Improved Innate Immune Function in Patients with Chronic Lymphocytic Leukemia Treated with Targeted Therapy in Clinical Trials.

PURPOSE: Patients with chronic lymphocytic leukemia (CLL) have increased risk of severe infections. Although adaptive immune dysfunction is well described, clinical tools for identifying patients at risk are lacking, warranting investigation of additional immune components. In contrast to chemotherapy, targeted agents could spare or even improve innate immune function. Therefore, we investigated innate immune phenotypes and function in patients with CLL before and during targeted treatment. EXPERIMENTAL DESIGN: Baseline and consecutive blood samples were collected from patients with CLL treated with acalabrutinib (n = 17) or ibrutinib+venetoclax (n = 18) in clinical trials. Innate immune function was assessed by TruCulture, a whole-blood ligand-stimulation assay quantifying cytokine release in response to standardized stimuli. Innate immune phenotypes were characterized by flow cytometry. As a proxy for infections, we mapped antimicrobial use before and during treatment. RESULTS: At baseline, patients with CLL displayed impaired stimulated cytokine responses to the endotoxin lipopolysaccharide (LPS) along with deactivated monocytes, enrichment of myeloid-derived suppressor cells and metamyelocytes, and elevated (unstimulated) proinflammatory cytokines. Two/three cycles of acalabrutinib or ibrutinib normalized LPS-stimulated responses, in parallel with decreased duration of infections. Innate immune profiles and elevated proinflammatory cytokines further normalized during longer-term acalabrutinib or ibrutinib+venetoclax, paralleled by decreased infection frequency. CONCLUSIONS: Innate immune impairment and infection susceptibility in patients with CLL were restored in parallel during targeted therapy. Thus, targeted treatment may reduce the risk of infections in CLL, as currently under investigation in the PreVent-ACaLL phase 2 trial of acalabrutinib+venetoclax for high-risk CLL (NCT03868722).

Immunogenicity of the 13-Valent Pneumococcal Conjugated Vaccine Followed by the 23-Valent Polysaccharide Vaccine in Chronic Lymphocytic Leukemia.

Patients with Chronic Lymphocytic Leukemia (CLL) have a 29- to 36-fold increased risk of invasive pneumococcal disease (IPD) compared to healthy adults. Therefore, most guidelines recommend vaccination with the 13-valent pneumococcal conjugated vaccine (PCV13) followed 2 months later by the 23-valent polysaccharide vaccine (PPSV23). Because both CLL as well as immunosuppressive treatment have been identified as major determinants of immunogenicity, we aimed to assess the vaccination schedule in untreated and treated CLL patients. We quantified pneumococcal IgG concentrations against five serotypes shared across both vaccines, and against four serotypes unique to PPSV23, before and eight weeks after vaccination. In this retrospective cohort study, we included 143 CLL patients, either treated (n = 38) or naive to treatment (n = 105). While antibody concentrations increased significantly after vaccination, the overall serologic response was low (10.5%), defined as a ≥4-fold antibody increase against ≥70% of the measured serotypes, and significantly influenced by treatment status and prior lymphocyte number. The serologic protection rate, defined as an antibody concentration of ≥1.3 µg/mL for ≥70% of serotypes, was 13% in untreated and 3% in treated CLL patients. Future research should focus on vaccine regimens with a higher immunogenic potential, such as multi-dose schedules with higher-valent T cell dependent conjugated vaccines.

Fixed-duration venetoclax plus obinutuzumab improves quality of life and geriatric impairments in FCR-unfit patients with CLL.

