Late transplant-associated thrombotic microangiopathy verified in bone marrow biopsy specimens is associated with chronic GVHD and viral infections

OBJECTIVES

To describe late transplant-associated thrombotic microangiopathy (TA-TMA) as chronic endothelial complication in bone marrow (BM) after allogeneic hematopoietic stem cell transplantation (HSCT).

METHODS

BM specimens along with conventional diagnostic parameters were assessed in 14 single-institutional patients with late TA-TMA (more than 100 days after HCST), including 11 late with history of early TA-TMA, 10 with early TA-TMA (within 100 days), and 12 non TA-TMA patients. Three non-HSCT patients served as control. The time points of BM biopsy were +1086, +798, +396, and +363 days after HSCT, respectively.

RESULTS

Late TA-TMA patients showed an increase of CD34+ and von Willebrand Factor (VWF)+ microvascular endothelial cells with atypical VWF+ conglomerates forming thickened VWF+ plaque sinus in the BM compared to patients without late TA-TMA and non-HSCT. Severe chronic (p = .002), steroid-refractory GVHD (p = .007) and reactivation of HHV6 (p = .002), EBV (p = .003), and adenovirus (p = .005) were pronounced in late TA-TMA. Overall and relapse-free survival were shorter in late TA-TMA than in patients without late TA-TMA (5-year OS and RFS: 78.6% vs. 90.2%, 71.4% vs. 86.4%, respectively).

CONCLUSION

Chronic allo-immune microangiopathy in BM associated with chronic, steroid-refractory GVHD and/or viral infections are key findings of late, high-risk TA-TMA, which deserves clinical attention.

High-risk additional chromosomal abnormalities at low blast counts herald death by CML

Blast crisis is one of the remaining challenges in chronic myeloid leukemia (CML). Whether additional chromosomal abnormalities (ACAs) enable an earlier recognition of imminent blastic proliferation and a timelier change of treatment is unknown. One thousand five hundred and ten imatinib-treated patients with Philadelphia-chromosome-positive (Ph+) CML randomized in CML-study IV were analyzed for ACA/Ph+ and blast increase. By impact on survival, ACAs were grouped into high risk (+8, +Ph, i(17q), +17, +19, +21, 3q26.2, 11q23, -7/7q abnormalities; complex) and low risk (all other). The presence of high- and low-risk ACAs was linked to six cohorts with different blast levels (1%, 5%, 10%, 15%, 20%, and 30%) in a Cox model. One hundred and twenty-three patients displayed ACA/Ph+ (8.1%), 91 were high risk. At low blast levels (1-15%), high-risk ACA showed an increased hazard to die compared to no ACA (ratios: 3.65 in blood; 6.12 in marrow) in contrast to low-risk ACA. No effect was observed at blast levels of 20-30%. Sixty-three patients with high-risk ACA (69%) died (n = 37) or were alive after progression or progression-related transplantation (n = 26). High-risk ACA at low blast counts identify end-phase CML earlier than current diagnostic systems. Mortality was lower with earlier treatment. Cytogenetic monitoring is indicated when signs of progression surface or response to therapy is unsatisfactory.

Serum Chemokine-release Profiles in AML-patients Might Contribute to Predict the Clinical Course of the Disease

