Study design and conduct
PD
PHYOX4 was a multinational, randomized, double‐blind, placebo‐controlled trial assessing the safety, pharmacokinetics (PK), and pharmacodynamics (PD) of a single dose of subcutaneous nedosiran in participants with PH3 (ClinicalTrials.gov number: NCT04555486). It was conducted between January 2021 and September 2021 in accordance with the provisions of the Declaration of Helsinki, Good Clinical Practice Guidelines of the International Conference on Harmonisation, and all applicable laws and regulations. Written informed consent was obtained from all adult participants and the parents or legal guardians of participating children. All children assented as appropriate. An independent Data and Safety Monitoring Committee (DSMC) monitored the trial for safety. Those who completed PHYOX4 were eligible for screening into the open-label extension study DCR-PHXC-301 to receive nedosiran on an ongoing basis (ClinicalTrials.gov Identifier: NCT04042402; PHYOX3), with DSMC approval.