Oxazyme in Patients With Hyperoxaluria

A Pilot Study to Evaluate the Safety and Efficacy of Oxazyme (OC4) in Patients With Hyperoxaluria

Hypothesis: Oral administration of the oxalate metabolizing enzyme Oxazyme (OC4) will degrade food-borne oxalate and hence prevent its absorption from the gastrointestinal tract. In addition, by reducing oxalate concentrations in the gastrointestinal fluid, oxalate secretion from blood to the intestinal tract may be increased. Both effects would decrease blood levels of oxalate, and hence oxalate excretion in the urine.

Oxazyme is an oxalate degrading compound that can potentially degrade food-borne oxalate and hence prevent its absorption from the gastrointestinal tract.

We propose a 20-patient open-label trial pilot study of one month of Oxazyme twice daily (1gm Oxazyme sachet dissolved in 150 ml water) among adult subjects with a history of calcium oxalate nephrolithiasis. Patients will be stratified into those with enteric hyperoxaluria after Roux-en-Y Gastric Bypass (RYGB, n=10) and those with idiopathic hyperoxaluria (n=10). The patients will perform two, 24-hour, urine collections immediately before starting Oxazyme and on the last two days of the treatment period.

Inclusion Criteria:

• Roux-en-Y gastric bypass hyperoxaluric Calcium oxalate (CaOx) stone subjects or Idiopathic hyperoxaluric CaOx stone subjects
• Patients must have or had radio-opaque stones present on x-ray, or a history consistent with the passage of a stone or stone surgery or Extracorporeal Shock Wave Lithotripsy (ESWL) in the last 5 years.
• Hyperoxaluria Ox/Cr ratio ≥36 mg/g
• The patient must be able to provide written informed consent
• Patients must be able to urinate reliably into a collection vessel to measure urine volume.
• Patients may be taking drugs for the prevention of stone disease, including pyridoxine, thiazides, citrate supplements and allopurinol, as long as there have been no changes in these medications for at least 3 months

Exclusion Criteria:

• Primary hyperoxaluria patients
• Use of Oxadrop, Oxabsorb, or other therapies affecting oxalate absorption from the gut, other than stable doses of calcium.
• Subjects who are pregnant. Women of childbearing potential must have a negative pregnancy test prior to enrollment and must practice some form of birth control during the trial.
• Patients on an unstable dose of any other drugs for the prevention of stone disease (i.e., pyridoxine, citrate supplements. etc.). Patients should have been on a stable dose for at least 3 months prior to randomization.