Expression patterns and prognostic potential of circular RNAs in mantle cell lymphoma: a study of younger patients from the MCL2 and MCL3 clinical trials.

Mantle cell lymphoma (MCL) is characterized by marked differences in outcome, emphasizing the need for strong prognostic biomarkers. Here, we explore expression patterns and prognostic relevance of circular RNAs (circRNAs), a group of endogenous non-coding RNA molecules, in MCL. We profiled the circRNA expression landscape using RNA-sequencing and explored the prognostic potential of 40 abundant circRNAs in samples from the Nordic MCL2 and MCL3 clinical trials, using NanoString nCounter Technology. We report a circRNA-based signature (circSCORE) developed in the training cohort MCL2 that is highly predictive of time to progression (TTP) and lymphoma-specific survival (LSS). The dismal outcome observed in the large proportion of patients assigned to the circSCORE high-risk group was confirmed in the independent validation cohort MCL3, both in terms of TTP (HR 3.0; P = 0.0004) and LSS (HR 3.6; P = 0.001). In Cox multiple regression analysis incorporating MIPI, Ki67 index, blastoid morphology and presence of TP53 mutations, circSCORE retained prognostic significance for TTP (HR 3.2; P = 0.01) and LSS (HR 4.6; P = 0.01). In conclusion, circRNAs are promising prognostic biomarkers in MCL and circSCORE improves identification of high-risk disease among younger patients treated with cytarabine-containing chemoimmunotherapy and autologous stem cell transplant.

Treatment of Older Patients With Mantle Cell Lymphoma (MCL): Long-Term Follow-Up of the Randomized European MCL Elderly Trial.

PURPOSE: In an update of the randomized, open-label, phase III European Mantle Cell Lymphoma (MCL) Elderly trial (ClinicalTrials.gov identifier: NCT00209209), published in 2012, we aimed to confirm results on long-term outcome focusing on efficacy and safety of long-term use of rituximab maintenance. PATIENTS AND METHODS: Five hundred sixty patients with newly diagnosed MCL underwent a first random assignment between rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) and rituximab, fludarabine, and cyclophosphamide (R-FC) induction, followed by a second random assignment in 316 responders between rituximab and interferon alfa maintenance, to be continued until progression. We compared progression-free survival from the second randomization and overall survival (OS) from the first or second randomizations. RESULTS: After a median follow-up time of 7.6 years, the previously described difference in OS between the induction arms persisted (median, 6.4 years after R-CHOP [n = 280] v 3.9 years after R-FC [n = 280]; P = .0054). Patients responding to R-CHOP had median progression-free survival and OS times of 5.4 and 9.8 years, respectively, when randomly assigned to rituximab (n = 87), compared with 1.9 years (P < .001) and 7.1 years (P = .0026), respectively, when randomly assigned to interferon alfa (n = 97). In 58% and 32% of patients treated with R-CHOP, rituximab maintenance was still ongoing 2 and 5 years from start of maintenance, respectively. After R-FC, rituximab maintenance was associated with an unexpectedly high cumulative incidence of death in remission (22% at 5 years). Toxicity of rituximab maintenance was low after R-CHOP (grade 3-4 leukopenia or infection < 5%) but more prominent in patients on rituximab maintenance after R-FC, in whom grade 3-4 leukopenia (up to 40%) and infections were frequent (up to 15%). CONCLUSION: The excellent results of R-CHOP followed by rituximab maintenance until progression for older patients with MCL persisted in a mature follow-up. Prolongation of rituximab maintenance beyond 2 years is effective and safe.

Clonal diversity predicts adverse outcome in chronic lymphocytic leukemia.

