Nonmyeloablative Alternative Donor Transplantation for Hodgkin and Non-Hodgkin Lymphoma: From the LWP-EBMT, Eurocord, and CIBMTR

Comparison of long-term outcomes after first HLA-mismatched unrelated donor transplantation with single unrelated cord blood transplantation using reduced-intensity or reduced-toxicity conditioning

BACKGROUND

No comparative data have shown significant survival differences between HLA-mismatched unrelated donor (MMUD) transplantation and cord blood (CB) transplantation, each with reduced-intensity/reduced-toxicity conditioning (RIC/RTC). However, advances in graft-versus-host disease (GVHD) prophylaxis might help update current strategies.

METHODS

We retrospectively compared the outcomes of first allogeneic hematopoietic cell transplantation from MMUDs (n = 15) or single unrelated CB (n = 35) after RIC/RTC.

RESULTS

The median age was 60 years. The MMUD group had a numerically lower 100-day incidence of grade III-IV acute GVHD (7% vs. 29%, P = 0.079) and non-relapse mortality (0% vs. 40%, P = 0.12). Eight MMUD recipients received anti-thymocyte globulin, bortezomib, or posttransplant cyclophosphamide for GVHD prophylaxis. They did not develop grade III-IV acute GVHD. The MMUD group had significantly better 5-year overall survival than the CB group (62% vs. 31%, P = 0.021), although relapse rates were similar. A multivariable analysis and sensitivity analysis also showed trends toward higher overall survival in the MMUD group.

CONCLUSION

MMUD with better GVHD prophylaxis might be preferred over CB in patients with older age and comorbidities.

Human Leukocyte Antigen-Haploidentical Haematopoietic Stem Cell Transplantation Using Post-Transplant Cyclophosphamide for Paediatric Haematological Malignancies

The use of human leukocyte antigen (HLA)-haploidentical haematopoietic stem cell transplantation (HSCT) with post-transplant cyclophosphamide (PTCY), which markedly reduces the risk of graft-versus-host disease, has rapidly increased worldwide, even in children. It was initially developed for post-transplant relapse or non-remission at transplant for patients with high-risk haematologic malignancies. However, this strategy is currently used more frequently for standard-risk, transplant-eligible paediatric haematological malignancies. It has recently been recognised in adults that the transplant outcomes after PTCY-based HLA-haploidentical HSCT are comparable with those achieved after HLA-matched HSCT. Therefore, even in children, parental donors who are HLA-haploidentical donors and cord blood are currently considered the next donor candidates when an HLA-matched related or unrelated donor is unavailable. This review addresses the current status of the use of haplo-HSCT with PTCY for paediatric haematologic malignancies and future directions for donor selection (sex, age, ABO blood type, and HLA disparity), donor source, the dose of infused CD34+ cells, optimal conditioning, the concomitant graft-versus-host disease prophylaxis other than PTCY, and the pharmacokinetic study of CY and CY metabolites. These aspects present key solutions for further improvements in the outcomes of haplo-HSCT with PTCY for paediatric haematological malignancies.

Impact of risk factors and long term survival analysis of patients with primary refractory Hodgkin lymphoma who underwent high dose chemotherapy and autologous stem cell transplant

BACKGROUND

Patients with primary refractory Hodgkin lymphoma (ref-HL) can still be salvaged with high dose chemotherapy (HDC) and autologous stem cell transplantation (auto-SCT). Outcome of patients with ref-HL is poorer than those with relapsed HL, but most studies have included patients with both relapsed and refractory diseases, and separate analyses or studies on patients with ref-HL are limited.

OBJECTIVE

This study aimed to evaluate the outcomes of HDC auto-SCT and impact of various prognostic factors on patients with ref-HL both at the time of primary treatment failure and also on subsequent survival at the time of failure post HDC auto-SCT.

STUDY DESIGN

This was a retrospective, single-institution, cohort analysis using HDC and auto-SCT database, approved by the Institutional Research Advisory Counsel and Ethics Committee for identifying patients. We used Fine and Gray competing risk analysis method, regression model for outcome analysis and Kaplan-Meier method (KM) for survival.

RESULTS

Two hundred consecutive ref-HL patients underwent HDC auto-SCT between 1996 to 2019. Median age was 22.75 years, median follow-up 106 months. Post auto-SCT, disease status was complete remission (CR), partial remission, and progressive disease in 122 (61%), 22 (11%), and 47 (23.5%) patients, respectively. KM median progression-free survival (PFS) after auto-SCT was 43.9 months (5:10 years, 49.3%:45.5%). Median overall survival (OS) was 168.6 months (5:10 years, 61.2%:56.2%). Eighty-five patients (44.5%) died - 69 (34.5%) due to disease. For both PFS and OS, multivariate analysis identified similar adverse factors. For PFS, stage III-IV at relapse (HR=1.65, P=0.045), mediastinal involvement (HR=2.01, P=0.009), and no CR after salvage chemotherapy (HR=2.2, P=0.001) as adverse factors. PFS with 0-1 (not reached), 2 (40.8), 3 adverse factors (5.4 months) were significant (p<0.001). For OS, stage III-IV at relapse (HR=1.68, P=0.045), mediastinal involvement (HR=2.52, P=0.007), and no CR after salvage chemotherapy (HR=2.15, P=0.004) were significant. OS with 0-1 (not reached), 2 (148.5) 3 adverse factors (34.4 months) were significant (p<0.001). Median OS after auto-SCT failure was 23.6 months; patients received post auto-SCT brentuximab/second SCT (not reached), other treatments (22.5 months), and supportive care (8.4) (p<0.001). OS with five risk factors, present at HDC auto-SCT failure, (stage III-IV, failure <12 months, tumor >5 cm, B-symptoms, low albumin) showed that 0-1:2:3-5 risk factors had 152:30.9:9.45 months OS (p<0.001).

