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.

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.

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.

Requests for IPD will generally be considered once review by major regulatory authorities (ie FDA, EMA) is complete and the primary publication is available.

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.

Sponsor staff will remain unblinded in this study.