NCI First International Workshop on the Biology, Prevention, and Treatment of Relapse after Allogeneic Hematopoietic Stem Cell Transplantation: Report from the Committee on Treatment of Relapse after Allogeneic Hematopoietic Stem Cell Transplantation

Immunotherapeutic approaches for the treatment of childhood, adolescent and young adult non-Hodgkin lymphoma

With the introduction of the anti-CD20 monoclonal antibody rituximab, B-cell non-Hodgkin lymphoma was the first malignancy successfully treated with an immunotherapeutic agent. Since then, numerous advances have expanded the repertoire of immunotherapeutic agents available for the treatment of a variety of malignancies, including many lymphoma subtypes. These include the introduction of monoclonal antibodies targeting a variety of cell surface proteins, including the successful targeting of immunoregulatory checkpoint receptors present on T-cells or tumour cells. Additionally, cellular immunotherapeutic approaches utilize T- or Natural Killer-cells generated with chimeric antigen receptors against cell surface proteins or Epstein-Barr virus-associated latent membrane proteins. The following review describes the current state of immunotherapy for non-Hodgkin lymphoma including a summary of currently available data and promising agents currently in clinical development with future promise in the treatment of childhood, adolescent and young adult non-Hodgkin lymphoma.

Keep in Mind Quality of Life: Outcome of a Ten-Year Series of Post-Transplantation Early Relapses in Childhood Acute Lymphoblastic Leukemia-A Report from the Grand Ouest Oncology Study Group for Children in France

Relapses of acute lymphoblastic leukemia (ALL) early after hematopoietic stem cell transplantations in children are uncommon but associated with a very poor prognosis. Whereas there are no current recommendations for the management of these relapses, the children's quality of life is an important issue. We studied the outcomes, including 1-year overall survival, complete remission, and quality of life, of 19 children with ALL who relapsed within the first year after their transplantation treated in the 5 participating centers between 2000 and 2011 Patients were distributed as follows: supportive care only (group A), outpatient treatment (mainly steroid and vincristine, group B), or intensive inpatient treatment (group C). There were no significant differences in 1-year overall survival (31.5% for the entire cohort) or remission rate for time between transplantation and relapse (< 6 months or 6 to 12 months), transplantation or disease characteristics, or treatment group. However, time spent in hospital (for treatment and complications) significantly differed between treatment groups B and C (20.8% ± 13.0 versus 59.1% ± 32.9, respectively; P < .05). No differences in organ toxicities, school attendance, or Lansky scores were found between treatment groups. Our sample size-limited data indicate, in a prepersonalized medicine era, that children treated with steroid and vincristine have the same prognosis as those treated with intensive therapy, but they may benefit from improved quality of life. Nevertheless, new therapeutic strategies are required and future prospective trials would help to establish recommendations.

Phase II Study of Haploidentical Natural Killer Cell Infusion for Treatment of Relapsed or Persistent Myeloid Malignancies Following Allogeneic Hematopoietic Cell Transplantation

We conducted a phase 2 study to determine the efficacy of HLA-haploidentical related donor natural killer (NK) cells after cyclophosphamide-based lymphodepletion in patients with relapsed or progressive acute myelogenous leukemia (AML) or myelodysplastic syndrome (MDS) following allogeneic hematopoietic cell transplantation (HCT). Eight patients (2 with MDS and 6 with AML) were treated with cyclophosphamide 50 mg/kg on day -3 and day -2 before infusion of NK cells isolated from a haploidentical related donor. One patient also received fludarabine 25 mg/m2/day for 4 days. Six doses of 1 million units of interleukin-2 (IL-2) were administered on alternating days beginning on day -1. The median number of NK cells infused was 10.6 × 10(6)/kg (range, 4.3 to 22.4 × 10(6)/kg), and the median number of CD3 cells infused was 2.1 × 10(3)/kg (range, 1.9 to 40 × 10(3)/kg). NK infusions were well tolerated, with a median time to neutrophil recovery of 19 days (range, 7 days to not achieved) and no incidence of graft-versus-host disease after NK infusion. One patient with AML and 1 patient with MDS achieved a complete response, but relapsed at 1.7 and 1.8 months, respectively. One patient with MDS experienced resolution of dysplastic features but persistence of clonal karyotype abnormalities; this patient was stable at 65 months after NK cell therapy. The median duration of survival was 12.9 months (range, 0.8 to 65.3 months). Chimerism analysis of CD3(-)/CD56(+) peripheral blood cells did not detect any circulating haploidentical NK cells after infusion. NK phenotyping was performed in 7 patients during and after IL-2 infusion. We found a slight trend toward greater expression of KIR2DL2/2DL3/2DS2 (5% versus 28%; P = .03) at 14 days in patients who survived longer than 6 months from NK cell infusion (n = 4) compared with those who died within 6 months of NK cell therapy (n = 3). In summary, our data support the safety of haploidentical NK cell infusion after allogeneic HCT.

New approaches to transplantation in acute myelogenous leukemia

Allogeneic hematopoietic stem cell transplantation (HSCT) is a curative therapeutic option for acute myelogenous leukemia (AML). This is due to the combined effect of chemo/radiation therapy and the immunologic graft-versus-leukemia effect. The field of HSCT has benefited from advances in a variety of “fronts,” including our increasing ability to break the human leukocyte antigen barrier, which has led to greater access to transplantation. Furthermore, progress in the biologic, genetic, and pharmacologic arenas is creating a scenario where traditional borders between transplant and non-transplant therapies are less clear. This overlap is exemplified by new approaches to pharmacologic maintenance of remission strategies after HSCT. In addition, cellular adoptive immunotherapy has the potential to exploit narrowly targeted anti-tumor effects within or outside the allogeneic HSCT “frame,” holding the promise of avoiding off target side effects, such as graft-versus-host disease. Here we discuss these and other lines of active investigation designed to improve outcomes of HSCT for AML.

