Approaches to relapse after allogeneic stem cell transplantation

Prognostic factors of second hematopoietic allogeneic stem cell transplantation among hematological malignancy patients relapsed after first hematopoietic stem cell transplantation: A single center study

Introduction

We aimed to evaluate prognostic factors of a second allogeneic stem cell transplantation (allo-HSCT2) among hematological malignancy patients who have relapsed after the first allo-HSCT(allo-HSCT1).

Methods

We retrospectively analyzed 199 hematological malignancy patients who received allo-HSCT2 as a salvage treatment post allo-HSCT1 relapse between November 2012 and October 2021.

Results

The median age at allo-HSCT2 was 23 (range: 3-60) years. The median time to relapse after HSCT1 was 9 (range: 1-72) months. Prior to allo-HSCT2, patients had the following hematopoietic cell transplantation-comorbidity indexes (HCT-CI): 127 with a score of 0, 52 with a score of 1, and 20 with a score of 2 or greater. Fifty percent of patients received chimeric antigen receptor (CAR) T-cell therapy following HSCT1 relapse. Disease status was minimal residual disease (MRD)-negative complete remission (CR) among 119 patients, MRD-positive CR among 37 patients and non-remission (NR) for 43 patients prior to allo-HSCT2. Allo-HSCT2 was performed from a new donor in 194 patients (97.4%) and 134 patients (67.3%) received a graft with a new mismatched haplotype. The median follow-up time was 24 months (range: 6-98 months), and the 2-year OS and LFS were 43.8% ± 4.0% and 42.1% ± 4.1%, respectively. The 2-year cumulative incidence of relapse (CIR) and non-relapse mortality (NRM) was 30.0%±4.8% and 38.5%±3.8%, respectively. Cox regression multivariate analysis showed that disease statusof MRD-negative CR, HCT-CI score of 0 prior to allo-HSCT2, and new mismatched haplotype donor were predictive factors of improved OS and LFS compared to patients without these characteristics. Based on these three favorable factors, we developed a predictive scoring system for patients who received allo-HSCT2. Patients with a prognostic score of 3 who had the three factors showed a superior 2-year OS of 63.3% ± 6.7% and LFS of 63.3% ± 6.7% and a lower CIR of 5.5% ± 3.1% than patients with a prognostic score of 0. Allo-HSCT2 is feasible and patients with good prognostic features prior to allo-HSCT2 -disease status of CR/MRD- and HCT-CI score of 0 as well as a second donor with a new mismatched haplotype could have the maximal benefit from the second allo-HSCT.

Conclusions

Allo-HSCT2 is feasible and patients with good prognostic features prior to allo-HSCT2 -disease status of CR/MRD- and HCT-CI score of 0 as well as a second donor with a new mismatched haplotype could have the maximal benefit from the second allo-HSCT.

Outcomes of allogenic hematopoietic cell transplantation for childhood chronic myeloid leukemia: Single-center experience

BACKGROUND/OBJECTIVES

Despite the apparent efficacy and favorable toxicity profile of TKIs, allogeneic SCT remains the only curative treatment for CML especially in younger patients, but TRM should be considered. We evaluated the clinical outcomes of pediatric CML patients who had SCT in our center.

METHODS

This retrospective study included children with CML, who received an allogeneic SCT at Children Cancer Hospital Egypt, 57357, from 2007 to 2017. All patients received myeloablative conditioning chemotherapy containing busulfan/cyclophosphamide followed by stem cell infusion from MRD.

RESULTS

From 121 patients diagnosed with CML, 43 had available MRD and subjected to HSCT while 78 patients continued TKI therapy. The median time to transplant from diagnosis was 13 months. At initial diagnosis, there were 39 patients in CP and 4 had blastic crises. Bone marrow harvest was the stem cell source in 32 patients, while 11 cases received mobilized peripheral blood stem cells with average stem cell dose of 4.45 × 10⁶ /kg. The probabilities of overall survival and event-free survival at 5 years were 97.4% and 79.8%, respectively. TRM at 100 days and TRM at 1-year post-transplant were 0%. The incidence of chronic GVHD was significantly higher in peripheral blood than bone marrow stem cell source (P = .004).

