Calliditas Announces Open Label Extension Results for Budesonide (Nefecon) in IgA Nephropathy

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Positive topline results showed treatment response consistent with NefIgArd findings, regardless of whether participants had previously been treated with Nefecon or placebo.

Calliditas Therapeutics has announced positive topline results from the global open-label extension of the phase 3 NefIgArd study of budesonide (Nefecon) in adult patients with primary IgA nephropathy (IgAN) on optimized renin-angiotensin system inhibitor (RASi) therapy.1

According to the April 24, 2024, release, open-label extension findings showed a treatment response consistent with the NefIgArd study across urine protein to creatinine ratio (UPCR) and estimated glomerular filtration rate (eGFR) endpoints, regardless of whether participants had previously been treated with Nefecon or placebo.1

“It is exciting to see these results on both proteinuria reduction and eGFR stabilization at 9 months across all patients irrespective of previous treatment regimen in the Phase 3 trial,” Renée Aguiar-Lucander, CEO of Calliditas Therapeutics, said in a press release.1 “These topline results support the study thesis that the response to retreatment with Nefecon was unaffected by previous treatment cycles. We look forward to presenting data at the upcoming ERA EDTA symposium.”

A global, phase 3, randomized, double-blind, placebo-controlled, multicenter study, NefIgArd was designed to evaluate the efficacy and safety of budesonide 16 mg once daily versus placebo in adult patients with primary IgAN in addition to optimized RASi therapy. Participants were randomly assigned in a 1:1 ratio to receive 16 mg/day of budesonide or matching placebo for 9 months, followed by a 15-month observational follow-up period without the study drug.1

Designed to act at the gut mucosal level, the oral, targeted-release formulation of budesonide was granted accelerated approval by the US Food and Drug Administration (FDA) for proteinuria reduction in adults with primary IgAN at risk of rapid disease progression on December 17, 2021. Calliditas Therapeutics AB submitted a supplemental New Drug Application to the FDA on June 21, 2023, which was accepted and granted Priority Review based on the full data set from NefIgArd.2

The NefIgArd study achieved both its primary and key secondary endpoints and was the basis for full approval by the US Food and Drug Administration (FDA) on December 20, 2023, when budesonide delayed-release capsules became the first treatment to receive approval from the FDA for reducing the loss of kidney function in adults with primary IgAN.1

The open-label extension study was designed to provide 9 months of treatment with budesonide for all patients who completed the NefIgArd study and who had > 1 g/g of proteinuria over 24 hours and > 30 ml/min of eGFR. A total of 119 patients were enrolled in the open-label extension and continued on optimized RASi therapy. Participants were treated for 9 months with budesonide 16 mg per day, including 45 patients who had previously had active treatment, and completed a follow-up visit 3 months after completion of treatment.1

Topline data from the open-label extension study showed the treatment response was consistent with findings from the NefIgArd study for the endpoints of UPCR and eGFR at 9 months across all patients, irrespective of whether they had previously been treated with budesonide or with placebo. Additionally, safety data after 9 months of treatment or retreatment with budesonide in patients who completed the NefIgArd study were consistent with previously reported data.1


  1. Calliditas Therapeutics. Calliditas Announces Positive NefIgArd Open Label Extension Results. April 24, 2024. Accessed April 24, 2024.
  2. Brooks, A. FDA Awards Full Approval to Budesonide (Tarpeyo) in Treatment of IgA Nephropathy. HCPLive. December 20, 2023. Accessed April 24, 2024.