Table 2.

IgAN RCTs evaluating corticosteroids following a run-in period, during which supportive care was optimized

Trial	Majority ethnicity	Primary outcomes	Key exclusion criteria	Regimen	Outcome
STOP-IgAN	European	Complete remission: PCR <0.2 g/g and eGFR decrease <5 ml/min per 1.73 m2 from baseline after 3 years	Creatinine clearance <30ml/min, rapidly progressive disease, IgAN variants (e.g., minimal change), secondary IgAN	eGFR ≥60 ml/min per 1.73 m2: 1 g methylprednisolone i.v. for 3 days at month 1, 3, and 5. 0.5mg/kg per 48 h oral prednisolone for 6 months.	17% experienced remission with treatment vs. 5% with placebo. No difference in rate of eGFR decline. Steroid-related adverse events in treatment group.
		Progression: eGFR reduction ≥15 ml/min per 1.73 m2 from baseline		eGFR <60 ml/min per 1.73 m2: oral cyclophosphamide 1.5 mg/kg/day for 3 months, then azathioprine 1.5 mg/kg/day + oral prednisolone for 3 years (10 mg/day for 3 months, then 7.6 mg/day)
TESTING	Asian	40% decline in eGFR, ESKD, or death due to kidney disease	IgAN variants (e.g., minimal change), secondary IgAN, >50% crescents on biopsy within 12 months	Original dosing: 0.8 mg/kg/day methylprednisolone	28% reached end point with treatment vs. 41.3% with placebo (pooled analysis of both doses). More steroid-related adverse events with treatment, including deaths. Benefits lost at 36 months of follow-up.
				Reduced dosing: 0.4 mg/kg/day methylprednisolone

eGFR, estimated glomerular filtration rate; ESKD, end-stage kidney disease; IgAN, IgA nephropathy; IIgANPT, international IgAN prediction tool; PCR, protein:creatinine ratio; RCT, randomized controlled trial.