In cancer or hematologic disorders, chemokines act as growth- or survival factors, regulating hematopoiesis and angiogenesis, determining metastatic spread and controlling leukocyte infiltration into tumors to inhibit antitumor immune responses. The aim was to quantify the release of CXCL8, -9, -10, CCL2, -5, and IL-12 in AML/MDS-pts' serum by cytometric bead array and to correlate data with clinical subtypes and courses. Minimal differences in serum-levels subdivided into various groups (e.g. age groups, FAB-types, blast-proportions, cytogenetic-risk-groups) were seen, but higher release of CXCL8, -9, -10 and lower release of CCL2 and -5 tendentially correlated with more favorable subtypes (<50 years of age, <80% blasts in PB). Comparing different stages of the disease higher CCL5-release in persisting disease and a significantly higher CCL2-release at relapse were found compared to first diagnosis - pointing to a change of 'disease activity' on a chemokine level. Correlations with later on achieved response to immunotherapy and occurrence of GVHD were seen: Higher values of CXCL8, -9, -10 and CCL2 and lower CCL5-values correlated with achieved response to immunotherapy. Predictive cut-off-values were evaluated separating the groups in 'responders' and 'non-responders'. Higher levels of CCL2 and -5 but lower levels of CXCL8, -9, -10 correlated with occurrence of GVHD. We conclude, that in AML-pts' serum higher values of CXCL8, -9, -10 and lower values of CCL5 and in part of CCL2 correlate with more favorable subtypes and improved antitumor'-reactive function. This knowledge can contribute to develop immune-modifying strategies that promote antileukemic adaptive immune responses.

Imatinib dose reduction in major molecular response of chronic myeloid leukemia: results from the German Chronic Myeloid Leukemia-Study IV

Standard first-line therapy of chronic myeloid leukemia is treatment with imatinib. In the randomized German Chronic Myeloid Leukemia-Study IV, more potent BCR-ABL inhibition with 800 mg (‘high-dose’) imatinib accelerated achievement of a deep molecular remission. However, whether and when a de-escalation of the dose intensity under high-dose imatinib can be safely performed without increasing the risk of losing deep molecular response is unknown. To gain insights into this clinically relevant question, we analyzed the outcome of imatinib dose reductions from 800 mg to 400 mg daily in the Chronic Myeloid Leukemia-Study IV. Of the 422 patients that were randomized to the 800 mg arm, 68 reduced imatinib to 400 mg after they had achieved at least a stable major molecular response. Of these 68 patients, 61 (90%) maintained major molecular remission on imatinib at 400 mg. Five of the seven patients who lost major molecular remission on the imatinib standard dose regained major molecular remission while still on 400 mg imatinib. Only two of 68 patients had to switch to more potent kinase inhibition to regain major molecular remission. Importantly, the lengths of the intervals between imatinib high-dose treatment before and after achieving major molecular remission were associated with the probabilities of maintaining major molecular remission with the standard dose of imatinib. Taken together, the data support the view that a deep molecular remission achieved with high-dose imatinib can be safely maintained with standard dose in most patients. Study protocol registered at clinicaltrials.gov 00055874.

Abstract A28: Donor lymphocyte infusion after allogeneic stem cell transplantation is a feasible therapy option with acceptable toxicity rates in patients with refractory Ewing’s sarcoma and rhabdomyosarcoma

Background: New therapy options are urgently needed for patients with treatment-refractory Ewing’s sarcoma (ES) or rhabdomyosarcoma (RMS). In these subgroups, the role of allogeneic stem cell transplantation (allo-SCT) to induce a graft-versus-tumor effect (GvT) remains unclear. Here, we describe our experience and the general feasibility of donor lymphocyte infusion (DLI) following allo-SCT for those patients.

Patients and Methods: We retrospectively evaluated data of eight patients with treatment-refractory ES (ES #1-4) and RMS (RMS #1-4) after DLI following allo-SCT. Data were individually evaluated for presence of graft-versus-host disease (GvHD), relapse-free survival (RFS), and overall survival (OS). Three of four ES and one of four RMS patients had received haploidentical grafts; the remaining patients received HLA-matched grafts prior to DLI. Patients received donor lymphocytes ranging from 2.5 x 104 to 1 x 108 CD3+ cells/kg body weight.

