A Real-Time Energy Monitoring System for an MRI Hybrid Ablation System.

The MRI hybrid ablation system is an approach to use the MR (magnetic resonance) scanner's radiofrequency amplifier itself as power source for ablation. Hereby, an electrode is connected to the MR internal radiofrequency amplifier. An average RF power is provided through a train of short RF pulses, which is sufficient to thermally destroy tissue. However, ablation with too high power values can cause tissue carbonizations, thus impeding the ablation procedure. Therefore, monitoring of the energy and the power absorbed inside the tissue is necessary. For this purpose, a measurement system was designed to measure the energy applied to the tissue when using the concept of an MRI hybrid ablation system. The system consists of a dual-directional coupler, RF-to-RMS sensors, and a microcontroller. The gradient calculation of the measured energy curve provides information about the absorbed RF power in the tissue. Validation measurements of the system were performed and compared with measurements from the MR-internal power measurement system. The energy monitoring system was also tested in an ablation experiment with ex-vivo animal tissue using the MRI hybrid ablation system. The measurements showed that the applied RF power can be monitored in real-time. It has been shown that the mean RF power absorbed in the patient decreased during an ablation procedure due to an occurring impedance mismatch and tissue changes. In further work, the influence of the monitoring system on the quality of the MR images should be investigated. Clinical relevance- This paper demonstrates an energy monitoring system for an RF ablation system, which can be used inside an MR environment.

Comparable outcome after haploidentical and HLA-matched allogeneic stem cell transplantation for high-risk acute myeloid leukemia following sequential conditioning-a matched pair analysis.

In acute myeloid leukemia (AML), primary refractory or relapsed disease, secondary AML, and leukemia with unfavorable genetics are considered high-risk AML (hrAML), with allogeneic stem cell transplantation (SCT) representing the standard treatment. Sequential conditioning has been successfully used for SCT in hrAML in HLA-matched transplants, and found its way into HLA-haploidentical SCT (haplo-SCT) later on. Hence, sequential conditioning had become standard for all patients with hrAML in our two centers, regardless of donor type. Thereby, HLA-matched family or unrelated transplants were first/second choice, post-transplant cyclophosphamide (PTCY)-based haplo-SCT was chosen in patients missing matched donors or requiring urgent transplantation. To compare the outcome after HLA-matched and haplo-SCT for hrAML following sequential conditioning, we performed a retrospective, matched-pair comparison, using disease stage, genetic subgroups and age as matching criteria. Thirty-four well-matched pairs were identified. At SCT, patients (median age 54 years) were untreated (9%), had remission (13%), or active disease (78%). Three-year overall and leukemia-free survival (OS/LFS) of the entire cohort was 56 ± 7%/49 ± 7%, without significant differences between donor types (OS after HLA-matched/haplo-SCT 62 ± 10%/52 ± 9% (p = 0.21), LFS 53 ± 10%/46 ± 9% (p = 0.26)). Similarly, the cumulative incidence of relapse, non-relapse-mortality and chronic GvHD, as well as GvHD-free, relapse-free survival (GRFS), and chronic GvHD-free, relapse-free survival (cGRFS), were comparable. However, a higher incidence of acute GvHD ≥ II° was observed after HLA-matched SCT (15 ± 1% versus 50 ± 2%, p = 0.001). In conclusion, sequential conditioning SCT achieved remarkable results in hrAML, independently from donor type. PTCY-based haplo-SCT produced results that were comparable to HLA-matched SCT and can be used as an alternative option.

Sequential HLA-haploidentical transplantation utilizing post-transplantation cyclophosphamide for GvHD prophylaxis in high-risk and relapsed/refractory AML/MDS.

This study evaluates the role of sequential therapy in HLA-haploidentical transplantation (haplo-HSCT) of high-risk, relapsed/refractory AML/MDS. We analyzed the course of 33 adults with active disease at time of transplantation (AML n = 30; MDS n = 3; median age 58 years, range: 32-71). Sequential therapy consisted of cytoreductive chemotherapy (FLAMSA n = 21; clofarabine n = 12) applied shortly prior to reduced intensity conditioning for T-cell-replete haplo-HSCT using post-transplantation cyclophosphamide as GvHD prophylaxis. No graft rejection was observed. Complete remission at day +30 was achieved in 97% of patients. CI of acute GvHD grade II-IV and chronic GvHD was 24% (no grade IV) and 23%, respectively. NRM at 1 and 3 years was 15%, each. Severe regimen-related toxicities (grade III-IV) were observed in 58%, predominantly involving the gastrointestinal tract (diarrhea 48%, mucositis 15%, transient elevation of transaminases 18%). Probability of relapse at 1 and 3 years was 28% and 35%. At a median follow-up of 36 months, the estimated 1- and 3-year overall survival was 56% and 48%. Disease-free survival was 49% and 40%, respectively. At 3 years, GvHD and relapse-free survival (GRFS) was 24% while chronic GvHD and relapse-free survival (CRFS) was 29%. Thus, our results indicate that sequential haplo-HSCT is an effective salvage treatment providing high anti-leukemic activity, favorable tolerance, and acceptable toxicity in patients suffering from advanced AML/MDS.

