FDA Clears First C5 Inhibitor for IgA Kidney Disease

FDA granted accelerated approval on 21 October 2026 to AstraZeneca's Ultomiris (ravulizumab) to reduce proteinuria in adults with primary IgA nephropathy (IgAN) who are at risk of rapid disease progression — the first complement C5 inhibitor cleared for the indication. The approval rests on a surrogate endpoint, proteinuria reduction, not yet on proof that the drug slows the kidney-function decline that actually defines the disease's outcome.

A surrogate endpoint, not a proven outcome

IgA nephropathy is the most common primary glomerular disease worldwide, and a meaningful share of patients progress to kidney failure despite maximized renin-angiotensin-system blockade. Proteinuria — protein leaking into urine as damaged glomeruli fail to filter it out — is the surrogate FDA has used to accelerate approvals in this disease before, on the premise that a large enough reduction is "reasonably likely" to predict a slower loss of kidney function over time. It is a premise, not a proof. AstraZeneca's own framing of the approval, as reported by HCPLive and BioPharm International, is explicit that whether ravulizumab actually preserves kidney function has not yet been shown; that question is the job of the confirmatory eGFR analysis still to come at week 106 of the I CAN trial.

What the interim data showed

I CAN is a randomized, double-blind, placebo-controlled Phase 3 trial enrolling adults with biopsy-confirmed IgAN, eGFR of at least 30 mL/min/1.73m², and UPCR of at least 0.75 or proteinuria of at least 1.0 g/day despite maximized standard-of-care therapy. The prespecified interim analysis behind this approval measured 24-hour UPCR at two timepoints: an early readout at week 10 (36.7% reduction on ravulizumab versus 8.5% on placebo) and the later week-34 readout that anchors the label (46.6% versus 5.6%, a placebo-adjusted 43.4% reduction, 95% CI 33.5–51.8%). AstraZeneca has additional late-breaking I CAN data scheduled for presentation at ASN Kidney Week, which convened this same week, though that data is outside the approval itself and this story does not rely on it.

What RA/QA teams should track

This is a familiar pattern for accelerated-approval watchers: a drug reaches patients years before its ultimate clinical benefit is confirmed, on the strength of a biomarker regulators have pre-agreed to accept provisionally. For sponsors and reviewers alike, the operational question is not whether the week-34 proteinuria data clears the bar — it did — but what happens at week 106, when the eGFR analysis either confirms the benefit or does not. A miss on a confirmatory endpoint is the scenario that has triggered FDA-mandated label changes and even withdrawal proceedings elsewhere in the accelerated-approval portfolio; a hit converts the approval to a traditional one. Ultomiris was already approved for complement-mediated diseases including paroxysmal nocturnal hemoglobinuria and atypical hemolytic uremic syndrome, so the safety database behind complement C5 inhibition is not new — what is new, and still open, is whether that mechanism specifically slows IgA nephropathy's course.

Frequently asked questions

What did FDA approve on 21 October 2026?

Accelerated approval for AstraZeneca's Ultomiris (ravulizumab), a complement C5 inhibitor, to reduce proteinuria in adults with primary IgA nephropathy (IgAN) at risk of rapid disease progression. AstraZeneca and multiple trade outlets describe it as the first and only C5 inhibitor approved for IgAN.

What is the evidence?

A prespecified interim analysis of the Phase 3 I CAN trial, a randomized, double-blind, placebo-controlled study. At week 34, ravulizumab cut 24-hour urine protein-to-creatinine ratio (UPCR) by 46.6 percent from baseline versus 5.6 percent on placebo — a placebo-adjusted reduction of 43.4 percent (95% CI, 33.5–51.8). At week 10 the gap was 36.7 percent versus 8.5 percent.

Why is this an accelerated approval rather than a full one?

Proteinuria reduction is a surrogate endpoint reasonably likely to predict clinical benefit, not the clinical benefit itself. AstraZeneca has not established that ravulizumab slows the loss of kidney function in IgAN. Continued approval is contingent on verifying benefit in a confirmatory trial, built around the I CAN trial's co-primary eGFR (kidney filtration rate) endpoint, due at week 106.

Who was eligible for the trial, and how is the drug dosed?

I CAN enrolled adults with biopsy-confirmed IgAN, estimated glomerular filtration rate (eGFR) of at least 30, and UPCR of at least 0.75 or proteinuria of at least 1.0 g/day despite maximized standard therapy such as an ACE inhibitor or ARB. Ultomiris is given as a weight-based intravenous infusion roughly every eight weeks after initial loading doses, alongside that standard background therapy — its established dosing pattern in its other approved indications.