Results: ES #4 and RMS #4 developed acute GvHD after DLI. Limited chronic GvHD was observed in RMS #3. In two patients, DLI was associated with stable disease for nine (ES #2) and six months (ES #4), respectively. RMS #4 showed partial remission lasting for eight months after one dose of DLI with 1 x 106 CD3+ cells/kg combined with local hyperthermia and chemotherapy. ES #4 had residual disease before allo-SCT and was converted to CR after DLI. Altogether, seven patients died of disease and none of toxicity. RMS #2 received seven doses up to 1 x 108 CD3+ cells/kg and IL-2 including surgery and chemotherapy and remained in CR for 97 months at the date of data assessment. Median follow-up after allo-SCT was 27.5 months.

Conclusion: DLI after allo-SCT is a feasible therapy option for treatment-refractory ES and RMS patients. In this analysis, DLI-related toxicity is acceptable. These findings have to be evaluated in prospective analyses.

Citation Format: Sebastian J. Schober, Maximilian Steinhauser, Angela Wawer, Irene Teichert-von Luettichau, Christoph Salat, Rolf D. Issels, Wolfgang Schwinger, Marek Ussowicz, Petar Antunovic, Luca Castagna, Hans-Jochem Kolb, Stefan E.G. Burdach, Uwe Thiel. Donor lymphocyte infusion after allogeneic stem cell transplantation is a feasible therapy option with acceptable toxicity rates in patients with refractory Ewing’s sarcoma and rhabdomyosarcoma [abstract]. In: Proceedings of the AACR Special Conference: Pediatric Cancer Research: From Basic Science to the Clinic; 2017 Dec 3-6; Atlanta, Georgia. Philadelphia (PA): AACR; Cancer Res 2018;78(19 Suppl):Abstract nr A28.

The influence of glucocorticoid receptor single nucleotide polymorphisms on outcome after haematopoietic stem cell transplantation

Haematopoietic stem cell transplantation (HSCT) remains the only cure for most haematological malignancies, however, the mortality rate remains high. Complications after HSCT include relapse, graft versus host disease (GvHD), graft rejection and infection. Over the last few years several groups, have demonstrated that non-HLA gene polymorphisms can be predictive of outcome after HSCT. Since the glucocorticoid cortisol is pivotal in the regulation of the immune system, we decided to examine single nucleotide polymorphisms (SNPs; rs6198, rs33388 and rs33389) within the glucocorticoid receptor (GR) and correlate with HSCT outcome. The training set consisted of patients (n = 458) who underwent HSCT for acute leukaemia between 1983 and 2005. In the recipients, the absence of the ACT haplotype and absence of the T allele of rs33388 were associated with decreased OS and the absence of the ACT haplotype, the absence of the T allele of rs33388 and the presence of the ATA haplotype were associated with increased risk of relapse. In addition, the presence of the ACT haplotype in the recipient showed a trend to be associated with increased risk of chronic graft versus host disease (cGvHD). The patients in this cohort received mainly myeloablative conditioning (n = 327). The SNPs in the glucocorticoid receptor were then investigated in a validation set (n = 251) of HSCT patients transplanted for acute leukaemia from 2006. This cohort contained significantly more patients that had received reduced intensity conditioning (RIC). Some of the results could be validated in these patients. However, contrary to the training set, the absence of the haplotype ACT in the donor in this cohort was associated with increased risk of cGvHD. Differences in the conditioning were shown to influence the results. These results are the first to associate GR SNPs with HSCT outcome and demonstrate the inherent problems of replicating SNP association studies in HSCT, due to different pre-transplant regimens.

Donor lymphocyte infusions in adolescents and young adults for control of advanced pediatric sarcoma

Background

Allogeneic stem cell transplantation (allo-SCT) and donor lymphocyte infusions (DLI) may induce a graft-versus-tumor effect in pediatric sarcoma patients. Here, we describe general feasibility, toxicity and efficacy of DLI after allo-SCT.