Chronic lymphocytic leukemia (CLL)-related symptoms and morbidity related to the advanced age at diagnosis impairs the well-being of older adult patients. Therefore, it is essential to tailor treatment according to geriatric characteristics and aim for an improvement in health-related quality of life (HRQoL) as a primary treatment goal. In the HOVON139/GiVe trial, 12 cycles of fixed-duration venetoclax plus obinutuzumab (Ven-O) were shown to be effective and tolerable in FCR (fludarabine, cyclophosphamide, rituximab)-unfit patients with CLL (n = 67). However, prolonged venetoclax exposure as consolidation treatment led to increased toxicity with limited effect on minimal residual disease. To assess the impact of geriatric assessment on treatment outcomes and the patients' HRQoL, patient-reported outcomes (PROs), including function, depression, cognition, nutrition, physical performance, muscle parameters, comorbidities, and the European Organization for Research and Treatment of Cancer C30 and CLL17 questionnaires were assessed. At baseline, geriatric impairments were present in >90% of patients and ≥2 impairments present in 60% of patients predicted grade ≥3 nonhematological toxicity. During treatment, the number of geriatric impairments diminished significantly and clinically relevant improvements in HRQoL subscales were reached for global health status, physical functioning, role functioning, emotional functioning, fatigue, dyspnea, physical condition or fatigue, and worries or fears related to health and functioning. These improvements were comparable for patients receiving venetoclax consolidation and patients in whom treatment could mostly be discontinued. Collectively, frontline fixed-duration Ven-O improves overall PROs in older, unfit patients with CLL with and without geriatric impairments. This study was registered at EudraCT as 2015-004985-27 and the Netherlands Trial Register as NTR6043.

Ibrutinib sensitizes CLL cells to venetoclax by interrupting TLR9-induced CD40 upregulation and protein translation.

Chronic lymphocytic leukemia (CLL) cells upregulate Bcl-2 proteins within the lymph node (LN) microenvironment. Signaling via B-cell receptor, Toll-like receptors and CD40 collectively reduce sensitivity to the BCL-2 inhibitor venetoclax. Time-limited treatment with venetoclax plus the BTK-inhibitor ibrutinib results in deep remissions, but how this combination affects LN-related signaling is not yet completely clear. Therefore, samples obtained from the HOVON141/VISION phase 2 clinical trial were used to analyze this. Two cycles of lead-in ibrutinib monotherapy resulted in decreased protein expression of Bcl-2 proteins in circulating CLL cells. Strikingly, at this timepoint CD40-induced venetoclax resistance was strongly attenuated, as was expression of CD40. Since CD40 signaling occurs within the CLL LN, we tested various LN-related signals that could affect CD40 signaling. While BCR stimulation had only a minor effect, TLR9 stimulation via CpG led to significantly increased CD40 expression and importantly, reverted the effects of ibrutinib treatment on venetoclax sensitivity by inducing overall protein translation. Together, these findings identify a novel effect of ibrutinib: interruption of TLR9-induced CD40 upregulation and translation of pro-survival proteins. This mechanism may potentially further inhibit priming of CLL cells in the LN microenvironment for venetoclax resistance.

Thrombotic and bleeding complications in patients with chronic lymphocytic leukemia and severe COVID-19: a study of ERIC, the European Research Initiative on CLL.

BACKGROUND: Patients with chronic lymphocytic leukemia (CLL) may be more susceptible to COVID-19 related poor outcomes, including thrombosis and death, due to the advanced age, the presence of comorbidities, and the disease and treatment-related immune deficiency. The aim of this study was to assess the risk of thrombosis and bleeding in patients with CLL affected by severe COVID-19. METHODS: This is a retrospective multicenter study conducted by ERIC, the European Research Initiative on CLL, including patients from 79 centers across 22 countries. Data collection was conducted between April and May 2021. The COVID-19 diagnosis was confirmed by the real-time polymerase chain reaction (RT-PCR) assay for SARS-CoV-2 on nasal or pharyngeal swabs. Severe cases of COVID-19 were defined by hospitalization and the need of oxygen or admission into ICU. Development and type of thrombotic events, presence and severity of bleeding complications were reported during treatment for COVID-19. Bleeding events were classified using ISTH definition. STROBE recommendations were used in order to enhance reporting. RESULTS: A total of 793 patients from 79 centers were included in the study with 593 being hospitalized (74.8%). Among these, 511 were defined as having severe COVID: 162 were admitted to the ICU while 349 received oxygen supplementation outside the ICU. Most patients (90.5%) were receiving thromboprophylaxis. During COVID-19 treatment, 11.1% developed a thromboembolic event, while 5.0% experienced bleeding. Thrombosis developed in 21.6% of patients who were not receiving thromboprophylaxis, in contrast to 10.6% of patients who were on thromboprophylaxis. Bleeding episodes were more frequent in patients receiving intermediate/therapeutic versus prophylactic doses of low-molecular-weight heparin (LWMH) (8.1% vs. 3.8%, respectively) and in elderly. In multivariate analysis, peak D-dimer level and C-reactive protein to albumin ratio were poor prognostic factors for thrombosis occurrence (OR = 1.022, 95%CI 1.007‒1.038 and OR = 1.025, 95%CI 1.001‒1.051, respectively), while thromboprophylaxis use was protective (OR = 0.199, 95%CI 0.061‒0.645). Age and LMWH intermediate/therapeutic dose administration were prognostic factors in multivariate model for bleeding (OR = 1.062, 95%CI 1.017-1.109 and OR = 2.438, 95%CI 1.023-5.813, respectively). CONCLUSIONS: Patients with CLL affected by severe COVID-19 are at a high risk of thrombosis if thromboprophylaxis is not used, but also at increased risk of bleeding under the LMWH intermediate/therapeutic dose administration.

