Inhibition of Tumor VEGFR2 Induces Serine 897 EphA2-Dependent Tumor Cell Invasion and Metastasis in NSCLC

Anti-angiogenic treatment targeting vascular endothelial growth factor (VEGF)-VEGFR2 signaling has shown limited efficacy in lung cancer patients. Here, we demonstrate that inhibition of VEGFR2 in tumor cells, expressed in ∼20% of non-squamous non-small cell lung cancer (NSCLC) patients, leads to a pro-invasive phenotype. Drug-induced inhibition of tumor VEGFR2 interferes with the formation of the EphA2/VEGFR2 heterocomplex, thereby allowing RSK to interact with Serine 897 of EphA2. Inhibition of RSK decreases phosphorylation of Serine 897 EphA2. Selective genetic modeling of Serine 897 of EphA2 or inhibition of EphA2 abrogates the formation of metastases in vivo upon VEGFR2 inhibition. In summary, these findings demonstrate that VEGFR2-targeted therapy conditions VEGFR2-positive NSCLC to Serine 897 EphA2-dependent aggressive tumor growth and metastasis. These data shed light on the molecular mechanisms explaining the limited efficacy of VEGFR2-targeted anti-angiogenic treatment in lung cancer patients.

Discovery of Candidate DNA Methylation Cancer Driver Genes

Epigenetic alterations, such as promoter hypermethylation, may drive cancer through tumor suppressor gene inactivation. However, we have limited ability to differentiate driver DNA methylation (DNAme) changes from passenger events. We developed DNAme driver inference-MethSig-accounting for the varying stochastic hypermethylation rate across the genome and between samples. We applied MethSig to bisulfite sequencing data of chronic lymphocytic leukemia (CLL), multiple myeloma, ductal carcinoma in situ, glioblastoma, and to methylation array data across 18 tumor types in TCGA. MethSig resulted in well-calibrated quantile-quantile plots and reproducible inference of likely DNAme drivers with increased sensitivity/specificity compared with benchmarked methods. CRISPR/Cas9 knockout of selected candidate CLL DNAme drivers provided a fitness advantage with and without therapeutic intervention. Notably, DNAme driver risk score was closely associated with adverse outcome in independent CLL cohorts. Collectively, MethSig represents a novel inference framework for DNAme driver discovery to chart the role of aberrant DNAme in cancer. SIGNIFICANCE: MethSig provides a novel statistical framework for the analysis of DNA methylation changes in cancer, to specifically identify candidate DNA methylation driver genes of cancer progression and relapse, empowering the discovery of epigenetic mechanisms that enhance cancer cell fitness.This article is highlighted in the In This Issue feature, p. 2113.

Integrative prognostic models predict long-term survival after immunochemotherapy in chronic lymphocytic leukemia patients

Chemoimmunotherapy with fludarabine, cyclophosphamide and rituximab (FCR) can induce long-term remissions in patients with chronic lymphocytic leukemia. Treatment efficacy with Bruton's tyrosine kinase inhibitors was found similar to FCR in untreated chronic lymphocytic leukemia patients with a mutated immunoglobulin heavy chain variable (IGHV) gene. In order to identify patients who specifically benefit from FCR, we developed integrative models including established prognostic parameters and gene expression profiling (GEP). GEP was conducted on n=337 CLL8 trial samples, “core” probe sets were summarized on gene levels and RMA normalized. Prognostic models were built using penalized Cox proportional hazards models with the smoothly clipped absolute deviation penalty. We identified a prognostic signature of less than a dozen genes, which substituted for established prognostic factors, including TP53 and IGHV gene mutation status. Independent prognostic impact was confirmed for treatment, β2-microglobulin and del(17p) regarding overall survival and for treatment, del(11q), del(17p) and SF3B1 mutation for progression-free survival. The combination of independent prognostic and GEP variables performed equal to models including only established non-GEP variables. GEP variables showed higher prognostic accuracy for patients with long progression-free survival compared to categorical variables like the IGHV gene mutation status and reliably predicted overall survival in CLL8 and an independent cohort. GEP-based prognostic models can help to identify patients who specifically benefit from FCR treatment. The CLL8 trial is registered under EUDRACT-2004-004938-14 and clinicaltrials gov. Identifier: NCT00281918.