Results

4 of 8 patients responded. ES#4 had stable disease (SD) for 9 months after DLI and RMS#4 partial response for 8 months with combined hyperthermia/chemotherapy. In ES#4, DLI led to SD for 6 months and reverted residual disease before allo-SCT into complete remission. After DLI, ES#4 and RMS#4 developed acute GvHD (°III-°IV), ES#4 also developed chronic GvHD. 5 patients including ES#4 lived longer than expected. Median survival after allo-SCT was 2.3 years, post-relapse survival (PRS) was 13 months. Off note, HLA-mismatched DLI were associated with a trend towards increased survival after allo-SCT and increased PRS compared to HLA-matched DLI (23 versus 3 months).

Materials and Methods

We studied eight adolescents and young adults (AYAs) with advanced Ewing sarcoma (ES#1-4) and rhabdomyosarcoma (RMS#1-4) who received DLI. Escalating doses ranged from 2.5 × 10⁴ to 1 × 10⁸ CD3⁺ cells/kg body weight. AYAs were evaluated for response to DLI, graft-versus-host disease (GvHD) and survival.

Conclusions

DLI after allo-SCT may control advanced pediatric sarcoma in AYAs with controllable toxicity.

Paramunity-inducing Factors (PINDs) in dendritic cell (DC) cultures lead to impaired antileukemic functionality of DC-stimulated T-cells

INTRODUCTION

Paramunity-inducing-Factors (PINDs) consist of attenuated/inactivated viruses of various poxvirus-genera, used in veterinary medicine as non-antigen-specific, non-immunising stimulators of the innate immune system against infectious and malignant diseases. Their danger-signaling-interactions were tested for their capacity to improve leukemic antigen-presentation on DC generated from AML-patients' blasts ('DC_leu') and DC-stimulation/activation of antileukemic T-cells.

METHODS

We analyzed, whether the addition of PINDs during DC cultures (15 healthy, 22 leukemic donors) and mixed lymphocyte culture (MLC, n = 15) with autologous (n = 6), allogeneic (n = 2) or T-cells after stem cell transplantation (SCT; n = 7) would alter the quality and quantity of DC, the composition of T-cell-subsets, and/or their antileukemic functionality (AF) as studied by FACS and functional Fluorolysis-cytotoxicity-assays.

RESULTS

Effects on 1. DC-cultures: PINDs in DC-cultures lead to increased proportions of mature DC and DC_leu, but reduced proportions of viable and overall, as well as TLR4- and TLR9-expressing DC. 2. MLC: PINDs increased early (CD8+) T-cell activation (CD69+), but reduced proportions of effector-T-cells after MLC 3. AF: Presence of PINDs in DC- and MLC-cultures reduced T-cells' as well as innate cells' antileukemic functionality. 4. Cytokine-release profile: Supernatants from PIND-treated DC- and MLC-cultures resembled an inhibitory microenvironment, correlating with impaired blast lysis.

CONCLUSIONS

Our data shows that addition of PINDs to DC-cultures and MLC result in a "blast-protective-capacity" leading to impaired AF, likely due to changes in the composition of T-/innate effector cells and the induction of an inhibitory microenvironment. PINDs might be promising in treating infectious diseases, but cannot be recommended for the treatment of AML-patients due to their inhibitory influence on antileukemic functionality.

Bone marrow involvement identifies a subgroup of advanced Ewing sarcoma patients with fatal outcome irrespective of therapy in contrast to curable patients with multiple bone metastases but unaffected marrow

Purpose

Advanced Ewing sarcomas have poor prognosis. They are defined by early relapse (<24 months after diagnosis) and/or by metastasis to multiple bones or bone marrow (BM). We analyzed risk factors, toxicity and survival in advanced Ewing sarcoma patients treated with the MetaEICESS vs. EICESS92 protocols.

Design

Of 44 patients, 18 patients were enrolled into two subsequent MetaEICESS protocols between 1992 and 2014, and compared to outcomes of 26 advanced Ewing sarcoma patients treated with EICESS 1992 between 1992 and 1996. MetaEICESS 1992 consisted of induction chemotherapy, whole body imaging directed radiotherapy to the primary tumor and metastases, tandem high-dose chemotherapy and autologous rescue. In MetaEICESS 2007 this treatment was complemented by allogeneic stem cell transplantation. EICESS 1992 comprised induction chemotherapy, local therapy to the primary tumor only followed by consolidation chemotherapy.

