Transplantation outcomes
The median administered CD34+ cell dose was the same between the scheduled and interrupted groups (2.2×106/kg and 2.0×106/kg for the scheduled and interrupted groups, respectively; P = 0.845). Engraftment was achieved in most enrolled patients (92% and 95% of the scheduled and interrupted groups, respectively; P = 1.000). The median days until engraftment was also not significantly different between the two groups (18 days vs. 19 days; P = 0.976). The 5-year OS and EFS in the interrupted group were the same as the scheduled group (53% vs. 52%; P = 0.955; and 47% vs. 45%;P = 0.908, respectively). These results are shown in Figure 2. Additionally, the 5-year NRM and RR were similar between the scheduled and interrupted groups (16% vs. 16%; P = 0.923; and 42% vs. 44%; P = 0.946, respectively). The incidence of transplantation-associated complications was not different between the two groups (VOD/SOS; 6.3% vs. 5.3%, P = 1.000, TMA; 4.7% vs. 0.0%, P = 1.000, interstitial pneumonia; 9.4% vs. 5.3%,P = 1.000).
The incidences of acute and chronic GVHD in the two cohorts are summarized in Table 2. Overall, aGVHD was more often identified in the scheduled group than in the interrupted group, although the differences were not statistically significant. The incidence of aGVHD in grades I–IV in the scheduled and interrupted groups was 42% and 26%, respectively (P = 0.286). Moreover, there was a trend toward a higher incidence of grades II–IV aGVHD in the scheduled group compared to the interrupted group (31% vs. 11%; P = 0.083). The incidence of aGVHD in grades III–IV was also higher in the scheduled group than in the interrupted group (19% vs. 5%; P = 0.280). Furthermore, the group with interrupted conditioning showed a marginally significant tendency toward a higher incidence of cGVHD than the scheduled conditioning group (42% vs. 19%; P = 0.063). The categorical variables entered into the multivariate model were age of ≥ 10 years, female, interruption of conditioning, use of cyclosporin, and tacrolimus. Consequently, interrupted conditioning for allo-HCT was confirmed by the multivariate analysis to be an independent risk factor for cGVHD (odds ratio: 3.72; 95% CI: 1.04–13.3; P = 0.043). Additionally, age of ≥ 10 years and female gender were also identified as significant risk factors for cGVHD. These results and the results of univariate analysis for cGVHD are shown in Tables 3 and 4.