Reduced-Intensity Conditioning Allogeneic Transplantation from Unrelated Donors: Evaluation of Mycophenolate Mofetil Plus Cyclosporin A as Graft-versus-Host Disease Prophylaxis

In the current study, we have analyzed the efficacy of cyclosporine A (CSA) plus mycophenolate mofetil (MMF) as graft-versus-host disease (GVHD) prophylaxis in the fludarabine plus melphalan or busulfan reduced intensity regimen (RIC) setting in a series of 44 patients receiving allogeneic transplantation from an unrelated donor. Only 23% were in the first complete remission at the time of transplant. Cumulative incidence of grades II-IV and III-IV acute GVHD (aGVHD) was 53% and 23%, respectively. Fifty-six percent had equal to or greater than grade 2 gut involvement. Cumulative incidence of overall and extensive chronic GVHD (cGVHD) was 93% and 63%, respectively. Ninety-two percent of patients who were evaluable +100 days after transplant were in complete remission. Relapse rate was 25% at 2 years. Event free (EFS) and overall survival (OS) at 2 years were 52%. Pharmacokinetic assays of mycophenolic acid (MPA) showed a therapeutic area under the curve (AUC) at the dosage of 3 g daily, although a large inter- and intraindividual variations of MPA plasma levels were found. In conclusion, the combination of CSA plus MMF in the fludarabine plus melphalan or busulfan RIC setting is feasible. Regarding GVHD, this combination allowed to control aGVHD but lead to a high incidence of cGVHD, so that newer strategies are required, especially in trying to decrease gastrointestinal involvement.     

Unrelated Donor Reduced-Intensity Allogeneic Hematopoietic Stem Cell Transplantation for Relapsed and Refractory Hodgkin Lymphoma

Myeloablative allogeneic hematopoietic cell transplantation (HCT) may cure patients with relapsed or refractory Hodgkin lymphoma (HL), but is associated with a high treatment-related mortality (TRM). Reduced-intensity and nonmyeloablative (RIC/NST) conditioning regimens aim to lower TRM. We analyzed the outcomes of 143 patients undergoing unrelated donor RIC/NST HCT for relapsed and refractory HL between 1999 and 2004 reported to the Center for International Blood and Marrow Transplant Research (CIBMTR). Patients were heavily pretreated, including autologous HCT in 89%. With a median follow-up of 25 months, the probability of TRM at day 100 and 2 years was 15% (95% confidence interval [CI] 10%-21%) and 33% (95% CI 25%-41%), respectively. The probabilities of progression free survival (PFS) and overall survival (OS) were 30% and 56% at 1 year and 20% and 37% at 2 years. The presence of extranodal disease and the Karnofsky Performance Scale (KPS) <90 were significant risk factors for TRM, PFS, and OS, whereas chemosensitivity at transplantation was not. Dose intensity of the conditioning regimen (RIC versus NST) did not impact outcomes. Unrelated donor HCT with RIC/NST can salvage some patients with relapsed/refractory HL, but relapse remains a common reason for treatment failure. Clinical studies should be aimed at reducing the incidence of acute graft-versus-host disease (GVHD) and relapse.     

Addition of Infliximab to Standard Acute Graft-versus-Host Disease Prophylaxis following Allogeneic Peripheral Blood Cell Transplantation

Infliximab, a chimeric monoclonal antibody (mAb) against tumor necrosis factor (TNF)-α, has shown activity against steroid refractory acute graft-versus-host disease (aGVHD). We conducted a prospective trial of infliximab for the prophylaxis of aGVHD. Patients older than 20 years undergoing myeloablative allogeneic stem cell transplantation (SCT) for hematologic malignancies were eligible. GVHD prophylaxis consisted of infliximab given 1 day prior to conditioning and then on days 0, +7, +14, +28, and +42, together with standard cyclosporine (CSA) and methotrexate (MTX). Nineteen patients with a median age of 53 years were enrolled. All patients received peripheral blood allografts from matched sibling (n = 14) or unrelated donors (n = 5). Results were compared with a matched historic control group (n = 30) treated contemporaneously at our institution. The cumulative incidences of grades II-IV aGVHD in the infliximab and control groups were 36.8% and 36.6%, respectively (P = .77). Rates of chronic GVHD were 78% and 61%, respectively (P = .22). Significantly more bacterial and invasive fungal infections were observed in the infliximab group (P = .01 and P = .02, respectively). Kaplan-Meier estimates of 2-year overall survival (OS) and progression free survival (PFS) for patients receiving infliximab were 42% and 36%, respectively. The corresponding numbers for patients in the control group were 46% and 43%, respectively. The addition of infliximab to standard GVHD prophylaxis did not lower the risk of GVHD and was associated with an increased risk of bacterial and invasive fungal infections.     