Results

In MetaEICESS 8/18 patients survived in complete remission vs. 2/26 in EICESS 1992 (p<0.05). Survival did not differ between MetaEICESS 2007 and MetaEICESS 1992. Three MetaEICESS patients died of complications, all in MetaEICESS 1992. After exclusion of patients succumbing to treatment related complications (n=3), 7/10 patients survived without BM involvement, in contrast to 0/5 patients with BM involvement. This was confirmed in a multivariate analysis. There was no correlation between BM involvement and the number of metastases at diagnosis.

Conclusion

The MetaEICESS protocols yield long-term disease-free survival in patients with advanced Ewing sarcoma. Allogeneic stem cell transplantation was not associated with increased death of complications. Bone marrow involvement is a risk factor distinct from multiple bone metastases.

Assessment of imatinib as first-line treatment of chronic myeloid leukemia: 10-year survival results of the randomized CML study IV and impact of non-CML determinants

Chronic myeloid leukemia (CML)-study IV was designed to explore whether treatment with imatinib (IM) at 400 mg/day (n=400) could be optimized by doubling the dose (n=420), adding interferon (IFN) (n=430) or cytarabine (n=158) or using IM after IFN-failure (n=128). From July 2002 to March 2012, 1551 newly diagnosed patients in chronic phase were randomized into a 5-arm study. The study was powered to detect a survival difference of 5% at 5 years. After a median observation time of 9.5 years, 10-year overall survival was 82%, 10-year progression-free survival was 80% and 10-year relative survival was 92%. Survival between IM400 mg and any experimental arm was not different. In a multivariate analysis, risk group, major-route chromosomal aberrations, comorbidities, smoking and treatment center (academic vs other) influenced survival significantly, but not any form of treatment optimization. Patients reaching the molecular response milestones at 3, 6 and 12 months had a significant survival advantage. For responders, monotherapy with IM400 mg provides a close to normal life expectancy independent of the time to response. Survival is more determined by patients' and disease factors than by initial treatment selection. Although improvements are also needed for refractory disease, more life-time can currently be gained by carefully addressing non-CML determinants of survival.

Comparison of matched sibling donors versus unrelated donors in allogeneic stem cell transplantation for primary refractory acute myeloid leukemia: a study on behalf of the Acute Leukemia Working Party of the EBMT

BACKGROUND

Primary refractory acute myeloid leukemia (PRF-AML) is associated with a dismal prognosis. Allogeneic stem cell transplantation (HSCT) in active disease is an alternative therapeutic strategy. The increased availability of unrelated donors together with the significant reduction in transplant-related mortality in recent years have opened the possibility for transplantation to a larger number of patients with PRF-AML. Moreover, transplant from unrelated donors may be associated with stronger graft-mediated anti-leukemic effect in comparison to transplantations from HLA-matched sibling donor, which may be of importance in the setting of PRF-AML.

METHODS

The current study aimed to address the issue of HSCT for PRF-AML and to compare the outcomes of HSCT from matched sibling donors (n = 660) versus unrelated donors (n = 381), for patients with PRF-AML between 2000 and 2013. The Kaplan-Meier estimator, the cumulative incidence function, and Cox proportional hazards regression models were used where appropriate.

RESULTS

HSCT provide patients with PRF-AML a 2-year leukemia-free survival and overall survival of about 25 and 30%, respectively. In multivariate analysis, two predictive factors, cytogenetics and time from diagnosis to transplant, were associated with lower leukemia-free survival, whereas Karnofsky performance status at transplant ≥90% was associated with better leukemia-free survival (LFS). Concerning relapse incidence, cytogenetics and time from diagnosis to transplant were associated with increased relapse. Reduced intensity conditioning regimen was the only factor associated with lower non-relapse mortality.

