Reduced-Intensity Compared to Nonmyeloablative Conditioning in Patients with Non-Hodgkin Lymphoma Undergoing Allogeneic Hematopoietic Stem Cell Transplantation

Reduced-intensity conditioning (RIC) and nonmyeloablative (NMA) conditioning are preferred for patients with non-Hodgkin lymphoma (NHL) undergoing allogeneic hematopoietic stem cell transplantation (allo-HCT). Although prior studies have suggested that higher-intensity regimens in RIC-NMA conditioning are associated with inferior outcomes in patients with NHL, the optimal conditioning regimen remains unknown. We performed a retrospective single-center analysis to determine outcomes of adult patients with B cell and T cell NHL who underwent allo-HCT and received either RIC or NMA conditioning between March 2008 and December 2019. RIC regimens included fludarabine-cyclophosphamide-thiotepa-4 Gy-total body irradiation (Flu-Cy-TT-4Gy-TBI), fludarabine-melphalan (Flu-Mel), fludarabine-cyclophosphamide-4 Gy-total body irradiation (Flu-Cy-4Gy-TBI), and fludarabine-busulfan-4 (Flu-Bu-4). The NMA regimen comprised fludarabine-cyclophosphamide-2 Gy-total body irradiation (Flu-Cy-2Gy-TBI). The primary outcome was overall survival (OS); secondary outcomes included progression-free survival (PFS), nonrelapse mortality (NRM), and the incidence of acute and chronic graft-versus-host-disease (GVHD). Of 279 transplants recipients (median age, 58 years), 110 received RIC (55% Flu-Mel, 38% Flu-Cy-TT-4Gy-TBI, 6% Flu-Bu-4, 1% Flu-Cy-4Gy-TBI) and 169 received NMA conditioning with Flu-Cy-2Gy-TBI. With a median of 64 months of follow-up post-allo-HCT, there was no significant difference in OS between the NMA and RIC groups (median, not reached [NR] versus 103 months; P = .1), and this was maintained on multivariable analysis. Similarly, after adjustment for all independently significant covariates (age, Karnofsky Performance Status [KPS], Hematopoietic Cell Transplantation Comorbidity Index [HCT-CI], and disease histology), the regression analysis showed no significant difference in PFS with RIC compared to NMA conditioning (hazard ratio [HR] 1.38; 95% confidence interval [CI], .92 to 2.09; P = .24). On univariable analysis, there was no significant difference in NRM between the RIC and NMA arms (100-day estimate, 10.0% versus 1.8%; P = .5). After adjustment for age, ethnicity, KPS, HCT-CI, GVHD prophylaxis, and donor source, RIC conditioning was associated with a significantly higher incidence of NRM compared to NMA conditioning (HR, 2.61; 95% CI, 1.04 to 6.52; P = .039). On multivariable analysis, compared with the NMA arm, the RIC arm had higher rates of grade II-IV (HR, 2.25; 95% CI, 1.31 to 3.86; P = .002) and grade III-IV acute GVHD (HR, 5.62; 95% CI, 2.03 to 15.6; P < .001). The findings of this study suggest that NMA conditioning with Flu-Cy-TBI-2Gy may be considered over more intensive RIC regimens for patients with NHL undergoing allo-HCT.

Fludarabine plus reduced-intensity busulfan versus fludarabine plus myeloablative busulfan in patients with non-Hodgkin lymphoma undergoing allogeneic hematopoietic cell transplantation