Clonal heterogeneity of FLT3-ITD detected by high-throughput amplicon sequencing correlates with adverse prognosis in acute myeloid leukemia.

In acute myeloid leukemia (AML), internal tandem duplications (ITDs) of FLT3 are frequent mutations associated with unfavorable prognosis. At diagnosis, the FLT3-ITD status is routinely assessed by fragment analysis, providing information about the length but not the position and sequence of the ITD. To overcome this limitation, we performed cDNA-based high-throughput amplicon sequencing (HTAS) in 250 FLT3-ITD positive AML patients, treated on German AML Cooperative Group (AMLCG) trials. FLT3-ITD status determined by routine diagnostics was confirmed by HTAS in 242 out of 250 patients (97%). The total number of ITDs detected by HTAS was higher than in routine diagnostics (n = 312 vs. n = 274). In particular, HTAS detected a higher number of ITDs per patient compared to fragment analysis, indicating higher sensitivity for subclonal ITDs. Patients with more than one ITD according to HTAS had a significantly shorter overall and relapse free survival. There was a close correlation between FLT3-ITD mRNA levels in fragment analysis and variant allele frequency in HTAS. However, the abundance of long ITDs (≥75nt) was underestimated by HTAS, as the size of the ITD affected the mappability of the corresponding sequence reads. In summary, this study demonstrates that HTAS is a feasible approach for FLT3-ITD detection in AML patients, delivering length, position, sequence and mutational burden of this alteration in a single assay with high sensitivity. Our findings provide insights into the clonal architecture of FLT3-ITD positive AML and have clinical implications.

Persistence of pre-leukemic clones during first remission and risk of relapse in acute myeloid leukemia.

Some patients with acute myeloid leukemia (AML) who are in complete remission after induction chemotherapy harbor persisting pre-leukemic clones, carrying a subset of leukemia-associated somatic mutations. There is conflicting evidence on the prognostic relevance of these clones for AML relapse. Here, we characterized paired pre-treatment and remission samples from 126 AML patients for mutations in 68 leukemia-associated genes. Fifty patients (40%) retained ≥1 mutation during remission at a VAF of ≥2%. Mutation persistence was most frequent in DNMT3A (65% of patients with mutations at diagnosis), SRSF2 (64%), TET2 (55%), and ASXL1 (46%), and significantly associated with older age (p < 0.0001) and, in multivariate analyses adjusting for age, genetic risk, and allogeneic transplantation, with inferior relapse-free survival (hazard ratio (HR), 2.34; p = 0.0039) and overall survival (HR, 2.14; p = 0.036). Patients with persisting mutations had a higher cumulative incidence of relapse before, but not after allogeneic stem cell transplantation. Our work underlines the relevance of mutation persistence during first remission as a novel risk factor in AML. Persistence of pre-leukemic clones may contribute to the inferior outcome of elderly AML patients. Allogeneic transplantation abrogated the increased relapse risk associated with persisting pre-leukemic clones, suggesting that mutation persistence may guide post-remission treatment.

Occurrence, risk factors and outcome of adenovirus infection in adult recipients of allogeneic hematopoietic stem cell transplantation.