PET-guided omission of radiotherapy in early-stage unfavourable Hodgkin lymphoma (GHSG HD17): a multicentre, open-label, randomised, phase 3 trial

BACKGROUND

Combined-modality treatment consisting of chemotherapy and consolidation radiotherapy is standard of care for patients with early-stage unfavourable Hodgkin lymphoma. However, the use of radiotherapy can have long-term sequelae, which is of particular concern, as Hodgkin lymphoma is frequently diagnosed in young adults with a median age of approximately 30 years. In the German Hodgkin Study Group HD17 trial, we investigated whether radiotherapy can be omitted without loss of efficacy in patients who have a complete metabolic response after receiving two cycles of escalated doses of etoposide, cyclophosphamide, and doxorubicin, and regular doses of bleomycin, vincristine, procarbazine, and prednisone (eBEACOPP) plus two cycles of doxorubicin, bleomycin, vinblastine, dacarbazine (ABVD) chemotherapy (2 + 2).

METHODS

In this multicentre, open-label, randomised, phase 3 trial, patients (aged 18-60 years) with newly diagnosed early-stage unfavourable Hodgkin lymphoma (all histologies) and an Eastern Cooperative Oncology Group performance status of 2 or less were enrolled at 224 hospitals and private practices in Germany, Switzerland, Austria, and the Netherlands. Patients were randomly assigned (1:1) to receive either standard combined-modality treatment, consisting of the 2 + 2 regimen (eBEACOPP consisted of 1250 mg/m² intravenous cyclophosphamide on day 1, 35 mg/m² intravenous doxorubicin on day 1, 200 mg/m² intravenous etoposide on days 1-3, 100 mg/m² oral procarbazine on days 1-7, 40 mg/m² oral prednisone on days 1-14, 1·4 mg/m² intravenous vincristine on day 8 [maximum dose of 2 mg per cycle], and 10 mg/m² intravenous bleomycin on day 8; ABVD consisted of 25 mg/m² intravenous doxorubicin, 10 mg/m² intravenous bleomycin, 6 mg/m² intravenous vinblastine, and 375 mg/m² intravenous dacarbazine, all given on days 1 and 15) followed by 30 Gy involved-field radiotherapy (standard combined-modality treatment group) or PET4-guided treatment, consisting of the 2 + 2 regimen followed by 30 Gy of involved-node radiotherapy only in patients with positive PET at the end of four cycles of chemotherapy (PET4; PET4-guided treatment group). Randomisation was done centrally and used the minimisation method and seven stratification factors (centre, age, sex, clinical symptoms, disease localisation, albumin concentration, and bulky disease), and patients and investigators were masked to treatment allocation until central review of the PET4 examination had been completed. With the final analysis presented here, the primary objective was to show non-inferiority of the PET4-guided strategy in a per-protocol analysis of the primary endpoint of progression-free survival. We defined non-inferiority as an absolute difference of 8% in the 5-year progression-free survival estimates between the two groups. Safety analyses were done in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, NCT01356680.

FINDINGS

Between Jan 13, 2012, and March 21, 2017, we enrolled and randomly assigned 1100 patients to the standard combined-modality treatment group (n=548) or to the PET4-guided treatment group (n=552); two patients in each group were found ineligible after randomisation. At a median follow-up of 46·2 months (IQR 32·7-61·2), 5-year progression-free survival was 97·3% (95% CI 94·5-98·7) in the standard combined-modality treatment group and 95·1% (92·0-97·0) in the PET4-guided treatment group (hazard ratio 0·523 [95% CI 0·226-1·211]). The between-group difference was 2·2% (95% CI -0·9 to 5·3) and excluded the non-inferiority margin of 8%. The most common grade 3 or 4 acute haematological adverse events were leucopenia (436 [83%] of 528 patients in the standard combined-modality treatment group vs 443 [84%] of 529 patients in the PET4-guided treatment group) and thrombocytopenia (139 [26%] vs 176 [33%]), and the most frequent acute non-haematological toxic effects were infection (32 [6%] vs 40 [8%]) and nausea or vomiting (38 [7%] vs 29 [6%]). The most common acute radiotherapy-associated adverse events were dysphagia (26 [6%] in the standard combined-modality treatment group vs three [2%] in the PET4-guided treatment group) and mucositis (nine [2%] vs none). 229 serious adverse events were reported by 161 (29%) of 546 patients in the combined-modality treatment group, and 235 serious adverse events were reported by 164 (30%) of 550 patients in the PET4-guided treatment group. One suspected unexpected serious adverse reaction (infection) leading to death was reported in the PET4-guided treatment group.

INTERPRETATION

PET4-negativity after treatment with 2 + 2 chemotherapy in patients with newly diagnosed early-stage unfavourable Hodgkin lymphoma allows omission of consolidation radiotherapy without a clinically relevant loss of efficacy. PET4-guided therapy could thereby reduce the proportion of patients at risk of the late effects of radiotherapy.