CD34-Selected Hematopoietic Stem Cell Transplants Conditioned with Myeloablative Regimens and Antithymocyte Globulin for Advanced Myelodysplastic Syndrome: Limited Graft-versus-Host Disease without Increased Relapse

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the only curative therapy for patients with myelodysplastic syndrome (MDS). Donor T cells are critical for the graft-versus-tumor effect but carry the risk of graft-versus-host disease (GVHD). CD34 selection with immunomagnetic beads has been an effective method of depleting alloreactive donor T cells from the peripheral blood graft and has been shown to result in significant reduction in acute and chronic GVHD. We analyzed the outcomes of 102 adults (median age, 57.6 years) with advanced MDS who received a CD34-selected allo-HSCT between January 1997 and April 2012 at Memorial Sloan Kettering Cancer Center. The cumulative incidences of grades II to IV acute GVHD were 9.8% at day 100 (95% confidence interval [CI], 5.0% to 16.5%) and 15.7% at day 180 (95% CI, 9.4% to 23.4%). The cumulative incidence of chronic GVHD at 1 year was 3.9% (95% CI, 1.3% to 9.0%). The cumulative incidences of relapse were 11.8% at 1 year (95% CI, 6.4% to 18.9%) and 15.7% at 2 years (95% CI, 9.4% to 23.4%). Forty-eight patients were alive with a median follow-up of 71.7 months. Rates of overall survival (OS) were 56.9% at 2 years (95% CI, 48% to 67.3%) and 49.3% at 5 years (95% CI, 40.4% to 60.2%). Rates of relapse-free survival (RFS) were 52.0% at 2 years (95% CI, 41.9% to 61.1%) and 47.6% at 5 years (95% CI, 37.5% to 56.9%). The cumulative incidences of nonrelapse mortality were 7.8% at day 100 (95% CI, 3.7% to 14.1%), 22.5% at 1 year (95% CI, 15.0% to 31.1%), and 33.4% at 5 years (95% CI, 24.2% to 42.6%) post-transplant. The incidence of chronic GVHD/RFS overlapped with RFS. These findings demonstrate that ex vivo T cell-depleted allo-HSCT by CD34 selection offers long-term OS and RFS with low incidences of acute and chronic GVHD and without an increased risk of relapse.

Efficacy of immune suppression tapering in treating relapse after reduced intensity allogeneic stem cell transplantation

For patients who relapse after allogeneic hematopoietic stem cell transplantation while still on immune suppression, there is anecdotal evidence that tapering the immune suppression may result in graft-versus-tumor activity. We reviewed the medical records of all patients with documented histological or radiographic disease recurrence within 1 year of stem cell transplantation while on immune suppression at our institution. The median time to relapse was 110 days (range, 18-311) after transplant. Among 123 patients with relapse treated with immune suppression tapering without chemotherapy, radiation, or donor lymphocyte infusion, 34 responded (33/101 reduced intensity conditioning transplant and 1/22 myeloablative conditioning transplant, 32.7% and 4.5% respectively; P=0.007). The median time to response after initiation of immune suppression tapering was 82 days (range, 16-189). Thirty-three patients (97.1%) had development or progression of acute or chronic graft-versus-host disease as a consequence of immune suppression tapering, at a median time of 39 days (range, 16-98). Six patients subsequently relapsed late after initial response to immune suppression tapering at a median time of 2 years (range, 0.9-3.8). The median overall survival from immune suppression tapering for responders was 5.1 years (range, 1.9-not estimable). When clinically feasible, immune suppression tapering alone in patients who relapse early after reduced intensity conditioning allogeneic stem cell transplantation can produce durable remissions, but is almost always associated with graft-versus-host disease.

High Graft CD8 Cell Dose Predicts Improved Survival and Enables Better Donor Selection in Allogeneic Stem-Cell Transplantation With Reduced-Intensity Conditioning

PURPOSE

To characterize the impact of graft T-cell composition on outcomes of reduced-intensity conditioned (RIC) allogeneic hematopoietic stem-cell transplantation (alloHSCT) in adults with hematologic malignancies.

PATIENTS AND METHODS

We evaluated associations between graft T-cell doses and outcomes in 200 patients who underwent RIC alloHSCT with a peripheral blood stem-cell graft. We then studied 21 alloHSCT donors to identify predictors of optimal graft T-cell content.

RESULTS

Higher CD8 cell doses were associated with a lower risk for relapse (adjusted hazard ratio [aHR], 0.43; P = .009) and improved relapse-free survival (aHR, 0.50; P = .006) and overall survival (aHR, 0.57; P = .04) without a significant increase in graft-versus-host disease or nonrelapse mortality. A cutoff level of 0.72 × 10(8) CD8 cells per kilogram optimally segregated patients receiving CD8(hi) and CD8(lo) grafts with differing overall survival (P = .007). Donor age inversely correlated with graft CD8 dose. Consequently, older donors were unlikely to provide a CD8(hi) graft, whereas approximately half of younger donors provided CD8(hi) grafts. Compared with recipients of older sibling donor grafts (consistently containing CD8(lo) doses), survival was significantly better for recipients of younger unrelated donor grafts with CD8(hi) doses (P = .03), but not for recipients of younger unrelated donor CD8(lo) grafts (P = .28). In addition, graft CD8 content could be predicted by measuring the proportion of CD8 cells in a screening blood sample from stem-cell donors.

CONCLUSION

Higher graft CD8 dose, which was restricted to young donors, predicted better survival in patients undergoing RIC alloHSCT.

How I treat adults with relapsed or refractory Philadelphia chromosome-negative acute lymphoblastic leukemia

The long-term prognosis of adult patients with relapsed Philadelphia chromosome-negative acute lymphoblastic lymphoma (ALL) is poor. Allogeneic stem cell transplant in second remission is the only curative approach and is the goal when feasible. There is no standard chemotherapy regimen for relapsed disease, although a few agents are approved for use in this setting. The bispecific CD19-directed CD3 T-cell engager, blinatumomab, has recently been granted accelerated approval by the US Food and Drug Administration for relapsed or refractory disease of B-cell lineage. For patients with relapsed T-cell ALL, nelarabine is available. Liposomal vincristine is also approved for relapsed disease. When selecting combination chemotherapy salvage options, evaluation of the prior treatment and timing of relapse informs treatment decisions. Monoclonal and cellular investigational therapies are quite promising and should be explored in the appropriate patient.

