Long-term survival outcomes of reduced-intensity allogeneic or autologous transplantation in relapsed grade 3 follicular lymphoma

Grade-3 follicular lymphoma (FL) has aggressive clinical behavior. To evaluate the optimal first transplantation approach in relapsed/refractory grade-3 FL patients, we compared the long-term outcomes after allogeneic (allo-) vs. autologous hematopoietic cell transplantation (auto-HCT) in the rituximab-era. A total of 197 patients undergoing first RIC allo-HCT or first auto-HCT during 2000-2012 were included. Rituximab-naïve patients were excluded. Allo-HCT recipients were younger; more heavily pretreated, and had a longer interval between diagnosis and HCT. The 5-year probabilities of non-relapse mortality (NRM), relapse/progression, progression-free survival (PFS) and overall survival (OS) for auto-HCT vs. allo-HCT groups were 4% vs. 27% (p<0.001); 61% vs. 20% (p<0.001); 36% vs. 51% (p=0.07) and 59% vs. 54% (p=0.7), respectively. On multivariate analysis auto-HCT was associated with reduced risk of NRM (RR=0.20; p=0.001). Within the first 11months post-HCT auto- and allo-HCT had similar risks of relapse/progression and PFS. Beyond 11months, auto-HCT was associated with higher risk of relapse/progression (RR=21.3; p=0.003) and inferior PFS (RR=3.2; p=0.005). In the first 24 months post-HCT, auto-HCT was associated with improved OS (RR=0.42; p=0.005), but in long-time survivors (beyond 24 months) it was associated with inferior OS (RR=3.6; p=0.04). RIC allo-HCT as the first transplant approach can provide improved PFS and OS, in long-term survivors.