CONCLUSIONS

HSCT was able to rescue about one quarter of the patients with PRF-AML. The donor type did not have any impact on PRF patients' outcomes. In contrast, time to transplant was a major prognostic factor for LFS. For patients with PRF-AML who do not have a matched sibling donor, HSCT from an unrelated donor is a suitable option, and therefore, initiation of an early search for allocating a suitable donor is indicated.

Ten-year survival after randomized comparison of imatinib (IM) 400 mg vs. IM 800 mg vs. IM + IFN vs. IM + Ara C vs. IM after IFN in chronic myeloid leukemia (CML)

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Background: It is unclear whether IM 400 mg is the optimum choice for the successful treatment of CML. Treatment optimization was therefore attempted. Methods: From July 2002 to March 2012, 1551 newly diagnosed patients in chronic phase (CP) were randomized into a 5-arm study to analyze 2 IM doses and 3 combinations. 1536 patients were evaluable, 400 for IM 400 mg, 420 for IM 800 mg, 430 for IM + Interferon (IFN), 158 for IM + Ara C and 128 for IM after IFN. Recruitment to the latter two arms was stopped after a pilot phase. Results: 10-year overall survival (OS) of all patients was 82%, 10-year progression free survival (PFS) 80%. 10-year OS was 80% with IM 400 mg, 79% with IM 800 mg, 84% with IM + IFN, 84% with IM + Ara C and 79% with IM after IFN. The differences were not significant. 10-year PFS was 80% with IM 400mg, 77% with IM 800mg, 83% with IM + IFN, 82% with IM + Ara C and 75% with IM after IFN. The differences were not significant either. Survival with any treatment was not significantly different from IM 400mg at any risk level by any risk score (Euro Sokal, EUTOS, ELTS). 87 patients progressed to blast crisis (BC). The 10-year cumulative incidence of BC was 5.8% (95% CI: 4.7%; 7.1%) equally distributed across treatment arms. Most BC occurred in the first 2 years. Median survival after BC was 7.9 months across treatment arms. 275 patients have died, 23 after stem cell transplantation in first CP. Two thirds of deaths were unrelated to CML. Incidence of death due to CML by competing risk analysis with death unrelated to CML as competing risk was not different between the 5-treatment arms. 10-year relative survival probability was 92% when compared to matched general population data. Patients reaching the cytogenetic or molecular response landmarks according to European LeukemiaNet criteria ( < 10% BCR-ABL IS at 3 months, < 1% BCR-ABL IS or complete cytogenetic remission at 6 months, < 0.1% BCR-ABL IS (MMR) at 12 months) had a significantly better survival than those not reaching the landmarks regardless of therapy. Conclusions: In conclusion, outcome of CML is currently more determined by prognostic markers than by choice of therapy. IM400 mg remains an excellent choice for initial therapy of CP-CML. Clinical trial information: NCT00055874.

Abstract 2462: MondoA mediates in vivo aggressiveness of common ALL and may serve as a T-cell immunotherapy target

Oncogene addiction provides ideal targets for immunotherapy. We previously described MondoA (also known as MLXIP, MAX like protein X interacting protein) as a metabolic stress sensor, required for leukemogenesis. Here we report on the expression of MondoA in common acute lymphoblastic leukemia (cALL) compared to other malignancies, its role in malignancy of cALL in vivo, downstream pathways and correlation with relapse risk. Given the non-accessibility of transcription factors by drugs or chimeric antigen receptor transgenic T cells (CARs), we tested the targetability of MondoA by allo-restricted, peptide specific T cells.