Survival of patients with acute myeloid leukemia relapsing after allogeneic hematopoietic cell transplantation: a center for international blood and marrow transplant research study

Acute myeloid leukemia (AML) relapse after allogeneic hematopoietic cell transplantation (alloHCT) remains a major therapeutic challenge. We studied outcomes of 1788 AML patients relapsing after alloHCT (1990 to 2010) during first or second complete remission (CR) to identify factors associated with longer postrelapse survival. Median time to post-HCT relapse was 7 months (range, 1 to 177). At relapse, 1231 patients (69%) received intensive therapy, including chemotherapy alone (n = 660), donor lymphocyte infusion (DLI) ± chemotherapy (n = 202), or second alloHCT ± chemotherapy ± DLI (n = 369), with subsequent CR rates of 29%. Median follow-up after relapse was 39 months (range, <1 to 193). Survival for all patients was 23% at 1 year after relapse; however, 3-year overall survival correlated with time from HCT to relapse (4% for relapse during the 1- to 6-month period, 12% during the 6-month to 2-year period, 26% during the 2- to 3-year period, and 38% for ≥3 years). In multivariable analysis, lower mortality was significantly associated with longer time from alloHCT to relapse (relative risk, .55 for 6 months to 2 years; relative risk, .39 for 2 to 3 years; and relative risk, .28 for ≥3 years; P < .0001) and a first HCT using reduced-intensity conditioning (relative risk, .77; 95% confidence interval [CI], .66 to .88; P = .0002). In contrast, inferior survival was associated with age >40 years (relative risk, 1.42; 95% CI, 1.24 to 1.64; P < .0001), active graft-versus-host disease at relapse (relative risk, 1.25; 95% CI, 1.13 to 1.39; P < .0001), adverse cytogenetics (relative risk, 1.37; 95% CI, 1.09 to 1.71; P = .0062), mismatched unrelated donor (relative risk, 1.61; 95% CI, 1.22 to 2.13; P = .0008), and use of cord blood for first HCT (relative risk, 1.23; 95% CI, 1.06 to 1.42; P = .0078). AML relapse after alloHCT predicted poor survival; however, patients who relapsed ≥6 months after their initial alloHCT had better survival and may benefit from intensive therapy, such as second alloHCT ± DLI.

Prophylaxis and treatment of acute lymphoblastic leukemia relapse after allogeneic hematopoietic stem cell transplantation

Relapse of acute lymphoblastic leukemia remains a major cause of death in patients following allogeneic hematopoietic stem cell transplantation. Several factors may affect the concurrence and outcome of relapse, which include graft-versus-host disease, minimal residual disease or intrinsic factors of the disease, and transplantation characteristics. The mainstay of relapse prevention and treatment is donor leukocyte infusions, targeted therapies, second transplantation, and other novel therapies. In this review, we mainly focus on addressing the impact of graft-versus-host disease on relapse and the prophylaxis and treatment of acute lymphoblastic leukemia relapse following allogeneic hematopoietic stem cell transplantation. We also make recommendations for critical strategies to prevent relapse after transplantation and challenges that must be addressed to ensure success.

Real-time assessment of relapse risk based on the WT1 marker in acute leukemia and myelodysplastic syndrome patients after hematopoietic cell transplantation

Relapse is the major cause of treatment failure after allogeneic hematopoietic cell transplantation (alloHCT) for acute leukemia and myelodysplastic syndrome (MDS). Wilms' tumor Ag (WT1) is overexpressed in the majority of acute leukemia and MDS patients and has been proposed as a universal diagnostic marker for detection of impending relapse. Comprehensive studies have shown that WT1 transcript levels have predictive value in acute leukemia patients in CR after chemotherapy. However, the focus of this study is the period after alloHCT for predicting relapse onset. We analyzed the accumulation of WT1 mRNA transcripts in PB of 82 leukemia and MDS patients and defined specific molecular ratios for relapse prediction. The extensively validated WT1/c-ABL ratio was used to normalize increases in WT1 transcript levels. The observed lead time of crossing or exceeding set WT1 levels is presented along with linear interpolation to estimate the calculated day the WT1 thresholds were crossed. The WT1/c-ABL transcript ratio of 50 or above yielded 100% specificity and 75% sensitivity reliably predicting future relapse with an observed average of 29.4 days (s.d.=19.8) and a calculated average of 63 days (s.d.=29.3) lead time before morphologic confirmation. A lower ratio of 20 or above gave lower specificity, but higher sensitivity (84.8% and 87.5%, respectively) identified more patients who relapsed, at earlier times, providing an earlier warning with actual average lead time of 49.1 days (s.d.=30.8) and calculated average of 78 days (s.d.=28.8). WT1 transcript levels serve as a diagnostic relapse test with greater sensitivity than the morphologic approach used in the clinic as a readout.

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.

Feasibility of treating post-transplantation minimal residual disease in children with acute leukemia

Outcomes are poor for patients with hematologic malignancies who experience overt relapse after allogeneic hematopoietic stem cell transplantation (HCT). Data on outcomes of post-transplantation minimal residual disease (MRD) are limited. In this single-institution, retrospective cohort analysis of children with acute leukemia and myelodysplastic syndrome, we document the pattern of relapse with a primary focus on outcomes of post-transplantation MRD. Forty of 93 patients (43%) who underwent a first allogeneic HCT and had systematic pretransplantation and post-transplantation MRD evaluations at +30, +60, +90, +180 days and +1 and +2 years post-transplantation experienced relapse. The median time to relapse was 4.8 months post-transplantation, with a median survival of 4 months post-relapse. Despite frequent, systematic, routine post-HCT disease restaging evaluation, 31 patients (78%) presented with overt disease at the time of relapse. Seven patients with acute leukemia who had post-transplantation MRD presented at a median of 1 month post-transplantation. Owing to rapid disease progression or treatment-related mortality, there was no improvement in survival in those patients whose leukemia was detected in a state of MRD post-transplantation. Our results suggest that early intervention strategies targeting post-transplantation MRD for relapse prevention in acute leukemia may not be feasible.