Minimal residual disease-guided stop and start of venetoclax plus ibrutinib for patients with relapsed or refractory chronic lymphocytic leukaemia (HOVON141/VISION): primary analysis of an open-label, randomised, phase 2 trial.

BACKGROUND: Targeted time-limited treatment options are needed for patients with relapsed or refractory chronic lymphocytic leukaemia. The aim of this study was to investigate the efficacy of minimal residual disease (MRD)-guided, time-limited ibrutinib plus venetoclax treatment in this patient group. METHODS: HOVON141/VISION was an open-label, randomised, phase 2 trial conducted in 47 hospitals in Belgium, Denmark, Finland, the Netherlands, Norway, and Sweden. Eligible participants were aged 18 years or older with previously treated chronic lymphocytic leukaemia with or without TP53 aberrations; had not been exposed to Bruton tyrosine-kinase inhibitors or BCL2 inhibitors; had a creatinine clearance rate of 30 mL/min or more; and required treatment according to International Workshop on Chronic Lymphocytic Leukemia 2018 criteria. Participants with undetectable MRD (<10-4; less than one chronic lymphocytic leukaemia cell per 10 000 leukocytes) in peripheral blood and bone marrow after 15 28-day cycles of oral ibrutinib (420 mg once daily) plus oral venetoclax (weekly ramp-up 20 mg, 50 mg, 100 mg, 200 mg, up to 400 mg once daily) were randomly assigned (1:2) to ibrutinib maintenance or treatment cessation. Patients who were MRD positive continued to receive ibrutinib monotherapy. Patients who became MRD (>10-2) during observation reinitiated treatment with ibrutinib plus venetoclax. The primary endpoint was progression-free survival at 12 months after random assignment in the treatment cessation group. Progression-free survival was analysed in the intention-to-treat population. All patients who received at least one dose of study drug were included in the safety assessment. The study is registered at ClinicalTrials.gov, NCT03226301, and is active but not recruiting. FINDINGS: Between July 12, 2017, and Jan 21, 2019, 230 patients were enrolled, 225 of whom were eligible. 188 (84%) of 225 completed treatment with ibrutinib plus venetoclax and were tested for MRD at cycle 15. After cycle 15, 78 (35%) patients had undetectable MRD and 72 (32%) were randomly assigned to a treatment group (24 to ibrutinib maintenance and 48 to treatment cessation). The remaining 153 patients were not randomly assigned and continued with ibrutinib monotherapy. Median follow-up of 208 patients still alive and not lost to follow-up at data cutoff on June 22, 2021, was 34·4 months (IQR 30·6-37·9). Progression-free survival after 12 months in the treatment cessation group was 98% (95% CI 89-100). Infections (in 130 [58%] of 225 patients), neutropenia (in 91 [40%] patients), and gastrointestinal adverse events (in 53 [24%] patients) were the most frequently reported; no new safety signals were detected. Serious adverse events were reported in 46 (40%) of 116 patients who were not randomly assigned and who continued ibrutinib maintenance after cycle 15, eight (33%) of 24 patients in the ibrutinib maintenance group, and four (8%) of 48 patients in the treatment cessation group. One patient who was not randomly assigned had a fatal adverse event (bleeding) deemed possibly related to ibrutinib. INTERPRETATION: These data point to a favourable benefit-risk profile of MRD-guided, time-limited treatment with ibrutinib plus venetoclax for patients with relapsed or refractory chronic lymphocytic leukaemia, suggesting that MRD-guided cessation and reinitiation is feasible in this patient population. FUNDING: AbbVie and Janssen.