CONCLUSION

Ref-HL patients have encouraging survival after HDC auto-SCT and can even be salvaged after auto-SCT failure. Based on prognostic factors, survival prediction is possible. Patients who fail to respond to HDC auto-SCT may benefit from newer treatments strategies and may qualify for enrollment in clinical trials.

The role of transplantation in Hodgkin lymphoma

Despite the success of frontline anthracycline-based chemotherapy for classical Hodgkin Lymphoma (cHL), approximately 15% of patients do not achieve an adequate response and require further therapy. For transplant-eligible patients, additional treatment followed by high-dose chemotherapy and autologous hematopoietic stem cell transplantation (autoHCT) provides a durable response in 50% of patients. The most refractory patients, including those requiring multiple lines of therapy to achieve a response or those relapsing after an autoHCT, may achieve long-term survival with allogeneic hematopoietic stem cell transplant (alloHCT). Contemporary salvage regimens used as a bridge to transplant have expanded to include not only non-cross resistant chemotherapy, but also brentuximab vedotin (BV) and checkpoint inhibitors (CPI). As the management of relapsed/refractory (R/R) cHL evolves with the introduction of novel agents, so too does the role of transplantation. The paradigm of chemosensitivity as a predictor for autoHCT efficacy is being challenged by favorable post- autoHCT outcomes in heavily pre-treated CPI-exposed patients. Contemporary supportive care measures, validated comorbidity assessments, and an increased donor pool with haploidentical donors have broadened the application of transplantation to an increasingly older and diverse patient population. Despite the introduction of increasingly effective treatment options for R/R cHL, transplantation continues to play an important role in the management of these patients. In this review, we explore the impact of salvage therapy on autoHCT, conditioning regimens, maintenance therapy and the diminishing role of alloHCT for patients with cHL.

Outcomes associated with allogeneic hematopoietic stem cell transplantation for relapsed and refractory Hodgkin lymphoma in the era of novel agents

BACKGROUND

Relapsed or refractory Hodgkin lymphoma (R/R HL) is a challenging disease with limited treatment options beyond brentuximab vedotin and checkpoint inhibitors. Herein we present the time-trend analysis of R/R HL patients who received allogeneic hematopoietic cell transplantation (allo-HCT) at our center from 2001-2017.

METHODS

The patients were divided into two distinct treatment cohorts: era1 (2001-2010), and era2 (2011-2017). The primary endpoint was overall survival (OS). Secondary endpoints included progression-free survival (PFS), non-relapse mortality (NRM), and cumulative incidence of acute and chronic graft versus host disease (GVHD).

RESULTS

Among the 51 patients included in the study, 29 were in era1, and 22 were in era2. There was decreased use of myeloablative conditioning in era2 (18% vs. 31%) compared to era1 and 95% of patients in era2 previously received brentuximab Vedotin (BV). Haploidentical donors were seen exclusively in era2 (0% vs. 14%) and more patients received alternative donor transplants (7% vs. 32%) in era2. The 4-year OS (34% vs. 83%, p < 0.001) and 4-year PFS (28% vs. 62%, p = 0.001) were significantly inferior in era1 compared to era2. The incidence of 1-year NRM was lower in era2 compared to era1 (5% vs. 34%, p = 0.06). The cumulative incidence of acute GVHD at day 100 was similar in both eras (p = 0.50), but the incidence of chronic GVHD at 1 year was higher in era2 compared to era1 (55% vs. 21%, p = 0.03).

CONCLUSIONS

Despite the advent of novel therapies, allo-HCT remains an important therapeutic option for patients with R/R HL.

Allogeneic hematopoietic stem cell transplantation in Hodgkin lymphoma in Switzerland, 20 years of experience: 2001-2020