Our human/murine xenotransplantation model with immunodeficient RAG2-/-gc-/- mice was used (Richter et al. 2009). NALM6 and 697 cALL lines were lentivirally transduced with MondoA short hairpin RNA (shRNA). Upon successful MondoA knock down (KD), KD and control lines were injected into the mice; CD10+ blasts in blood, spleen and marrow were assessed. MondoA specific T cells were generated by priming of donor HLAA0201 negative (A2-) T-cells with A2+ dendritic cells bearing MondoA peptides, multimer-based sorting and subcloning of A2-CD8+ T-cells. For priming of T cells, five MondoA peptides were chosen by SYMPEITHI, BIMAS and NetCTL1.2. analyses. Peptide 428 stabilized best A2 expression on TAP-deficient T2 cells. Specificity and functionality of T cell clones were tested by ELISpot interferon gamma (IFg) and granzyme B assays with six MondoA+ leukemia lines (A2+, A2-). Off target effects of MondoA specific T-cell clones were assessed by IFg reactivity against the MondoA expressing A2+ NALM6 cell line vs. A2+ and A2- EBV immortalized lymphoblastoid cell lines from six donors. Peptide homology was assessed with BLAST algorithms in SWISSPROT.

We found MondoA to be most strongly expressed in pediatric cALL and AML. Moreover MondoA expression was high in gastrointestinal stromal tumors and alveolar rabdomyosarcoma. MondoA KD in cALL cell lines and their subsequent analysis in xenograft mice resulted in a reduced number of leukemic blasts in blood, marrow and spleen. Spleen size and weight normalized in treated mice after MondoA KD. Further microarray analysis revealed an induction of aerobic glycolysis switch genes and hypoxia-response by MondoA. Consequently, HIF1A stabilization required MondoA expression and tied to these results, MondoA overexpression correlated with relapse risk; its expression was 63% higher in the very high-risk group as compared to the non-high-risk group of cALL. Therapeutically, MondoA-derived peptide antigens and A2+ cALL lines were successfully recognized and killed by specific, allo-restricted CD8+ T cells.

In conclusion, our findings demonstrate that MondoA maintains leukemic burden and aggressiveness of cALL in vivo possibly by modulating metabolic and hypoxia stress response. Moreover, we identified MondoA as a promising target for immunotherapy of cALL.

Citation Format: Alexandra Sipol, Thomas G. P. Grunewald, Juliane Schmaeh, David Schirmer, Monique L. den Boer, Rebeca Alba Rubío, Michaela Baldauf, Caroline Wernicke, Hans-Jochem Kolb, Martin Horstmann, Gunnar Cario, Guünther Richter, Stefan Burdach. MondoA mediates in vivo aggressiveness of common ALL and may serve as a T-cell immunotherapy target. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2462.

Deep Molecular Response Is Reached by the Majority of Patients Treated With Imatinib, Predicts Survival, and Is Achieved More Quickly by Optimized High-Dose Imatinib: Results From the Randomized CML-Study IV

Purpose

Deep molecular response (MR4.5) defines a subgroup of patients with chronic myeloid leukemia (CML) who may stay in unmaintained remission after treatment discontinuation. It is unclear how many patients achieve MR4.5 under different treatment modalities and whether MR4.5 predicts survival.

Patients and Methods

Patients from the randomized CML-Study IV were analyzed for confirmed MR4.5 which was defined as ≥ 4.5 log reduction of BCR-ABL on the international scale (IS) and determined by reverse transcriptase polymerase chain reaction in two consecutive analyses. Landmark analyses were performed to assess the impact of MR4.5 on survival.

Results

Of 1,551 randomly assigned patients, 1,524 were assessable. After a median observation time of 67.5 months, 5-year overall survival (OS) was 90%, 5-year progression-free-survival was 87.5%, and 8-year OS was 86%. The cumulative incidence of MR4.5 after 9 years was 70% (median, 4.9 years); confirmed MR4.5 was 54%. MR4.5 was reached more quickly with optimized high-dose imatinib than with imatinib 400 mg/day (P = .016). Independent of treatment approach, confirmed MR4.5 at 4 years predicted significantly higher survival probabilities than 0.1% to 1% IS, which corresponds to complete cytogenetic remission (8-year OS, 92% v 83%; P = .047). High-dose imatinib and early major molecular remission predicted MR4.5. No patient with confirmed MR4.5 has experienced progression.

