Hematoma Expansion and Clinical Outcomes in Patients With Factor-Xa Inhibitor-Related Atraumatic Intracerebral Hemorrhage Treated Within the ANNEXA-4 Trial Versus Real-World Usual Care.

BACKGROUND AND PURPOSE: It is unestablished whether andexanet alfa, compared with guideline-based usual care including prothrombin complex concentrates, is associated with reduced hematoma expansion (HE) and mortality in patients with factor-Xa inhibitor-related intracerebral hemorrhage (ICH). We compared the occurrence of HE and clinical outcomes in patients treated either with andexanet alfa or with usual care during the acute phase of factor-Xa inhibitor-related ICH. METHODS: Data were extracted from the multicenter, prospective, single-arm ANNEXA-4 trial (Andexanet Alfa, a Novel Antidote to the Anticoagulation Effects of Factor Xa Inhibitors) and a multicenter observational cohort study, RETRACE-II (German-Wide Multicenter Analysis of Oral Anticoagulant-Associated Intracerebral Hemorrhage - Part Two). HE was based on computed tomography scans performed within 36 hours from baseline imaging. Inverse probability of treatment weighting was performed to adjust for baseline comorbidities and ICH severity. Patients presenting with atraumatic ICH while receiving apixaban or rivaroxaban within 18 hours of admission were included. Patients with secondary ICH or not fulfilling the inclusion criteria for the ANNEXA-4 trial were excluded. We compared ANNEXA-4 patients, who received andexanet alfa for hemostatic treatment, with RETRACE-II patients who were treated with usual care, primarily administration of prothrombin complex concentrates. Primary outcome was rate of HE defined as relative increase of ≥35%. Secondary outcomes comprised mean absolute change in hematoma volume, as well as in-hospital mortality and functional outcome. RESULTS: Overall, 182 patients with factor-Xa inhibitor-related ICH (85 receiving andexanet alfa versus 97 receiving usual care) were selected for analysis. There were no relevant differences regarding demographic or clinical characteristics between both groups. HE occurred in 11 of 80 (14%) andexanet alfa patients compared with 21 of 67 (36%) usual care patients (adjusted relative risk, 0.40 [95% CI, 0.20-0.78]; P=0.005), with a reduction in mean overall hematoma volume change of 7 mL. There were no statistically significant differences among in-hospital mortality or functional outcomes. Sensitivity analysis including only usual care patients receiving prothrombin complex concentrates demonstrated consistent results. CONCLUSIONS: As compared with usual care, andexanet alfa was associated with a lower rate of HE in atraumatic factor-Xa inhibitor-related ICH, however, without translating into significantly improved clinical outcomes. A comparative trial is needed to confirm the benefit on limiting HE and to explore clinical outcomes across patient subgroups and by time to treatment. Registration: URL: https://clinicaltrials.gov; Unique identifier: NCT02329327 and NCT03093233.

Foxp3+ regulatory T cells protect the liver from immune damage and compromise virus control during acute experimental hepatitis B virus infection in mice.

UNLABELLED: The strength of antiviral T cell responses correlates with clearance of hepatitis B virus (HBV) infection, but the immunological mechanisms mitigating or suppressing HBV-specific T cells are still poorly understood. In this study, we examined the role of CD4(+) Foxp3(+) regulatory T cells (Tregs) in a mouse model of acute HBV infection. We initiated HBV infection via an adenoviral vector transferring a 1.3-fold overlength HBV genome (AdHBV) into transgenic DEREG mice, where Tregs can be transiently but selectively depleted by injection of diphtheria toxin. The effect of Treg depletion on the outcome of HBV infection was characterized by detailed virological, immunological, and histopathological analysis. Numbers of Tregs increase in the liver rapidly after initiation of HBV replication. Initial depletion of Tregs revealed their complex regulatory function during acute infection. Tregs mitigated immunomediated liver damage by down-regulating the antiviral activity of effector T cells by limiting cytokine production and cytotoxicity, but did not influence development of HBV-specific CD8 T cells or development of memory T cells. Furthermore, Tregs controlled the recruitment of innate immune cells such as macrophages and dendritic cells to the infected liver. As a consequence, Tregs significantly delayed clearance of HBV from blood and infected hepatocytes. CONCLUSION: Tregs limit immunomediated liver damage early after an acute infection of the liver, thereby contributing to conservation of tissue integrity and organ function at the cost of prolonging virus clearance.