Despite the high cure rate with initial therapy, approximately 10% of Hodgkin lymphoma (HL) patients are refractory to initial treatment, and up to 30% of patients will relapse after achieving initial complete remission. Despite promising initial results of treatment by immune checkpoint inhibitors, most patients will eventually progress. We analyzed 62 adult patients with relapsed or refractory HL (rrHL) treated by allogeneic hematopoietic stem cell transplantation (allo-HSCT) in one of three University Hospitals of Switzerland (Zurich, Basel, and Geneva) between May 2001 and January 2020. The primary endpoint was overall survival (OS). Secondary endpoints were relapse-free survival (RFS), non-relapse mortality (NRM), and relapse incidence, which were assessed in univariate analysis. The median follow-up was 61 months (interquartile range 59-139). The 2- and 5-year OS was 54% (standard error (SE) ±12) and 50.2% (SE ±13.3), respectively, and the 2- and 5-year RFS was 40.7% (SE ±16.3) and 34.4% (SE ±19.0), respectively. NRM was 23.1% (SE ±2.2) and 27.4% (SE ±2.5) at 2 and 5 years, respectively. The cumulative incidence of relapse was 36.1% (SE ±5.6) at 2 years and 38.2% (SE ±6.6) at 5 years. Our analysis of allo-HSCT outcomes in the context of rrHL shows encouraging OS and RFS rates, with the mortality rate reaching plateau at 50% at 2 years after allo-HSCT. This confirms that allo-HSCT still remains as a potentially curative option for half of patients with rrHL.

In 2022, which is preferred: haploidentical or cord transplant?

Allogeneic hematopoietic stem cell transplantation is the treatment of choice for high-risk hematological malignancies such as acute myeloid and lymphocytic leukemia, myelodysplastic syndrome, and myeloproliferative disorders. Alternative donor transplantation from either haploidentical (haplo-SCT) or cord blood donor (CBT) is an established therapeutic alternative for patients who need transplants but lack a human leukocyte antigen-matched donor. Although haplo-SCT (mainly non-T-cell-depleted haplo-SCT with posttransplant cyclophosphamide) is increasing while CBT is decreasing worldwide (Figure 1), recent developments in CBT, especially cord blood expansion and other strategies to improve engraftment and immune reconstitution post-CBT, make CBT still a valuable option. This article discusses the 2 options based on the currently available data, focusing on adults, and tries to give some clues to help the transplant physician choose a haploidentical vs a cord blood donor. Given the limited numbers of published or ongoing well-designed randomized controlled trials comparing haplo-SCT to CBT and the overall similar clinical results in the available, mostly registry-based, and single-center studies, with substantial heterogeneity and variability, the decision to perform haplo-SCT or CBT in a given patient depends not only on the patient, disease, and donor characteristics and donor availability (although most if not all patients should have in principle an alternative donor) but also on the transplant physician's discretion and, most importantly, the center's experience and preference and ongoing protocols and strategies.

Filling the Gap: The Immune Therapeutic Armamentarium for Relapsed/Refractory Hodgkin Lymphoma

Despite years of clinical progress which made Hodgkin lymphoma (HL) one of the most curable malignancies with conventional chemotherapy, refractoriness and recurrence may still affect up to 20–30% of patients. The revolution brought by the advent of immunotherapy in all kinds of neoplastic disorders is more than evident in this disease because anti-CD30 antibodies and checkpoint inhibitors have been able to rescue patients previously remaining without therapeutic options. Autologous hematopoietic cell transplantation still represents a significant step in the treatment algorithm for chemosensitive HL; however, the possibility to induce complete responses after allogeneic transplant procedures in patients receiving reduced-intensity conditioning regimens informs on its sensitivity to immunological control. Furthermore, the investigational application of adoptive T cell transfer therapies paves the way for future indications in this setting. Here, we seek to provide a fresh and up-to-date overview of the new immunotherapeutic agents dominating the scene of relapsed/refractory HL. In this optic, we will also review all the potential molecular mechanisms of tumor resistance, theoretically responsible for treatment failures, and we will discuss the place of allogeneic stem cell transplantation in the era of novel therapies.

Umbilical cord blood: an undervalued and underutilized resource in allogeneic hematopoietic stem cell transplant and novel cell therapy applications

PURPOSE OF REVIEW

The purpose of this review is to primarily discuss the unwarranted decline in the use of umbilical cord blood (UCB) as a source of donor hematopoietic stem cells (HSC) for hematopoietic cell transplantation (HCT) and the resulting important implications in addressing healthcare inequities, and secondly to highlight the incredible potential of UCB and related birthing tissues for the development of a broad range of therapies to treat human disease including but not limited to oncology, neurologic, cardiac, orthopedic and immunologic conditions.

RECENT FINDINGS

When current best practices are followed, unrelated donor umbilical cord blood transplant (CBT) can provide superior quality of life-related survival compared to other allogeneic HSC donor sources (sibling, matched or mismatched unrelated, and haploidentical) through decreased risks of relapse and chronic graft vs. host disease. Current best practices include improved UCB donor selection criteria with consideration of higher resolution human leukocyte antigen (HLA) typing and CD34+ cell dose, availability of newer myeloablative but reduced toxicity conditioning regimens, and rigorous supportive care in the early posttransplant period with monitoring for known complications, especially related to viral and other infections that may require intervention. Emerging best practice may include the use of ex vivo expanded single-unit CBT rather than double-unit CBT (dCBT) or 'haplo-cord' transplant, and the incorporation of posttransplant cyclophosphamide as with haploidentical transplant and/or incorporation of novel posttransplant therapies to reduce the risk of relapse, such as NK cell adoptive transfer. Novel, non-HCT uses of UCB and birthing tissue include the production of UCB-derived immune effector cell therapies such as unmodified NK cells, chimeric antigen receptor-natural killer cells and immune T-cell populations, the isolation of mesenchymal stem cells for immune modulatory treatments and derivation of induced pluripotent stem cells haplobanks for regenerative medicine development and population studies to facilitate exploration of drug development through functional genomics.