BACKGROUND: Adenovirus (ADV) infections can have a high mortality in immunocompromised patients and are difficult to treat. OBJECTIVES AND STUDY DESIGN: We retrospectively analyzed occurrence and risk factors of ADV infection in 399 adults with hematological disorders undergoing hematopoietic stem cell transplantation (allo-HSCT), focusing on alternative donor transplantation (ADT) and disseminated disease. RESULTS: ADV infection occurred in 42 patients (10.5%). Disease was localized in 18 and disseminated in 6 patients. ADV infection was observed in 15% after ADT, performed in 29% of all recipients, and was less frequent (6%) in T-cell-replete (TCR) haploidentical transplantation using post-transplantation cyclophosphamide (PTCY) than in other ADT protocols. Lower age, the use of alternative donor grafts and acute graft-versus-host disease (GvHD)≥grade II were risk factors for ADV infection. After failure of standard antiviral treatment, three patients with disseminated ADV disease received one dose of ADV-specific T cells, resulting in virological response in 2/3 patients, clearance of ADV viremia in 2/2 patients, and survival of 1/3 patients; both patients with pneumonia died. CONCLUSIONS: ADV infection was of moderate occurrence in our adult recipients of allo-HSCT despite a high proportion of potential high-risk patients receiving ADT. TCR strategies using PTCY might limit ADV complications in haploidentical transplantation. Despite feasible adoptive therapy strategies, outcome of disseminated disease remains dismal.

[Hemolytic anemias and vitamin B12 deficieny]. / Hämolytische Anämien und Vitamin-B12-Mangel.

Hemolytic anemias consist of corpuscular, immun-hemolytic and toxic hemolytic anemias. Within the group of corpuscular hemolytic anemias, except for the paroxysmal nocturnal hemoglobinuria (PNH), all symptoms are caused by underlying heredetiary disorders within the red blood cell membran (hereditary spherocytosis), deficiencies of red cell enzymes (G6PDH- and pyrovatkinase deficiency) or disorders in the hemoglobin molecule (thalassaemia and sickle cell disease). Immune-hemolytic anemias are acquired hemolytic anemias and hemolysis is caused by auto- or allo-antibodies which are directed against red blood cell antigens. They are classified as warm, cold, mixed type or drug-induced hemolytic anemia. Therapy consists of glucocorticoids and other immunsuppressive drugs. Pernicious anemia is the most important vitamin B12 deficiency disorder. Diagnosis relies on cobalamin deficiency and antibodies to intrinsic factor. The management should focus on a possibly life-long replacement treatment with cobalamin.

Virus infection in HLA-haploidentical hematopoietic stem cell transplantation: incidence in the context of immune recovery in two different transplantation settings.

We retrospectively compared the incidence of virus infections and outcome in the context of immune reconstitution in two different HLA-haploidentical transplantation (haplo-HSCT) settings. The first was a combined T-cell-replete and T-cell-deplete approach using antithymocyte globulin (ATG) prior to transplantation in patients with hematological diseases (cTCR/TCD group, 28 patients; median age 31 years). The second was a T-cell-replete (TCR) approach using high-dose posttransplantation cyclophosphamide (TCR/PTCY group, 27 patients; median age 43 years). The incidence of herpesvirus infection was markedly lower in the TCR/PTCY (22 %) than in the cTCR/TCD group (93 %). Recovery of CD4+ T cells on day +100 was faster in the TCR/PTCY group. CMV reactivation was 30 % in the TCR/PTCY compared to 57 % in the cTCR/TCD group, and control with antiviral treatment was superior after TCR/PTCY transplantation (100 vs 50 % cTCR/TCD). Twenty-five percent of the patients in the cTCR/TCD group but no patient in the TCR/PTCY group developed PTLD. While 1-year OS was not different (TCR/PTCY 59 % vs cTCR/TCD 39 %; p = 0.28), virus infection-related mortality (VIRM) was significantly lower after TCR/PTCY transplantation (1-year VIRM, 0 % TCR/PTCY vs 29 % cTCR/TCD; p = 0.009). On day +100, predictors of better OS were lymphocytes >300/µl, CD3+ T cells >200/µl, and CD4+ T cells >150/µl, whereas the application of steroids >1 mg/kg was correlated with worse outcome. Our results suggest that by presumably preserving antiviral immunity and allowing fast immune recovery of CD4+ T cells, the TCR approach using posttransplantation cyclophosphamide is well suited to handle the important issue of herpesvirus infection after haplo-HSCT.

Isolated trisomy 13 defines a homogeneous AML subgroup with high frequency of mutations in spliceosome genes and poor prognosis.