Clinical outcomes of AML patients relapsing after matched-related donor and umbilical cord blood transplantation

AML relapse remains the leading cause of transplant failure among Allo-SCT recipients. A single institution study was conducted on 348 patients with AML who received an Allo-SCT from an umbilical cord blood (UCB, 222) or HLA-matched-related (RD, 126) donor between 2000-2011. Relapse after Allo-SCT occurred in 72 UCB and 32 RD transplant recipients. Three patients achieved CR after withdrawal of immune suppression with no further therapy. Fifty-two patients received intensive post-relapse therapy, defined as systemic chemotherapy (22 UCB, 7 RD), second Allo-SCT (nine UCB, two RD), or DLI±systemic chemotherapy (0 UCB, 12 RD); of these, 25% achieved CR (21% UCB vs 35% RD, P=0.16). Survival at 1 year after relapse was 22% for all patients (19% UCB vs 28% RD, P=0.36). In multivariable analysis, post-relapse mortality was lower in patients receiving intensive therapy for relapse (hazard ratio (HR)=0.4; 95% confidence interval (CI) 0.2-0.6, P<0.01) and higher in patients with peripheral blood blasts above the median (HR=3.8; 95% CI 2.2-6.6, P<0.01), active infection (HR=1.9; 95% CI 1.0-3.5, P=0.05) and non-infectious medical complications (HR=2.0; 95% CI 1.2-3.5, P=0.01). In conclusion, patients with AML relapsing after Allo-SCT who were in good-enough clinical condition to receive intensive therapy had superior short-term survival.

Prognostic index for relapsed acute leukemia after allogeneic stem cell transplant

We retrospectively studied patients who relapsed after allogeneic stem cell transplantation (SCT) to identify factors influencing outcomes. Of the 296 patients (196 with AML and 100 with ALL), 102 (34%) experienced relapse at a median of 222 days (range: 30-2,748) after SCT. Multivariable analysis showed that high disease risk (hazard risk [HR]: 1.95; 95% confidence interval [CI]: 1.17-3.24; p = 0.010), unrelated donor (HR: 1.76; 95% CI: 1.10-2.80; p = 0.018), and interval of < 180 days from SCT to relapse (HR: 2.10; 95% CI: 1.26-3.51; p = 0.004) were independent factors of 2-year post-relapse survival (PRS). These factors were used as a prognostic index for PRS. The 2-year PRS in patients of score 0, score 1, score 2, and score 3 was 38%, 19%, 3%, and 0%, respectively (p < 0.001). Our new prognostic index may be helpful for selecting the treatment for relapsed patients after SCT.

Factors predictive of relapse of acute leukemia in children after allogeneic hematopoietic cell transplantation

The presence of minimal residual disease (MRD) before transplantation is the most important prognostic risk factor predictive of post-transplantation relapse in hematologic malignancies. However, MRD alone does not adequately predict relapse in all patients. To improve upon the ability to identify patients likely to relapse, we evaluated risk factors, in addition to MRD, that may be associated with development of post-transplantation relapse. In this single institution, retrospective cohort study of children with acute leukemia or myelodysplastic syndrome who had undergone a first allogeneic transplantation and had pretransplantation MRD evaluation, 40 of 93 patients (43%) experienced relapse. Univariate analysis demonstrated that African American race, high initial white blood cell count, central nervous system (CNS) disease at diagnosis, short first complete remission, nonmyeloablative (NMA) conditioning, lack of remission, and MRD before transplantation were associated with worse relapse-free survival (RFS). In a Cox multivariable analysis, CNS disease (P = .009), lack of remission (P = .01), and NMA conditioning (P = .04) were independently associated with inferior RFS. Among those in a morphologic complete remission who underwent a myeloablative transplantation, having both CNS disease at diagnosis (specifically in acute lymphoblastic leukemia) and MRD positivity was an independent risk factor predictive of relapse, which has not been previously reported. Results from our study support the existence of risk factors complimentary to pretransplantation MRD. Validation in a larger independent homogenous cohort is needed to develop a prognostic tool for clinical use to predict post-transplantation relapse.

Isolated Granulocytic Sarcoma of the Breast after Allogeneic Stem Cell Transplantation: A Rare Involvement Also Detected by 18FDG-PET/CT

Granulocytic sarcoma is a tumor consisting of myeloid blasts with or without maturation that occurs at an anatomical site other than bone marrow. Most frequently affected sites are skin, lymph nodes, gastrointestinal tract, bone, soft tissue and testes. AML may manifest as granulocytic sarcoma at diagnosis or relapse. Although it has been considered to be rare relapse as granulocytic sarcoma after stem cell transplantation is being increasingly reported. However it is rare without bone marrow involvement and in AML M6 subtype. Breast is also a rare involvement. We report a 30-year-old woman with AML M6 relapsed 16 months after allogeneic stem cell transplantation as a granulocytic sarcoma in right breast without bone marrow involvement. She was treated with systemic chemotherapy but died of sepsis. 18FDG-PET/CT images were also obtained and detected lesions other than detected by breast ultrasound. The incidence of granulocytic sarcoma may increase if suspected or new diagnostic modalities are performed.

Donor-derived CD19-targeted T cells cause regression of malignancy persisting after allogeneic hematopoietic stem cell transplantation

New treatments are needed for B-cell malignancies persisting after allogeneic hematopoietic stem cell transplantation (alloHSCT). We conducted a clinical trial of allogeneic T cells genetically modified to express a chimeric antigen receptor (CAR) targeting the B-cell antigen CD19. T cells for genetic modification were obtained from each patient's alloHSCT donor. All patients had malignancy that persisted after alloHSCT and standard donor lymphocyte infusions (DLIs). Patients did not receive chemotherapy prior to the CAR T-cell infusions and were not lymphocyte depleted at the time of the infusions. The 10 treated patients received a single infusion of allogeneic anti-CD19-CAR T cells. Three patients had regressions of their malignancies. One patient with chronic lymphocytic leukemia (CLL) obtained an ongoing complete remission after treatment with allogeneic anti-CD19-CAR T cells, another CLL patient had tumor lysis syndrome as his leukemia dramatically regressed, and a patient with mantle cell lymphoma obtained an ongoing partial remission. None of the 10 patients developed graft-versus-host disease (GVHD). Toxicities included transient hypotension and fever. We detected cells containing the anti-CD19-CAR gene in the blood of 8 of 10 patients. These results show for the first time that donor-derived allogeneic anti-CD19-CAR T cells can cause regression of B-cell malignancies resistant to standard DLIs without causing GVHD.

