Tranexamic acid offered no benefit over placebo as bleeding prophylaxis in patients with haematologic malignancies undergoing therapies that can induce thrombocytopenia, according to a new study presented at the American Society of Hematology (ASH 2020) Annual Meeting (ASH 2020).

“All haemostasis is complex, but bleeding associated with the treatment of haematologic malignancy is perhaps more so, given the widespread microvascular and endothelial damage that occurs with chemotherapy, GVHD, and infections,” said Dr Terry B. Gernsheimer, of the University of Washington, who presented results of the a-TREAT trial.

The authors hypothesised that an inhibitor of fibrinolysis might be helpful in decreasing the high rates of bleeding seen in patients treated for haematologic malignancies. Tranexamic acid is a potent inhibitor of fibrinolysis.

“Although not uncommonly used in this setting, there was a lack of evidence that it is efficacious,” Dr Gernsheimer said.

During a press briefing, she added that there was a sense that use of tranexamic acid had been increasing in anticipation of positive trial evidence – so the new results should play an important role in changing that practice.

The new study compared tranexamic acid to placebo in 330 patients undergoing haematologic malignancy therapy who were likely to have treatment-induced thrombocytopenia.

But its findings were negative, with no significant differences between the TXA and placebo groups. In the placebo group, 48.8% of patients had a grade 2 or higher bleed, compared with 45.4% in the tranexamic acid group, for an odds ratio of 0.86 (95% CI, 0.52-1.38).

There was also no difference when the patients were divided by allogeneic transplant, autologous transplant, or chemotherapy. Secondary outcomes including mean days alive without bleeding and mean platelet transfusions also did not differ between the groups.

The researchers also conducted a post-hoc analysis of patients with grade 3 or worse bleeding; these proved to be rare events, with no difference between tranexamic acid and placebo.

There was, however, a significant increase in thrombotic events with tranexamic acid. These occurred in 19.5% of patients receiving tranexamic acid and in 11.0% of those receiving placebo, which was statistically significant.

Dr Gernsheimer stressed, though, that the majority of these events were central line occlusions without an associated thrombus. In fact, fewer non-catheter thrombotic events were seen in the tranexamic acid group, though this did not reach statistical significance, and there was no difference in mortality.

“We cannot rule out the usefulness of tranexamic acid in other settings of thrombocytopenia, such as the treatment of active bleeding, refractoriness to platelet transfusion, or prophylaxis for a procedure,” Dr Gernsheimer concluded.

During the press briefing, Dr Lisa Hicks, of St. Michael’s Hospital in Toronto, who was not involved with the study, said the findings have important real-world implications.

“The results suggest that tranexamic acid should not be routinely used as prophylaxis in non-bleeding patients with low platelet counts and blood cancer.”