Allogeneic hematopoietic cell transplantation (HCT) offers a possible cure for patients with relapsed and refractory non-Hodgkin lymphoma (NHL) through potentially beneficial graft versus lymphoma effects. However, allogeneic HCT is associated with high nonrelapse mortality (NRM). Fludarabine with reduced-intensity busulfan (Flu/Bu2) and myeloablative busulfan (Flu/Bu4) are commonly used in conditioning regimens for allogeneic HCT; however, data on their use in patients with NHL is limited. We investigated the effect of busulfan dose on outcomes by comparing Flu/Bu2 and Flu/Bu4 in patients with NHL who underwent allogeneic HCT. Our study included 415 adult patients with NHL who received Flu/Bu2 (315 patients) or Flu/Bu4 (100 patients) between January 2008 and December 2019. All patients were enrolled in the Transplant Registry Unified Management Program 2 of the Japanese Data Center for Hematopoietic Cell Transplantation. The primary endpoint was the 5-year overall survival (OS). To minimize potential confounding factors that may influence outcomes, we performed propensity score matching. The 5-year OS was 50.6% (95% confidence interval (CI), 39.4%-60.8%) and 32.2% (95% CI, 22.4-42.4%) in the Flu/Bu2 and Flu/Bu4 groups, respectively (p = 0.006). The hazard ratio comparing the two groups was 2.13 (95% CI, 1.30-3.50; p = 0.003). Both groups had a similar 5-year cumulative incidence of relapse (38.2% vs 41.3%; p = 0.581), and the Flu/Bu4 group had a higher cumulative incidence of 5-year NRM (15.7% vs 31.9%; p = 0.043). In this study, Flu/Bu4 was associated with worse OS compared with Flu/Bu2 because of high NRM in patients with NHL.

Outcomes after allogeneic hematopoietic stem cell transplantation for adults with primary mediastinal B cell lymphoma: a SFGM-TC and LYSA study

Background: Despite therapeutic progress, 10 to 30% of adult patients with primary mediastinal B cell lymphoma (PMBCL) are primary refractory or experience early relapse (R/R). Allogeneic stem cell transplantation (allo-HSCT) thus remains a potentially curative option in this setting.Material and Methods: In this multicenter retrospective study, the outcomes of 33 French and Belgian adult patients allo-transplanted for R/R PMBCL between January 1999 and December 2018, were examined.Results: At allo-HSCT time, patients had received a median of 3 treatment lines, 50% of them were in complete response, 40% in partial response and 10% had a progressive disease. Forty-two percent of the donors were siblings and 39% matched related. The median follow-up for alive patients was 78 months (3.5-157). Considering the whole cohort, 2-year overall survival (OS), progression free survival (PFS) and graft-versus-host disease-free/relapse-free survival (GRFS) were 48% (95%CI: 33-70), 47% (95%CI: 33-68) and 38.5% (95%CI: 25-60) respectively. Cumulative incidence of relapse and non-relapse mortality rates were respectively 34% (95%CI: 18-50) and 18% (95%CI: 7-34). Disease status at transplant was the only factor predicting survivals, patients with progressive disease showing significant lower 2-year PFS (HR: 6.12, 95%CI: 1.32-28.31, p = 0.02) and OS (HR: 7.04, 95%CI: 1.52-32.75, p = 0.013). A plateau was observed for OS and PFS after 4 years with 10 patients alive after this date, suggesting that almost one third of the patients effectively salvaged and undergoing allo-SCT could be cured.Conclusion: This study indicates that allo-HSCT is a valid therapeutic option for R/R PMBCL, providing durable remissions.

Curative allogeneic hematopoietic stem cell transplantation following reduced toxicity conditioning in adults with primary immunodeficiency

Primary immunodeficiencies (PID) are heterogeneous inborn errors of the immune system. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is curative and safe at the pediatric age but remains underperformed in adults. We report our experience on 32 consecutive adult patients with various PID including 17 (53%) with a combined immune deficiency, six (19%) with a disease of immune dysregulation and nine (28%) with a chronic granulomatous disease (CGD) who underwent an allo-HSCT between 2011 and 2020. The median age at transplant was 27 years (17-41). All assessable patients engrafted. The majority of patients received a fludarabine-Busulfan (FB) based regimen (FB2-3 in 16, FB4 in 12). Overall survival (OS) was 80.4% (100% for CGD and 74% for other PID patients) at 9 months and beyond (median follow-up 51.6 months). Six patients died, all in the first-year post-transplant. Cumulative incidences of grade II-IV acute GVHD/chronic GVHD were 18%/22%. Stem cell source, GVHD prophylaxis and conditioning intensity had no impact on OS. All surviving patients had over 90% donor chimerism, immune reconstitution, no sign of active PID related complications and were clinically improved. Allo-HSCT is effective in young adults PID patients with an acceptable toxicity and should be discussed in case of life-threatening PID.

