Good response to oxymetholone in adult aplastic anemia

In Thailand, stem cell transplantation and horse antithymocyte globulin (ATG) are not accessible for most adult aplastic anemia (AA) patients. Alternative therapies are required. We conducted a cohort study of 110 adult AA patients treated with oxymetholone alone for at least 30 days from 2013 to 2023. Response at month 6 and prognostic factors were evaluated. The mean age was 63.4 years old and 58.2% were female. Severe and very severe AA (SAA/VSAA) comprised 64.5% and 3.6%, respectively. The initial oxymetholone daily dose was 150 mg in 66.4%. The overall response was 56.4% (50.7% for SAA/VSAA), with a median time to transfusion independence of 11.8 weeks. Deaths were regarded as no response. Seventeen (17.9%) patients discontinued the treatment due to side effects, especially hepatitis (15/17). Androgenic side effects (55.5%) mostly occurred within the first month. Multivariate analysis identified that baseline reticulocyte count > 10 × 10⁹/L (adjusted odds ratio [OR] 7.3, 95% confidence interval [CI] (2.55-21.11), oily skin (OR 4.93, 95%CI 1.50-16.26) and acne (OR 9.78, 95%CI 2.11-45.28) occurring within 2 months were predictive for responses. The SKAR scoring system using these three factors showed an area under the ROC curve of 0.87 (95%CI 0.80-0.92). The 5-year overall survival rate was 77.4%. Poor performance status (p < 0.001) and response status (p < 0.001) significantly impacted mortality. Responding patients demonstrated 94.5% 5-year survival. In conclusion, androgen is a useful treatment option for AA in Thailand. The score based on reticulocytes and androgenic effects could predict the response and potentially help decision-making.