Conclusion

MR4.5 is a new molecular predictor of long-term outcome, is reached by a majority of patients treated with imatinib, and is achieved more quickly with optimized high-dose imatinib, which may provide an improved therapeutic basis for treatment discontinuation in CML.

CD4(+)and CD8(+)T-cell reactions against leukemia-associated- or minor-histocompatibility-antigens in AML-patients after allogeneic SCT

T-cells play an important role in the remission-maintenance in AML-patients (pts) after SCT, however the role of LAA- (WT1, PR1, PRAME) or minor-histocompatibility (mHag, HA1) antigen-specific CD4(+) and CD8(+)T-cells is not defined. A LAA/HA1-peptide/protein stimulation, cloning and monitoring strategy for specific CD8(+)/CD4(+)T-cells in AML-pts after SCT is given. Our results show that (1) LAA-peptide-specific CD8+T-cells are detectable in every AML-pt after SCT. CD8(+)T-cells, recognizing two different antigens detectable in 5 of 7 cases correlate with long-lasting remissions. Clonal TCR-Vβ-restriction exemplarily proven by spectratyping in PRAME-specific CD8(+)T-cells; high PRAME-peptide-reactivity was CD4(+)-associated, as shown by IFN-γ-release. (2) Two types of antigen-presenting cells (APCs) were tested for presentation of LAA/HA1-proteins to CD4(+)T-cells: miniEBV-transduced lymphoblastoid cells (B-cell-source) and CD4-depleted MNC (source for B-cell/monocyte/DC). We provide a refined cloning-system for proliferating, CD40L(+)CD4(+)T-cells after LAA/HA1-stimulation. CD4(+)T-cells produced cytokines (GM-CSF, IFN-γ) upon exposure to LAA/HA1-stimulation until after at least 7 restimulations and demonstrated cytotoxic activity against naive blasts, but not fibroblasts. Antileukemic activity of unstimulated, stimulated or cloned CD4(+)T-cells correlated with defined T-cell-subtypes and the clinical course of the disease. In conclusion we provide immunological tools to enrich and monitor LAA/HA1-CD4(+)- and CD8(+)T-cells in AML-pts after SCT and generate data with relevant prognostic value. We were able to demonstrate the presence of LAA-peptide-specific CD8(+)T-cell clones in AML-pts after SCT. In addition, we were also able to enrich specific antileukemic reactive CD4(+)T-cells without GvH-reactivity upon repeated LAA/HA1-protein stimulation and limiting dilution cloning.

Younger patients with chronic myeloid leukemia do well in spite of poor prognostic indicators: results from the randomized CML study IV

Since the advent of tyrosine kinase inhibitors, the impact of age on outcome of chronic myeloid leukemia (CML) patients has changed. We therefore analyzed patients from the randomized CML study IV to investigate disease manifestations and outcome in different age groups. One thousand five hundred twenty-four patients with BCR-ABL-positive chronic phase CML were divided into four age groups: (1) 16–29 years, n = 120; (2) 30–44 years, n = 383; (3) 45–59 years, n = 495; and (4) ≥60 years, n = 526. Group 1 (adolescents and young adults (AYAs)) presented with more aggressive disease features (larger spleen size, more frequent symptoms of organomegaly, higher white blood count, higher percentage of peripheral blasts and lower hemoglobin levels) than the other age groups. In addition, a higher rate of patients with BCR-ABL transcript levels >10 % on the international scale (IS) at 3 months was observed. After a median observation time of 67.5 months, no inferior survival and no differences in cytogenetic and molecular remissions or progression rates were observed. We conclude that AYAs show more aggressive features and poor prognostic indicators possibly indicating differences in disease biology. This, however, does not affect outcome.