Refined graft-versus-host disease/relapse-free survival in transplant from HLA-identical related or unrelated donors in acute myeloid leukemia

Anti-T-lymphocyte globulin improves GvHD-free and relapse-free survival in myelofibrosis after matched related or unrelated donor transplantation

Acute and chronic graft-versus-host disease (GvHD) are major complications of allogeneic hematopoietic cell transplantation (alloHCT). In vivo T-cell depletion with anti-T-lymphocyte globulin (ATLG) as part of the conditioning regimen prior to alloHCT is frequently used as GvHD prophylaxis, but data on its role in myelofibrosis is scarce. We took advantage of an international collaborative network to investigate the impact of ATLG in myelofibrosis undergoing first alloHCT. We included 707 patients (n = 469 ATLG and n = 238 non-ATLG prophylaxis). The cumulative incidence of acute GvHD grade II-IV was 30% for the ATLG group vs. 56% for the non-ATLG group (P < 0.001). Acute GvHD grade III-IV occurred in 20% vs. 25%, respectively (P = 0.01). Incidence of mild-to-severe chronic GvHD was 49% vs. 50% (P = 0.52), while ATLG showed significantly lower rates of severe chronic GvHD (7% vs. 18%; P = 0.04). GvHD-free and relapse-free survival (GRFS) at 6 years was 45% for the ATLG group vs. 37% for the non-ATLG group (P = 0.02), driven by significantly improved GRFS of ATLG in matched related and matched unrelated donors. No significant differences in risk for relapse, non-relapse mortality, and overall survival were observed. Multivariable modeling for GRFS showed a 48% reduced risk of GvHD, relapse, or death when using ATLG.

Graft-versus-host disease and impact on relapse in myelofibrosis undergoing hematopoietic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation (alloHSCT) remains the only curative treatment for myelofibrosis (MF). Relapse occurs in 10-30% and remains a major factor for dismal outcomes. Previous work suggested that graft-versus-host disease (GVHD) might be associated with risk of relapse. This study included 341 patients undergoing their first (n = 308) or second (n = 33) alloHSCT. Anti-T-lymphocyte or antithymocyte globulin was used for GVHD prophylaxis in almost all patients. Median time to neutrophile and platelet engraftment was 13 days and 19 days, respectively. The cumulative incidence of acute GVHD grade II-IV was 41% (median, 31 days; range, 7-112). Grade III-IV acute GVHD was observed in 22%. The cumulative incidence of chronic GVHD was 61%. Liver was affected in 23% of acute GVHD cases and 46% of chronic GVHD cases. Severe acute GVHD was associated with high non-relapse mortality. The development of acute GVHD grade II and moderate GVHD was an independent factor for reduced risk for relapse after transplantation without increased risk for non-relapse mortality, while especially acute GVHD grade IV was associated with high non-relapse mortality. Last, we identified that ongoing response to ruxolitinib, accelerated-phase MF at time of transplantation and splenectomy prior to transplantation were independent predictors for relapse.

Low- versus standard-dose post-transplant cyclophosphamide as GVHD prophylaxis for haploidentical transplantation

Haploidentical haematopoietic cell transplantation (haplo-HCT) using post-transplant cyclophosphamide (PTCY) as graft-versus-host disease (GVHD) prophylaxis is the standard of care for various haematological malignancies. The original PTCY dose after haplo-HCT was 100 mg/kg, but no dose-finding studies have been performed to identify the optimal dose. We performed a retrospective analysis to compare standard-dose PTCY (100 mg/kg) with reduced-dose PTCY (80 mg/kg): 969 in the standard-dose group and 538 in the reduced-dose group. As there was a significant difference between the two groups regarding patient and transplant characteristics, we performed propensity score (PS) matching. After PS matching, 425 patients in each group were included. The probabilities of 2-year OS were 55.9% in the standard-dose group and 47.0% in the reduced-dose group (p = 0.36). The cumulative incidences of 2-year non-relapse mortality were 21.3% in the standard-dose group and 20.5% in the reduced-dose group (p = 0.55). There was no significant difference in the incidence of acute (grade II-IV 29.2% [95% CI, 24.9-33.6] vs. 25.3% [95% CI, 21.3-29.6]; grade III-IV 7.3% [95% CI, 5.1-10.0] vs. 6.6% [95% CI, 4.5-9.3]) or chronic GVHD. In conclusion, reduced- and standard-dose PTCY were comparable in terms of major clinical outcomes.

