Diffuse alveolar hemorrhage after hematopoietic cell transplantation- response to treatments and risk factors for mortality

Intrapulmonary administration of recombinant activated factor VII in pediatric, adolescent, and young adult oncology and hematopoietic cell transplant patients with pulmonary hemorrhage

Introduction

Diffuse alveolar hemorrhage (DAH) is a devastating disease process with 50-100% mortality in oncology and hematopoietic cell transplant (HCT) recipients. High concentrations of tissue factors have been demonstrated in the alveolar wall in acute respiratory distress syndrome and DAH, along with elevated levels of tissue factor pathway inhibitors. Activated recombinant factor VII (rFVIIa) activates the tissue factor pathway, successfully overcoming the tissue factor pathway inhibitor (TFPI) inhibition of activation of Factor X. Intrapulmonary administration (IP) of rFVIIa in DAH is described in small case series with successful hemostasis and minimal complications.

Methods

We completed a single center retrospective descriptive study of treatment with rFVIIa and outcomes in pediatric oncology and HCT patients with pulmonary hemorrhage at a quaternary hematology/oncology hospital between 2011 and 2019. We aimed to assess the safety and survival of patients with pulmonary hemorrhage who received of IP rFVIIa.

Results

We identified 31 patients with pulmonary hemorrhage requiring ICU care. Thirteen patients received intrapulmonary rFVIIa, while eighteen patients did not. Overall, 13 of 31 patients (41.9%) survived ICU discharge. ICU survival (n=6) amongst those in the IP rFVIIa group was 46.2% compared to 38.9% (n=7) in those who did not receive IP therapy (p=0.69). Hospital survival was 46.2% in the IP group and 27.8% in the non-IP group (p=0.45). There were no adverse events noted from use of IP FVIIa.

Conclusions

Intrapulmonary rFVIIa can be safely administered in pediatric oncology patients with pulmonary hemorrhage and should be considered a viable treatment option for these patients.

Diffuse Alveolar Hemorrhage in Hematopoietic Cell Transplantation

Diffuse alveolar hemorrhage (DAH) is a morbid syndrome that occurs after autologous and allogeneic hematopoietic cell transplantation in children and adults. DAH manifests most often in the first few weeks following transplantation. It presents with pneumonia-like symptoms and acute respiratory failure, often requiring high levels of oxygen supplementation or mechanical ventilatory support. Hemoptysis is variably present. Chest radiographs typically feature widespread alveolar filling, sometimes with peripheral sparing and pleural effusions. The diagnosis is suspected when serial bronchoalveolar lavages return increasingly bloody fluid. DAH is differentiated from infectious causes of alveolar hemorrhage when extensive microbiological testing reveals no pulmonary pathogens. The cause is poorly understood, though preclinical and clinical studies implicate pretransplant conditioning regimens, particularly those using high doses of total-body-irradiation, acute graft-versus-host disease (GVHD), medications used to prevent GVHD, and other factors. Treatment consists of supportive care, systemic corticosteroids, platelet transfusions, and sometimes includes antifibrinolytic drugs and topical procoagulant factors. Therapeutic blockade of tumor necrosis factor-α showed promise in observational studies, but its benefit for DAH remains uncertain after small clinical trials. Even with these treatments, mortality from progression and relapse is high. Future investigational therapies could target the vascular endothelial cell biology theorized to contribute to alveolar bleeding and pathways that contribute to susceptibility, inflammation, cellular resilience, and tissue repair. This review will help clinicians navigate through the limited evidence to diagnose and treat DAH, counsel patients and families, and plan for future research.