SUMMARY

The potential of allogeneic UCB for HCT and novel cell-based therapies is undervalued and underutilized. The inventory of high-quality UCB units available from public cord blood banks (CBB) should be expanding rather than contracting in order to address ongoing healthcare inequities and to maintain a valuable source of cellular starting material for cell and gene therapies and regenerative medicine approaches. The expertise in Good Manufacturing Practice-grade manufacturing provided by CBB should be supported to effectively partner with groups developing UCB for novel cell-based therapies.

Improved survival after single-unit cord blood transplantation using fludarabine and melphalan-based reduced-intensity conditioning for malignant lymphoma: impact of melphalan dose and graft-versus-host disease prophylaxis with mycophenolate mofetil

We evaluated 413 adult patients with lymphoma who underwent unrelated cord blood transplantation (UCBT) with fludarabine and melphalan (FM)-based reduced-intensity conditioning between 2002 and 2017 to investigate longitudinal changes in outcomes and the optimal melphalan dose and graft-versus-host disease (GVHD) prophylaxis regimen. Outcomes were compared between FM80/100 (melphalan dose: 80 or 100 mg/m²) and FM140 (melphalan dose: 140 mg/m²), as well as between calcineurin inhibitor (CNI) plus methotrexate (MTX), CNI plus mycophenolate mofetil (MMF), and CNI alone. The 3-year overall survival (OS) and non-relapse mortality (NRM) rates improved over time (OS: 27% in 2000s vs. 42% in 2010s, p < 0.001; NRM: 43% in 2000s vs. 26% in 2010s, p < 0.001). Multivariable analysis showed that in the 2000s, melphalan dose and GVHD prophylaxis regimen did not affect any outcomes. In the 2010s, FM80/100 (vs. FM140) related to better OS (hazard ratio [HR] 0.62, p = 0.01) and NRM (HR 0.52, p = 0.016). MTX + CNI and CNI alone (vs. CNI + MMF) related to worse OS (CNI + MTX, HR 2.01, p < 0.001; CNI alone, HR 2.65, p < 0.001) and relapse/progression (CNI + MTX, HR 2.40, p < 0.001; CNI alone, HR 2.13, p = 0.023). In recent years, the use of FM80/100 and CNI + MMF significantly reduced the risk of NRM and relapse/progression, respectively, and resulted in better OS after UCBT for lymphoma.

Successful HLA-haploidentical stem cell transplantation with post-transplant cyclophosphamide in an older patient with chronic active Epstein-Barr virus infection

Chronic active Epstein-Barr virus infection (CAEBV) is a subtype of EBV-associated T/NK cell lymphoproliferative disease and is only curable by allogeneic hematopoietic stem cell transplantation. However, finding a human leukocyte antigen (HLA)-matched donor at a suitable time can sometimes be difficult. We report the case of a 60-year-old woman who received prednisolone (PSL) after being diagnosed with autoimmune hepatitis 3 years earlier. She suddenly developed high fever and impaired liver function. Based on a high EBV DNA load in the peripheral blood, CAEBV was diagnosed. The patient was started on cooling therapy with PSL, cyclosporine, and etoposide, which reduced symptoms. Subsequently, she received HLA-haploidentical stem cell transplantation (haplo-SCT) with reduced-intensity conditioning (fludarabine 25 mg/m² for 5 days, melphalan 50 mg/m² for 2 days, and total body irradiation at 2 Gy) and post-transplant cyclophosphamide (PTCy) because she lacked an HLA-matched donor. Liver function was restored, and EBV DNA load in peripheral white blood cells became undetectable. The patient is alive without relapse or severe complications over 1 year after transplantation. To our knowledge, this is the first report of successful haplo-SCT with PTCy for CAEBV. This approach may be an alternative therapeutic option for CAEBV patients lacking an HLA-matched donor.

KIR in Allogeneic Hematopoietic Stem Cell Transplantation: Need for a Unified Paradigm for Donor Selection

Allogeneic hematopoietic stem cell transplantation (aHSCT) is a lifesaving therapy for hematological malignancies. For years, a fully matched HLA donor was a requisite for the procedure. However, new immunosuppressive strategies have enabled the recruitment of viable alternative donors, particularly haploidentical donors. Over 95% of patients have at least two potential haploidentical donors available to them. To identify the best haploidentical donor, the assessment of new immunogenetic criteria could help. To this end, the clinical benefit of KIR genotyping in aHSCT has been widely studied but remains contentious. This review aims to evaluate the importance of KIR-driven NK cell alloreactivity in the context of aHSCT and explain potential reasons for the discrepancies in the literature. Here, through a non-systematic review, we highlight how the studies in this field and their respective predictive models or scoring strategies could be conceptually opposed, explaining why the role of NK cells remains unclear in aHCST outcomes. We evaluate the limitations of each published prediction model and describe how every scoring strategy to date only partly delivers the requirements for optimally effective NK cells in aHSCT. Finally, we propose approaches toward finding the optimal use of KIR genotyping in aHSCT for a unified criterion for donor selection.