Postallogeneic monitoring with molecular markers detected by pretransplant next-generation or Sanger sequencing predicts clinical relapse in patients with myelodysplastic/myeloproliferative neoplasms

Relapse is the major cause of treatment failure after allogeneic stem-cell transplantation (AHSCT) for patients with myelodysplastic syndrome/myeloproliferative syndrome neoplasms (MDS/MPN). We evaluated the impact of molecular mutations on outcome and the value of molecular monitoring post-transplantation. We screened 45 patients with chronic myelomonocytic leukemia (n = 39 patients, including seven with transformed-acute myeloid leukemia), MDS/MPN unclassifiable (n = 5), and atypical BCR-ABL1-negative CML (n = 1) for mutations in ASXL1, CBL, NRAS, and TET2 genes by molecular genetics including a sensitive next-generation sequencing (NGS) technique. In 36 patients, sufficient DNA was available for molecular analyses. In particular, TET2 and CBL mutations were screened applying amplicon deep sequencing. In 89% of cases, at least one mutation could be detected: ASXL1: n = 18 (50%); CBL: n = 7 (19%); TET2: n = 15 (42%); and NRAS: n = 11 (32%). Survival after AHSCT at 5 yr was 46% (95% CI 28-64%) and was not influenced by any mutation. After a median of 6 months after AHSCT in 33% of the patients, one of the molecular markers was still detectable, resulting in a higher incidence of relapse than in patients with undetectable mutations (50% vs. 15%, P = 0.04). In conclusion, pretransplant molecular mutation analysis can help to detect biomarkers in patients with MPN/MDS, which may be subsequently used as minimal residual disease markers after AHSCT.

Proceedings from the National Cancer Institute's Second International Workshop on the Biology, Prevention, and Treatment of Relapse after Hematopoietic Stem Cell Transplantation: introduction

Despite advances in hematopoietic stem cell transplantation (HSCT) for the treatment of hematologic malignancies, relapse remains the leading cause of death after transplant. Biologic and clinical investigations are needed to combat this primary cause of death after transplantation. The National Cancer Institute held international workshops in 2009 and 2012 to help address this problem. Three major initiatives for coordinated research were proposed: 1) To establish multicenter networks for basic, translational, epidemiologic and clinical research; 2) To establish a network of biorepositories for the collection of samples before and after HSCT to aid in laboratory and clinical studies; and 3) To refine, implement and study proposed definitions for disease-specific response and relapse and for monitoring of minimal residual disease. The workshop in 2012 also featured nine presentations, summaries of which follow in three manuscripts.

Strategies to reduce relapse after allogeneic hematopoietic cell transplantation in acute myeloid leukemia

The incidence of acute myeloid leukemia (AML) is expected to increase in conjunction with our ageing population. Although it is proving to be a heterogeneous disease process, the only treatment with proven survival benefit for poor risk AML remains allogeneic hematopoietic cell transplant. Although this is presumed to be a curative strategy, many patients relapse after transplant, prompting us to examine various ways that we can improve outcomes. These efforts involve every step of AML diagnostics and therapy, including the intricate processes of conditioning, graft manipulation and immunomodulation. The hope is that improvement in these steps will ultimately improve survival and decrease relapse rates for AML patients after transplant.

Outcomes of autologous or allogeneic stem cell transplantation for non-Hodgkin lymphoma

Transplant outcomes of autologous or allogeneic stem cell transplantation (SCT) have not been elucidated as a single cohort in non-Hodgkin lymphoma (NHL). We analyzed the outcomes of 270 adult recipients receiving autologous (auto) SCT (n = 198) or allogeneic (allo) SCT (n = 72) for NHL between the years 2000 and 2010. Five-year overall survival rates for B and T cell NHL were 58% and 50%, respectively (allo-SCT 51% vs. 54% for B and T-cell NHL, and auto-SCT 60% vs. 47% for B and T cell lymphoma, respectively). In multivariate analysis, the number of chemotherapy regimens and disease status pre-SCT were independently associated with long-term outcome after SCT (for both auto- and allo-SCT). We conclude that the type of transplantation offered to patients, based on patient selection and disease-related factors, can achieve long-term survival, highlighting the importance of further improvement in disease control and reducing procedure-related mortality. The role of transplantation needs to be reevaluated in the era of targeted therapy.

Outcome and prognostic factors for patients who relapse after allogeneic hematopoietic stem cell transplantation

Disease relapse remains a major obstacle to the success of allogeneic hematopoietic stem cell transplantation (HSCT), yet little is known about the relevant prognostic factors after relapse. We studied 1080 patients transplanted between 2004 and 2008, among whom 351 relapsed. The 3-year postrelapse overall survival (prOS) rate was 19%. Risk factors for mortality after relapse included shorter time to relapse, higher disease risk index at HSCT, myeloablative conditioning, high pretransplantation comorbidity index, and graft-versus-host disease (GVHD) occurring before relapse. Important prognostic factors did not vary by disease type. Based on this, we could stratify patients into 3 groups, with 3-year prOS rates of 36%, 14%, and 3% (P < .0001). This score was validated in an historical cohort of 276 patients. Postrelapse donor lymphocyte infusion or repeat HSCT was associated with improved prOS, as was the development of GVHD after relapse. These differences remained significant in models that accounted for other prognostic factors and in landmark analyses of patients who survived at least 2 months from relapse. The results of this study may aid with prognostication and management of patients who relapse after HSCT and motivate the design of clinical trials aimed at relapse prevention or treatment in higher-risk patients.