Chronic GVHD: review advances in prevention, novel endpoints, and targeted strategies

Allogeneic hematopoietic cell transplantation (allo-HCT) is a curative therapy for many malignant and non-malignant hematologic disorders. Chronic graft-versus-host (cGVHD) disease remains a significant hurdle for long-term survival in patients post allo-HCT, and it remains the leading cause of late non-relapse mortality. The risk factors for development of cGVHD include degree of human leukocyte antigen (HLA) disparity, increasing recipient age, use of peripheral blood stem cells as a source, myeloablative conditioning regimens, prior acute GVHD (aGVHD), and female donor to male recipient. Our biological understanding of cGVHD is mostly derived from transplantation mouse models and patient data. There are three distinct phases in the development of cGVHD. Approaches to prevent GVHD include pharmacologic strategies such as calcineurin inhibitors (cyclosporine, tacrolimus) combined with methotrexate or mTOR inhibitors (sirolimus), and IMP dehydrogenase inhibitors (mycophenolate mofetil). Increasingly, posttransplant cyclophosphamide is emerging as a promising strategy for GVCHD prevention especially in a setting of reduced intensity conditioning. Other approaches include serotherapy (ATG, Campath) and graft manipulation strategies. A significant obstacle to evaluating the response of novel GVHD-directed therapies has been standardized response assessments. This has functioned as a barrier to designing and interpreting clinical trials that are structured around the treatment of cGVHD. Novel endpoints including failure-free survival, Graft-versus-host disease-free, relapse-free survival (GRFS), and current GVHD-free, relapse-free survival (CGRFS) may create a clearer picture for post-HCT outcomes. Targeted therapies including Bruton's tyrosine kinase inhibition, JAK1/2 inhibition, and ROCK2 inhibitors have improved cGVHD therapy, especially in the steroid refractory setting. Continued improvement in prophylactic strategies for cGVHD, identification of accurate cGVHD treatment endpoints, and access to novel therapeutic agents are expected to improve cGVHD outcomes.

Comparison of transplant outcomes between haploidentical transplantation and single cord blood transplantation in non-remission acute myeloid leukaemia: A nationwide retrospective study

Allogeneic haematopoietic stem cell transplantation (HSCT) is a potentially curative treatment for some patients with acute myeloid leukaemia (AML) who are refractory to chemotherapy. Cord blood transplantation (CBT) is a reasonable option in such cases because of its rapid availability. Recently, a growing number of human leucocyte antigen (HLA)-haploidentical related donor HSCTs (haplo-HSCTs) have been performed, although its effectiveness remains undetermined. Using the Japanese nationwide transplantation registry data, we identified 2438 patients aged ≥16 years who received CBT or haplo-HSCT as their first transplant for non-remission AML between January 2008 and December 2018. After 2:1 propensity score matching, 918 patients in the CBT group and 459 patients in the haplo-HSCT group were selected. In this matched cohort, no significant difference in overall survival (OS) was observed between the CBT and haplo-HSCT groups (hazard ratio [HR] of haplo-HSCT to CBT 1.02, 95% confidence interval [CI] 0.89-1.16). Similarly, no significant difference in the cumulative incidence of relapse (HR 1.09, 95% CI 0.93-1.28) or non-relapse mortality (HR 0.94, 95% CI 0.76-1.18). Subgroup analysis showed that CBT was significantly associated with preferable OS in patients receiving myeloablative conditioning. Our data showed comparable outcomes between haplo-HSCT and CBT recipients with non-remission AML.

Determinants of refined GvHD-free, relapse-free survival after reduced-intensity allogeneic hematopoietic cell transplantation in older patients with myeloid malignancies

BACKGROUND

Older patients with AML/MDS have a poor prognosis with alloHCT as the only curative option. However alloHCT is challenging given its high TRM. Recently, a composite endpoint of GRFS was proposed to define transplant success. A single centre retrospective analysis was performed to determine the main variables influencing GRFS.

PATIENTS AND METHODSMETHODS

91 consecutive patients≥ 60 years (median 64 years, range 60-74) with AML/MDS who received reduced-intensity alloHCT during 2001-2017 analysed. Disease risk index (DRI) at HCT was low/intermediate in 47pts (52%) and high in 44 pts (48%).

