A Pilot Study to Evaluate the Feasibility of Anti-Fibrinolytic Agents in Reducing Hemorrhagic Complications in Pediatric Patients with Thrombocytopenia

Background: The risk of bleeding remains high in thrombocytopenic pediatric hematology-oncology patients despite the use of prophylactic platelet transfusions. In one study, WHO grade 2 or higher bleeding occurred in >80% of pediatric subjects receiving hematopoietic stem cell transplantation or chemotherapy despite a platelet transfusion threshold of 10,000/µl. The risk of bleeding is not decreased with higher transfusion thresholds or increased platelet doses. Bleeding episodes are associated with increased mortality rates, greater utilization of resources and increased transfusion requirements. We examined the use of anti-fibrinolytic agents in decreasing bleeding events and platelet transfusions.

Methods: We conducted a randomized double-blinded Phase 2 trial of tranexamic acid versus placebo in inpatient pediatric patients undergoing chemotherapy or HSCT expected to have prolonged thrombocytopenia. All patients admitted to the Oncology or HSCT services were screened for eligibility. Patients consenting for enrollment received either tranexamic acid 10m/kg/dose or normal saline every 8 hours while the platelet count as <30,000/ul until discharge or spontaneous platelet recovery (maximum 30 days). We conducted daily hemostatic assessments using the WHO bleeding scale and monitored adverse events and platelet transfusion requirements. Follow-up assessments took place at 7 and 30 days following completion of study medication. Primary aims were to assess safety and feasibility of tranexamic acid in children with hypoproliferative thrombocytopenia.

Results: We screened 697 admissions over 11 months, 31 patients were eligible for enrollment. Enrollment was suspended in March 2020 for COVID reasons though screening continued through July 2020. An additional 10 eligible patients were identified in this period. The most common reasons for ineligibility included recent asparaginase administration, predicted inpatient stay <5 days and age ≤ 2 or ≥ 18 years. Eleven patients enrolled and completed all study procedures. There were no missed doses of medication, 88.4% of doses were administered within one hour of prescribed time. Patients remained on study for a mean of 11.1 days. Five patients each met criteria for spontaneous platelet count recovery or discharge, 1 patient received the study medication for 30 days. Bleeding (all grades) occurred on 29.5% of days. Grade 2 or higher bleeding occurred on 4.9% of days and was experienced by 27.3% of patients. The most common sites of bleeding were oral/nasal and cutaneous. Subjects received a median of 2 platelet transfusions per patient. There were no thromboembolic events or serious adverse events.

Conclusion: Tranexamic acid is well tolerated can be safely administered to pediatric oncology patients as an adjunct to therapy. We are planning a multi-center randomized controlled trial to assess the efficacy of tranexamic acid in reducing bleeding complications in this population.