Adding melphalan to fludarabine and a myeloablative dose of busulfan improved survival after allogeneic hematopoietic stem cell transplantation in a propensity score-matched cohort of hematological malignancies

Fludarabine and a myeloablative dose of busulfan (Flu/Bu4) can improve prognosis after allogeneic hematopoietic stem cell transplantation (HSCT) with melphalan (Mel). We investigated the prognostic impact of adding Mel to Flu/Bu4 by comparing between Flu/Bu4/Mel and Flu/Bu4 groups. This study included 846 propensity score (PS)-matched patients who received either Flu/Bu4/Mel (n = 423) or Flu/Bu4 (n = 423) from 2394 patients enrolled in a multicenter prospective registry, from January 2010 to December 2016. The primary endpoint (5-year overall survival [OS]), and the prognostic impact of adding Mel was evaluated using Cox regression analysis. The study population median age was 58 (interquartile 50-64) years and 61.0% were male. Patient characteristics were well-balanced between groups. Five-year OS was 34.2% (95% confidence interval [CI]: 27.3-41.1%) and 30.1% (24.8-35.6%) in the Flu/Bu4/Mel and Flu/Bu4 groups, respectively (log-rank P = 0.019). The adjusted hazard ratio of adding Mel was 0.77 (95% CI: 0.62-0.96) (P = 0.022) for the 5-year OS, and this attributed to a lower incidence of 5-year relapse (0.71, 0.56-0.90, P = 0.005) and relapse associated mortality (0.73, 0.57-0.95, P = 0.018). There was no statistical difference in 5-year non-relapse mortality between groups (log-rank P = 0.855). Flu/Bu4/Mel was associated with better 5-year OS compared to Flu/Bu4 in a PS-matched cohort after allogeneic HSCT.

Association of Reduced-Intensity Conditioning Regimens With Overall Survival Among Patients With Non-Hodgkin Lymphoma Undergoing Allogeneic Transplant

Importance

Reduced-intensity conditioning and nonmyeloablative conditioning (RIC-NMAC) regimens are frequently used in allogeneic hematopoietic cell transplant (HCT) for non-Hodgkin lymphoma. However, the optimal RIC-NMAC regimen in allogeneic HCT for non-Hodgkin lymphoma is not known.

Objective

To investigate whether RIC-NMAC regimens at a higher end of the intensity spectrum are associated with increased nonrelapse mortality and lower overall survival compared with RIC-NMAC regimens at the lower end of the intensity spectrum in patients with non-Hodgkin lymphoma undergoing allogeneic HCT.

Design, Setting, and Participants

This cohort study used data from 1823 adult patients with non-Hodgkin lymphoma in the Center for International Blood and Marrow Transplant Research registry. Included patients underwent allogeneic HCT using matched related or unrelated donors between January 2008 and December 2016. Statistical analysis was performed from June 1, 2019, to February 10, 2020.

Interventions

Patients received 1 of 4 RIC-NMAC regimens: fludarabine-intravenous busulfan (Flu-Bu), approximately 6.4 mg/kg (n = 458); fludarabine-melphalan (Flu-Mel140), 140 mg/m2 (n = 885); fludarabine-cyclophosphamide (Flu-Cy) (n = 391); or Flu-Cy with 2 Gy total body irradiation (Flu-Cy-2GyTBI) (n = 89).

Main Outcomes and Measures

The primary outcome was overall survival. Secondary outcomes were nonrelapse mortality, incidence of relapse, progression-free survival, and the incidence of acute and chronic graft-vs-host disease (GVHD).