Genomic analyses of chronic lymphocytic leukemia (CLL) identified somatic mutations and associations of clonal diversity with adverse outcomes. Clonal evolution likely has therapeutic implications but its dynamic is less well studied. We studied clonal composition and prognostic value of seven recurrently mutated driver genes using targeted next-generation sequencing in 643 CLL patients and found higher frequencies of mutations in TP53 (35 vs. 12%, p < 0.001) and SF3B1 (20 vs. 11%, p < 0.05) and increased number of (sub)clonal (p < 0.0001) mutations in treated patients. We next performed an in-depth evaluation of clonal evolution on untreated CLL patients (50 "progressors" and 17 matched "non-progressors") using a 404 gene-sequencing panel and identified novel mutated genes such as AXIN1, SDHA, SUZ12, and FOXO3. Progressors carried more mutations at initial presentation (2.5 vs. 1, p < 0.0001). Mutations in specific genes were associated with increased (SF3B1, ATM, and FBXW7) or decreased progression risk (AXIN1 and MYD88). Mutations affecting specific signaling pathways, such as Notch and MAP kinase pathway were enriched in progressive relative to non-progressive patients. These data extend earlier findings that specific genomic alterations and diversity of subclones are associated with disease progression and persistence of disease in CLL and identify novel recurrently mutated genes and associated outcomes.

Deep targeted sequencing of TP53 in chronic lymphocytic leukemia: clinical impact at diagnosis and at time of treatment.

In chronic lymphocytic leukemia, TP53 mutations and deletion of chromosome 17p are well-characterized biomarkers associated with poor progression-free and overall survival following chemoimmunotherapy. Patients harboring low burden TP53 mutations with variant allele frequencies of 0.3-15% have been shown to have similar dismal outcome as those with high burden mutations. We here describe a highly sensitive deep targeted next-generation sequencing assay allowing for the detection of TP53 mutations as low as 0.2% variant allele frequency. Within a consecutive, single center cohort of 290 newly diagnosed patients with chronic lymphocytic leukemia, deletion of chromosome 17p was the only TP53 aberration significantly associated with shorter overall survival and treatment-free survival. We were unable to demonstrate any impact of TP53 mutations, whether high burden (variant allele frequency >10%) or low burden (variant allele frequency ≤10%), in the absence of deletion of chromosome 17p. In addition, the impact of high burden TP53 aberration (deletion of chromosome 17p and/or TP53 mutation with variant allele frequency >10%) was only evident for patients with IGHV unmutated status; no impact of TP53 aberrations on outcome was seen for patients with IGHV mutated status. In 61 patients at time of treatment, the prognostic impact of TP53 mutations over 1% variant allele frequency could be confirmed. This study furthers the identification of a clinical significant limit of detection for robust TP53 mutation analysis in chronic lymphocytic leukemia. Multicenter studies are needed for validation of ultra-sensitive TP53 mutation assays in order to define and implement a technical as well as a clinical lower limit of detection.

Ibrutinib, lenalidomide, and rituximab in relapsed or refractory mantle cell lymphoma (PHILEMON): a multicentre, open-label, single-arm, phase 2 trial.

BACKGROUND: Regimens based on ibrutinib alone and lenalidomide and rituximab in combination show high activity in patients with relapsed or refractory mantle cell lymphoma. We hypothesised that the combination of all three drugs would improve efficacy compared with previously published data on either regimen alone. METHODS: In this multicentre, open-label, single-arm, phase 2 trial, we enrolled patients aged 18 years or older with relapsed or refractory mantle cell lymphoma who had previously been treated with at least one rituximab-containing regimen, an Eastern Cooperative Oncology Group performance status score of 0-3, and at least one site of measurable disease, and who met criteria for several laboratory-assessed parameters. Treatment was divided into an induction phase of 12 cycles of 28 days with all three drugs and a maintenance phase with ibrutinib and rituximab only (cycle duration 56 days), given until disease progression or unacceptable toxicity. In the induction phase, patients received intravenous (375 mg/m2) or subcutaneous (1400 mg) rituximab once a week during cycle 1 and then once every 8 weeks. Oral ibrutinib (560 mg once a day) was given to patients every day in the cycle, whereas oral lenalidomide (15 mg once a day) was given on days 1-21. The primary endpoint was overall response assessed in the intention-to-treat population according to Lugano criteria. Safety analysis included all patients who received the treatment, irrespective of eligibility or duration of treatment. The trial is ongoing, but is no longer accruing patients, and is registered with ClinicalTrials.gov, number NCT02460276. FINDINGS: Between April 30, 2015, and June 1, 2016, we enrolled 50 patients with relapsed or refractory mantle cell lymphoma at ten centres in Sweden, Finland, Norway, and Denmark. At a median follow-up of 17·8 months (IQR 14·7-20·9), 38 (76%, 95% CI 63-86) patients had an overall response, including 28 (56%, 42-69) patients who had a complete response and ten (20%, 11-33) who had a partial response. The most common grade 3-4 adverse events were neutropenia (in 19 [38%] of 50 patients), infections (in 11 [22%] patients), and cutaneous toxicity (in seven [14%] patients). There were three treatment-related deaths during the study, two due to sepsis and one due to embolic stroke. INTERPRETATION: Our results provide preliminary evidence that the triplet combination of ibrutinib, lenalidomide, and rituximab is an active regimen in patients with relapsed or refractory mantle cell lymphoma, and should be evaluated in a prospective randomised controlled trial. FUNDING: Janssen and Celgene.

