Allogeneic stem cell transplantation against aggressive lymphomas: graft-versus-lymphoma effects in peripheral T-cell lymphoma and diffuse large B-cell lymphoma after myeloablative conditioning

Allogeneic stem cell transplantation (alloSCT) represents a curative option for patients with relapsed/refractory (r/r) aggressive lymphomas. We compared outcomes of alloSCT in r/r PTCL and r/r DLBCL pts (n = 150) who underwent identical myeloablative conditioning chemotherapy, GvHD prophylaxis, and relapse management. 5-year PFS and OS were significantly superior in PTCL compared to DLBCL (56% vs. 24%; 56% vs. 28%; p ≤ 0.005). A landmark analysis (day≥ +100 post-alloSCT) markedly favored outcomes in PTCL vs. DLBCL: 5-year PFS and OS of 76% vs. 30% and 76% and 35%, respectively (p ≤ 0.003). Non-relapse mortality was comparable (35% PTCL vs. 34% DLBCL, p = 0.894), whereas post-alloSCT relapse mortality was significantly higher in DLBCL (36% vs. 10%, p = 0.0007). The occurence of limited chronic GvHD did not improve outcomes in DLBCL, whereas extensive chronic GvHD was a negative risk factor for both (HR 2.09 and 2.80, p ≤ 0.006). In conclusion, we gained evidence for strong graft-versus-lymphoma activity against PTCL but not DLBCL.