Probability of overall survival after BMT for SAA, by conditioning regimen. The 1-year probability of survival was 83% (95% CI, 73%-92%) and 89% (95% CI, 80%-95%) after cyclophosphamide alone and cyclophosphamide plus ATG, respectively (P = .39). Corresponding 5-year probability was 74% (95% CI, 61%-84%) and 80% (95% CI, 69%-88%), P = .44.