Cheung 2018.

Methods	Study design: parallel, 2‐arm RCT Time frame: not reported Duration of follow‐up: intervention administered for 52 weeks; subjects will be followed for a further 12 months
Participants	Setting: multicentre Country: The UK Inclusion criteria: biopsy‐proven IgAN with persistent proteinuria (24 h urine protein excretion > 0.5 g) despite best supportive measures are at increased risk of progression to ESKD Number (analysed/randomised): not reported/21 Mean age ± SD (years): not reported Sex (M/F): not reported Exclusion criteria: Subjects with severely reduced kidney function
Interventions	Treatment group Belimumab (Benlysta ‐ IgG1 monoclonal antibody) given fortnightly then monthly by IV infusion at a dose of 10 mg/kg Control group Placebo Co‐interventions ACEi or ARB
Outcomes	Percent change from baseline in UPCR at week 52 Change from baseline in eGFR at week 52 Levels of poorly glycosylates IgA1, IgA1 immune complexes, pharmacodynamic biomarker QoL
Notes	Conference abstract Trials registration identification number: not reported Funding: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Insufficient information to permit judgement
Allocation concealment (selection bias)	Unclear risk	Insufficient information to permit judgement
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double‐blind study
Blinding of outcome assessment (detection bias) All outcomes	High risk	Blinding of outcome assessment not specifically reported. Key outcomes were objective laboratory measures and were unlikely to be affected by any knowledge of treatment allocation. Interpretation of subjective outcomes may have been influenced by knowledge of treatment allocation
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Insufficient information to permit judgement
Selective reporting (reporting bias)	High risk	There was no pre‐specified protocol identified for this study. The study did not report extractable data for the key outcomes that would be expected for a study of this type (e.g., death (any cause), infection, malignancy, ESKD, doubling of SCr, complete remission, SCr)
Other bias	Unclear risk	Insufficient information to permit judgement