FUNDING

Deutsche Krebshilfe.

Bendamustine, followed by ofatumumab and ibrutinib in chronic lymphocytic leukemia (CLL2-BIO): primary endpoint analysis of a multicenter, open-label phase-II trial

The introduction of targeted agents has revolutionized the treatment of chronic lymphocytic leukemia but only few patients achieve a complete remission and minimal residual disease negativity with ibrutinib monotherapy. This multicenter, investigator-initiated, phase II study is evaluating sequential treatment with two cycles of bendamustine debulking for patients with a higher tumor load, followed by ofatumumab and ibrutinib induction and maintenance treatment. An all-comer population, irrespective of prior treatment, physical fitness and genetic factors, was included. The primary endpoint was the investigator-assessed overall response rate at the end of induction treatment. Of 66 patients enrolled, one patient with early treatment discontinuation was excluded from the efficacy analysis as predefined by the protocol. Thirty-nine patients (60%) were treatment-naïve and 26 patients (40%) had relapsed/refractory chronic lymphocytic leukemia, 21 patients (32%) had a del(17p) and/or TP53 mutation and 45 patients (69%) had unmutated IGHV status. At the end of the induction, 60 of 65 patients (92%) responded and nine (14%) achieved minimal residual disease negativity (<10^-4) in peripheral blood. No unexpected or cumulative toxicities occurred. The most common grade 3 or 4 adverse events, according to the Common Toxicity Criteria, were neutropenia, anemia, infusion-related reactions, and diarrhea. This sequential treatment of bendamustine debulking, followed by ofatumumab and ibrutinib was well tolerated without unexpected safety signals and showed a good efficacy with an overall response rate of 92%. Ongoing maintenance treatment aims at deeper responses with minimal residual disease negativity. However, ibrutinib should still be used as a single agent outside clinical trials. Clinicaltrials.gov number: NCT02689141.

Noncanonical effector functions of the T-memory-like T-PLL cell are shaped by cooperative TCL1A and TCR signaling

T-cell prolymphocytic leukemia (T-PLL) is a poor-prognostic neoplasm. Differentiation stage and immune-effector functions of the underlying tumor cell are insufficiently characterized. Constitutive activation of the T-cell leukemia 1A (TCL1A) oncogene distinguishes the (pre)leukemic cell from regular postthymic T cells. We assessed activation-response patterns of the T-PLL lymphocyte and interrogated the modulatory impact by TCL1A. Immunophenotypic and gene expression profiles revealed a unique spectrum of memory-type differentiation of T-PLL with predominant central-memory stages and frequent noncanonical patterns. Virtually all T-PLL expressed a T-cell receptor (TCR) and/or CD28-coreceptor without overrepresentation of specific TCR clonotypes. The highly activated leukemic cells also revealed losses of negative-regulatory TCR coreceptors (eg, CTLA4). TCR stimulation of T-PLL cells evoked higher-than-normal cell-cycle transition and profiles of cytokine release that resembled those of normal memory T cells. More activated phenotypes and higher TCL1A correlated with inferior clinical outcomes. TCL1A was linked to the marked resistance of T-PLL to activation- and FAS-induced cell death. Enforced TCL1A enhanced phospho-activation of TCR kinases, second-messenger generation, and JAK/STAT or NFAT transcriptional responses. This reduced the input thresholds for IL-2 secretion in a sensitizer-like fashion. Mice of TCL1A-initiated protracted T-PLL development resembled such features. When equipped with epitope-defined TCRs or chimeric antigen receptors, these Lckpr-hTCL1Atg T cells gained a leukemogenic growth advantage in scenarios of receptor stimulation. Overall, we propose a model of T-PLL pathogenesis in which TCL1A enhances TCR signals and drives the accumulation of death-resistant memory-type cells that use amplified low-level stimulatory input, and whose loss of negative coregulators additionally maintains their activated state. Treatment rationales are provided by combined interception in TCR and survival signaling.