Sirolimus in Combination with Cyclosporine or Tacrolimus Plus Methotrexate for Prevention of Graft-versus-Host Disease following Hematopoietic Cell Transplantation from Unrelated Donors

In 2 consecutive prospective clinical trials, we evaluated the efficacy of sirolimus together with a calcineurin inhibitor (cyclosporine or tacrolimus) and low-dose methotrexate for prevention of graft-versus-host disease (GVHD) after unrelated hematopoietic cell transplantation (HCT). Nine patients received sirolimus with cyclosporine, and 17 received sirolimus with tacrolimus. The incidence of grade II-IV GVHD was 77%, with the median onset at day 7 after HCT. Because of toxicity, administration of sirolimus was discontinued earlier than planned in 11 patients, but after the onset of GVHD. Three patients developed renal failure requiring hemodialysis. Accrual in both studies was terminated because of lack of efficacy. In these studies, the addition of sirolimus to regimens containing a calcineurin inhibitor and methotrexate appeared to cause toxicity and provided no detectable improvement in preventing GVHD.     

Unrelated Donor Allogeneic Hematopoietic Stem Cell Transplantation for Patients with Hemoglobinopathies Using a Reduced-Intensity Conditioning Regimen and Third-Party Mesenchymal Stromal Cells

Allogeneic hematopoietic stem cell transplantation for patients with a hemoglobinopathy can be curative but is limited by donor availability. Although positive results are frequently observed in those with an HLA-matched sibling donor, use of unrelated donors has been complicated by poor engraftment, excessive regimen-related toxicity, and graft-versus-host disease (GVHD). As a potential strategy to address these obstacles, a pilot study was designed that incorporated both a reduced-intensity conditioning and mesenchymal stromal cells (MSCs). Six patients were enrolled, including 4 with high-risk sickle cell disease (SCD) and 2 with transfusion-dependent thalassemia major. Conditioning consisted of fludarabine (150 mg/m²), melphalan (140 mg/m²), and alemtuzumab (60 mg for patients weighing > 30 kg and .9 mg/kg for patients weighing <30 kg). Two patients received HLA 7/8 allele matched bone marrow and 4 received 4-5/6 HLA matched umbilical cord blood as the source of HSCs. MSCs were of bone marrow origin and derived from a parent in 1 patient and from an unrelated third-party donor in the remaining 5 patients. GVHD prophylaxis consisted of cyclosporine A and mycophenolate mofetil. One patient had neutropenic graft failure, 2 had autologous hematopoietic recovery, and 3 had hematopoietic recovery with complete chimerism. The 2 SCD patients with autologous hematopoietic recovery are alive. The remaining 4 died either from opportunistic infection, GVHD, or intracranial hemorrhage. Although no infusion-related toxicity was seen, the cotransplantation of MSCs was not sufficient for reliable engraftment in patients with advanced hemoglobinopathy. Although poor engraftment has been observed in nearly all such trials to date in this patient population, there was no evidence to suggest that MSCs had any positive impact on engraftment. Because of the lack of improved engraftment and unacceptably high transplant-related mortality, the study was prematurely terminated. Further investigations into understanding the mechanisms of graft resistance and development of strategies to overcome this barrier are needed to move this field forward.     

