Oxabact: truly a new treatment option in patients with (primary) hyperoxaluria?

Introduction: Hyperoxaluria is one leading risk factor for recurrent kidney stone disease and progressive nephrocalcinosis. In patients with a primary form (PH, endogenous oxalate overproduction), severe hyperoxaluria often leads to early end-stage renal failure (ESRD). Humans cannot further metabolize oxalate, but Oxalobacter formigenes, an anaerobic microbe normally colonizing the intestinal tract, uses oxalate as its sole source of energy. Orally administered Oxalobacter/Oxabact, hence using Oxalobacter's oxalate degrading enzymes for oxalate elimination via the intestinal tract is regarded as a new treatment option. Areas covered: This review is an intense overview of animal and human data, both basic research, as well as clinical studies with a focus on human studies in patients with PH type I. A discussion of pitfalls and clues of the recent and future Oxalobacter/Oxabact trials is included. Expert opinion: There is important scientific evidence that Oxalobacter/Oxabact medication is helpful in treating patients with any form of hyperoxaluria. Hence, major socio-economic effects would be achievable, as most of the patients with PH type I are currently untreatable and reach early ESRD and often premature death. The only curative current treatment option in these patients is combined liver-kidney or pre-emptive liver transplantation, both expensive procedures bearing great risk potentials.