In acute myeloid leukemia (AML), isolated trisomy 13 (AML+13) is a rare chromosomal abnormality whose prognostic relevance is poorly characterized. We analyzed the clinical course of 34 AML+13 patients enrolled in the German AMLCG-1999 and SAL trials and performed exome sequencing, targeted candidate gene sequencing and gene expression profiling. Relapse-free (RFS) and overall survival (OS) of AML+13 patients were inferior compared to other ELN Intermediate-II patients (n=855) (median RFS, 7.8 vs 14.1 months, P = .006; median OS 9.3 vs. 14.8 months, P = .004). Besides the known high frequency of RUNX1 mutations (75%), we identified mutations in spliceosome components in 88%, including SRSF2 codon 95 mutations in 81%. Recurring mutations were detected in ASXL1 (44%) and BCOR (25%). Two patients carried mutations in CEBPZ, suggesting that CEBPZ is a novel recurrently mutated gene in AML. Gene expression analysis revealed a homogeneous expression profile including upregulation of FOXO1 and FLT3 and downregulation of SPRY2. This is the most comprehensive clinical and biological characterization of AML+13 to date, and reveals a striking clustering of lesions in a few genes, defining AML+13 as a genetically homogeneous subgroup with alterations in a few critical cellular pathways. Clinicaltrials.gov identifiers: AMLCG-1999: NCT00266136; AML96: NCT00180115; AML2003: NCT00180102; and AML60+: NCT00893373.

Molecular response assessment by quantitative real-time polymerase chain reaction after induction therapy in NPM1-mutated patients identifies those at high risk of relapse.

Monitoring minimal residual disease is an important way to identify patients with acute myeloid leukemia at high risk of relapse. In this study we investigated the prognostic potential of minimal residual disease monitoring by quantitative real-time polymerase chain reaction analysis of NPM1 mutations in patients treated in the AMLCG 1999, 2004 and 2008 trials. Minimal residual disease was monitored - in aplasia, after induction therapy, after consolidation therapy, and during follow-up - in 588 samples from 158 patients positive for NPM1 mutations A, B and D (with a sensitivity of 10(-6)). One hundred and twenty-seven patients (80.4%) achieved complete remission after induction therapy and, of these, 56 patients (44.1%) relapsed. At each checkpoint, minimal residual disease cut-offs were calculated. After induction therapy a cut-off NPM1 mutation ratio of 0.01 was associated with a high hazard ratio of 4.26 and the highest sensitivity of 76% for the prediction of relapse. This was reflected in a cumulative incidence of relapse after 2 years of 77.8% for patients with ratios above the cut-off versus 26.4% for those with ratios below the cut-off. In the favorable subgroup according to European LeukemiaNet, the cut-off after induction therapy also separated the cohort into two prognostic groups with a cumulative incidence of relapse of 76% versus 6% after 2 years. Our data demonstrate that in addition to pre-therapeutic factors, the course of minimal residual disease in an individual is an important prognostic factor and could be included in clinical trials for the guidance of post-remission therapy. The trials from which data were obtained were registered at www.clinicaltrials.gov (#NCT01382147, #NCT00266136) and at the European Leukemia Trial Registry (#LN_AMLINT2004_230).

Feasibility of clofarabine cytoreduction followed by haploidentical hematopoietic stem cell transplantation in patients with relapsed or refractory advanced acute leukemia.

Clofarabine is a novel purine nucleoside analogue with immunosuppressive and anti-leukemic activity in acute lymphoblastic and myeloid leukemia (AML, ALL). This retrospective study was performed to evaluate the feasibility and anti-leukemic activity of a sequential therapy using clofarabine for cytoreduction followed by conditioning for haploidentical hematopoietic stem cell transplantation (HSCT) in patients with non-remission acute leukemia. Patients received clofarabine (5 × 30 mg/m² IV) followed by a T cell replete haploidentical transplantation for AML (n = 15) or ALL (n = 3). Conditioning consisted of fludarabine, cyclophosphamide plus either melphalan, total body irradiation or treosulfan/etoposide. High-dose cyclophosphamide was administered for post-grafting immunosuppression. Neutrophil engraftment was achieved in 83 % and complete remission in 78% at day +30. The rate of acute graft versus host disease (GvHD) grade II-IV was 22%, while chronic GvHD occured in five patients (28%). Non-relapse mortality (NRM) after 1 year was 23%. At a median follow-up of 19 months, estimated overall survival and relapse-free survival at 1 year from haploidentical HSCT were 56 and 39%, respectively. Non-hematological regimen-related grade III-IV toxicity was observed in ten patients (56%) and included most commonly transient elevation of liver enzymes (44%), mucositis (40%), and skin reactions including hand-foot syndrome (17%), creatinine elevation (17%), and nausea/vomiting (17%). The concept of a sequential therapy using clofarabine for cytoreduction followed by haploidentical HSCT proved to be feasible and allows successful engraftment, while providing an acceptable toxicity profile and anti-leukemic efficacy in patients with advanced acute leukemia. NRM and rate of GvHD were comparable to results after HSCT from HLA-matched donors.