Early Donor Chimerism Levels Predict Relapse and Survival after Allogeneic Stem Cell Transplantation with Reduced-Intensity Conditioning

The success of hematopoietic stem cell transplantation (HSCT) with reduced-intensity conditioning (RIC) is limited by a high rate of disease relapse. Early risk assessment could potentially improve outcomes by identifying appropriate patients for preemptive strategies that may ameliorate this high risk. Using a series of landmark analyses, we investigated the predictive value of early (day-30) donor chimerism measurements on disease relapse, graft-versus-host disease, and survival in a cohort of 121 patients allografted with a uniform RIC regimen. Chimerism levels were analyzed as continuous variables. In multivariate analysis, day-30 whole blood chimerism levels were significantly associated with relapse (hazard ratio [HR] = .90, P < .001), relapse-free survival (HR = .89, P < .001), and overall survival (HR = .94, P = .01). Day-30 T cell chimerism levels were also significantly associated with relapse (HR = .97, P = .002), relapse-free survival (HR = .97, P < .001), and overall survival (HR = .99, P = .05). Multivariate models that included T cell chimerism provided a better prediction for these outcomes compared with whole blood chimerism. Day-30 chimerism levels were not associated with acute or chronic graft-versus-host disease. We found that high donor chimerism levels were significantly associated with a low lymphocyte count in the recipient before transplant, highlighting the impact of pretransplant lymphopenia on the kinetics of engraftment after RIC HSCT. In summary, low donor chimerism levels are associated with relapse and mortality and can potentially be used as an early predictive and prognostic marker. These findings can be used to design novel approaches to prevent relapse and to improve survival after RIC HSCT.     

Long-Term Outcomes of Allogeneic Hematopoietic Cell Transplant with Fludarabine and Melphalan Conditioning and Tacrolimus/Sirolimus as Graft-versus-Host Disease Prophylaxis in Patients with Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is associated with poor survival in older adults, and allogeneic hematopoietic cell transplant (HCT) with reduced-intensity conditioning (RIC) has been an increasingly used strategy in this population. At City of Hope we conducted a retrospective analysis of 72 patients who underwent allogeneic HCT with fludarabine and melphalan (FluMel) as the conditioning regimen between 2005 and 2018, from either a matched sibling or fully matched unrelated donor while in complete remission. Tacrolimus and sirolimus (T/S) were used as graft-versus-host disease (GVHD) prophylaxis. Overall survival and progression-free survival at 4 years post-HCT were 58% and 44%, respectively. The cumulative incidences of relapse/progression and nonrelapse mortality at 4 years were 34% and 22%, respectively. Patients with Philadelphia chromosome–positive (Ph+) ALL had a significantly lower cumulative incidence of relapse/progression (20% versus 48% for patients with Ph-negative status, P = .007). In conclusion, RIC HCT with FluMel conditioning and T/S GVHD prophylaxis was associated with favorable outcomes in patients with Ph+ ALL and should be considered as a viable consolidative therapy for adult patients with ALL.     

Calcineurin Inhibitors Replacement by Ruxolitinib as Graft-versus-Host Disease Prophylaxis for Patients after Allogeneic Stem Cell Transplantation

Graft-versus-host disease (GVHD) is a common complication of allogeneic stem cell transplantation (allo-SCT) that carries a high mortality. Although calcineurin inhibitors (CNIs) have been widely used in GVHD prophylaxis, the incidence of acute GVHD (aGVHD) remains at roughly 30% to 50%. Moreover, some allo-SCT recipients cannot tolerate CNI. Thus, improved GVHD prevention methods are needed. Our study aimed to determine the prophylactic value of ruxolitinib for GVHD in CNI-intolerant patients after allo-SCT. Between September 2017 and March 2019, 10 patients with hematopoietic malignancies after allo-SCT who were intolerant to CNI at our center were enrolled in this study. The regimens were based on a myeloablative busulfan and cyclophosphamide regimen. Antithymocyte globulin was administered to patients with an HLA-haploidentical related donor (HRD) at a dosage of 6 mg/kg. All received ruxolitinib to replace CNI as GVHD prophylaxis. Ruxolitinib was initiated at 5 to 10 mg twice daily until 2 to 3 months post-transplantation and then tapered gradually, and in the absence of GVHD, discontinued by day +180. Eight patients had acute leukemia, 1 patient had myeloproliferative neoplasm, and 1 patient had natural killer T cell (NK/T) lymphoma. The donor type was a matched sibling donor in 3 patients and an HLA-haploidentical related donor (HRD) in 7 patients. All patients received CNI plus short-course of methotrexate as GVHD prophylaxis, but showed intolerance to CNI within 45 days post-transplantation. After ruxolitinib replacement, only 1 patient (10%) developed grade II skin aGVHD within 100 days, and only 1 patient developed severe aGVHD after 100 days. Two patients developed moderate/severe chronic GVHD (cGVHD) after tapering or stopping ruxolitinib, resulting in a 1-year cumulative incidence of moderate/severe cGVHD of 21.4%. Cytomegalovirus (CMV) reactivation occurred in 4 patients (40%), and Epstein-Barr virus (EBV) reactivation occurred in 3 patients (30%). None of the patients developed CMV disease or EBV post-transplantation lymphoproliferative disorder. After a median follow-up of 11 months (range, 2 to 15.5 months), 2 patients (20%) relapsed and 7 (70%) were alive, of whom 6 (60%) were negative for minimal residual disease and 4 were off immunosuppressant therapy. The prophylactic application of ruxolitinib for CNI-intolerant patients after allo-SCT appears to be safe and effective in preventing GVHD, but this awaits further study in larger cohorts.     

