A Phase 1b Study to Evaluate the PK of CSL300 (Clazakizumab) in Chinese Subjects With End Stage Kidney Disease (ESKD)

A Phase 1b, Randomized, Multicenter, Placebo-controlled Study to Evaluate the Pharmacokinetics and Safety of CSL300 (Clazakizumab) in Chinese Subjects With End Stage Kidney Disease Undergoing Dialysis

This is a phase 1b, partial-blind (Sponsor unblinded), randomized, multicenter, placebo-controlled study. The primary objective of this study is to evaluate the pharmacokinetics (PK) of CSL300 after single and multiple doses in Chinese participants with end stage kidney disease (ESKD) undergoing dialysis.

Study Overview

• Status: Not yet recruiting
• Conditions: End Stage Kidney Disease (ESKD)
• Intervention / Treatment: Biological: CSL300; Other: Placebo

• Study Type: Interventional
• Enrollment (Estimated): 24
• Phase: Phase 1

Contacts and Locations

• Study Contact: Name: Trial Registration Coordinator; Phone Number: +16108784697; Email: clinicaltrials@cslbehring.com

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Participants has provided written informed consent and is willing and able to adhere to all protocol requirements.
• Aged 18 or older, inclusive, at the time of providing written informed consent.
• Diagnosis of ESKD undergoing maintenance dialysis for at least 12 weeks before Screening.

Exclusion Criteria:

• Exclusion related to risk of infection: concomitant use of systemic immunosuppressant agents, primary immunodeficiency, positive test for active tuberculosis (TB), history of latent TB without completion of full course of prophylactic treatment, evidence of human immunodeficiency virus infection during Screening, seropositivity for hepatitis B surface antigen or positive hepatitis B virus (HBV) DNA during Screening, seropositivity for hepatitis C virus ribonucleic acid during Screening, diagnosis of clinically significant active infection, history of / OR current invasive fungal infection OR other opportunistic infection OR recurrent cellulitis (defined as 2 or more episodes in the year prior to screening), administration of a live vaccine within 6 weeks of start of Screening, presence of urinary catheter, or evidence of wet gangrene or nonhealing ulcers.
• Exclusion related to laboratory abnormalities: abnormal liver function tests, neutropenia, thrombocytopenia, or significant anemia.
• Exclusion related to medical history: any life-threatening disease expected to result in death within 12 months (other than cardiovascular disease), evidence of active hepatic disease and / or moderate or severe hepatic impairment, recent unplanned hospitalization (< 30 days) prior to Screening, recent (< 3 months) major surgery or planned major surgery known at the time of Screening, poorly controlled hypertension, a present or previous (< 5 years) malignancy except for basal cell carcinoma, fully excised squamous cell carcinoma of the skin, or nonrecurrent (< 5 years of Screening) cervical carcinoma in situ, active or recent (< 30 days of Screening) clinically severe bleeding, a scheduled kidney transplant within 6 months of Screening, a history of anaphylaxis or hypersensitivity to CSL300 or any constituents of the product, or a history of demyelinating disorders.
• Exclusion related to risk of gastrointestinal perforation: a history of GI perforation, inflammatory bowel disease (except fully excised ulcerative colitis), or peptic ulcer disease (< 12 months before Screening), a history of diverticular disease or diverticulitis (except if disease has been fully excised). An incidental finding of diverticulosis (presence of small diverticula) and no history of symptoms, complications, or any episodes requiring treatment may be eligible for the study based on investigator's judgment. However, any history of complications, inflammation, or infection suggestive of diverticulitis or diverticular disease is exclusionary, inflammatory bowel disease (ie, Crohn's disease, ulcerative colitis except if fully excised, or prior gastric bypass surgery.
• Exclusion related to treatment compliance: evidence of inadequate dialysis, unwillingness or inability to comply with study procedures, a history of noncompliance with medical treatments, or ongoing alcohol or illicit substance abuse.
• Current or recent participation in research study involving an experimental agent < 3 months of Screening.
• Pregnant, breastfeeding, or unwillingness to practice adequate contraception during the study and for 5 months after the last dose of investigational product.
• The presence of any condition that in the opinion of the Investigator would (1) compromise the safety of the participant in case of participation in the study, (2) compromise the quality of the data, and / or (3) limit the life expectancy of the participant to < 1 year.
• The Sponsor determines that the participant is no longer needed for participation in study.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: CSL300 (Clazakizumab); Participants will receive CSL300 once every 4 weeks (Q4W) as a slow intravenous (IV) bolus, for a total of 20 weeks during the Treatment Period.	Biological: CSL300; CSL300 is a humanized anti-interleukin 6 (anti-IL-6) monoclonal antibody (mAb).
Placebo Comparator: Placebo; Participants will receive a placebo matching to CSL300 Q4W as a slow IV bolus, for a total of 20 weeks during the treatment period.	Other: Placebo; Placebo is a solution for injection matching the excipient content and concentration of the CSL300 product, minus the active ingredient.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Area Under the Concentration-time (AUC) Curve of CSL300 Over 1 Dosing Interval After Multiple Doses (AUC0-tau,MD)	Day 85 up to Day 113
Trough Concentration at Steady State (Ctrough,ss)	Up to Day 141

