•Recombinant porcine factor VIII (rpFVIII) is a hemostatic treatment for bleeding in acquired hemophilia A.•The efficacy of rpFVIII can be negatively affected by cross-reacting anti-human FVIII antibodies.•In this cohort, 52% of patients with acquired hemophilia A had baseline cross-reacting antibodies.•Cross-reacting antibodies were associated with decreased FVIII activity levels post-rpFVIII infusion.