CONCLUSION

Considering the excellent survival rates and very low TRM, HSCT is still a valid option for pediatric patients with newly diagnosed CML with best using marrow stem cell source to avoid a significant risk of cGVHD and its related complications.

Wide Variability in the Time Required for Immunotoxins to Kill B Lineage Acute Lymphoblastic Leukemia Cells: Implications for Trial Design

PURPOSE

Recombinant immunotoxins (rITs) targeting CD22 are highly active in hairy cell leukemia, but less so in acute lymphoblastic leukemia (ALL). This study aims to understand the variable activity of an rIT against ALL toward improving responses in clinical application.

EXPERIMENTAL DESIGN

We determined in vitro activity of rITs by WST-8 assays and the time needed to kill ALL cell lines and patient-derived ALL blasts by flow cytometry. The findings were translated into two systemic ALL xenograft models. Differences in time needed to kill KOPN-8 cells for distinct rITs were addressed biochemically.

RESULTS

In vitro activity (IC50) of anti-CD22 rIT varied 210-fold from 0.02 to 4.6 ng/mL. Activity also varied greatly depending on the time ALL cells were exposed to immunotoxin from < 30 minutes to > 4 days. For KOPN-8, the difference in exposure time was related to intracellular rIT processing. We showed in newly developed ALL xenograft models, where immunotoxins have a short half-life, that the needed exposure time in vitro predicted the responses in vivo By replacing bolus dose with small doses at frequent intervals or with continuous infusion, responses were substantially improved. We confirmed exposure time variability on patient-derived ALL samples and showed a correlation between exposure time needed to reach maximal cytotoxicity in vitro and their clinical response.

CONCLUSIONS

The exposure time needed for rITs targeting CD22 to kill ALL cells varies widely. Our results suggest that ALL patients would have a better response rate to anti-CD22 immunotoxins if treated by continuous infusion rather than by bolus injections. Clin Cancer Res; 22(19); 4913-22. ©2016 AACR.

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.

Current status of hematopoietic stem cell transplant in chronic myeloid leukemia

Indications for hematopoietic stem cell transplant (HSCT) in chronic myeloid leukemia (CML) have changed over time. This change has largely been influenced by the advent of tyrosine kinase inhibitors, increased understanding of the mechanisms underlying disease phase progression as well as drug resistance, refinement of transplant techniques and exploitation of graft versus leukemia effect in this disease. Here, we have discussed the status of HSCT in CML in the present era with regards to the current indications, factors determining outcome and management strategies for posttransplant relapse.

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.

Second allogeneic stem cell transplantation in hematologic malignancies: a single-center experience

Patients with hematologic malignancies who relapse after their first hematopoietic stem cell transplantation tend to have poor prognoses. One option for these patients is a second allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, there are few reports of second allo-HSCT therapy in children with relapsed hematologic malignancies. Patient outcomes in 27 individuals with acute leukemia who received at least 2 allo-HSCTs at the Samsung Medical Center between May 1997 and September 2010 were analyzed retrospectively. After a median follow-up of 33 months, 11 of 27 patients (40.7%) were alive and in stable remission. The 5-year overall survival rate for all 27 patients was 32.6%. There was no statistically significant difference in the survival rates of patients differing in their sex, the stem cell source, the donor type, or the presence of acute or chronic graft-versus-host disease. Remission before the second allo-HSCT was the only prognostic factor that influenced the survival rates (44.1% vs. 11.1%, P=0.009). Of 16 cases of mortality, 9 mortality cases (56.3%) were associated with relapse and 7 cases (43.7%) were associated with treatment-related mortality. Therefore, a second allo-HSCT offers the chance of stable remission for some patients with acute hematologic malignancies who relapse after their first allo-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.