RESULTS

After median follow-up for survivors of 56 months (range 7-144), 37 (40.6%) patients were alive. The OS, LFS and GRFS were 61.4%, 58.1%, 49.1% at 1 year and 35.5%, 32.3% and 23.1% at 5 years, respectively. The 1-year and 5-year incidences of NRM and relapse were 26.9%, 21.3% and 47.9% and 35.4%, respectively. In univariate analysis, high DRI was the strongest factor for worse OS (HR 2.121; p = 0.049), LFS (HR 1.924; p = 0.0123) and GRFS (HR 2.319; p = 0.0005). The donor age ≥ 62 years had a negative impact on OS (HR 2.110; p = 0.0345) and GRFS (HR 2.014; p = 0.0341). High DRI (HR 2.652; p = 0.0003) and donor age (HR 2.304; p = 0.0257) retained its significance in multivariate analysis for GRFS.

CONCLUSION

A significant portion of older patients with myeloid malignancies survive alloHCT without experiencing GRFS event with DRI as the main determinant of outcome. Negative impact of donor age≥ 62 years suggests preference of a young donor, regardless of being related or unrelated.

Comparing cord blood transplantation and matched related donor transplantation in non-remission acute myeloid leukemia

Cord blood transplantation (CBT) is an alternative donor transplantation method and has the advantages of rapid availability and the possibility of inducing a more potent graft-versus-leukemia effect, leading to a lower relapse rate for patients with non-remission relapse and refractory acute myeloid leukemia (R/R AML). This study aimed to investigate the impact of CBT, compared to human leukocyte antigen-matched related donor transplantation (MRDT). This study included 2451 adult patients with non-remission R/R AML who received CBT (1738 patients) or MRDT (713 patients) between January 2009 and December 2018. Five-year progression-free survival (PFS) and the prognostic impact of CBT were evaluated using a propensity score (PS) matching analysis. After PS matching, the patient characteristics were well balanced between the groups. The five-year PFS was 25.2% (95% confidence interval [CI]: 21.2-29.5%) in the CBT group and 18.1% (95% CI: 14.5-22.0%) in the MRDT group (P = 0.009). The adjusted hazard ratio (HR) was 0.83 (95% CI: 0.69-1.00, P = 0.045); this was due to a more pronounced decrease in the relapse rate (HR: 0.78, 95% CI: 0.69-0.89, P < 0.001) than an increase in the NRM (1.42, 1.15-1.76, P = 0.001). In this population, CBT was associated with a better 5-year PFS than MRDT after allogeneic HSCT.

The impact of cytogenetic risk on the outcomes of allogeneic hematopoietic cell transplantation in patients with relapsed/refractory acute myeloid leukemia: On behalf of the acute leukemia working party (ALWP) of the European group for blood and marrow transplantation (EBMT)

Karyotypic analysis at time of diagnosis has an important value in determining initial response to treatment, remission duration and overall survival (OS) in acute myeloid leukemia (AML). Less is known about its value before allogeneic hematopoietic cell transplantation (allo-HCT) in patients transplanted with active disease, either relapsed or primary refractory (Rel-Ref) AML. We explored the impact of cytogenetic risk (stratification according to MRC-UK) in 2089 patients with either Ref (n = 972) or Rel AML (n = 1117) transplanted during the period 2000-2017. Overall, 154 patients had a favorable risk, 1283 had an intermediate risk and 652 had an adverse cytogenetic risk. Median follow-up was 49 months. Compared to the favorable risk group, intermediate and adverse risk patients were associated with worse leukemia-free survival and OS and also with a higher incidence of relapse. In a subgroup analysis of patients in the intermediate risk group harboring Fms-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD), this remained an important prognostic factor, being associated with worse outcomes. When analyzing patients according to the intensity of the conditioning regimen, no differences were observed for the main transplant outcomes. In conclusion, in patients diagnosed with AML and transplanted with active disease, karyotype remains an important prognostic factor, allowing splitting patients into different risk groups according to their cytogenetics. Similarly, FLT3-ITD mutation also remains a negative prognostic factor in this population.

Impact of donor type on long-term graft-versus-host disease-free/relapse-free survival for adult acute lymphoblastic leukemia in first remission