Preventing and monitoring for tumor lysis syndrome and other toxicities of venetoclax during treatment of chronic lymphocytic leukemia

Recent developments in the management of chronic lymphocytic leukemia (CLL) have moved the standard of care away from chemoimmunotherapy to targeted agents such as oral kinase inhibitors or BCL-2 antagonists, alone or in combination with anti-CD20 antibodies. Two different treatment approaches have evolved: continuous, indefinite treatment and, more recently, fixed-duration combination treatment. With venetoclax-based treatment, there is a requirement to follow the established guidelines for close monitoring during initiation and ramp up, to reduce the risk of tumor lysis syndrome. The patient's risk should be assessed before the initiation of venetoclax. Appropriate management strategies should be used, including uricosuric agents, hydration, and routine laboratory monitoring, per guidelines. With early identification, immediate management, and dose adjustments, we suggest that tumor lysis syndrome and other toxicities, such as neutropenia and infections, with venetoclax-based treatment can be dealt with successfully.

Micro-RNA networks in T-cell prolymphocytic leukemia reflect T-cell activation and shape DNA damage response and survival pathways

T-cell prolymphocytic leukemia (T-PLL) is a poor-prognostic mature T-cell malignancy. It typically presents with exponentially rising lymphocyte counts, splenomegaly, and bone marrow infiltration. Effective treatment options are scarce and a better understanding of TPLL’s pathogenesis is desirable. Activation of the TCL1 proto-oncogene and loss-of-function perturbations of the tumor suppressor ATM are TPLL’s genomic hallmarks. The leukemic cell reveals a phenotype of active T-cell receptor (TCR) signaling and aberrant DNA damage responses. Regulatory networks based on the profile of microRNA (miR) have not been described for T-PLL. In a combined approach of small-RNA and transcriptome sequencing in 46 clinically and moleculary well-characterized T-PLL, we identified a global T-PLL-specific miR expression profile that involves 34 significantly deregulated miR species. This pattern strikingly resembled miR-ome signatures of TCR-activated T cells. By integrating these T-PLL miR profiles with transcriptome data, we uncovered regulatory networks associated with cell survival signaling and DNA damage response pathways. Despite a miR-ome that discerned leukemic from normal T cells, there were also robust subsets of T-PLL defined by a small set of specific miR. Most prominently, miR-141 and the miR- 200c-cluster separated cases into two major subgroups. Furthermore, increased expression of miR-223-3p as well as reduced expression of miR-21 and the miR-29 cluster were associated with more activated Tcell phenotypes and more aggressive disease presentations. Based on the implicated pathobiological role of these miR deregulations, targeting strategies around their effectors appear worth pursuing. We also established a combinatorial miR-based overall survival score for T-PLL (miROS-T-PLL), that might improve current clinical stratifications.

BIOM-40. ANALYSIS OF SERUM MIRNA IN GLIOBLASTOMA PATIENTS: TARGETED ENRICHMENT OF EXTRACELLULAR VESICLES ENHANCES SPECIFICITY FOR PROGNOSTIC SIGNATURE

Glioblastoma is a devastating disease, for which biomarkers allowing a prediction of prognosis are urgently needed. microRNAs have been described as potentially valuable biomarkers in cancer. Here, we studied a panel of microRNAs in extracellular vesicles (EV) from the serum of glioblastoma patients and also in total serum without prior EV separation, and evaluated their correlation with the survival of these patients. Our study included 55 patients in total, 26 (47.3%) of which were treated within the multicenter Phase III CeTeG/NOA-09 trial and 29 (52.7%) in the Division of Clinical Neurooncology of the University Hospital of Bonn, as well as 10 healthy volunteers (HV). Blood was drawn from patients during the adjuvant chemotherapeutic treatment. A panel of 15 microRNAs was studied by quantitative real-time PCR in EV that were separated by size-exclusion chromatography, followed by CDxx* immunoprecipitation (SEC+CDxx*), and compared with those from total serum of glioblastoma patients and HV. Comparing SEC+CDxx* to total serum, we found evidence for enrichment of miR-21-3p and miR-106a-5p and, conversely, lower levels of miR-15b-3p in SEC+CDxx* EV. miR-15b-3p and miR-21-3p were upregulated in serum of glioblastoma patients compared to healthy subjects. Significant correlation with survival of the patients was found for levels of miR-15b-3p in total serum and miR-15b-3p, miR-21-3p, miR-106a-5p and miR-328-3p in SEC+CDxx* EV. Combining miR-15b-3p in serum or miR-106a-5p in SEC+CDxx* EV with any one of the other three microRNAs in SEC+CDxx* EV allowed for a prognostic stratification of glioblastoma patients. We have thus identified four microRNAs whose levels, in combination, can predict the prognosis for these patients. *=Cluster of Differentiation xx (CDxx); Molecule cannot be specifically mentioned due to pending patent.

