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

Phase 1

Recruiting

• Conditions: Systemic Lupus Erythematosus
• Interventions: Drug: Budoprutug

• Registration Number: NCT07011043
• Lead Sponsor: Climb Bio, Inc.

Brief Summary

The main objective is to assess the safety and tolerability of budoprutug in adults with SLE. Pharmacokinetics, pharmacodynamics, and preliminary clinical efficacy will also be assessed.

Detailed Description

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, open-label study will evaluate budoprutug administered as a single intravenous infusion 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 following a single infusion.

Study Timeline

• Study First Submitted: 2025-05-06
• Study First Submitted QC: 2025-06-06
• Study First Posted: 2025-06-08
• Study Start: 2025-07-10
• Status Verified: 2025-11
• Last Update Submitted: 2025-11-03
• Last Update Posted: 2025-11-05
• Primary Completion: 2027-04
• Study Completion: 2027-04-01

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 30

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 >=8.
4. Inadequate response to at least 2 therapeutic interventions, including at least one oral immunosuppressive or biologic standard-of care therapy.

Exclusion Criteria

1. Active neuropsychiatric SLE.
2. History of inflammatory or autoimmune diseases including, but not limited to, rheumatoid arthritis, scleroderma, myositis, vasculitis, inflammatory bowel disease, or other conditions that require immune suppressive therapy. Subjects with stable concurrent Sjogren's, asthma, or autoimmune thyroid disease may be considered for participation.
3. Active systemic infection or history of chronic, recurrent, latent, or recent serious infections.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SEQUENTIAL

Arm && Interventions

Group	Intervention	Description
Cohort 1: Dose Level A	Budoprutug	-
Cohort 2: Dose Level B	Budoprutug	-
Cohort 3: Dose Level C	Budoprutug	-
Cohort 4: Dose Level D	Budoprutug	-

Primary Outcome Measures

Name	Time	Method
Change from Baseline in Systolic Blood Pressure	Up to Week 24	Mean change from baseline in systolic blood pressure (mmHg).
Change from Baseline in Diastolic Blood Pressure	Up to Week 24	Mean change from baseline in diastolic blood pressure (mmHg).
Change from Baseline in Heart Rate	Up to Week 24	Mean change from baseline in heart rate (bpm).
Incidence of Treatment-Emergent Adverse Events (TEAEs)	Up to Week 24	Number of participants experiencing TEAEs, graded per NCI CTCAE v5.0.
Incidence of Clinical Laboratory Abnormalities	Up to Week 24	Number of participants with clinically significant laboratory abnormalities.
Change from Baseline in Respiratory Rate	Up to Week 24	Mean change from baseline in respiratory rate.
Change from Baseline in Body Temperature	Up to Week 24	Mean change from baseline in body temperature (°C).
Change from Baseline in PR Interval	Up to Week 24	Mean change from baseline in PR interval (ms).
Change from Baseline in QRS Duration	Up to Week 24	Mean change from baseline in QRS duration (ms).
Change from Baseline in QT Interval	Up to Week 24	Mean change from baseline in QT interval (ms).
Change from Baseline in QTc Interval	Up to Week 24	Mean change from baseline in corrected QT interval (QTc).

Secondary Outcome Measures

Name	Time	Method
Maximum Observed Plasma Concentration (Cmax)	Up to Week 24	Measurement of the maximum observed plasma concentration.
Time to Maximum Observed Concentration (Tmax)	Up to Week 24	Measurement of the time to maximum observed concentration.
Terminal Half-Life (T1/2)	Up to Week 24	Measurement of the terminal half-life in days.
Apparent Clearance (CL/F) of budoprutug	Up to Week 24	Measurement of the apparent clearance in L/hour.
Change from Baseline in Circulating B Cell Count	Up to Week 24	Change in absolute number of CD19+ B cells in peripheral blood.
Incidence of Anti-Drug Antibodies (ADAs)	Up to Week 24	Number of participants with detectable ADAs.
ADA Titer Over Time	Up to Week 24	Measurement of ADA titer over time.
Volume of Distribution (Vd)	Up to Week 24	Measurement of the volume of distribution in liters.
Area Under the Curve (AUC) of Budoprutug	Up to Week 24	Measurement of the area under the drug concentration-time curve.

Trial Locations

Locations (15)

Climb Bio Investigative Site# 359101; 🇧🇬 Plovdiv, Bulgaria

Climb Bio Investigative Site# 359102; 🇧🇬 Sofia, Bulgaria

Climb Bio Investigative Site# 300102; 🇬🇷 Exochi, Thessaloniki, Greece

Climb Bio Investigative Site# 300103; 🇬🇷 Thessaloniki, Thessaloniki, Greece

Climb Bio Investigative Site# 400101; 🇷🇴 Cluj-Napoca, Romania

Climb Bio Investigative Site# 340101; 🇪🇸 Sabadell, Barcelona, Spain

Climb Bio Investigative Site# 340102; 🇪🇸 A Coruña, Spain

Climb Bio Investigative Site #100101; 🇺🇸 San Antonio, Texas, United States

Climb Bio Investigative Site #100103; 🇵🇷 Caguas, Puerto Rico

Climb Bio Investigative Site #380102; 🇺🇦 Ivano-Frankivsk, Ukraine

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