Diagnosis, treatment and supportive management of chronic lymphocytic leukemia: recommendations of the Dutch HOVON CLL working group.

Management of patients with chronic lymphocytic leukemia (CLL) is changing due to considerable advances in the therapeutic armamentarium, and new therapies will possibly continue to emerge in the near future. Therefore, the CLL working group of the Dutch-Belgium Haemato-Oncology Cooperative Group for Adults in the Netherlands (HOVON) necessitated revising the Dutch CLL guidelines. The current guideline is based on the expert opinion of the HOVON CLL working group members and focusses on well-designed clinical trials taking into account efficacy with special emphasis on toxicity, treatment duration and treatment intensity. This article provides recommendations on diagnosis, treatment strategies in front-line and relapsed setting and provides supportive care measurements during novel-based therapies as well as for infectious CLL-related complications. The recommendations presented here are intended to provide guidance for the management of CLL patients in the Netherlands, and take into account the availability of treatment strategies at the time of this publication.

Venetoclax consolidation after fixed-duration venetoclax plus obinutuzumab for previously untreated chronic lymphocytic leukaemia (HOVON 139/GiVe): primary endpoint analysis of a multicentre, open-label, randomised, parallel-group, phase 2 trial.

BACKGROUND: Fixed-duration 12 cycles of venetoclax plus obinutuzumab is established as first-line treatment for patients with chronic lymphocytic leukaemia. We aimed to determine the activity and safety of 12 cycles of venetoclax consolidation after fixed-duration venetoclax plus obinutuzumab for previously untreated patients with chronic lymphocytic leukaemia who were unfit for fludarabine-based treatment, and whether this could be guided by minimal residual disease status. METHODS: We conducted an open-label, randomised, parallel-group, phase 2 trial (HOVON 139/GiVe) at 25 hospitals in the Netherlands. Eligible patients were aged 18 years or older with previously untreated chronic lymphocytic leukaemia, had an ECOG performance status of 0-2, and were unfit for fludarabine-based treatment. All patients received two debulking cycles of intravenous obinutuzumab (100 mg on day 1, 900 mg on day 2, and 1000 mg on days 8, 15, and day 1 of cycle two), followed by fixed-duration venetoclax plus obinutuzumab for 12 cycles (six cycles of intravenous obinutuzumab 1000 mg on day 1 and 12 during 28-day cycles of oral venetoclax, starting with a 5-week ramp-up and then 400 mg once daily until completion of cycle 12). Patients were then randomly assigned (1:1) by minimal residual disease status in peripheral blood, to receive either 12 cycles of venetoclax consolidation irrespective of minimal residual disease or venetoclax consolidation only if minimal residual disease was detected at randomisation. The primary endpoint was undetectable minimal residual disease in bone marrow and no progressive disease 3 months after end of consolidation treatment (or corresponding timepoint) by intention-to-treat. Safety was assessed in all patients who received at least one dose of any study drug. This is the primary endpoint analysis of this trial, which is ongoing and is registered with EudraCT (2015-004985-27). FINDINGS: Between Oct 28, 2016, and May 31, 2018, 70 patients were enrolled, of whom 67 (47 [70%] men and 20 [30%] women) received fixed-duration treatment and 62 were randomly assigned to receive 12 cycles of venetoclax consolidation (n=32) or minimal residual disease-guided venetoclax consolidation (n=30; one of whom was minimal residual disease positive at randomisation). Median follow-up was 35·2 months (IQR 31·5-41·3). 16 (50% [95% CI 32-68]) of 32 patients in the consolidation group and 16 (53% [34-72]) of 30 in the minimal residual disease-guided consolidation group met the primary endpoint of undetectable minimal residual disease in bone marrow and no progressive disease. 22 (69%) of 32 patients in the venetoclax consolidation group and 11 (37%) of 30 in the minimal residual disease-guided consolidation group had any adverse event (grade 2-4; mainly infections). The most common grade 3 or worse adverse events were infection (two [6%] of 32 patients in the consolidation group and one [3%] of 30 in the minimal residual disease-guided consolidation group) and neutropenia (two [6%] and two [7%]). There were no treatment-related deaths. INTERPRETATION: Consolidation with venetoclax 12-cycle treatment increases the duration of known side-effects and does not prevent the loss of minimal residual disease response and subsequent risk of disease relapse. FUNDING: F Hoffmann-La Roche.

