Reduction of plasma oxalate levels by oral application of Oxalobacter formigenes in 2 patients with infantile oxalosis.

[primary hyperoxaluria type 1]

The spectrum of primary hyperoxaluria type I is extremely heterogeneous , ranging from singular to recurrent urolithiasis and early end-stage renal disease (ESRD ). In infantile oxalosis , the most devastating form , ESRD occurs as early as within the first weeks of life . No kidney replacement therapy sufficiently removes endogenously overproduced oxalate . However , curative combined liver -kidney transplant often is impracticable in small infants . Oxalobacter formigenes (O formigenes ), an anaerobic oxalate-degrading bacterium , is a colonizer of the healthy human colon . Oral administration of O formigenes has been shown to significantly decrease urine and plasma oxalate levels in patients with primary hyperoxaluria . We report compassionate use of O formigenes in two 11 -month -old girls with infantile oxalosis and ESRD . They received O formigenes twice a day for 4 weeks (or until transplant ). Dialysis regimens were unchanged . Plasma oxalate levels decreased from >110 μmol /L before to 71 .53 μmol /L under treatment in patient 1 and from >90 to 68 .56 μmol /L (first treatment period ) and 50 .05 μmol /L (second treatment period ) in patient 2 . O formigenes was well tolerated . No serious side effects were reported . Extremely increased plasma oxalate levels in patients with infantile oxalosis may enable intestinal elimination of endogenous oxalate in the presence of O formigenes . Therefore , O formigenes therapy may be helpful as a bridging procedure until transplant in such patients .