A new study has compared two major blood clot treatments in cancer patients – heparin tinzaparin and warfarin – and found that through the former didn’t reduce recurrent venous thromboembolism, it did lower the rate of clinically relevant nonmajor bleeding.
According to statistics, venous thromboembolism (VTE; blood clots in the deep veins) is a major cause of illness and death in patients with cancer. Treatment options are available and as per the clinical practice guidelines, doctors recommend low-molecular-weight heparin over warfarin.
Researchers, in a new study published in JAMA, say that these recommendations are largely based on results from a single, large randomized trial with supportive evidence from additional smaller studies that were conducted over a decade ago in academic centers primarily in North America and Western Europe.
For their latest study, researchers including Agnes Y. Y. Lee, M.D., M.Sc., of the University of British Columbia, Vancouver, randomly assigned 900 adult patients with active cancer and documented deep vein thrombosis or pulmonary embolism to tinzaparin once daily for 6 months vs conventional therapy with tinzaparin once daily for 5 to 10 days followed by warfarin at a dose adjusted to maintain the international normalized ratio (INR) within the therapeutic range for 6 months.
The international study saw enrollment from 164 centers in Asia, Africa, Europe, and North, Central, and South America between August 2010 and November 2013. Participants were followed up for 180 days and for 30 days after the last study medication dose for collection of safety data.
Researchers found recurrent VTE occurred in 31 of 449 patients treated with tinzaparin and 45 of 451 patients treated with warfarin (6-month cumulative incidence, 7.2 percent for tinzaparin vs 10.5 percent for warfarin).
Further, there were no differences in major bleeding (12 patients for tinzaparin vs 11 patients for warfarin) or overall mortality (150 patients for tinzaparin vs 138 patients for warfarin).
Tinzaparin significantly reduced the risk of clinically relevant nonmajor bleeding (included bleeding that required any medical or surgical intervention but was not fatal; did not occur in a critical area or organ; or did not cause a fall in hemoglobin of greater than 2 g/dL or lead to a transfusion of 2 or more units of whole blood or red cells) compared with warfarin (49 of 449 patients for tinzaparin vs 69 of 451 patients for warfarin).
“Together with the adverse events data, [this trial] demonstrated that tinzaparin, even when given at a full therapeutic dose for up to 6 months, is safe in a broad oncology population,” the authors write.
“Further studies are needed to assess whether the efficacy outcomes would be different in patients at higher risk of recurrent VTE.”