Thrombotic Microangiopathy Associated with Sirolimus Level after Allogeneic Hematopoietic Cell Transplantation with Tacrolimus/Sirolimus-Based Graft-versus-Host Disease Prophylaxis

Posttransplantation thrombotic microangiopathy (TMA) is a multifactorial complication of allogeneic hematopoietic cell transplantation (allo-HCT) whose incidence is increased with the use of a sirolimus plus tacrolimus (SIR/TAC) regimen for acute graft-versus-host disease (aGVHD) prophylaxis. We evaluated the incidence and possible risk factors for TMA in a case series of 177 patients who received allo-HCT using SIR/TAC-based GVHD prophylaxis. The patients received either a sibling donor graft (n = 82) or a matched unrelated donor graft (n = 95). Within the first 100 days post-HCT, 30 patients (17%) were diagnosed with TMA, and an additional 9 patients (5%) were classified as probable TMA cases. The median time to onset of TMA was 4.6 weeks (range, 1.6-10.6 weeks). Thirty-four patients developed both TMA and aGVHD, with the majority (81%) developing aGVHD first. Multivariate analysis identified the following factors as associated with increased risk of TMA: day 14 serum sirolimus level ≥9.9 ng/mL (hazard ratio [HR], 2.19; 95% confidence interval [CI], 1.13-4.27; P = .02), presence of previous aGVHD grade II-IV (HR, 3.04; 95% CI, 1.38-6.71; P < .01), and fully myeloablative conditioning (HR, 3.47; 95% CI, 1.60-7.53; P < .01). These risk factors for TMA suggest that when using a SIR/TAC regimen for GVHD prophylaxis, careful monitoring and adjustment of the sirolimus dosage is critical, particularly in patients with active aGVHD.     

Extended CCR5 Blockade for Graft-versus-Host Disease Prophylaxis Improves Outcomes of Reduced-Intensity Unrelated Donor Hematopoietic Cell Transplantation: A Phase II Clinical Trial

Graft-versus-host disease (GVHD) remains the most common treatment-related complication after allogeneic hematopoietic cell transplantation (allo-HCT). Lymphocyte migration plays a critical role in the pathogenesis of GVHD. A previous phase I/II trial demonstrated that CCR5 blockade with maraviroc in the first 30days after allo-HCT resulted in a low incidence of early acute GVHD, primarily in visceral organs, but with no impact on late acute or chronic GVHD.We conducted a phase II trial to examine the efficacy of an extended course of maraviroc, administered through post-transplantation day +90 in addition to standard prophylaxis in 37 recipients of reduced-intensity-conditioned unrelated donor allo-HCT performed to treat hematologic malignancies.Extended maraviroc treatment was safe and feasible. The primary study endpoint, day +180 rate of grade II-IV acute GVHD, was 22 ± 7%, liver GVHD was not observed, and gut GVHD was uncommon. The day +180 rate of grade III-IV acute GVHD was 5 ± 4%. The 1-year rate of moderate to severe chronic GVHD was 8 ± 5% and that of disease relapse was 30 ± 8%. Overall survival at 1 year was 70 ± 8%. Compared with the previously studied short course of maraviroc, the extended course resulted in a significantly higher GVHD-free, relapse-free survival (adjusted hazard ratio [HR], .45; 95% confidence interval [CI], .25 to .82; P?=?.009) and overall survival (adjusted HR, .48; 95% CI, .24 to .96; P?=?.037). A combined analysis of both trials showed that high maraviroc trough concentrations on the day of hematopoietic cell infusion were associated with lower rates of acute GVHD.An extended course of maraviroc after reduced-intensity-conditioned unrelated donor allo-HCT is safe and effective in preventing acute and chronic GVHD and is associated with favorable survival.     

