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Abstract: TH-PO766

A 24-Month Interim Analysis of a Phase 2 Trial Evaluating the Long-Term Efficacy and Safety of Oxabact OC5 in Dialysis Patients with Primary Hyperoxaluria Type 1 (PH1)

Session Information

  • Pediatric CKD
    November 07, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
    Abstract Time: 10:00 AM - 12:00 PM

Category: Pediatric Nephrology

  • 1700 Pediatric Nephrology


  • Hoppe, Bernd, University Hospital Bonn, Bonn, Germany
  • Dehmel, Bastian, OxThera IP AB, Lucerne, Switzerland
  • Banos, Ana, OxThera AB, Trångsund, Sweden
  • Herberg, Ulrike, University of Bonn, Bonn, Germany

In PH1, endogenous overproduction of oxalate in the liver results in significantly elevated plasma oxalate (Pox), high urinary oxalate excretion, recurrent urolithiasis and/or progressive nephrocalcinosis. This can lead to end-stage renal disease (ESRD) with patients requiring dialysis and combined liver and kidney transplantation. Dialysis is insufficient to remove oxalate and cannot match the endogenous production, resulting in high Pox and thus systemic oxalate deposition. Oxabact (OC5), is a formulation of Oxalobacter formigenes,an oxalate-metabolizing bacterium, that induces active secretion of oxalate from plasma to the intestinal lumen. This Phase II, open-label single-arm study investigated efficacy in reducing Pox and safety of OC5 in PH1 patients on a stable dialysis regimen.


Patients received OC5 (≥109 CFU lyophilized O. formigenesper dose, twice a day) until transplantation or until they reached a maximum of 36 months treatment duration. Pox was evaluated monthly. Cardiac function (echocardiography) was evaluated every 6 months. Safety was assessed continuously. This 24-months interim analysis represents the longest treatment intervention observed in patients with PH1 on dialysis to date.


Eight subjects with a mean (SD) age of 33 (13) years were enrolled into the long-term treatment study. Three patients discontinued before reaching 24 months of treatment; two due to non-compliance to treatment and one due to a liver transplantation. The drop-outs did not have an impact on results. Total Pox was 158.3 (43.9) μmol/L at baseline (n=8), 119.8 (11.3) μmol/L at Week 52 (n=6), and was further reduced to 94.6 (31.9) μmol/L at Week 104 (n=5). Mean Left ventricular ejection fraction improved from 51.6 % at baseline (n=8) to 59.8% at Week 52 (n=6) and 59.4% at Week 104 (n=5). Seven subjects reported any Adverse Event (AE), most frequent AEs were infections and infestations and gastrointestinal disorders. Four subjects experienced 5 serious AEs, unrelated to treatment


Two years treatment with OC5 reduced mean Pox by approximately 40% in PH1 patients with ESRD without intensifying their dialysis regimen. This was also associated with an improved and stabilized cardiac function. OC5 was safe and well-tolerated.


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