(P-TS-96) Platelet Transfusion Support in Patients Undergoing Hematopoietic Cell Transplantation for Glanzmann Thrombasthenia: A Case Series

Background/Case Studies: Glanzmann thrombasthenia (GT) is a rare autosomal recessive bleeding disorder caused by defects in platelet glycoprotein GPIIb/IIIa, resulting in impaired platelet (PLT) aggregation. Patients are at risk for acute and chronic mucocutaneous bleeding which can be life threatening. Alloimmunization with anti-GPIIb/IIIa or anti-HLA antibodies, occurs in up to 30% of patients with GT. Allogeneic hematopoietic cell transplantation (HCT) is a curative therapy. Peri-HCT challenges include managing bleeding risk/PLT refractoriness and determining transfusion thresholds in the setting of dysfunctional but normal PLT counts.

Study

Design/Methods: This Human Subjects Review board approved retrospective case review included 5 GT patients who underwent allogeneic HCT between 2008 and 2024. Data on vascular access, bleeding events, transfusion practices, and hemostatic therapies were extracted with chart review.

Results/Findings: Table 1 lists HCT and transfusion details. Four patients had non-tunneled peripherally inserted cutaneous central (PICC) lines; one had a tunneled central line. Two patients received recombinant factor VIIa (rFVIIa) before PICC placement. Patients 1, 2, and 5 received rituximab or rituximab/daratumumab pre-conditioning and had good increments with PLT transfusions despite anti-GPIIb/IIIa antibodies. Prophylactic PLT transfusions were given on day -3 for Patients 1–3 even with normal PLT count due to risk of bleeding with conditioning. Four patients had PLT transfusion threshold of 50,000/µL: Patient 5 (HCT year 2008) for significant bleeding, patient 2 (HCT 2011) due to care team experience with bleeding in patient 5, patient 3 (HCT 2024) due to arachnoid cyst, and patient 1 (HCT 2024) for one week with brief anticoagulation dosing for PICC thrombus. Patient 1 subsequently had PLT threshold 10,000/µL. Patient 4 (HCT 2015) had PLT transfusion threshold of 10,000/µL throughout HCT. Patients 1 and 4 had no significant bleeding. Patient 2 had minor epistaxis. Patient 3 had recurrent epistaxis treated with intranasal tranexamic acid. Patient 5 had hematemesis treated with aminocaproic acid until PLT engraftment and severe epistaxis requiring nasal packing and recombinant factor rFVIIa. Patients 1 and 3 received HLA-matched PLTs peri-HCT; patients 2, 4 and 5 received random donor PLTs. Only patients 3 and 5 received PLT transfusion beyond day +17.

Conclusions: This case series highlights key considerations for peri-HCT hemostasis management. Prophylactic PLT transfusion may be considered pre-nadir due to intrinsic dysfunction of recipient PLTs. A PLT transfusion threshold of 10,000/µL may suffice in the absence of additional risk factors. PICCs may be favored over tunneled central lines to reduce bleeding risk. Epistaxis was the most common bleeding symptom post-HCT. Early hematology consultation is essential to determine alternative therapies for managing bleeding symptoms throughout HCT.