Umbilical Cord Blood or HLA-Haploidentical Transplantation: Real-World Outcomes versus Randomized Trial Outcomes

Randomized clinical trials offer the highest-quality data for modifying clinical practice. Results of a phase III randomized trial of nonmyeloablative transplantation for adults with high-risk hematologic malignancies with 2 umbilical cord blood (UCB) units (n = 183) or HLA-haploidentical relative bone marrow (Haplo-BM; n = 154) revealed a 2-year progression-free survival (PFS) of 41% after Haplo-BM transplantation and 35% after 2-unit UCB transplantation (P = .41), with overall survival (OS) of 57% and 46%, respectively (P = .04). We sought to examine the generalizability of BMT CTN 1101 to a contemporaneous cohort beyond the trial's prespecified 2-year outcomes. All transplantations were performed between June 2012 and June 2018 in the United States. We hypothesized that the results of a rigorous phase III randomized trial would be generalizable. Changes in graft selection for HLA-haploidentical relative transplantation during the trial period allowed comparison of outcomes after transplantation with Haplo-BM with those after haploidentical peripheral blood (Haplo-PB). The trial's broad eligibility criteria were applied to the data source of the Center for International Blood and Marrow Transplant Research to select nontrial subjects. Extended follow-up of trial subjects was obtained from this data source. Three separate analyses were performed: (1) trial subjects beyond the trial's 2-year endpoint; (2) comparison of trial subjects with a contemporaneous cohort of nontrial subjects (195 2-unit UCB, 358 Haplo-BM, and 403 Haplo-PB); and (3) comparison of nontrial subjects by donor and graft type. Multivariate analyses were performed using Cox proportional hazards models for comparison of outcomes by treatment groups. With longer follow-up of the trial cohorts, 5-year PFS (37% versus 29%; P = .08) and OS (42% versus 36%; P = .06) were not significantly different between the treatment groups. We then compared the trial results with outcomes of comparable real-world transplantations. Five-year OS did not differ between trial and nontrial 2-unit UCB transplantations (36% versus 41%; P = .48) or between trial and nontrial Haplo-BM transplantations (42% versus 47%; P = .80), confirming generalizability. The randomized trial did not accrue as planned and therefore lacked the statistical power to detect a 15% difference in PFS. With substantially larger numbers of nontrial Haplo-BM transplantations, 5-year survival was higher after nontrial Haplo-BM compared with trial 2-unit UCB (47% versus 36%; P = .012). Nontrial patients who underwent Haplo-PB transplantation had higher 5-year survival (54%) compared with trial Haplo-BM (hazard ratio [HR], 0.76; P = .044) and nontrial Haplo-BM (HR, 0.78; P = .026). Similarly, survival was better after Haplo-PB compared with trial UCB (HR, 0.57; P < .0001) and nontrial UCB (HR, 0.63; P = .0002). When considering alternative donor low-intensity conditioning regimen transplantation, a haploidentical relative is preferred, and PB is the preferred graft source.

Impact of donor types on reduced-intensity conditioning allogeneic stem cell transplant for mature lymphoid malignancies

We retrospectively compared the outcomes of reduced-intensity conditioning (RIC) transplantation from matched related donors (MRD; n = 266), matched unrelated donors (MUD; n = 277), and umbilical cord blood (UCB; n = 513) for mature lymphoid malignancies. The 3-year overall survival rates for the MRD, MUD, and UCB groups were 54%, 59%, and 40%, respectively (P < 0.001). Multivariate analysis showed no differences in survival between the MRD group and the MUD or UCB group. However, survival was significantly affected by the conditioning regimen and graft-versus-host disease (GVHD) prophylaxis in the UCB group, but not in the MRD and MUD groups. Notably, multivariate analysis showed that the risk of overall mortality in the UCB recipients who received the optimal conditioning regimen and GVHD prophylaxis (n = 116) was lower than that in the MRD group (relative risk [RR], 0.69; P = 0.03) and tended to be lower than that in the MUD group (RR, 0.75; P = 0.09). Our results suggest that UCB transplantation performed with the optimal conditioning regimen and GVHD prophylaxis is highly effective. Moreover, UCB is readily available. Thus, UCB transplantation with the optimal conditioning regimen and GVHD prophylaxis is preferable to MUD transplantation when MRD are not available in the setting of RIC transplantation for mature lymphoid malignancies.

Comparison of haploidentical and umbilical cord blood transplantation after myeloablative conditioning

Three-year survival is similar after PTCy haplo- and UCB transplant.

Lower relapse but higher nonrelapse mortality in ≤5/8 matched UCB as compared with haplo- and 6-8/8 UCB transplant.

