By Kristina Rebelo
SAN DIEGO -- November 2, 2009 -- The use of tenecteplase instilled into the catheter lumen significantly improved haemodialysis (HD) catheter function as measured by blood flow rate (BFR), and has a favourable safety profile, according to 2 studies presented here October 30 at the American Society of Nephrology (ASN) Renal Week 2009.
Researchers presented the results of the phase 3 Tenecteplase for Restoration of Function in Dysfunctional Hemodialysis Catheters (TROPICS) 3 and TROPICS 4 studies. TROPICS 3 was randomised, double-blind, and placebo-controlled, while TROPICS 4 was an open-label study.
The dysfunction in the catheters of patients with renal disease can cause blood clots to form and can hinder the blood flow, causing either inadequate dialysis or even making dialysis impossible altogether, according to lead investigator of TROPICS 4, Steven Fishbane, MD, Winthrop University Hospital, and Stony Brook University Medical Center, Mineola, New York.
For TROPICS 3, James A. Tumlin, MD, University of Tennessee at Chattanooga, Chattanooga, Tennessee, and colleagues randomised 140 patients with end-stage renal disease with cuffed, tunnelled haemodialysis catheters to receive a 1-hour dwell of tenecteplase 2 mg or placebo in each lumen.
Treatment success was defined as a blood flow rate of >=300 mL/min and a >25 mL/min increase from baseline 30 minutes prior to and at the end of HD.
After the initial 1-hour dwell, 21.6% of patients receiving tenecteplase had treatment success compared with 5.3% of patients receiving placebo (P = .004).
In TROPICS 4, researchers similarly administered a 1-hour intracatheter dwell of tenecteplase 2 mg to patients with cuffed, tunnelled haemodialysis catheters.
Of the 223 patients, 34.1% had treatment success. Of 116 pts who received an extended dwell of tenecteplase 2 mg, 49.1% had treatment success at the end of the next haemodialysis session.
The safety profile was favourable, with a low incidence of targeted adverse events consistent with rates reported in the literature.
One of the stated study limitations of TROPICS 4 was that it was open label, Dr. Fishbane said, "but in terms of evidence, the results were so consistent with TROPICS 3 that we're comfortable that the results are highly meaningful and that they mirror so precisely what the double-blinded studies showed."
Dr. Fishbane said that a large educational push is necessary to explain the negative consequences of another very common problem, and that is the reversing of the lines in dialysis patients.
"It's a very common practice in some facilities for the nurses and technicians to reverse the lines, to switch connections to the arterial and venous side of the catheter to restore the blood flow in some cases, but this comes at a price to the patient where you get a reduction in effectiveness of dialysis and it gives a false impression that the process is going well because the negative effect is hidden," said Dr. Fishbane, who added that oftentimes, the treating physician is not aware that a "cosmetic fix" has taken place and that the lines have been reversed.
Funding for this study was provided by Genentech, Inc.
[Presentations titles: A Phase III, Randomized, Double-Blind, Placebo-Controlled Study of Tenecteplase for Improvement of Hemodialysis Catheter Function: TROPICS 3. Abstracts F-FC298
AND
A Phase III, Open-Label Study of Tenecteplase for Improvement of Hemodialysis Catheter Function: TROPICS 4. Abstract F-PO1555]
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