Depth and durability of response to ibrutinib in CLL: 5-year follow-up of a phase 2 study.

The safety and efficacy of ibrutinib (420 mg) in chronic lymphocytic leukemia (CLL) were evaluated in a phase 2 study; 51 patients had TP53 aberration (TP53 cohort) and 35 were enrolled because of age 65 years or older (elderly cohort). Both cohorts included patients with treatment-naive (TN) and relapsed/refractory (RR) CLL. With the median follow-up of 4.8 years, 49 (57.0%) of 86 patients remain on study. Treatment was discontinued for progressive disease in 20 (23.3%) patients and for adverse events in 5 (5.8%). Atrial fibrillation occurred in 18 (20.9%) patients for a rate of 6.4 per 100 patient-years. No serious bleeding occurred. The overall response rate at 6 months, the primary study endpoint, was 95.8% for the TP53 cohort (95% confidence interval, 85.7%-99.5%) and 93.9% for the elderly cohort (95% confidence interval, 79.8%-99.3%). Depth of response improved with time: at best response, 14 (29.2%) of 48 patients in the TP53 cohort and 9 (27.3%) of 33 in the elderly cohort achieved a complete response. Median minimal residual disease (MRD) in peripheral blood was 3.8 × 10-2 at 4 years, with MRD-negative (<10-4) remissions in 5 (10.2%) patients. In the TP53 cohort, the estimated 5-year progression-free survival (PFS) was 74.4% in TN-CLL compared with 19.4% in RR-CLL (P = .0002), and overall survival (OS) was 85.3% vs 53.7%, respectively (P = .023). In the elderly cohort, the estimated 5-year PFS and OS in RR-CLL were 64.8% and 71.6%, respectively, and no event occurred in TN-CLL. Long-term administration of ibrutinib was well tolerated and provided durable disease control for most patients. This trial was registered at www.clinicaltrials.gov as #NCT01500733.

Optimising outcomes for patients with chronic lymphocytic leukaemia on ibrutinib therapy: European recommendations for clinical practice.

Ibrutinib is indicated in Europe for the treatment of several B-cell malignancies, including chronic lymphocytic leukaemia (CLL). However, despite the high efficacy and favourable toxicity profile of ibrutinib, recent data suggest that it is not always administered optimally in clinical practice, with an increased tendency for dose reduction and a higher frequency of discontinuation. An expert panel of European haematologists was convened to identify practical issues pertinent to physicians involved in the therapeutic management of ibrutinib-treated CLL patients and here we outline the findings. Practical management recommendations are given for treating patients with ibrutinib and clinical considerations for the management of adverse events (AEs) that can be associated with ibrutinib treatment are addressed. This article highlights that patients should be monitored for treatment emergent adverse events, most of which are mild, transient and generally occur early in therapy and that, even with more challenging AEs, patients can often be maintained on therapy with minimal disruption through careful management. The necessity to use the correct ibrutinib dose, along with increased awareness, vigilance, mitigation and management of AEs, are all recommended to maximise outcomes for CLL patients treated with ibrutinib.