Immunotherapy following relapse of acute leukaemia after T-cell-replete allogeneic peripheral blood progenitor cell transplantation: importance of new onset chronic graft-versus-host disease

INTRODUCTION

To further define the relative impact of immunotherapy and subsequent development of graft-versus-host disease (GVHD) on survival in patients with relapsed acute leukaemia postallogeneic hematopoietic stem cell transplant (SCT), we performed a single-centre retrospective analysis of 32 actively treated patients between 2003 and 2011.

METHODS

A total of 13 patients were identified who were treated actively with cessation of immunosuppression ± Fludarabine, Cytarabine, G-CSF (FLAG) induction, but no donor leucocyte infusion (DLI) (non-DLI group) and 19 patients received the same step-wise therapy plus G-CSF mobilized DLI (G-DLI group).

RESULTS

Groups were not statistically different with regards to baseline characteristics; however, the G-DLI group contained more sibling donors as opposed to unrelated donors than the non-DLI group. With a median follow-up of 47 months, the median overall survival (OS) of the non-DLI and G-DLI groups was not statistically different (8 months vs. 9 months, respectively, P = 0.5). Survival at 3 years was <10% in both groups. Univariate analysis identified response to FLAG, and new onset chronic GVHD as the only factors associated with improved OS.

CONCLUSION

Second donor stem cell infusions are unwarranted in the treatment of relapse after allogeneic SCT and therapeutic strategies should focus on cytoreduction followed by immune modulation with the aim of invoking chronic GVHD.

Proceedings from the National Cancer Institute's Second International Workshop on the Biology, Prevention, and Treatment of Relapse After Hematopoietic Stem Cell Transplantation: part III. Prevention and treatment of relapse after allogeneic transplantation

In the Second Annual National Cancer Institute's Workshop on the Biology, Prevention, and Treatment of Relapse after Hematopoietic Stem Cell Transplantation, the Scientific/Educational Session on the Prevention and Treatment of Relapse after Allogeneic Transplantation highlighted progress in developing new therapeutic approaches since the first relapse workshop. Recent insights that might provide a basis for the development of novel, practical clinical trials were emphasized, including utilization of newer agents, optimization of donor lymphocyte infusion (DLI), and investigation of novel cellular therapies. Dr. de Lima discussed pre-emptive and maintenance strategies to prevent relapse after transplantation, for example, recent promising results suggestive of enhanced graft-versus-tumor activity with hypomethylating agents. Dr. Schmid provided an overview of adjunctive strategies to improve cell therapy for relapse, including cytoreduction before DLI, combination of targeted agents with DLI, and considerations in use of second transplantations. Dr. Porter addressed strategies to enhance T cell function, including ex vivo activated T cells and T cell engineering, and immunomodulatory approaches to enhance T cell function in vivo, including exogenous cytokines and modulation of costimulatory pathways.

Risk-adapted donor lymphocyte infusion based on chimerism and donor source in pediatric leukemia

Donor lymphocyte infusion (DLI) is commonly used to treat leukemia relapse following stem cell transplantation. In florid relapse, however, the efficacy of DLI is limited with substantial risk of severe graft-versus-host disease (GvHD). Here, we develop a novel risk-adapted strategy characterized by pre-emptive DLI initiated at the time of mixed chimerism, a small starting dose based on donor source, dose-escalation guided by real-time chimerism monitoring and withholding of DLI immediately in patients achieving full donor chimerism. A total of 178 DLIs were given to 38 patients with mixed chimerism; thereafter, 33 patients (86.8%) had donor chimerism successfully increased, including 30 (78.9%) who had chimerism fully converted back to 100% donor. Cumulative incidence of relapse was significantly lower (P=0.00004) and overall survival higher (P=0.0003) in patients with chimerism fully corrected as compared with those of patients whose chimerism remained mixed. Only 13.2% of the patients developed acute grade III-IV GvHD with no associated mortality. In conclusion, the risk-adapted DLI strategy is useful in minimizing the risk of childhood leukemia relapse, GvHD and death.

Second allograft for hematologic relapse of acute leukemia after first allogeneic stem-cell transplantation from related and unrelated donors: the role of donor change

PURPOSE

To evaluate the role of a second allogeneic hematopoietic stem-cell transplantation (HSCT2) given for relapsed acute leukemia (AL) after related or unrelated first hematopoietic stem-cell transplantation (HSCT1) and to analyze the role of donor change for HSCT2 in both settings.

PATIENTS AND METHODS

We performed a retrospective registry study on 179 HSCT2s given for relapse after HSCT1 from matched related donors (n = 75) or unrelated donors (n = 104), using identical or alternative donors for HSCT2. Separate analyses were performed according to donor at HSCT1.

RESULTS

Independent of donor, 74% of patients achieved complete remission after HSCT2, and half of these patients experienced relapse again. Overall survival (OS) at 2 years was 25% ± 4% (39% ± 7% after related HSCT2; 19% ± 4% after unrelated HSCT2). Long-term survivors were observed even after two unrelated HSCT2s. Multivariate analysis for OS from HSCT2 confirmed established risk factors (remission duration after HSCT1: hazard ratio [HR], 2.37; 95% CI, 1.61 to 3.46; P < .001; stage at HSCT2: HR, 0.53; 95% CI, 0.34 to 0.83; P = .006). Outcome of HSCT2 was better after related HSCT1 than after unrelated HSCT1 (2-year OS: 37% ± 6% v 16% ± 4%, respectively; HR, 0.68; 95% CI, 0.47 to 0.98; P = .042, multivariate Cox regression). After both related and unrelated HSCT1, selecting a new donor for HSCT2 did not result in a relevant improvement in OS compared with HSCT2 from the original donor; however, donor change was not detrimental either.

CONCLUSION

After relapse from allogeneic HSCT1, HSCT2 can induce 2-year OS in approximately 25% of patients. Unrelated HSCT2 is feasible after related and unrelated HSCT1. Donor change for HSCT2 is a valid option. However, a clear advantage in terms of OS could not be demonstrated.

Autologous CLL cell vaccination early after transplant induces leukemia-specific T cells

BACKGROUND

Patients with advanced hematologic malignancies remain at risk for relapse following reduced-intensity conditioning (RIC) allogeneic hematopoietic stem cell transplantation (allo-HSCT). We conducted a prospective clinical trial to test whether vaccination with whole leukemia cells early after transplantation facilitates the expansion of leukemia-reactive T cells and thereby enhances antitumor immunity.

