Tu183 - Clinical Characteristics Associated with Early Immune Reconstitution in Patients with Congenital Athymia After Treatment with Allogeneic Processed Thymus Tissue-agdc
Abstract Text: Congenital athymia (CA) is an ultra-rare disorder that results in severe immune deficiency and dysregulation due to lack of naïve T cells. Allogeneic processed thymus tissue-agdc is approved for immune reconstitution in pediatric patients with CA (typical and atypical phenotypes), based on increased naïve T-cells after implantation through month 24.
In the efficacy analysis population (n=95), mean age at implantation was 298 days, 52.6% had the typical phenotype, 65.3% received immunosuppressants, 93.7% experienced an infection-related adverse event (AE) in year 1, and 72.6% were alive at last follow-up.
The analysis aims to identify clinical features associated with early immune reconstitution post-implantation, defined as >100 naïve CD4+ cells/mm3 at 6 months (M6). This was achieved by 26.9% (18 of 67) of patients vs 70.2% (40 of 57) who achieved immune reconstitution at 12 months (M12). Patients with early immune reconstitution had a lower mean age at implantation (M6=132.1 days; M12=232.4 days), the majority had a typical phenotype (M6=72.2%; M12 62.5%), and immunosuppressant medications decreased over time (M6=38.9%; M12=27.5%). The proportion of patients with infection-related AEs was lower in the early reconstitution group (M6=61.1%; M12=85.0%). All patients in both groups were alive at last follow-up.
In summary, earlier age at implantation, typical phenotype, and decreased immunosuppressant medication use could contribute to earlier immune reconstitution in some patients receiving allogeneic processed thymus tissue-agdc. Although early immune reconstitution is associated with fewer infection-related AEs; patients carry a high risk from infections in the first-year post-implantation.