TP53 mutations identify younger mantle cell lymphoma patients who do not benefit from intensive chemoimmunotherapy.

Despite recent advances in lymphoma treatment, mantle cell lymphoma (MCL) remains incurable, and we are still unable to identify patients who will not benefit from the current standard of care. Here, we explore the prognostic value of recurrent genetic aberrations in diagnostic bone marrow (BM) specimens from 183 younger patients with MCL from the Nordic MCL2 and MCL3 trials, which represent current standard-of-care regimens. In the univariate model, mutations of TP53 (11%) and NOTCH1 (4%), and deletions of TP53 (16%) and CDKN2A (20%), were significantly associated with inferior outcomes (together with MIPI, MIPI-c, blastoid morphology, and Ki67 > 30%); however, in multivariate analyses, only TP53 mutations (HR, 6.2; P < .0001) retained prognostic impact for overall survival (OS), whereas TP53 mutations (HR, 6.9; P < .0001) and MIPI-c high-risk (HR, 2.6; P = .003) had independent prognostic impact on time to relapse. TP53-mutated cases had a dismal outcome, with a median OS of 1.8 years, and 50% relapsed at 1.0 years, compared to a median OS of 12.7 years for TP53-unmutated cases (P < .0001). TP53 mutations were significantly associated with Ki67 > 30%, blastoid morphology, MIPI high-risk, and inferior responses to both induction- and high-dose chemotherapy. In conclusion, we show that TP53 mutations identify a phenotypically distinct and highly aggressive form of MCL with poor or no response to regimens including cytarabine, rituximab, and autologous stem-cell transplant (ASCT). We suggest patients with MCL should be stratified according to TP53 status, and that patients with TP53 mutations should be considered for experimental frontline trials exploring novel agents.

Soluble CD52 is an indicator of disease activity in chronic lymphocytic leukemia.

CD52 is a glycoprotein expressed on normal as well as leukemic immune cells and shed as soluble CD52 (sCD52). We studied sCD52 levels in three CLL cohorts: the 'early', the 'high-risk', and the 'ibrutinib-treated'. The 'high-risk' patients had significantly higher sCD52 levels than the 'early' patients. For the 'early' patients, high sCD52 levels were associated with a significantly shorter time to first treatment. Regarding prognostic factors, no clear correlations with stage, IGHV, or beta-2-microglobulin were found; in a cox multivariate analysis of the 'early' patients, sCD52 and IGHV both had independent prognostic value. Following chemo-immunotherapy, sCD52 decreased in parallel with leukocytes while during ibrutinib treatment and ibrutinib-induced ymphocytosis, sCD52 decreased along with lymph node reductions. In vitro IgM stimulation of CLL cells led to increased sCD52 levels in the medium. Our findings indicate that sCD52 reflects disease activity and potentially treatment efficacy in CLL.

15-year follow-up of the Second Nordic Mantle Cell Lymphoma trial (MCL2): prolonged remissions without survival plateau.

In recent decades, the prognosis of Mantle Cell Lymphoma (MCL) has been significantly improved by intensified first-line regimens containing cytarabine, rituximab and consolidation with high-dose-therapy and autologous stem cell transplantation. One such strategy is the Nordic MCL2 regimen, developed by the Nordic Lymphoma Group. We here present the 15-year updated results of the Nordic MCL2 study after a median follow-up of 11·4 years: For all patients on an intent-to-treat basis, the median overall and progression-free survival was 12·7 and 8·5 years, respectively. The MCL International Prognostic Index (MIPI), biological MIPI, including Ki67 expression (MIPI-B) and the MIPI-B including mIR-18b expression (MIPI-B-miR), in particular, significantly divided patients into distinct risk groups. Despite very long response durations of the low and intermediate risk groups, we observed a continuous pattern of relapse and the survival curves never reached a plateau. In conclusion, despite half of the patients being still alive and 40% in first remission after more than 12 years, we still see an excess disease-related mortality, even among patients experiencing long remissions. Even though we consider the Nordic regimen as a very good choice of regimen, we recommend inclusion in prospective studies to explore the benefit of novel agents in the frontline treatment of MCL.

miR-18b overexpression identifies mantle cell lymphoma patients with poor outcome and improves the MIPI-B prognosticator.