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Participants With Treatment Emergent Adverse Events (TEAEs), Serious Adverse Events (SAEs), and Adverse Event of Special Interests (AESIs)	The following adverse events (AEs) are defined as AESIs: relevant infections (tuberculosis, herpes simplex virus, herpes zoster, human papillomavirus, human immunodeficiency virus, hepatitis B, hepatitis C, and invasive fungal infections), and demyelinating disorders.	Up to Day 225 (End of Study [EoS])
Percentage of Participants With TEAEs, SAEs, and AESIs	The following AEs are defined as AESIs: relevant infections (tuberculosis, herpes simplex virus, herpes zoster, human papillomavirus, human immunodeficiency virus, hepatitis B, hepatitis C, and invasive fungal infections), and demyelinating disorders.	Up to Day 225 (EoS)
Percentage of Participants With a Clinically Significant Change From Baseline in Laboratory Test Results	Laboratory assessments will include hematology parameters such as white blood cells (leukocytes), neutrophils, and platelets; chemistry evaluations including alanine aminotransferase (ALT), aspartate aminotransferase (AST), and total bilirubin; a lipid panel comprising total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and triglycerides; and immunogenicity testing.	At Baseline and up to Day 225 (EoS)
Number of Participants With Antidrug Antibodies	The detection of antibodies to CSL300 will be performed using a validated immunoassay method.	At Days 1, 29, 85, and 169
Maximum Observed Concentration (Cmax) of CSL300		Up to Day 169
Area Under the Concentration-Time Curve From Time 0 to Day 28 (AUC0-28d) of CSL300		Up to Day 28
Trough Concentration (Ctrough) of CSL300		Up to Day 141
Time to Reach Cmax (Tmax) of CSL300		Up to Day 85
Change From Baseline on log-scale High-Sensitivity C-reactive Protein (hs-CRP)		At Baseline, Week 12, and Week 24
Plasma Interleukin-6 (IL-6) Free and Total Levels		At Weeks 12 and 24

Collaborators and Investigators

• Sponsor: CSL Behring

Study record dates

Study Major Dates

• Study Start (Estimated): June 30, 2026
• Primary Completion (Estimated): August 30, 2027
• Study Completion (Estimated): November 30, 2027

Study Registration Dates

• First Submitted: May 26, 2026
• First Submitted That Met QC Criteria: May 26, 2026
• First Posted (Actual): June 2, 2026

Study Record Updates

• Last Update Posted (Actual): June 2, 2026
• Last Update Submitted That Met QC Criteria: May 26, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Systemic inflammation; Diabetes mellitus; Atherosclerotic cardiovascular disease; Interleukin-6; High-sensitivity C-reactive protein; Humanized Monoclonal antibody; High-density lipoprotein cholesterol
• Additional Relevant MeSH Terms: Urogenital Diseases; Endocrine System Diseases; Vascular Diseases; Cardiovascular Diseases; Pathologic Processes; Male Urogenital Diseases; Kidney Diseases; Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Chronic Disease; Disease Attributes; Metabolic Diseases; Glucose Metabolism Disorders; Renal Insufficiency; Arteriosclerosis; Arterial Occlusive Diseases; Renal Insufficiency, Chronic; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Diabetes Mellitus; Kidney Failure, Chronic; Atherosclerosis
• Other Study ID Numbers: CSL300_1001

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: CSL will consider on a case-by-case basis requests to share Individual Patient Data (IPD) with external bona-fide, qualified scientific and medical researchers. For information on the process and requirements for submitting a voluntary data sharing request for IPD, please contact CSL at clinicaltrials@cslbehring.com.
• IPD Sharing Time Frame: Requests for IPD will generally be considered once review by major regulatory authorities (ie FDA, EMA) is complete and the primary publication is available.

IPD Sharing Access Criteria

Proposed research should seek to answer a previously unanswered important medical or scientific question.

Applicable country specific privacy and other laws and regulations will be considered and may prevent sharing of IPD.

If the request is approved and the researcher has executed an appropriate data sharing agreement, IPD that has been appropriately anonymized will be available.

• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP

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