We assessed the impact of donor type on long-term outcomes of allogeneic hematopoietic cell transplantation (HCT) in 440 consecutive adults with acute lymphoblastic leukemia (ALL) in first complete remission (CR1), particularly focusing on the donor type-specific difference in graft-versus-host disease (GVHD)-free/relapse-free survival (GRFS). Donor sources were matched sibling donor (MSD; n = 199), matched unrelated donor (MUD; n = 110), 1-allele-mismatched unrelated donor (1-MMUD; n = 83), and cord blood (CB; n = 48). Cumulative incidence of severe chronic GVHD was 14.8% for MSD-HCT, 30.1% for MUD-HCT, 9.6% for 1-MMUD-HCT, and 4.2% for CBT, respectively (P < 0.001), while no difference was observed in grade III-IV acute GVHD. After a median follow-up of 58.1 months, cumulative incidence of relapse was 26.1% for MSD-HCT, 27.2% for MUD-HCT, 31.2% for 1-MMUD-HCT, and 7.2% for CBT, respectively (P = 0.042). Disease-free survival and overall survival were comparable among all donor sources. However, GRFS for MSD-HCT, MUD-HCT, 1-MMUD-HCT, and CBT was 33.1%, 14.5%, 42.1%, and 50.3%, respectively (P = 0.001). In multivariate analysis, CBT showed a comparable GRFS to MSD-HCT (HR, 0.78; P = 0.290), while MUD-HCT was associated with a poorer GRFS (HR, 1.53; P = 0.002). Given the encouraging GRFS of CBT, our data suggest that CBT remains a valid option for adult ALL in CR1.

Allogeneic peripheral blood stem cell transplantation with anti-thymocyte globulin versus allogeneic bone marrow transplantation without anti-thymocyte globulin

We compared severe graft-versus-host-disease (GvHD) free and relapse-free survival and other transplantation outcomes of acute myeloid leukemia (AML) patients given bone marrow (BM) without anti-thymocyte globulin (ATG) versus peripheral blood stem cells (PBSC) with ATG after myeloablative conditioning. In the cohort of patients receiving grafts from a human leukocyte antigen (HLA)-matched sibling donor, patients given PBSC with ATG (n=1,021) and those given BM without ATG (n=1,633) presented comparable severe GvHD-free relapse-free survival (GRSF)(hazard ratio [HR]=0.9, 95% confidence interval [CI]: 0.8-1.1, P=0.5) and overall survival (HR=1.0, 95% CI: 0.8-1.2, P=0.8). They had however, a lower incidence of chronic GvHD (cGvHD) (HR=0.7, 95% CI: 0.6-0.9, P=0.01). In the cohort of patients receiving grafts from HLA-matched unrelated donor , patients given PBSC with ATG (n=2,318) had better severe GvHD-free and relapse-free survival (GRFS) than those given BM without ATG (n=303) (HR=0.8, 95% CI: 0.6-0.9, P=0.001). They also had a lower incidence of cGvHD (HR=0.6, 95% CI: 0.5-0.8, P=0.0006) and better overall survival (HR=0.8, 95% CI: 0.6-1.0, P=0.04). In summary, these data suggest that PBSC with ATG results in comparable (in the case of sibling donor) or significantly better (in the case of unrelated donor) severe GRFS than BM without ATG in patients with AML in complete remission receiving grafts after myeloablative conditioning.

Haploidentical transplantation and posttransplant cyclophosphamide for treating aplastic anemia patients: a report from the EBMT Severe Aplastic Anemia Working Party

In the absence of an HLA-matched donor, the best treatment for acquired aplastic anemia patients refractory to immunosuppression is unclear. We collected and analyzed data from all acquired aplastic anemia patients who underwent a haploidentical transplantation with posttransplant cyclophosphamide in Europe from 2011 to 2017 (n = 33). The cumulative incidence of neutrophil engraftment was 67% (CI_95%: 51-83%) at D +28 and was unaffected by age group, stem cell source, ATG use, or Baltimore conditioning regimen. The cumulative incidence of grades II-III acute GvHD was 23% at D +100, and limited chronic GvHD was 10% (0-20) at 2 years, without cases of grade IV acute or extensive chronic GvHD. Two-year overall survival was 78% (64-93), and 2-year graft-versus-host disease-free survival was 63% (46-81). In univariate analysis, the 2-year OS was higher among patients who received the Baltimore conditioning regimen (93% (81-100) versus 64% (41-87), p = 0.03), whereas age group, stem cell source, and ATG use had no effect. Our results using unmanipulated haploidentical transplantation and posttransplant cyclophosphamide for treating refractory AA patients are encouraging, but warrant confirmation in a prospective study with a larger number of patients and longer follow-up.

