Survival Outcomes
The one-year OS rate for the entire cohort was 62% [95% confidence
interval (CI), 0.427–0.758]. There was no significant difference
between primary and relapsed cases with respect to the one-year OS rate
(61% vs. 69%, p = 0.328); patients with PD at IREC initiation
showed poorer one-year survival rate compared to the other patients
(21% vs. 77%, p < 0.001). The cumulative incidence of
relapse or PD at one year after IREC was 45% (95% CI, 0.279–0.606);
patients with PD at the initiation of IREC showed a higher cumulative
incidence of relapse or PD compared to the other patients (86% vs.
26%, p < 0.001).
Patients with UGT1A1 gene polymorphism (heterozygous and
homozygous groups) showed a better one-year survival rate than wild-type
patients (77% vs 48%, p = 0.026) (Figure 2 ); similar
results were obtained in an analysis limited to primary cases (n = 36),
excluding seven relapsed cases (80% vs. 44%, p = 0.012). There
was no significant difference in the cumulative incidence of relapse in
patients with and without UGT1A1 gene polymorphism
(Figure 3 ).
After IREC, 16 patients received a total of 24 stem cell
transplantations: 11 autologous peripheral blood stem cell
transplantations and 13 cord blood transplantations. Treatment-related
death was observed in one patient (UPN15). This patient underwent
autologous peripheral blood stem cell transplantation using busulfan +
melphalan regimen after three courses of IREC therapy; she died six
months after transplantation due to a late-onset non-infectious
pulmonary complication.