Haploidentical hematopoietic stem cell transplantation (haplo-HSCT) has emerged as an important treatment modality. Most reports comparing haplo-HSCT with posttransplant cyclophosphamide (PTCy) and other donor sources have focused on outcomes in older adults treated with reduced intensity conditioning. Therefore, in the current study, we evaluated outcomes in patients with hematological malignancy treated with myeloablative conditioning prior to haplo- (n = 375) or umbilical cord blood (UCB; n = 333) HSCT. All haplo recipients received a 4 of 8 HLA-matched graft, whereas recipients of UCB were matched at 6-8/8 (n = 145) or ≤5/8 (n = 188) HLA antigens. Recipients of 6-8/8 UCB transplants were younger (14 years vs 21 and 29 years) and more likely to have lower comorbidity scores compared with recipients of ≤5/8 UCB and haplo-HSCT (81% vs 69% and 63%, respectively). UCB recipients were more likely to have acute lymphoblastic leukemia and transplanted in second complete remission (CR), whereas haplo-HSCT recipients were more likely to have acute myeloid leukemia in the first CR. Other characteristics, including cytogenetic risk, were similar. Survival at 3 years was similar for the donor sources (66% haplo- and 61% after ≤5/8 and 58% after 6-8/8 UCB). Notably, relapse at 3 years was lower in recipients of ≤5/8 UCB (21%, P = .03) compared with haplo- (36%) and 6-8/8 UCB (30%). However, nonrelapse mortality was higher in ≤5/8 UCB (21%) compared with other groups (P < .0001). These data suggest that haplo-HSCT with PTCy after myeloablative conditioning provides an overall survival outcome comparable to that after UCB regardless HLA match group.

Absence of prostacyclin greatly relieves cyclophosphamide-induced cystitis and bladder pain in mice

Cyclophosphamide (CP) has been widely used in the treatment of various malignancies and autoimmune diseases, but acrolein, a byproduct of CP, causes severe hemorrhagic cystitis as the major side effect of CP. On the other hand, a large amount of prostacyclin (PGI₂ ) is produced in bladder tissues, and PGI₂ has been shown to play a critical role in bladder homeostasis. PGI₂ is biosynthesized from prostaglandin (PG) H₂ , the common precursor of PGs, by PGI₂ synthase (PTGIS) and is known to also be involved in inflammatory responses. However, little is known about the roles of PTGIS-derived PGI₂ in bladder inflammation including CP-induced hemorrhagic cystitis. Using both genetic and pharmacological approaches, we here revealed that PTGIS-derived PGI₂ -IP (PGI₂ receptor) signaling exacerbated CP-induced bladder inflammatory reactions. Ptgis deficiency attenuated CP-induced vascular permeability and chemokine-mediated neutrophil migration into bladder tissues and then suppressed hemorrhagic cystitis. Treatment with RO1138452, an IP selective antagonist, also suppressed CP-induced cystitis. We further found that cystitis-related nociceptive behavior was also relieved in both Ptgis^-/- mice and RO1138452-treated mice. Our findings may provide new drug targets for bladder inflammation and inflammatory pain in CP-induced hemorrhagic cystitis.

Optimizing selection of double cord blood units for transplantation of adult patients with malignant diseases

Double-unit unrelated cord blood transplantation (DUCBT) is an option in patients for whom a single unit is not sufficient to provide an adequate number of cells. As current guidelines on UCB unit selection are mainly based on single-unit UCB data, we performed a retrospective analysis of 1375 adult recipients of DUCBT for hematologic malignancies to determine optimal criteria for graft selection. Cryopreserved total nucleated cells (TNCs; ≤3.5 vs >3.5 × 107/kg: hazard ratio [HR], 1.53; 30% vs 45%; P = .01), number of HLA mismatches (≥2 vs 0-1: HR, 1.28; 42% vs 48%; P = .01), and ABO compatibility (minor/major ABO incompatibility vs compatibility: HR, 1.28; P = .04) were independent risk factors for OS. Cryopreserved CD34+ cell dose ≥0.7 × 105/kg in the winning UCB was associated with improved OS (HR, 1.34; P = .03). Low TNC (≤3.5 × 107/kg) and CD34+ (≤1.4 × 105/kg) cell doses were related to decreased neutrophil recovery (HR, 0.65 [P = .01] and HR, 0.81 [P = .01], respectively). DUCBT recipients with ≥2 HLA mismatches had a higher incidence of grade II-IV and III-IV acute graft-versus-host disease (HR, 1.26 [P = .03] and 1.59 [P = .02], respectively). Low TNC dose (HR, 1.57; P = .02) and receiving UCB with ≥2 HLA mismatches (HR, 1.35; P = .03) were associated with increased transplant-related mortality. Our data support selecting adequately HLA-matched UCB units with a double-unit cryopreserved TNC dose >3.5 × 107/kg and CD34+ cell dose of ≥0.7 × 105/kg per unit in DUCBT candidates.