Outcomes of immunological interventions for mixed chimerism following allogeneic stem cell transplantation in children with juvenile myelomonocytic leukemia

BACKGROUND

For children with juvenile myelomonocytic leukemia (JMML) who undergo stem cell transplantation (SCT), the role of immunological interventions including withdrawal of immunosuppressive therapy (IST) and donor lymphocyte infusion (DLI) for treatment of disease recurrence remains uncertain.

PROCEDURE

We analyzed serial chimerism status following SCT and evaluated the efficacy of immunological interventions for the management of mixed chimerism (MC) in children with JMML.

RESULTS

Chimerism analysis was available in 26 SCT cases following the first and second SCT. MC was observed in 16 cases and withdrawal of IST was performed in 14 cases immediately after identification of MC. Donor lymphocyte infusion (DLI) was performed in five MC cases. Eight MC cases were observed at the time of neutrophil recovery. Following withdrawal of IST, three cases achieved complete chimerism (CC) while the proportion of autologous cells increased rapidly in the remaining five cases. Six MC cases were observed after achievement of hematological remission (HR) and responses to withdrawal of IST were observed in two cases. In the remaining four cases, despite withdrawal of IST, the proportion of autologous cells increased. Five cases received DLI but only one case responded.

CONCLUSION

Although the benefits of immunological interventions for MC after SCT in JMML were limited, some patients did achieve HR as a result of these treatment modalities without a second SCT. Close monitoring of donor chimerism and early detection of MC is helpful in guiding treatment after SCT in children with JMML.

The second therapeutic trial for children with hematological malignancies who relapsed after their first allogeneic SCT: long-term outcomes

The impact of a second all-SCT on the long-term outcomes of children who relapse after allo-SCT has been unclear. We retrospectively analyzed the long-term outcomes of different salvage treatments for such children. Sixty-six children with hematological malignancies (40 ALL, 22 AML, three MDS, and one CML) who relapsed after a first allo-SCT received either a second allo-SCT (n = 16) or CTx and/or DLI (n = 50). The median follow-up for all children was 9.1 yr. The five-yr OS after relapse was significantly better in patients who underwent a second allo-SCT (42.9%) than in patients treated with CTx and/or DLI (11.8%) (p < 0.05). However, this advantage diminished with increasing time. The eight-yr OS for these groups of patients were 21.4% and 11.8%, respectively (p = n.s.). Among the 16 patients who received a second allo-SCT, two died more than five yr after the second allo-SCT. A second allo-SCT can therefore lead to a prolonged OS in patients who relapse after allo-SCT. However, a second allo-SCT should be selected carefully. This is because the mortality rate is still high, even when there is an extensive duration of time following the second allo-SCT.

Protein Kinase C-θ (PKC-θ) in Natural Killer Cell Function and Anti-Tumor Immunity

The protein kinase C-θ (PKCθ), which is essential for T cell function and survival, is also required for efficient anti-tumor immune surveillance. Natural killer (NK) cells, which express PKCθ, play a prominent role in this process, mainly by elimination of tumor cells with reduced or absent major histocompatibility complex class-I (MHC-I) expression. This justifies the increased interest of the use of activated NK cells in anti-tumor immunotherapy in the clinic. The in vivo development of MHC-I-deficient tumors is much favored in PKCθ^−/− mice compared with wild-type mice. Recent data offer some clues on the mechanism that could explain the important role of PKCθ in NK cell-mediated anti-tumor immune surveillance: some studies show that PKCθ is implicated in signal transduction and anti-tumoral activity of NK cells elicited by interleukin (IL)-12 or IL-15, while others show that it is implicated in NK cell functional activation mediated by certain killer-activating receptors. Alternatively, the possibility that PKCθ is involved in NK cell degranulation is discussed, since recent data indicate that it is implicated in microtubule-organizing center polarization to the immune synapse in CD4⁺ T cells. The implication of PKC isoforms in degranulation has been more extensively studied in cytotoxic T lymphocyte, and these studies will be also summarized.