Recent studies show that mantle cell lymphoma (MCL) express aberrant microRNA (miRNA) profiles; however, the clinical effect of miRNA expression has not previously been examined and validated in large prospective homogenously treated cohorts. We performed genome-wide miRNA microarray profiling of 74 diagnostic MCL samples from the Nordic MCL2 trial (screening cohort). Prognostic miRNAs were validated in diagnostic MCL samples from 94 patients of the independent Nordic MCL3 trial (validation cohort). Three miRNAs (miR-18b, miR-92a, and miR-378d) were significantly differentially expressed in patients who died of MCL in both cohorts. MiR-18b was superior to miR-92a and miR-378d in predicting high risk. Thus, we generated a new biological MCL International Prognostic Index (MIPI-B)-miR prognosticator, combining expression levels of miR-18b with MIPI-B data. Compared to the MIPI-B, this prognosticator improved identification of high-risk patients with regard to cause-specific, overall, and progression-free survival. Transfection of 2 MCL cell lines with miR-18b decreased their proliferation rate without inducing apoptosis, suggesting that miR-18b may render MCL cells resistant to chemotherapy by decelerating cell proliferation. We conclude that overexpression of miR-18b identifies patients with poor prognosis in 2 large prospective MCL cohorts and adds prognostic information to the MIPI-B. MiR-18b may reduce the proliferation rate of MCL cells as a mechanism of chemoresistance.

Ibrutinib for previously untreated and relapsed or refractory chronic lymphocytic leukaemia with TP53 aberrations: a phase 2, single-arm trial.

BACKGROUND: Patients with chronic lymphocytic leukaemia (CLL) with TP53 aberrations respond poorly to first-line chemoimmunotherapy, resulting in early relapse and short survival. We investigated the safety and activity of ibrutinib in previously untreated and relapsed or refractory CLL with TP53 aberrations. METHODS: In this investigator-initiated, single-arm phase 2 study, we enrolled eligible adult patients with active CLL with TP53 aberrations at the National Institutes of Health Clinical Center (Bethesda, MD, USA). Patients received 28-day cycles of ibrutinib 420 mg orally once daily until disease progression or the occurrence of limiting toxicities. The primary endpoint was overall response to treatment at 24 weeks in all evaluable patients. This study is registered with ClinicalTrials.gov, number NCT01500733, and is fully enrolled. FINDINGS: Between Dec 22, 2011, and Jan 2, 2014, we enrolled 51 patients; 47 had CLL with deletion 17p13.1 and four carried a TP53 mutation in the absence of deletion 17p13.1. All patients had active disease requiring therapy. 35 enrolled patients had previously untreated CLL and 16 had relapsed or refractory disease. Median follow-up was 24 months (IQR 12.9-27.0). 33 previously untreated patients and 15 patients with relapsed or refractory CLL were evaluable for response at 24 weeks. 32 (97%; 95% CI 86-100) of 33 previously untreated patients achieved an objective response, including partial response in 18 patients (55%) and partial response with lymphocytosis in 14 (42%). One patient had progressive disease at 0.4 months. 12 (80%; 95% CI 52-96) of the 15 patients with relapsed or refractory CLL had an objective response: six (40%) achieved a partial response and six (40%) a partial response with lymphocytosis; the remaining three (20%) patients had stable disease. Grade 3 or worse treatment-related adverse events were neutropenia in 12 (24%) patients (grade 4 in one [2%] patient), anaemia in seven (14%) patients, and thrombocytopenia in five (10%) patients (grade 4 in one [2%] patient). Grade 3 pneumonia occurred in three (6%) patients, and grade 3 rash in one (2%) patient. INTERPRETATION: The activity and safety profile of single-agent ibrutinib in CLL with TP53 aberrations is encouraging and supports its consideration as a novel treatment option for patients with this high-risk disease in both first-line and second-line settings. FUNDING: Intramural Research Program of the National Heart, Lung, and Blood Institute and the National Cancer Institute, Danish Cancer Society, Novo Nordisk Foundation, National Institutes of Health Medical Research Scholars Program, and Pharmacyclics Inc.

