Inclusion Criteria: 

• Documentation of PH1 as determined by genetic analysis confirming pathogenic mutations in the alanine-glyoxylate aminotransferase (AGXT) gene (valid historical laboratory data will be reviewed and approved by the Sponsor)
• Age at time of signing the informed consent/assent form:
  • Cohorts 1-3: ≥ 18 years to ≤ 64 years
  • Cohort 4: ≥ 6 years to < 18 years (Note: the first participant in Cohort 4 must be ≥ 12 to < 18 years old)
• Mean of 2 valid 24-hour UOx ≥ 0.7 mmol/24 hours/1.73 m2
• Weight ≤ 90 kg

Exclusion Criteria: 

• Confirmed diagnosis of primary hyperoxaluria type 2 or type 3
• History of a liver, kidney or combined liver/kidney transplant
• Currently on dialysis, or anticipated requirement for dialysis within the initial 24 months of the trial (Study Period 1)
• Participant has previously used (within past 24 months from signing of informed consent/assent) or is currently receiving an approved or investigational urinary oxalate lowering RNA interference (RNAi) or siRNA therapy
• Medical history includes clinical evidence of extrarenal systemic oxalosis, as determined by the Investigator
• History of liver cirrhosis
• Anticipated survival <2 years in the opinion of the Investigator

Note: Other protocol defined Inclusion/Exclusion Criteria may apply.

Eligibility last updated 2/07/2025. Questions regarding updates should be directed to the study team contact.