METHODS

We enrolled 22 patients with advanced chronic lymphocytic leukemia (CLL), 18 of whom received up to 6 vaccines initiated between days 30 and 45 after transplantation. Each vaccine consisted of irradiated autologous tumor cells admixed with GM-CSF-secreting bystander cells. Serial patient PBMC samples following transplantation were collected, and the impact of vaccination on T cell activity was evaluated.

RESULTS

At a median follow-up of 2.9 (range, 1-4) years, the estimated 2-year progression-free and overall survival rates of vaccinated subjects were 82% (95% CI, 54%-94%) and 88% (95% CI, 59%-97%), respectively. Although vaccination only had a modest impact on recovering T cell numbers, CD8+ T cells from vaccinated patients consistently reacted against autologous tumor, but not alloantigen-bearing recipient cells with increased secretion of the effector cytokine IFN-γ, unlike T cells from nonvaccinated CLL patients undergoing allo-HSCT. Further analysis confirmed that 17% (range, 13%-33%) of CD8+ T cell clones isolated from 4 vaccinated patients by limiting dilution of bulk tumor-reactive T cells solely reacted against CLL-associated antigens.

CONCLUSION

Our studies suggest that autologous tumor cell vaccination is an effective strategy to advance long-term leukemia control following allo-HSCT.

TRIAL REGISTRATION

Clinicaltrials.gov NCT00442130.

FUNDING

NCI (5R21CA115043-2), NHLBI (5R01HL103532-03), and Leukemia and Lymphoma Society Translational Research Program.

Immunotherapy for pediatric leukemia

Substantial progress has been made in the treatment of leukemia in childhood. Despite this, leukemia remains a leading cause of pediatric cancer-related mortality and the prognosis is guarded for individuals with relapsed or refractory disease. Standard therapies are associated with a wide array of acute and long-term toxicities and further treatment intensification may not be tolerable or beneficial. The curative potential of allogeneic stem cell transplantation is due in part to the graft-versus-leukemia effect, which provides evidence for the therapeutic capacity of immune-based therapies. In recent years there have been significant advances in the development and application of immunotherapy in the treatment of leukemias, including the demonstration of activity in chemotherapy-resistant cases. This review summarizes immunotherapeutic approaches in the treatment of pediatric leukemia including current results and future directions.

Primary treatment of leukemia relapses after allogeneic hematopoietic stem cell transplantation with reduced-intensity conditioning second transplantation from the original donor

Acute leukemia relapsing after allogeneic hematopoietic stem cell transplantation (HSCT) has dismal outcome. Consecutive consenting patients (acute myeloid leukemia: N = 71; acute lymphoblastic leukemia: N = 37), at a median age of 37 (16-57) years, who had relapsed 7.9 (1.3-132) months post-HSCT, were treated with three cytarabine-based intensive regimens as reduced-intensity conditioning (RIC), followed by infusion of mobilized HSC from the original donors. There were four treatment-related mortalities (TRMs). Of 104 evaluable cases, 72 patients (67%) achieved complete remission (CR)/CR with incomplete hematologic recovery (CRi). The median overall survival (OS) of the entire cohort was 11.6 months. The OS of patients achieving CR/CRi after the first RIC/HSCT was 18.8 months, as compared with 3.9 months for those not (P < 0.01). For 32 patients with nonremission, 11 received a repeat RIC-HSCT, leading to CR/CRi in three cases. Therefore, 75/108 (69%) of patients achieved CR/CRi after one or two courses of RIC-HSCT. Among CR/CRi patients, 48 cases relapsed again after 6.1 (1.0-64.4) months. Thirty cases received a repeat RIC-HSCT, leading to CR/CRi in 22 patients. Multivariate analyses showed a significant impact of remission duration after initial HSCT (P = 0.026) and the presence of acute graft-versus-host disease after RIC-HSCT (P = 0.011) on CR/CRi. RIC-HSCT as primary treatment for acute leukemic relapses post-HSCT induced a high CR rate with low TRM. Optimal postremission treatment remains to be defined.

Cellular therapy following allogeneic stem-cell transplantation

Allogeneic hematopoietic stem-cell transplantation (HSCT) is the most effective approach for many patients with hematologic malignancies. Unfortunately, relapse remains the most common cause of death after allogeneic HSCT, and the prognosis of relapsed disease is poor for most patients. Induction of a graft-versus-leukemia (GVL), or graft-versus-tumor, effect through the use of donor leukocyte infusion (DLI), or donor lymphocyte infusion, has been remarkably successful for relapsed chronic myelogenous leukemia. Unfortunately, response to DLI in other hematologic malignancies is much less common and depends on many factors including histology, pace and extent of relapse, and time from HSCT to relapse. Furthermore, graft-versus-host disease (GVHD) is common after DLI and often limits successful immunotherapy. Ultimately, manipulations to minimize GVHD while preserving or enhancing GVL are necessary to improve outcomes for relapse after allogeneic HSCT.

Azacitidine and donor lymphocyte infusions as first salvage therapy for relapse of AML or MDS after allogeneic stem cell transplantation

The combination of azacitidine and donor lymphocyte infusions (DLI) as first salvage therapy for relapse after allogeneic transplantation (allo-HSCT) was studied in 30 patients with acute myeloid leukemia (AML; n=28) or myelodysplastic syndromes (MDS; n=2) within a prospective single-arm multicenter phase-II trial. Treatment schedule contained up to eight cycles azacitidine (100 mg/m(2)/day, days 1-5, every 28 days) followed by DLI (from 1-5 × 10(6) to 1-5 × 10(8) CD3(+)cells/kg) after every second azacitidine cycle. A median of three courses azacitidine (range 1-8) were administered, and 22 patients (73%) received DLI. Overall response rate was 30%, including seven complete remissions (CRs, 23%) and two partial remissions (7%). Five patients remain in CR for a median of 777 days (range 461-888). Patients with MDS or AML with myelodysplasia-related changes were more likely to respond (P=0.011), and a lower blast count (P=0.039) as well as high-risk cytogenetics (P=0.035) correlated with the likelihood to achieve CR. Incidence of acute and chronic graft-versus-host disease was 37% and 17%, respectively. Neutropenia and thrombocytopenia grade III/IV occurred during 65% and 63% of treatment cycles, while infections were the most common grade III/IV non-hematological toxicity. Azacitidine and DLI as salvage therapy is safe, induces long-term remissions and may become an alternative for patients with AML or MDS relapsing after allo-HSCT.