Hematopoietic Stem Cell Transplantation in T Cell and Natural Killer Cell Lymphomas: Update on Recent Advances

Mature T and natural killer (NK) cell non-Hodgkin lymphoma (T-NHL) has a poor prognosis. Data from existing retrospective and prospective studies have suggested that high-dose chemotherapy followed by autologous hematopoietic cell transplantation (auto-HCT) may improve the survival in patients with chemosensitive disease, either in the upfront or salvage setting. Auto-HCT is currently recommended to be used as frontline consolidation in peripheral T cell lymphoma not otherwise specified, angioimmunoblastic T cell lymphoma, anaplastic large cell lymphoma-anaplastic lymphoma kinase negative, NK/T cell (disseminated), and enteropathy-associated T cell lymphoma. However, about one-third of patients never reach transplantation because of early relapse or refractory disease. Allogeneic hematopoietic cell transplantation (allo-HCT), via its immunologic graft-versus-lymphoma effect, has been used to salvage patients with relapsed or refractory disease, resulting in long-term disease-free survival in a fraction of patients. However, the higher risk of transplant-related mortality due to regimen-related toxicities, graft-versus-host disease, and post-transplant infectious complications continues to limit the mainstream adoption of allo-HCT for this disease. Despite that, allo-HCT has been incorporated as part of the frontline treatment for aggressive subtypes of T-NHL, such as γδ T cell lymphoma and aggressive NK cell leukemia. Recent attempts to incorporate novel targeted T cell directed therapies into the treatment pathway of T-NHL may enhance treatment response and enable more patients to reach transplant, offering an alternative means of treating this disease.

Safety and efficacy of a nonmyeloablative pretransplant conditioning regimen using total lymphoid irradiation with volumetric modulated arc therapy in healthy dogs: A pilot study

Allogeneic hematopoietic cell transplantation (HCT) has been an effective treatment for human patients with haematological malignancies (Baron & Storb, 2006; Bair et al., 2020; Copelan et al., 2019). However, the optimal pretransplant conditioning treatment is unclear in canine allogeneic HCT. This pilot study aimed to evaluate the safety and efficacy of total lymphoid irradiation (TLI) with volumetric modulated arc therapy (VMAT) for a nonmyeloablative HCT conditioning. Six healthy dogs were treated with 8 or 12 Gy TLI using VMAT. Haematological and physical changes were recorded over 8 weeks. To assess the effect of peripheral lymphocyte condition, lymphocyte subset and proliferative ability were examined. At the end of the experiment, necropsy was performed. All dogs showed mild‐to‐moderate neutropenia and thrombocytopenia, and these haematological changes resolved spontaneously. One dog treated with 8 Gy TLI developed transient cutaneous infection. No major complication was seen in the other seven dogs. Myelocytes and erythroblast cytopenia of bone marrow were detected in two dogs treated with 12 Gy TLI. This study is the first report of TLI using VMAT in dogs, and results suggest that this regimen is a feasible nonmyeloablative treatment.

Hodgkin Lymphoma-Review on Pathogenesis, Diagnosis, Current and Future Treatment Approaches for Adult Patients

Hodgkin lymphoma (HL) is a rare malignancy accounting for roughly 15% of all lymphomas and mostly affecting young patients. A second peak is seen in patients above 60 years of age. The history of HL treatment represents a remarkable success story in which HL has turned from an incurable disease to a neoplasm with an excellent prognosis. First-line treatment with stage-adapted treatment consisting of chemotherapy and/or radiotherapy results in cure rates of approximately 80%. Second-line treatment mostly consists of intensive salvage chemotherapy followed by high-dose chemotherapy (HDCT) and autologous stem cell transplantation (ASCT). Novel approaches such as antibody drug conjugates and immunomodulatory drugs have shown impressive results in clinical trials in refractory and relapsed HL and are now increasingly implemented in earlier treatment lines. This review gives a comprehensive overview on HL addressing epidemiology, pathophysiology and current treatment options as well as recent developments and perspectives.

Double unrelated umbilical cord blood vs HLA-haploidentical bone marrow transplantation: the BMT CTN 1101 trial

Results of 2 parallel phase 2 trials of transplantation of unrelated umbilical cord blood (UCB) or bone marrow (BM) from HLA-haploidentical relatives provided equipoise for direct comparison of these donor sources. Between June 2012 and June 2018, 368 patients aged 18 to 70 years with chemotherapy-sensitive lymphoma or acute leukemia in remission were randomly assigned to undergo UCB (n = 186) or haploidentical (n = 182) transplant. Reduced-intensity conditioning comprised total-body irradiation with cyclophosphamide and fludarabine for both donor types. Graft-versus-host disease prophylaxis for UCB transplantation was cyclosporine and mycophenolate mofetil (MMF) and for haploidentical transplantation, posttransplant cyclophosphamide, tacrolimus, and MMF. The primary end point was 2-year progression-free survival (PFS). Treatment groups had similar age, sex, self-reported ethnic origin, performance status, disease, and disease status at randomization. Two-year PFS was 35% (95% confidence interval [CI], 28% to 42%) compared with 41% (95% CI, 34% to 48%) after UCB and haploidentical transplants, respectively (P = .41). Prespecified analysis of secondary end points recorded higher 2-year nonrelapse mortality after UCB, 18% (95% CI, 13% to 24%), compared with haploidentical transplantation, 11% (95% CI, 6% to 16%), P = .04. This led to lower 2-year overall survival (OS) after UCB compared with haploidentical transplantation, 46% (95% CI, 38-53) and 57% (95% CI 49% to 64%), respectively (P = .04). The trial did not demonstrate a statistically significant difference in the primary end point, 2-year PFS, between the donor sources. Although both donor sources extend access to reduced-intensity transplantation, analyses of secondary end points, including OS, favor haploidentical BM donors. This trial was registered at www.clinicaltrials.gov as #NCT01597778.

