Jeroen J.W.M. Janssen

Drug-induced histone eviction from open chromatin contributes to the chemotherapeutic effects of doxorubicin

DNA topoisomerase II inhibitors are a major class of cancer chemotherapeutics, which are thought to eliminate cancer cells by inducing DNA double-strand breaks. Here we identify a novel activity for the anthracycline class of DNA topoisomerase II inhibitors: histone eviction from open chromosomal areas. We show that anthracyclines promote histone eviction irrespective of their ability to induce DNA double-strand breaks. The histone variant H2AX, which is a key component of the DNA damage response, is also evicted by anthracyclines, and H2AX eviction is associated with attenuated DNA repair. Histone eviction deregulates the transcriptome in cancer cells and organs such as the heart, and can drive apoptosis of topoisomerase-negative acute myeloid leukaemia blasts in patients. We define a novel mechanism of action of anthracycline anticancer drugs doxorubicin and daunorubicin on chromatin biology, with important consequences for DNA damage responses, epigenetics, transcription, side effects and cancer therapy.

Lenalidomide maintenance after nonmyeloablative allogeneic stem cell transplantation in multiple myeloma is not feasible: results of the HOVON 76 Trial.

To improve the outcome of allogeneic stem cell transplantation (allo-SCT) in multiple myeloma as part of first-line treatment, we prospectively investigated the feasibility and efficacy of lenalidomide maintenance. Patients started maintenance 1 to 6 months after nonmyeloablative allo-SCT. Lenalidomide was dosed 10 mg on days 1 to 21 of a 28-day schedule for a total of 24 cycles. Peripheral blood samples were taken to evaluate immune modulating effects. Thirty-five eligible patients were enrolled, and 30 started with lenalidomide. After 2 cycles, 14 patients (47%) had to stop treatment, mainly because of the development of acute graft versus host disease (GVHD). In total, 13 patients (43%) stopped treatment because of development of GVHD, 5 patients (17%) because of other adverse events, and 5 patients (17%) because of progression. Responses improved in 37% of patients, and the estimated 1-year progression-free survival from start of maintenance was 69% (90% confidence interval, 53%-81%). Lenalidomide increased the frequency of human leukocyte antigen-DR(+) T cells and regulatory T cells, without correlation with clinical parameters. In conclusion, lenalidomide maintenance 10 mg daily after nonmyeloablative allo-SCT with unmanipulated graft in multiple myeloma patients is not feasible, mainly because of the induction of acute GVHD. This trial was registered at www.trialregister.nl as #NTR1645.

Donor versus no-donor comparison of newly diagnosed myeloma patients included in the HOVON-50 multiple myeloma study.

To prospectively evaluate allogeneic stem cell transplantation (allo-SCT) for myeloma as part of first-line therapy, a donor versus no-donor analysis was performed of patients treated in the HOVON-50 study, a study that was originally designed to examine thalidomide combined with intensive therapy. Two hundred sixty patients having received an autologous-SCT fulfilled the criteria to be included, 138 patients without an HLA-identical sibling donor and 122 patients with a donor. After a median follow-up of 77 months, complete remission, progression-free survival (PFS), and overall survival were not significantly different between the 2 groups. PFS at 6 years was 28% for patients with a donor versus 22% for patients without a donor (P = .19) and overall survival at 6 years from high-dose melphalan was 55%, irrespective of having a donor (P = .68). Cumulative incidence of nonrelapse mortality at 6 years after autologous-SCT was 16% in the donor group versus 3% in the no-donor group (P < .001). However, PFS was significantly prolonged in the 99 patients who actually proceeded to allo-SCT compared with the 115 patients who continued maintenance or received a second high-dose melphalan, but the difference did not translate into a prolonged survival benefit. These results do not support a general application of allo-SCT in all myeloma patients as part of first-line therapy.

High INDO (indoleamine 2,3-dioxygenase) mRNA level in blasts of acute myeloid leukemic patients predicts poor clinical outcome

In this study on patients with acute myeloid leukemia, a high INDO expression in leukemic blasts was associated with a poor outcome. Indoleamine 2,3-dioxygenase degrades the amino acid tryptophan which is essential for T cells. Tryptophan depletion causes T-cell cycle arrest and solid tumors that express high levels of indoleamine 2,3-dioxygenase can create immune suppression. Recently, blasts of patients with acute myeloid leukemia were shown to express indoleamine 2,3-dioxygenase. We determined INDO (encoding gene for indoleamine 2,3-dioxygenase) mRNA expression in leukemic blasts of 286 patients with acute myeloid leukemia by gene-expression profiling. Results were validated by quantitative polymerase chain reaction analysis in blasts of an independent cohort of 71 patients. High INDO expression was correlated to significantly shortened overall and relapse-free survival. Correlation of INDO expression to relevant known prognostic factors and survival identified high INDO expression as a strong negative independent predicting variable for overall and relapse-free survival. Inhibition of indoleamine 2,3-dioxygenase expressed by myeloid leukemic blasts may result in breaking immune tolerance and offers new therapeutic options for patients with acute myeloid leukemia.

