Evaluate the Effect of ALLN-177 in Reducing Urinary Oxalate in Patients With Secondary Hyperoxaluria and Kidney Stones Over 28 Days

This is a multicenter, randomized, double-blind, placebo controlled study to evaluate the
efficacy of ALLN 177 compared with placebo in reducing the urinary excretion of oxalate in
subjects with secondary hyperoxaluria and kidney stones. ALLN-177 is an orally administered
form of oxalate decarboxylase. The goal of therapy with ALLN-177 is to reduce urinary
oxalate excretion by decreasing the absorption of oxalate from the gastrointestinal tract.

Eligible subjects will be randomized to 28 days of treatment with ALLN-177 (7,500 units) or
placebo three times daily with meals. Urinary oxalate excretion will be assessed by 24-hr
urine collections throughout the study.

The study allows for 44 subjects.

Inclusion Criteria:

- History of enteric or idiopathic hyperoxaluria and at least one kidney stone within
the last two years.

Exclusion Criteria:

- Hyperuricemia

- Glomerular filtration rate < 45 mL/min/1.73m2

- Hypercalcemia or hyperthyroidism

- Autoimmune disorder requiring systemic steroids

- Acute renal colic, primary hyperoxaluria, pure uric acid and/or cysteine stones,
renal tubular acidosis, chronic urinary tract infection, or acute renal failure