OUTCOME OF SEVERE APLASTIC ANEMIA WITH DIFFERENT ABSOLUTE NEUTROPHIL COUNTS FOLLOWING IMMUNOSUPPRESSIVE THERAPY: A SINGLE-CENTER RETROSPECTIVE STUDY IN PR CHINA (2013 – 2017)

Treatment of severe aplastic anemia (SAA) is a challenging problem. Patients with higher absolute neutrophil counts (ANC) have better overall response rate (ORR) and longer overall survival (OS) following immunosuppressive therapy (IST). A retrospective analysis was conducted at The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China between January 2013 and December 2017 involving SAA patients (n = 80) who were treated with anti-thymocyte globulin-based IST combined with cyclosporine A. Median follow-up time was 23 months. ORR at 3 months (17%) and 6 months (33%) in Group 1 patients (n = 18; ANC <1.0×108/l) are significantly lower than Group 2 (n = 25; 1.0×108/l ≤ ANC <2.0×108/l) and Group 3 (n = 37; 2.0×108/l ≤ ANC <5.0×108/l) (p-value = 0.005 and 0.01 respectively). OS of Group 1 patients (34%) is significantly lower than the other two groups. Treated patients who responded at month 8 post-IST had better OS compared to non-responders (80% vs 44%). Univariate and multivariate analysis showed ANC is a significant factor for OS (p-values = 0.026 and 0.044 respectively). Of 24 patients who died during the follow-up period, 11 patients died of severe infection leading to septicemia in 8 patients, 7 from hemorrhage, 5 due to heart failure and 1 caused by acute myeloid leukemia. In conclusion, the study highlights absolute neutrophil counts could serve as a simple predictor of response to immunosuppressive therapy in patients with severe aplastic anemia, which should provide a guide to improved therapeutic treatment in those at high risk to succumb to fatal outcome.