Results of a multicenter, phase II clinical trial, published in the online issue of the Journal of the American Society of Nephrology, indicate that using a renal tubule assist device (RAD), which is a conventional hemofilter device lined with monolayers of human renal tubule cells grown from donor kidneys, is superior to conventional renal replacement therapy alone in reducing the mortality risk and improving clinical outcome in acute renal failure patients.

James A. Tumlin, M.D., nephrologist, Clinical Research Division, Southeast Renal Associates, Charlotte, North Carolina, and colleagues conducted the controlled, randomized, open-label trial, which included 58 patients with acute renal failure requiring continuous renal replacement therapy. Patients were randomly assigned to either RAD treatment and conventional continuous renal replacement therapy or only renal replacement therapy. The primary end-point for efficacy was all-cause death at 28 days, with additional end-points of all-cause deaths at 90 and 180 days, time for renal function recovery, and safety.

The data from the study demonstrated a mortality rate of 33% in the RAD group, and 61% in the renal replacement group, at 28 days. The survival rate through 180 days was also considerably higher in the RAD group, with a 50% lower risk of mortality compared to the renal replacement therapy group. Based on the results, the researchers concluded that RAD therapy was well tolerated and aided faster recovery of renal function.

Earlier, Humes et al (Kidney International, 2004) had studied the benefits of combining human renal tubule cell therapy to conventional renal replacement therapy. In their study, which was a phase I/II trial, 10 patients with acute renal failure and multi-organ failure were treated with RAD. The bioartificial kidney comprised of a synthetic hemofilter connected to a bioreactor cartridge enclosing human proximal tubule cells inside an extracorporeal perfusion circuit fitted in the conventional hemofiltration pump systems. The device demonstrated good viability, durability, and functionality in the ex vivo clinical setting, with appreciable metabolic and endocrinologic activity. A 3-day follow-up in the intensive care unit showed an improvement in 90% of the patients, and 60% of them survived beyond 30 days.

Acute renal failure is the rapid loss of renal function, commonly as a result of acute tubular necrosis, obstructive uropathy, acute nephritic syndrome, infections such as septicemia or acute pyelonephritis, and certain disorders such as idiopathic thrombocytopenic thrombotic purpura (ITTP) and scleroderma. Symptoms of renal failure include oliguria, anuria, nocturia, and fluid retention in the body. Acute renal failure is treated using diuretics and by performing dialysis. The renal tubule assist device appears to be a very promising treatment modality for renal failure patients, and definitely deserves larger clinical trials.

References

1. Tumlin J, Wali R, Williams W, et al. Efficacy and Safety of Renal Tubule Cell Therapy for Acute Renal Failure. Journal of the American Society of Nephrology. 2008 Feb 13 [Epub ahead of print].

2. Humes HD, Weitzel WF, Bartlett RH, et al. Initial clinical results of the bioartificial kidney containing human cells in ICU patients with acute renal failure. Kidney International. 2004 Oct;66(4):1578-88.