Allogeneic stem cell transplantation in second complete remission for core binding factor acute myeloid leukemia: a study from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation

Core binding factor acute myeloid leukemia (AML) comprises two subtypes with distinct cytogenetic abnormalities of either t(8;21)(q22;q22) or inv(16)(p13q22)/t(16;16)(p13;q22). Since long-term response to chemotherapy in these leukemias is relatively good, allogeneic hematopoietic stem cell transplantation is considered in patients who relapse and achieve second complete remission. To evaluate the outcomes of allogeneic transplantation in this indication, we studied 631 patients reported to the European Society for Blood and Marrow Transplantation Registry between the years 2000 and 2014. Leukemia-free survival probabilities at two and five years were 59.1% and 54.1%, while overall survival probabilities were 65% and 58.2%, respectively. The incidence of relapse and risk of non-relapse mortality at the same time points were 19.8% and 22.5% for relapse and 20.9% and 23.3% for non-relapse mortality, respectively. The most important adverse factors influencing leukemia-free and overall survival were: leukemia with t(8;21), presence of three or more additional chromosomal abnormalities, and Karnofsky performance score <80. Relapse risk was increased in t(8;21) leukemia and associated with additional cytogenetic abnormalities as well as reduced intensity conditioning. Measurable residual disease in molecular evaluation before transplantation was associated with increased risk of relapse and inferior leukemia-free survival.

Outcomes of Salvage Haploidentical Transplant with Post-Transplant Cyclophosphamide for Rescuing Graft Failure Patients: a Report on Behalf of the Francophone Society of Bone Marrow Transplantation and Cellular Therapy

Prognosis of patients with graft failure is dismal, and retransplantation is the sole option for long-term survival. To address the interest of haploidentical transplantation as a salvage option in this context, we analyzed data from 24 patients with graft failure or loss retransplanted with a haploidentical donor who received post-transplant cyclophosphamide (PTCy) as graft-versus-host disease prophylaxis (GVHD). Fludarabine-based reduced-intensity conditioning was used in 23 patients and the Baltimore regimen in 14 patients. The median delay between previous and salvage transplantation for graft failure was 63 days (range, 39 to 98). In addition to PTCy, all patients received cyclosporine, and 22 patients also received mycophenolate mofetil for GVHD prophylaxis. With a median follow-up of 353 days (range, 16 to 2010), 1-year overall survival (OS) was 56% (95% confidence interval, 38% to 81%). Transplant complications accounted for 80% of deaths. The cumulative incidence of neutrophil engraftment at day +30 was 79%. Cumulative incidence of grades II to IV acute GVHD at day 100 was 14%, and 1-year cumulative incidence of chronic GVHD was 31%. One-year cumulative incidence of relapse was 13%. Stem cell source did not impact on engraftment, GVHD, relapse, or OS. Salvage haploidentical transplant with PTCy for rescuing graft failure patients leads to an acceptable 1-year OS and might be a valid option in this poor situation.

Assessment of Individual versus Composite Endpoints of Acute Graft-versus-Host Disease in Determining Long-Term Survival after Allogeneic Transplantation

The overall composite of graft-versus-host disease (GVHD)-free, relapse-free survival (GRFS), defined as survival free of grade III-IV acute GVHD (aGVHD), chronic GVHD (cGVHD) requiring systemic immunosuppressive therapy (IST), or relapse, has emerged as a useful composite in clinical trials and to capture clinically meaningful events that impact quantity and quality of survival after allogeneic hematopoietic cell transplantation (HCT). We reviewed 565 consecutive patients aged ≥18 years undergoing HCT for hematologic malignancy to analyze how baseline incidence, specifics of clinical definitions, and proposed reductions in any one individual event may dynamically alter the overall performance of the composite To determine the relative impact of each GRFS event (excluding death), we accounted for competing risks using Fine and Gray methods, and correlated each event with overall survival (OS) using Kaplan-Meier methods. The consequences of modulating individual or composite endpoints on OS, such as hypothesized reductions of events of an HCT interventional trial, were examined using Monte Carlo simulations. The median age of the cohort was 54 years (range, 18 to 73 years). The majority of patients received HLA-matched unrelated donor HCT (53%), consisting of peripheral blood stem cell grafts (90%) after myeloablative conditioning (68%). Relapse conferred the greatest risk for death (hazard ratio [HR], 7.89; 95% confidence interval [CI], 5.83 to 10.69), followed by grade III-IV aGVHD (HR, 6.16; 95% CI, 4.42 to 8.56) and cGVHD requiring IST (HR, 1.69; 95% CI, 1.16 to 2.46). The overall GRFS composite correlated with an HR of 4.81 (95% CI, 3.61 to 6.41), which was lower compared with either relapse or grade III-IV aGVHD. Statistical simulations found that modulating the combined risk of both relapse and grade III-IV aGVHD predicted the greatest change in 5-year OS. These simulations suggest that GRFS as currently defined may be less optimal for correlating with OS, and further refinement of composite endpoints is needed. Nonetheless, composite endpoints may be particularly helpful in mitigating potential difficulties in interpretation when competing risks are present, most commonly seen in HCT studies.