Improvement in survival of refractory AA patients over time. The data indicate the outcomes for 174 patients with SAA who were unresponsive to initial IST at 6 months. Three patient groups were identified, group 1 (n = 43, December 1989-October 1996); group 2 (n = 51, November 1996-October 2002); and group 3 (n = 80, November 2002-April 2008).The first column indicates survival curves censored for HSCT and the second graph is not censored for HSCT. A significantly improved 5-year OS for nonresponders to IST was seen in group 3 compared with other groups. Adapted and modified with permission from Valdez et al.³⁸