Vaccination of chronic myeloid leukemia patients with autologous in vitro cultured leukemic dendritic cells

Vaccination of chronic myeloid leukemia patients with autologous in vitro cultured leukemic dendritic cells

Economic evaluation of posaconazole vs. standard azole prophylaxis in high risk neutropenic patients in the Netherlands.

Background:  Acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) patients experience prolonged neutropenia after treatment with intensive chemotherapy, leading to a high risk of invasive fungal infections (IFI). The present study evaluates the cost effectiveness of posaconazole vs. standard azoles for the prevention of IFIs in neutropenic patients in the Netherlands.

Polymorphisms in the multidrug resistance gene MDR1 (ABCB1) predict for molecular resistance in patients with newly diagnosed chronic myeloid leukemia receiving high-dose imatinib

To the editor: Recently, Dulucq and coworkers reported that multidrug resistance gene ( MDR1 ) polymorphisms were associated with major molecular responses (MMRs) to standard-dose imatinib in chronic myeloid leukemia (CML).[1][1] Significantly more patients homozygous for allele 1236T achieved a

Imatinib discontinuation in chronic phase myeloid leukaemia patients in sustained complete molecular response: A randomised trial of the Dutch-Belgian Cooperative Trial for Haemato-Oncology (HOVON)

BACKGROUND Tyrosine kinase inhibitors treatment in responding chronic myeloid leukaemia (CML) patients is generally continued indefinitely. In this randomised phase II trial, we investigated whether CML patients in molecular response(4.5) (MR(4.5), quantitative reverse-transcription polymerase chain reaction (RQ-PCR)) after previous combination therapy with imatinib and cytarabine may discontinue imatinib treatment safely. PATIENTS AND METHODS Thirty-three patients from the HOVON 51 study with an MR(4.5) for at least 2 years who were still on imatinib treatment were randomised between continuation of imatinib (arm A, n=18) or discontinuation of imatinib (arm B, n=15). RESULTS After a median follow up of 36 months since randomisation, 3 patients (17%) in arm A and 10 patients (67%) in arm B had a molecular relapse. All 3 relapsing patients in arm A had also stopped imatinib after randomisation. All but one relapsing patient relapsed within 7 months after discontinuation of imatinib. The molecular relapse rate at 12 and 24 months after randomisation was 0% and 6% (arm A) and 53% and 67% (arm B) respectively. As-treated analysis revealed 56% and 61% relapses at 1 and 2 years since cessation in patients who discontinued imatinib, in contrast to 0% of patients who continued imatinib. All evaluable patients remained sensitive to imatinib after reinitiation and regained a molecular response. CONCLUSION Our data suggest that discontinuation of imatinib is safe in patients with durable MR(4.5).

Biomarker profiling of steroid-resistant acute GVHD in patients after infusion of mesenchymal stromal cells

We performed a prospective phase II study to evaluate clinical safety and outcome in 48 patients with steroid-refractory grade II–IV acute graft-versus-host disease (aGVHD) treated with mesenchymal stromal cells (MSCs). Clinical outcomes were correlated to comprehensive analyses of soluble and cellular biomarkers. Complete resolution (CR) of aGVHD at day 28 (CR-28) occurred in 12 (25%) patients, CR lasting >1 month (CR-B) occurred in 24 (50%) patients. One-year overall survival was significantly improved in CR-28 (75 versus 33%, P=0.020) and CR-B (79 versus 8%, P<0.001) versus non-CR patients. A six soluble biomarker-panel was predictive for mortality (HR 2.924; CI 1.485–5.758) when measured before MSC-administration. Suppression of tumorigenicity 2 (ST2) was only predictive for mortality 2 weeks after but not before MSC-administration (HR 2.389; CI 1.144–4.989). In addition, an increase in immature myeloid dendritic cells associated with decreased mortality (HR 0.554, CI 0.389–0.790). Patients had persisting T-cell responses against defined virus- and leukemia-associated antigens. In conclusion, our data emphasize the need to carefully assess biomarkers in cohorts with homogeneous GVHD treatments. Biomarkers might become an additional valuable component of composite end points for the rapid and efficient testing of novel compounds to decrease lifecycle of clinical testing and improve the success rate of phase II/III trials.

Identification of genes potentially involved in disease transformation of CML.

In patients with chronic myeloid leukemia (CML) who do not reach a (near) complete cytogenetic response, the disease progresses over several years from an indolent, chronic phase into a rapidly fatal blast crisis. Events that are responsible for this transformation process are largely unknown. To identify changes in gene expression that occurred during the course of the disease, we performed cDNA subtraction on sequentially stored peripheral blood mononuclear cell pellets, collected throughout the course of disease of a single CML patient. In total, 32 differentially expressed sequences were identified, of which 27 corresponded to known genes. On quantitative PCR, eight of these genes, YWHAZ, GAS2, IL8, IL6, PBEF1, CCL4, SAT and MMRN, showed comparable differential expression in additional CML patient samples. This set of genes can be considered as a starting point for further research on causes of disease transformation in CML and may lead to new targets in the treatment of resistant CML.