Secondary Analyses of ANNEXA-I Trial Assessing Andexanet Alfa in Intracranial Hemorrhage: Ashkan Shoamanesh, MD

WATCH TIME: 10 minutes

"Our findings show that hematoma growth rate is a strong predictor of expansion. The benefit of andexanet alfa is robust, but careful patient selection can further enhance outcomes."

Andexanet alfa (Andexxa; AstraZeneca), an FDA-approved treatment, is designed to reverse the anticoagulant effects of factor Xa (FXa) inhibitors, such as rivaroxaban or apixaban, when reversal of anticoagulation is needed because of life-threatening or uncontrolled bleeding. The agent received approval in May 2018 based on 2 phase 3 trials—ANNEXA-A (NCT02207725) and ANNEXA-R (NCT02220725). In the trials, among the apixaban-treated participants, anti-factor Xa activity, a measure of factor Xa inhibition, was reduced by 94% in those who received an andexant bolus (n = 24) compared with those on placebo (P <.001).¹

Following the approval, investigators conducted the phase 4 post-marketing ANNEXA-I trial(NCT03661528) which compared the effects of andexanet alfa with standard care among patients with acute intracerebral hemorrhage (ICH) on a FXa inhibitor presenting in 6 hours of symptom onset. In June 2023, AstraZeneca stopped the investigation and since then, investigators have conducted secondary analyses on the trial to provide additional data on hematoma expansion and thrombotic events.² Data from these analyses were presented at the 2024 International Stroke Conference (ISC), February 7-9, in Phoenix, Arizona, by lead author Ashkan Shoamanesh, MD, and colleagues.³

Shoamanesh, an associate professor of neurology at McMaster University, had a recent conversation with NeurologyLive® after meeting to discuss the primary outcomes of the ANNEXA-I trial and further explained the reason why the study stopped early. He also spoke about how baseline intracranial hemorrhage volume and prescan hematoma growth rate can contribute to predicting hematoma expansion. In addition, Shoamanesh talked about the potential impact thrombotic events may have on patients undergoing andexanet alfa, and how it can relate to the findings from the analyses.

Click here for more coverage of ISC 2024.

REFERENCES
1. Siegal DM, Curnutte JT, Connolly SJ, et al. Andexanet alfa for the reversal of factor Xa inhibitor activity. N Engl J Med. 2015;373:2413-2424. doi:10.1056/NEJMoa1510991
2. ANDEXXA phase IV trial stopped early after achieving pre-specified criteria on hemostatic efficacy versus usual care. News release. AstraZeneca. June 5, 2023. Accessed June 13, 2023. https://www.astrazeneca-us.com/media/press-releases/2023/andexxa-phase-iv-trial-stopped-early-after-achieving-pre-specified-criteria-on-hemostatic-efficacy-versus-usual-care.html
3. Shoamanesh A, Demchuk AM, Seiffge D, et al. Secondary Analyses to Optimize Response to Andexanet From ANNEXa-I. Presented at: 2024 International Stroke Conference; February 7-9; Phoenix, AZ. Abstract LB19.