Allogeneic Stem Cell Transplantation in Mantle Cell Lymphoma in the Era of New Drugs and CAR-T Cell Therapy

MCL is an uncommon lymphoproliferative disorder that has been regarded as incurable since its identification as a distinct entity. Allogeneic transplantation for two decades has represented the only option capable of ensuring prolonged remissions and possibly cure. Despite its efficacy, its application has been limited by feasibility limitations and substantial toxicity, particularly in elderly patients. Nevertheless, the experience accumulated over time has been wide though often scattered among retrospective and small prospective studies. In this review, we aimed at critically revise and discuss available evidence on allogeneic transplantation in MCL, trying to put available evidence into the 2020 perspective, characterized by unprecedented development of novel promising therapeutic agents and regimens.

Haploidentical Stem Cell Transplantation in Lymphomas-Expectations and Pitfalls

T-cell replete Haploidentical stem cell transplantation (Haplo-SCT) with Post-transplant cyclophosphamide (PT-Cy) is an emerging therapeutic option for patients with advanced relapsed or refractory lymphoma. The feasibility of this platform is supported by several retrospective studies showing a toxicity profile that is improved relative to umbilical cord blood and mismatched unrelated donor (UD) transplant and comparable to matched unrelated donor transplant. In particular, cumulative incidence of chronic graft-versus-host disease (GVHD) is reduced after Haplo-SCT relative to UD and matched related donor (MRD) transplant thanks to PT-Cy employed as GVHD prophylaxis. This achievement, together with a similar incidence of acute GVHD and disease relapse, results in a promising advantage of Haplo-SCT in terms of relapse-free/GVHD free survival. Unmet needs of the Haplo-SCT platform are represented by the persistence of a not negligible rate of non-relapse mortality, especially due to infections and disease relapse. Future efforts are warranted in order to reduce life-threatening infections and to employ Halo-SCT with PT-Cy as a platform to build new immunotherapeutic strategies.

Nonmyeloablative Conditioning Regimen before T Cell Replete Haploidentical Transplantation with Post-Transplant Cyclophosphamide for Advanced Hodgkin and Non-Hodgkin Lymphomas

Allogeneic hematopoietic stem cell transplantation (allo-SCT) is a valid option in patients with refractory lymphomas. HLA haploidentical stem cell transplantation (haplo-SCT) expanded the accessibility to allogeneic hematopoietic cell transplantation. The aims of study were to retrospectively assess the toxicity and efficacy of haplo-SCT using nonmyeloablative conditioning in patients with advanced lymphoma. In total, 147 patients with advanced lymphoma at 2 partner institutions were included. Patients received a uniform nonmyeloablative conditioning regimen and graft-versus-host disease (GVHD) prophylaxis. The primary endpoints were progression-free survival (PFS), overall survival (OS), GVHD, nonrelapse mortality, and GVHD, relapse-free survival (GRFS). Median follow-up was 39 months (range, 6 to 114 months). The median age was 46 years (range, 19 to 71 years). Sixty-five percent of patients were in complete remission (CR) at transplantation. Cumulative incidence of grade II to IV acute GVHD was 30% (95% confidence interval [Cl], 23% to 38%). Two-year cumulative incidence of all grades of chronic GVHD was 13% (95% CI, 8% to 20%). Two-year cumulative incidence of disease relapse was 19% (95% CI, 14% to 27%), with a higher incidence in patients not being in CR at allo-HCT (CR versus not CR: 12% versus 33%, P = .006). Two-year PFS, OS, and GRFS were 66% (95% CI, 59-75), 73% (95% CI, 66-81), and 56% (95% CI, 48-65), respectively. Haplo-SCT with post-transplantation cyclophosphamide may be considered a valid option for patients with aggressive lymphoma and deserves further evaluation.

Evolution of the role of haploidentical stem cell transplantation: past, present, and future

INTRODUCTION

The accessibility to haplo-donors has led to an increase in the number of haplo-HSCT worldwide. A systematic search of the PubMed database between 2000 to present was performed.

AREAS COVERED

In this review, the authors discussed the most used approaches to perform haplo-HSCT and its results: T-cell depletion (TCD, including Perugia platform and its modifications) and T-cell repleted haplo (TCR, including the high-dose post-transplant cyclophosphamide strategy (Baltimore protocol) and the Beijing protocol). The improvements and modifications made to the different strategies have increased the indications of haplo-HSCT, including both malignant and nonmalignant disorders. Focusing on the Baltimore protocol, the authors review the results of the retrospective studies that have compared it to other donor transplants. The limitations of this strategy in terms of toxicity, graft complications, and GVHD are also discussed in detail. Finally, possible approaches to improve the outcomes of TCR haplo-HSCT are presented.

EXPERT OPINION

The recent advances in the field of haplo-HSCT have allowed a large number of patients with incurable diseases to benefit from this procedure despite not having a matched donor. With all available strategies, virtually no patient who needs an allogeneic transplant should be excluded by the absence of a donor.