Risk factors for adverse outcomes following haploidentical hematopoietic cell transplantation with posttransplant cyclophosphamide: a two-center analysis.

Allogeneic hematopoietic cell transplantation (HCT) is a potentially curative therapy for several malignant hematologic diseases and alternative donors, including haploidentical, play a significant role in HCT. Despite the increasing use of haplo-HCT with PTCy, some questions remain open. The objective of the present study was to investigate risk factors for adverse outcomes after haplo-HCT with PTCy. This is a retrospective study conducted at two Brazilian centers. A total of 103 patients with hematologic malignancies who underwent first allogeneic, haploidentical HCT with PTCy were included. Risk factors for death were age at transplant (HR = 1.03 for each year; p = 0.002) and high/very high disease risk index (DRI; HR = 2.77; p = 0.0007) and mother as the donor compared with other donors (HR = 3.53; p = 0.005). In multivariate analysis, PFS was significantly poorer for older patients (HR = 1.02; p = 0.006), high/very high DRI (HR = 2.39; p = 0.003), and mother as the donor compared with other donors (HR = 3.18; p = 0.006). Relapse rate was higher for high/very high DRI (HR = 4.01; p = 0.002) and mother as the donor compared with other donors (HR = 2.52; p = 0.05). NRM was higher for older patients (HR = 1.03 for each year; p = 0.03). Tacrolimus was a protective factor for grades II-IV aGVHD (HR = 0.46; p = 0.04) compared with cyclosporine. Peripheral blood (PBSC) was a risk factor for cGVHD (HR = 3.48; p = 0.006), while tacrolimus was protective (HR = 0.30; p = 0.009). Mother as the donor compared with other donors was also a risk factor for poorer OS, PFS, and relapse, suggesting that this combination should be avoided. Tacrolimus was protective for both grades II-IV aGVHD and cGVHD, suggesting that tacrolimus may be more effective than cyclosporine in preventing GVHD. PBSC was a risk factor for cGVHD without any impact on relapse. Prospective studies comparing tacrolimus with cyclosporine are awaited.