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Kidney Week

Abstract: PO1625

PHYOX3: A Long-Term, Open-Label Extension Trial of Nedosiran in Patients with Primary Hyperoxaluria Type 1, 2, or 3

Session Information

Category: Genetic Diseases of the Kidneys

  • 1002 Genetic Diseases of the Kidneys: Non-Cystic


  • Coenen, Martin, University Hospital Bonn, Bonn, Germany
  • Schalk, Gesa, University Hospital Bonn, Bonn, Germany
  • Cochat, Pierre, Hôpital Femme Mere Enfant HCL, Bron, France
  • Lipkin, Graham, Queen Elizabeth Hospital Birmingham, Birmingham, United Kingdom
  • Lieske, John C., Mayo Clinic Minnesota, Rochester, Minnesota, United States
  • Groothoff, Jaap, Amsterdam UMC (Academic Medical Center), Amsterdam, Netherlands
  • Baum, Michelle Amy, Boston Children's Hospital, Boston, Massachusetts, United States
  • Hoppe, Bernd, Dicerna Pharmaceuticals, Inc., Lexington, Massachusetts, United States
  • Rosskamp, Ralf, Dicerna Pharmaceuticals, Inc., Lexington, Massachusetts, United States

Primary hyperoxaluria (PH) is an ultra-rare, autosomal recessive genetic disorder characterized by overproduction of oxalate in the liver. Clinical manifestations can include nephrocalcinosis, recurrent kidney stones, progressive renal impairment, and systemic oxalosis. Nedosiran (formerly DCR-PHXC) is an investigational RNAi therapy administered monthly by subcutaneous injection. It is designed to reduce hepatic LDHA protein thereby inhibiting the final step responsible for overproduction of oxalate in PH1, PH2, and PH3.


This is an interim analysis of multidose data from the ongoing open-label, rollover extension PHYOX3 trial (NCT04042402) to evaluate long-term safety and efficacy of nedosiran in patients with genetically confirmed PH1, PH2 or PH3. Patients aged 6 years or more who have completed a previous nedosiran trial and their siblings with genetically confirmed PH are eligible.


As of May 2020, 16 participants were enrolled (13 PH1, 3 PH2) in this study. Total exposure (based on 15 participants) to monthly dosing of nedosiran has exceeded 3 years based on the cumulative duration of patient participation in the trial. Seven participants have had exposure to at least 3 monthly doses of nedosiran.
Treatment-emergent adverse events (AEs) were observed in 11 participants. Seven participants experienced 33 AEs considered related to study drug: administration-site events (18), blood chemistry findings (6), pain (2), dysuria (1), nasal congestion (1), edema (1), and erectile dysfunction (1). Three AEs were uncoded at this time. None of the participants experienced injection-site reactions (defined as occurring 4 hr or more after injection). All drug-related AEs were mild. There were no drug-related serious AEs.
Six out of the 7 participants who have had exposure to at least 3 monthly doses of nedosiran showed normalization or near-normalization of urinary oxalate excretion (defined as < 0.46 mmol/24 hr/1.73 m2 and ≥ 0.46-0.60 mmol/24 hr/1.73 m2, respectively) on at least 2 visits after the first dose.


Nedosiran has shown an acceptable safety profile in the interim analysis.This and the sustained reduction of urinary oxalate excretion are encouraging signs of potential long-term safety and clinical benefit of a multidose regimen of nedosiran.


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