Prognostic impact of prevalent chronic lymphocytic leukemia stereotyped subsets: analysis within prospective clinical trials of the German CLL Study Group (GCLLSG)

Almost one-third of all patients with chronic lymphocytic leukemia (CLL) express stereotyped B cell receptor immunoglobulins (BcR IG) and can be assigned to distinct subsets, each with a particular BcR IG. The largest stereotyped subsets are #1, #2, #4 and #8, associated with specific clinicobiological characteristics and outcomes in retrospective studies. We assessed the associations and prognostic value of these BcR IG in prospective multicenter clinical trials reflective of two different clinical situations: i) early-stage patients (watch-and-wait arm of the CLL1 trial) (n=592); ii) patients in need of treatment, enrolled in 3 phase III trials (CLL8, CLL10, CLL11), treated with different chemo-immunotherapies (n=1861). Subset #1 was associated with del(11q), higher CLL international prognostic index (CLL-IPI) scores and similar clinical course to CLL with unmutated immunoglobulin heavy variable (IGHV) genes (U-CLL) in both early and advanced stage groups. IGHV-mutated (M-CLL) subset #2 cases had shorter time-to-first-treatment (TTFT) versus other M-CLL cases in the early-stage cohort (HR: 4.2, CI: 2-8.6, p<0.001), and shorter time-to-next-treatment (TTNT) in the advanced-stage cohort (HR: 2, CI: 1.2-3.3, p=0.005). M-CLL subset #4 was associated with lower CLL-IPI scores and younger age at diagnosis; in both cohorts, these patients showed a trend towards better outcomes versus other M-CLL. U-CLL subset #8 was associated with trisomy 12. Overall, this study shows that major stereotyped subsets have distinctive characteristics. For the first time in prospective multicenter clinical trials, subset # 2 appeared as an independent prognostic factor for earlier TTFT and TTNT and should be proposed for risk stratification of patients.

Venetoclax plus bendamustine-rituximab or bendamustine-obinutuzumab in chronic lymphocytic leukemia: final results of a phase 1b study (GO28440)

Venetoclax (Ven), an orally administered, potent BCL-2 inhibitor, has demonstrated efficacy in chronic lymphocytic leukaemia (CLL) in combination with rituximab (R) or obinutuzumab (G). Our aim was to investigate the addition of bendamustine (B) to these Ven-containing regimens in relapsed/refractory (R/R) or first-line (1L) CLL. This multi-arm, non-randomized, open-label, phase 1b study was designed to evaluate the maximum tolerated dose (MTD) and safety/tolerability of Ven with BR/BG, with 3+3 dose-escalation followed by safety expansion. Patients received Ven (schedule A) or BR/BG first (schedule B) to compare safety and determine dose/schedule for expansion. Six Ven-BR/-BG cycles were to be administered, then Ven monotherapy until disease progression (R/R) or fixed-duration 1-year treatment (1L). Overall, 33 R/R and 50 1L patients were enrolled. No dose-limiting toxicities were observed (doses 100-400-mg), and the MTD was not reached. Safety was similar between schedules; no tumour lysis syndrome (TLS) occurred during dose-finding. Schedule B and Ven 400-mg were chosen for expansion. The most frequent grade 3-4 toxicity was neutropenia: R/R 64%, 1L Ven-BR 85%, 1L Ven-BG 55%. Grade 3-4 infection rate was: R/R 27%, 1L Ven-BR 0%, 1L Ven-BG 27%. During expansion, one clinical and two laboratory TLS cases occurred. Fewer than half the patients completed six combination therapy cycles with all study drugs; rates of bendamustine discontinuation were high. Overall response rate was 91% in R/R and 100% in 1L patients (16/49 1L patients received Ven for >1 year). In conclusion, addition of bendamustine to Ven-R/-G increased toxicity without apparent efficacy benefit.

Onco-Cardiology: Consensus Paper of the German Cardiac Society, the German Society for Pediatric Cardiology and Congenital Heart Defects and the German Society for Hematology and Medical Oncology

The acute and long-lasting side effects of modern multimodal tumour therapy significantly impair quality of life and survival of patients afflicted with malignancies. The key components of this therapy include radiotherapy, conventional chemotherapy, immunotherapy and targeted therapies. In addition to established tumour therapy strategies, up to 30 new therapies are approved each year with only incompletely characterised side effects. This consensus paper discusses the risk factors that contribute to the development of a potentially adverse reaction to tumour therapy and, in addition, defines specific side effect profiles for different treatment groups. The focus is on novel therapeutics and recommendations for the surveillance and treatment of specific patient groups.