Preconditioning Absolute Lymphocyte Count and Transplantation Outcomes in Matched Related Donor Allogeneic Hematopoietic Stem Cell Transplantation Recipients with Reduced-Intensity Conditioning and Antithymocyte Globulin Treatment

The integration of antithymocyte globulin (ATG) into therapy has significantly reduced the incidence of graft-versus-host disease (GVHD) and is being actively used in allogeneic hematopoietic stem cell transplantation (allo-HSCT). The ATG dosage is determined by the recipient's body weight, but some insist that this approach does not reflect the actual target of ATG. In this respect, weight-based dosing may lead to ATG overdose, particularly in recipients with a relatively low absolute lymphocyte count (ALC). We retrospectively analyzed 84 patients with acute leukemia or myelodysplastic syndrome who underwent matched related donor (MRD) allo-HSCT with reduced-intensity conditioning (RIC) at a single institution. Patients were dichotomized according to the ALC measured on the first day of conditioning (day -7) to investigate the associations of the ALC with GVHD and survival outcomes. The median duration of follow-up was 29 months. The preconditioning ALC was closely correlated with the ALC at the first ATG administration (day -3). The cumulative incidences of both acute GVHD and chronic GVHD were significantly lower in the preconditioning ALC <500/μL group compared with the ALC ≥500/μL group. There was no significant difference in disease relapse incidence between the 2 groups; however, mortality was significantly higher in the ALC <500/μL group. Multivariate analysis including disease status, modified European Blood and Marrow Transplantation score, and preconditioning ALC (≥500/μL versus <500/μL) identified disease status and ALC as being independently associated with overall survival (OS). In particular, infection was the most common cause of death in the ALC <500/μL group. Our data suggest that uniform weight-based ATG dosing in MRD allo-HSCT with RIC is associated with an increase in nonrelapse mortality and a relatively inferior OS in patients with a significantly low preconditioning ALC. Therefore, alternative strategies for the integration of ATG should be considered in allo-HSCT, at least for patients with a substantially low preconditioning ALC.     

Severe Infections after Unrelated Donor Allogeneic Hematopoietic Stem Cell Transplantation in Adults: Comparison of Cord Blood Transplantation with Peripheral Blood and Bone Marrow Transplantation

We evaluated the occurrence of severe infections in 192 consecutive adult recipients of volunteer unrelated donor allogeneic hematopoietic stem cell transplants, with a detailed analysis of severe infections after receipt of cord blood transplants (CBTs; n = 48) or bone marrow transplants (BMTs)/peripheral blood stem cell transplants (PBSCTs; n = 144). At a 3-year median follow-up, CBT recipients had a higher risk of developing any severe infection (85% versus 69% in BMT/PBSCT recipients, P < .01). CBT recipients had a higher incidence of severe bacterial infections before day +100, but at 3 years the risks of these and other infections were similar in the CBT and BMT/PBSCT groups. In addition, the 100-day and 3-year incidences of infection-related mortality (IRM) did not differ between groups (P = .2 and .5, respectively). In multivariate analysis, the most significant risk factor for IRM in all 192 patients was monocytopenia (.2 × 10⁹/L). In CBT recipients, only neutropenia (.2 × 10⁹/L) on day +30 and low nucleated cell dose infusion (<2 × 10⁷/kg) showed a trend for increased IRM (P = .05 in both cases). Stem cell source had no effect on day +100 or 3-year nonrelapse mortality (NRM), cytomegalovirus infection, cytomegalovirus disease (7% versus 6%), or overall survival (36% versus 39%, respectively). The number of mismatches in HLA (A, B, and DRB1) had no effect on any outcome in CBT recipients. In contrast, in the BMT/PBSCT group, the presence of any mismatch by low or high-resolution HLA typing (A, B, C, and DRB1) increased NRM and decreased overall survival (P < .01). IRM was the primary or secondary cause of death in 61% and 59% of CBT and BMT/PBSCT recipients who died, respectively. Our results confirm the relevance of severe infectious complications as source of severe morbidity and NRM after volunteer unrelated donor hematopoietic stem cell transplantation in adults, but suggest that CBT recipients have a similar risk of dying from an infection if an accurate selection of a cord blood unit is done.     

