This is a Phase 2a study of glycolate oxidase inhibitor LLX-424 in patients with a history of kidney stones. Eligible subjects with a history of kidney stones will be randomized to receive study drug (LLX-424 or placebo) for 8 weeks.

This is a Phase 2a, randomized, double-blind, placebo-controlled study designed to assess the safety, tolerability, PK, and PD effects of LLX-424 in patients with a history of kidney stones.

Following completion of screening procedures, on Study Day 1, eligible subjects will be randomized in a 2:1 ratio to receive either LLX-424 or matching placebo, respectively.

An outpatient safety Follow-up Visit will be scheduled on Day 63 or 7 days after the last dose (end of study visit).

Inclusion Criteria:

• History of kidney stones documented in medical records
• 24-hour urine oxalate excretion
• Body mass index 18.5 to 38 kg/m2 inclusive
• Estimated glomerular filtration rate ≥ 60 mL/min/1.73m2

Exclusion Criteria:

• History or medical record evidence of kidney stones that are not calcium oxalate
• Unstable kidney function
• Spot urine protein to creatinine ratio ≥ 1 mg/mg at screening
• History of kidney transplantation
• Hemoglobin A1c > 9.5% at screening
• History of enteric hyperoxaluria, intestinal malabsorption, bariatric surgery, intestinal surgery, inflammatory bowel disease
• History or evidence of cirrhosis