE; anti-CD19; Biologics; Monoclonal
• Other Study ID Numbers: TNT119-SLE-102

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