CHICAGO (FRONTLINE MEDICAL NEWS) – Tinzaparin was safe and effective as an anticoagulant for hemodialysis patients based on results from the Intermittent Hemodialysis Anticoagulation with Tinzaparin (HEMO-TIN) trial presented at the annual meeting sponsored by the American Society for Nephrology.

In the multicenter randomized controlled trial of 192 adults on hemodialysis, tinzaparin, a low molecular weight heparin with antithrombotic properties, was compared with unfractionated heparin. Tinzaparin has been considered for hemodialysis patients because it is thought to be less dependent on renal clearance than are other low molecular weight heparins, Christine Ribic, MD, MSc , of McMaster University, Hamilton, Ont., said in reporting the results.

In the study , subjects were receiving hemodialysis three times weekly at one of four facilities in Ontario; 95 were randomized to receive tinzaparin and 94 received unfractionated heparin. The patients had a mean age of about 65 years, 58% were male, and 71% were Caucasian. End-stage renal disease was due to diabetic nephropathy in 43%. Nearly 90% of the patients were receiving darbepoetin.

After 3 months, the 78 patients remaining in the tinzaparin group crossed over to receive unfractionated heparin for 3 months. The 79 patients remaining in the unfractionated heparin group crossed over to receive tinzaparin for 3 months. Of these 156 patients, 125 completed the 3-month crossover phase.

There were 421 bleeding events in the 12,125 hemodialysis sessions studied. They were evenly distributed in the groups, with 212 (50.4%) in those receiving unfractionated heparin and 209 (49.6%) in those receiving tinzaparin. The prevalence of major bleeds (2.1 vs 1.6%), clinically important nonmajor bleeds (1.2% vs 0.2%), and minor bleeds (47.0% vs 47.7%) was also similar between the unfractionated heparin and tinzaparin groups.

Anti-Xa heparin levels were used as a surrogate measure of low molecular weight heparin activity levels and bleeding risk due to bioaccumulation. In tinzaparin-treated patients, anti-Xa heparin levels never exceeded a value of 0.2 either before or after dialysis. This value was considered the threshold between safety and increased risk for bleeding. This threshold level was routinely exceeded pre- and post-dialysis in patients receiving unfractionated heparin at baseline and both before and after crossover.

Grade 4 clotting was similar for tinzaparin and unfractionated heparin, occurring in 23 of 6,095 (0.4%) unfractionated heparin hemodialysis sessions and 41 of 6030 (0.7%) tinzaparin hemodialysis sessions. Mean dialyzer clotting scores and mean air trap clotting scores were also comparable.

The trial was supported by Leo Pharma, the maker of tinzaparin (innohep), in collaboration with McMaster University. Dr. Ribic is the sponsor of the trial.