Results

Of 1823 patients, 1186 (65%) were male, with a mean (SD) age of 54.8 (9.9) years. The 4-year adjusted OS was 58% in the Flu-Bu cohort, 67% in the Flu-Cy-2GyTBI cohort, 49% in the Flu-Mel140 cohort, and 63% in the Flu-Cy cohort (P < .001). After adjustment for age, Karnofsky performance score, HCT comorbidity index, NHL subtype, remission status at HCT, and the use of antithymocyte globulin or alemtuzumab, the regression analysis showed a significantly higher mortality risk associated with Flu-Mel140 compared with Flu-Bu (hazard ratio [HR], 1.34; 95% CI, 1.13-1.59; P < .001). Compared with the Flu-Cy cohort, the Flu-Mel140 cohort had a higher risk of chronic GVHD (HR, 1.38; 95% CI, 1.15-1.65; P < .001). The Flu-Mel140 regimen was associated with a higher nonrelapse mortality risk (HR, 1.78; 95% CI, 1.37-2.31; P < .001) compared with the Flu-Bu regimen.

Conclusions and Relevance

The findings suggest that use of the more intense RIC-NMAC regimen, Flu-Mel140, may have a negative association with overall survival and may be associated with higher nonrelapse mortality. The Flu-Bu and Flu-Cy regimens with or without 2GyTBI regimens appeared to provide comparable overall survival.

Multicenter Phase II Study on Haploidentical Bone Marrow Transplantation Using a Reduced-Intensity Conditioning Regimen and Posttransplantation Cyclophosphamide in Patients with Poor-Prognosis Lymphomas

Allogeneic stem cell transplantation from haploidentical donors using unmanipulated bone marrow and posttransplantation cyclophosphamide has been largely employed to cure high-risk lymphomas. However, the increased incidence of relapse associated with the use of a nonmyeloablative conditioning regimen is still considered a concerning issue. The aim of our study was to prospectively evaluate the efficacy and feasibility of a reduced-intensity conditioning regimen, including thiotepa, cyclophosphamide, and fludarabine, in high-risk lymphoma patients. This was a prospective multicenter study. We enrolled 49 patients, of whom 47 were evaluable. Graft source (bone marrow) and graft-versus-host disease (GVHD) prophylaxis were the same for all patients. The primary endpoint was the proportion of patients free of disease progression at 1 year. The primary endpoint was met, as 29 out of 47 patients were alive and free of disease at 1 year (1-year progression-free survival, 60%). Forty-five recipients engrafted and achieved full donor chimerism at day 100. The cumulative incidences (CIs) of ANC engraftment at 30 days and platelet engraftment at 60 days were 89% and 83%, respectively. Two patients experienced graft failure. The CIs of day 100 grades 2 to 4 acute GVHD and 2-year moderate-to-severe chronic GVHD were 26% and 16%, respectively. With a median follow-up of 47.5 months (range, 22 to 74), the 4-year progression-free survival and overall survival were 54% and 64%, respectively. The 4-year CI of relapse was 28%, and the 4-year nonrelapse mortality was 15%. Thiotepa-based reduced-intensity conditioning was well tolerated with encouraging survival in a cohort of patients with poor-prognosis lymphoma. Both the incidence of relapse and nonrelapse mortality were acceptable.

Discussion on the indication of allogeneic stem cell transplantation for advanced cutaneous T cell lymphomas

Advanced cutaneous T cell lymphoma (CTCL) patients have a dismal prognosis, especially those relapsing or progressing after systemic therapy. No curative therapies are available, but some new agents have prolonged disease-free survival time with a good toxicity profile. Allogeneic stem cell transplantation (allo-SCT) offers the longest disease-free survival, potentially representing the best therapeutic option for eligible patients. In the present article, we discuss current evidence about allo-SCT for CTCL patients, timing, and new therapeutic options before allo-SCT, taking into account some considerations that may impact clinical outcome.