Protocol description of the HOVON 141/VISION trial: a prospective, multicentre, randomised phase II trial of ibrutinib plus venetoclax in patients with creatinine clearance ≥30 mL/min who have relapsed or refractory chronic lymphocytic leukaemia (RR-CLL) with or without TP53 aberrations.

INTRODUCTION: Literature is scarce on the combination treatment of ibrutinib and venetoclax (IV) is scarce in relapsed or refractory chronic lymphocytic leukaemia (RR-CLL). Especially, the possibility of stopping ibrutinib in RR-CLL patients in deep remission is unclear. METHODS AND ANALYSIS: In the HOVON 141/VISION trial, patients with RR-CLL are treated with 12 cycles of IV after a short induction with ibrutinib. Patients reaching undetectable minimal residual disease (uMRD) after 12 cycles of IV are randomised 1:2 to continue ibrutinib or stop treatment. The persistence of uMRD after stopping IV is studied. In addition, in patients who become positive for MRD again after stopping, IV treatment is reinitiated. The efficacy of this approach with regard to progression-free survival 12 months after randomisation is the primary endpoint of the study. ETHICS AND DISSEMINATION: This protocol respects the Helsinki declaration and has been approved by the ethical committee of the Amsterdam Medical Center. Study findings will be disseminated through peer-reviewed papers. All patients who fulfil the inclusion criteria and no-exclusion criteria, and have signed the informed consent form are included in the study. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov Registry (NCT03226301).

Changes in primary and secondary hemostasis in patients with CLL treated with venetoclax and ibrutinib.

Bleeding is a common adverse event following ibrutinib monotherapy. However, it remains unclear how hemostasis is affected by venetoclax in combination with ibrutinib. Here we investigated hemostasis in patients with chronic lymphocytic leukemia (CLL) at baseline, during ibrutinib monotherapy, and during venetoclax and ibrutinib combination therapy or venetoclax monotherapy. Primary hemostasis, assessed by Multiplate using adenosine diphosphate (ADP), arachidonic acid (AA), and thrombin receptor agonist peptide (TRAP-6), was impaired in all CLL patients at baseline, remained unchanged upon ibrutinib monotherapy, and improved significantly following venetoclax added to ibrutinib or as monotherapy. Secondary hemostasis assessed by thromboelastography (TEG) was normal and unchanged throughout treatment. The frequency of clinical bleeding events was the highest during ibrutinib monotherapy, in line with the demonstrated improved primary hemostasis upon addition of venetoclax, thus pointing toward a treatment option for CLL patients with increased bleeding risk.

Proteomic markers with prognostic impact on outcome of chronic lymphocytic leukemia patients under chemo-immunotherapy: results from the HOVON 109 study.

Despite recent identification of several prognostic markers, there is still a need for new prognostic parameters able to predict clinical outcome in chronic lymphocytic leukemia (CLL) patients. Here, we aimed to validate the prognostic ability of known (proteomic) markers measured pretreatment and to search for new proteomic markers that might be related to treatment response in CLL. To this end, baseline serum samples of 51 CLL patients treated with chemo-immunotherapy were analyzed for 360 proteomic markers, using Olink technology. Median event-free survival (EFS) was 23 months (range: 1.25-60.9). Patients with high levels of sCD23 (>11.27, p = 0.026), sCD27 (>11.03, p = 0.04), SPINT1 (>1.6, p = 0.001), and LY9 (>8.22, p = 0.0003) had a shorter EFS than those with marker levels below the median. The effect of sCD23 on EFS differed between immunoglobulin heavy chain variable gene-mutated and unmutated patients, with the shortest EFS for unmutated CLL patients with sCD23 levels above the median. Taken together, our results validate the prognostic impact of sCD23 and highlight SPINT1 and LY9 as possible promising markers for treatment response in CLL patients.