Sustained disease-free survival achieved with withdrawal of immunosuppression after rapid relapse of myelodysplastic syndrome following myeloablative allogeneic hematopoietic transplantation: a case report

INTRODUCTION

Relapse after allogeneic hematopoietic stem cell transplantation in patients with myelodysplasia is a challenging problem with limited treatment options. Attempts to induce a graft-versus-leukemia effect have been used with limited success. In patients with myelodysplasia, sustained complete remissions have generally been limited to patients with long-term remission after transplant and those with low numbers of marrow blasts.

CASE PRESENTATION

We report the case of a 41-year-old Caucasian woman with relapsed myelodysplastic syndrome and a high blast percentage six months after undergoing an allogeneic transplant who achieved a sustained complete remission after withdrawal of immunosuppression alone.

CONCLUSION

This case highlights the importance of a reasonable period of observation after withdrawing immunosuppression to induce graft-versus-leukemia, and the potential effectiveness of that approach.

Extramedullary relapse of acute myeloid leukemia after allogeneic hematopoietic stem cell transplantation: an easily overlooked but significant pattern of relapse

Acute myeloid leukemia may manifest as myeloid sarcoma in a variety of extramedullary (EM) tissues at diagnosis or at relapse. Although EM relapse after allogeneic hematopoietic stem cell transplantation (alloSCT) has been considered to be rare, recent studies have suggested that it occurs in 5% to 12% of patients who receive alloSCT, accounting for 7% to 46% of total relapses. The incidence of EM relapse after immunomodulation (eg, donor lymphocyte infusion) or a second SCT is even higher. Moreover, patients with EM relapse are more likely to have had preceding acute graft-versus-host disease or chronic graft-versus-host disease relative to those with bone marrow relapse. Collectively, these observations suggest that the preferential occurrence of the graft-versus-leukemia effect underlies the pathogenesis of EM relapse. Establishing an early diagnosis of EM relapse has been challenging because of the immense diversity in the relapse sites; however, recent studies have suggested the usefulness of (18)F-fluorodeoxyglucose positron emission tomography scans in the detection of EM relapse. As a treatment for EM relapse, a combination of local and systemic therapy should be considered, because local therapy alone often results in subsequent systemic relapse. The prognosis for patients who develop EM relapse after SCT remains poor but is slightly better than that after bone marrow relapse. In addition to an early diagnosis with new modalities, clinical studies using new agents that may offer systemic activity while preserving the graft-versus-leukemia effect are warranted as part of an effort to improve the clinical outcome.

Treatment, risk factors, and outcome of adults with relapsed AML after reduced intensity conditioning for allogeneic stem cell transplantation

Because information on management and outcome of AML relapse after allogeneic hematopoietic stem cell transplantation (HSCT) with reduced intensity conditioning (RIC) is scarce, a retrospective registry study was performed by the Acute Leukemia Working Party of EBMT. Among 2815 RIC transplants performed for AML in complete remission (CR) between 1999 and 2008, cumulative incidence of relapse was 32% ± 1%. Relapsed patients (263) were included into a detailed analysis of risk factors for overall survival (OS) and building of a prognostic score. CR was reinduced in 32%; remission duration after transplantation was the only prognostic factor for response (P = .003). Estimated 2-year OS from relapse was 14%, thereby resembling results of AML relapse after standard conditioning. Among variables available at the time of relapse, remission after HSCT > 5 months (hazard ratio [HR] = 0.50, 95% confidence interval [CI], 0.37-0.67, P < .001), bone marrow blasts less than 27% (HR = 0.53, 95% CI, 0.40-0.72, P < .001), and absence of acute GVHD after HSCT (HR = 0.67, 95% CI, 0.49-0.93, P = .017) were associated with better OS. Based on these factors, 3 prognostic groups could be discriminated, showing OS of 32% ± 7%, 19% ± 4%, and 4% ± 2% at 2 years (P < .0001). Long-term survival was achieved almost exclusively after successful induction of CR by cytoreductive therapy, followed either by donor lymphocyte infusion or second HSCT for consolidation.

Current status of allogeneic transplantation for aggressive non-Hodgkin lymphoma

PURPOSE OF REVIEW

To provide a succinct update on the role of allogeneic stem cell transplantation (allo-SCT) in the management of patients with aggressive lymphomas. To clarify the indications for allogeneic transplantation vis-à-vis autologous transplant and to discuss the rationale and potential benefits of reduced intensity conditioning (RIC), nonmyeloablative (NMA) transplant, T-cell depletion and variations in graft vs. host disease (GVHD) prophylaxis.

RECENT FINDINGS

Considerable effort has been spent in developing transplant regimens with reduced toxicity and reduced GVHD. The role of allogeneic transplantation has also been redefined in light of advances in lymphoma classification, diagnostic methods, particularly PET scan and advances in transplant technology. Haplo and umbilical cord blood SCT allow identification of a donor for nearly all patients.

SUMMARY

In diffuse large B-cell lymphoma, the outcome of allo-SCT depends on patient characteristics and chemosensitivity. It is useful after failure of auto-SCT and in partial responses to salvage therapy. Allo-SCT may be the treatment of choice for advanced T-cell and natural killer cell lymphoma and for adult T-cell leukemia-lymphoma. Prophylactic or preemptive donor lymphocyte infusion may be useful, but requires controlled studies. RIC and NMA conditioning have reduced early toxicity but are associated with increased risk for disease recurrence. Promising data have been reported from a novel conditioning regimen combining NMA with ibritumomab tiuxetan. T-cell depletion reduces chronic GVHD but has some increase in rate of recurrence. Rapamycin may be associated with reduction in risk for disease recurrence.