Low-Dose Anti-T Lymphoglobulin as Prophylaxis for Graft-versus-Host Disease in Unrelated Donor Transplantations for Acute Leukemias and Myelodysplastic Syndromes

Chronic graft-versus-host disease (cGVHD) is a major complication after stem cell transplantation (HSCT). Several randomized studies already demonstrated that anti-T lymphoglobulin (ATLG) is effective in preventing GVHD after myeloablative unrelated and HLA-identical sibling transplants. However, the issue of doses and the potential increase of relapses still remain unsolved. Here we report data on 190 patients with acute leukemia and myelodysplastic syndrome who underwent an unrelated HSCT with low-dose ATLG (15 to 30 mg/kg) given at an earlier timing (days –6 to –2). HSCT was performed from HLA 10/10 (n?=?62, 33%), 9/10 (n?=?91, 48%), 8/10 (n?=?30, 16%), and <8/10 (n?=?7, 4%) identical unrelated donor. Peripheral blood was the stem cell source in 42% (n?=?80). Median follow-up was 51 months. Grades II to IV and III to IV acute GVHD were 26% and 9%, respectively, and 2-year overall and moderate to severe cGVHD were 23% and 14%, respectively. The 3-year incidences of relapse and nonrelapse mortality were 26% and 18%, respectively. The rates of 3-year overall survival (OS), disease-free survival (DFS), and GVHD-free and relapse-free survival (GRFS) were 60%, 56% and 44%, respectively. Factors such as younger donor, good performance status, and early disease were associated with better outcome in terms of OS, DFS, and GRFS. Our data indicate that doses of ATLG lower that those used in randomized clinical trials can be used for GVHD prevention, even in the adult setting, without clear increases in relapse and infections; these findings need to be further validated by a prospective randomized study.     

Analysis of Donor and Recipient ABO Incompatibility and Antibody-Associated Complications after Allogeneic Stem Cell Transplantation with Reduced-Intensity Conditioning

Allogeneic hematopoietic stem cell transplantation (HSCT) can be performed across the ABO blood group barrier. The impact of ABO incompatibility on clinical outcome is controversial. A retrospective analysis of 310 patients who underwent HSCT with reduced-intensity conditioning between 1998 and 2011 was performed to investigate the frequency and clinical implications of anti-RBC antibodies in passenger lymphocyte syndrome (PLS) after minor ABO mismatch (mm), persistent or recurring recipient type ABO antibodies (PRABO) after major ABO mm HSCT, and autoimmune hemolytic anemia (AIHA). Transplantation characteristics and clinical outcome were analyzed by univariate and multivariate analysis for groups with or without anti-RBC antibodies. ABO blood group incompatibility did not affect clinical outcome despite an increased requirement of blood transfusion. Twelve patients with AIHA, 6 patients with PLS, and 12 patients with PRABO post-HSCT were identified. AIHA did not affect overall survival (OS) or transplant-related mortality (TRM), but patients with AIHA had a lower incidence of grades II to IV acute graft-versus-host disease (P = .05). OS in the PLS group was 0% compared with 61% in the whole group receiving minor ABO mm transplants (P < .001). Comparing PRABO patients with those receiving a major ABO mm HSCT, the OS was 17% versus 73% (P = .002) and TRM was 50% versus 21% (P = .03). At our center, PLS after minor ABO mm and PRABO antibodies after major ABO mm HSCT are significant risk factors for decreased OS and TRM. Our results suggest that occurrence of unexpected ABO antibodies after HSCT warrant a wider investigation individual to find the underlying cause.