Not all IGHV3-21 chronic lymphocytic leukemias are equal: prognostic considerations.

An unresolved issue in chronic lymphocytic leukemia (CLL) is whether IGHV3-21 gene usage, in general, or the expression of stereotyped B-cell receptor immunoglobulin defining subset #2 (IGHV3-21/IGLV3-21), in particular, determines outcome for IGHV3-21-utilizing cases. We reappraised this issue in 8593 CLL patients of whom 437 (5%) used the IGHV3-21 gene with 254/437 (58%) classified as subset #2. Within subset #2, immunoglobulin heavy variable (IGHV)-mutated cases predominated, whereas non-subset #2/IGHV3-21 was enriched for IGHV-unmutated cases (P = .002). Subset #2 exhibited significantly shorter time-to-first-treatment (TTFT) compared with non-subset #2/IGHV3-21 (22 vs 60 months, P = .001). No such difference was observed between non-subset #2/IGHV3-21 vs the remaining CLL with similar IGHV mutational status. In conclusion, IGHV3-21 CLL should not be axiomatically considered a homogeneous entity with adverse prognosis, given that only subset #2 emerges as uniformly aggressive, contrasting non-subset #2/IGVH3-21 patients whose prognosis depends on IGHV mutational status as the remaining CLL.

Computerized image analysis of the Ki-67 proliferation index in mantle cell lymphoma.

AIMS: Manual counting of the fraction of Ki-67-positive cells (the Ki-67 index) in 1000 tumour cells is considered the 'gold standard' to predict prognosis in mantle cell lymphoma (MCL). This time-consuming method is replaced by the faster, but less accurate, semiquantitative estimation in routine practice. The aim of this study was to investigate the use of computerized image analysis software for scoring of Ki-67 in MCL. METHODS AND RESULTS: We developed an automated method for determining the Ki-67 index by computerized image analysis and tested it using a cohort of 62 MCL patients. The data were compared to Ki-67 scores obtained by semiquantitative estimation and image-based manual counting. When using the Ki-67 index as a continuous parameter, both image-based manual counting and computerized image analysis were related inversely to survival (P = 0.020 and P = 0.025, respectively). Ki-67 index obtained by semiquantitative estimation was not associated significantly with survival (P = 0.093). The results were validated in a second patient cohort with similar results. CONCLUSION: Computerized image analysis of the Ki-67 index in MCL is an attractive alternative to semiquantitative estimation and can be introduced easily in a routine diagnostic setting for risk stratification in MCL.

PTK2 expression and immunochemotherapy outcome in chronic lymphocytic leukemia.

Addition of rituximab (R) to fludarabine and cyclophosphamide (FC) has significantly improved patient outcomes in chronic lymphocytic leukemia (CLL). Whether baseline gene expression can identify patients who will benefit from immunochemotherapy over chemotherapy alone has not been determined. We assessed genome-wide expression of 300 pretreatment specimens from a subset of 552 patients in REACH, a study of FC or R-FC in relapsed CLL. An independent test set was derived from 282 pretreatment specimens from CLL8, a study of FC or R-FC in treatment-naïve patients. Genes specific for benefit from R-FC were determined by assessing treatment-gene interactions in Cox proportional hazards models. REACH patients with higher pretreatment protein tyrosine kinase 2 (PTK2) messenger RNA levels derived greater benefit from R-FC, with significant improvements in progression-free survival, independent of known prognostic factors in a multivariate model. Examination of PTK2 gene expression in CLL8 patients yielded similar results. Furthermore, PTK2 inhibition blunted R-dependent cell death in vitro. This retrospective analysis from 2 independent trials revealed that increased PTK2 expression is associated with improved outcomes for CLL patients treated with R-FC vs FC. PTK2 expression may be a useful biomarker for patient selection in future trials. These trials were registered at www.clinicaltrials.gov as #NCT00090051 (REACH) and #NCT00281918 (CLL8).