COVID-19 severity and mortality in patients with chronic lymphocytic leukemia: a joint study by ERIC, the European Research Initiative on CLL, and CLL Campus.

Chronic lymphocytic leukemia (CLL) is a disease of the elderly, characterized by immunodeficiency. Hence, patients with CLL might be considered more susceptible to severe complications from COVID-19. We undertook this retrospective international multicenter study to characterize the course of COVID-19 in patients with CLL and identify potential predictors of outcome. Of 190 patients with CLL and confirmed COVID-19 diagnosed between 28/03/2020 and 22/05/2020, 151 (79%) presented with severe COVID-19 (need of oxygen and/or intensive care admission). Severe COVID-19 was associated with more advanced age (≥65 years) (odds ratio 3.72 [95% CI 1.79-7.71]). Only 60 patients (39.7%) with severe COVID-19 were receiving or had recent (≤12 months) treatment for CLL at the time of COVID-19 versus 30/39 (76.9%) patients with mild disease. Hospitalization rate for severe COVID-19 was lower (p < 0.05) for patients on ibrutinib versus those on other regimens or off treatment. Of 151 patients with severe disease, 55 (36.4%) succumbed versus only 1/38 (2.6%) with mild disease; age and comorbidities did not impact on mortality. In CLL, (1) COVID-19 severity increases with age; (2) antileukemic treatment (particularly BTK inhibitors) appears to exert a protective effect; (3) age and comorbidities did not impact on mortality, alluding to a relevant role of CLL and immunodeficiency.

Distinct immune composition in lymph node and peripheral blood of CLL patients is reshaped during venetoclax treatment.

Morbidity and mortality due to immunosuppression remain among the foremost clinical challenges in chronic lymphocytic leukemia (CLL). Although immunosuppression is considered to originate within the lymph node (LN) microenvironment, alterations in T and natural killer (NK) cells have almost exclusively been studied in peripheral blood (PB). Whereas chemoimmunotherapy further deteriorates immune function, novel targeted agents like the B-cell lymphoma 2 inhibitor venetoclax potentially spare nonmalignant lymphocytes; however, the effects of venetoclax on nonleukemic cells have not been explored. We address these unresolved issues using a comprehensive analysis of nonmalignant lymphocytes in paired LN and PB samples from untreated CLL patients, and by analyzing the effects of venetoclax-based treatment regimens on the immune system in PB samples from previously untreated and relapsed/refractory patients. CLL-derived LNs contained twice the amount of suppressive regulatory T cells (Tregs) and CLL supportive follicular T helper (Tfh) cells compared with PB. This was accompanied by a low frequency of cytotoxic lymphocytes. The expression of PD-1 by CD8+ T cells was significantly higher in LN compared with PB. Venetoclax-based treatment led to deep responses in the majority of patients, but also to decreased absolute numbers of B, T, and NK cells. Tfh cell, Treg, and PD-1+ CD8+ T cell numbers were reduced more than fivefold after venetoclax-based therapy, and overproduction of inflammatory cytokines was reduced. Furthermore, we observed restoration of NK cell function. These data support the notion that the immunosuppressive state in CLL is more prominent within the LN. Venetoclax-based regimens reduced the immunosuppressive footprint of CLL, suggesting immune recovery after the elimination of leukemic cells.

Ruxolitinib in Myelofibrosis and Baseline Thrombocytopenia in Real Life: Results in Dutch Patients and Review of the Literature.

BACKGROUND: Ruxolitinib is an approved treatment for myelofibrosis patients, but data regarding patients with baseline thrombocytopenia are limited. The EXPAND study recently suggested tolerability of ruxolitinib, with a maximum starting dose of 10 mg 2 times a day (BID). However, the small sample size and vigorous follow-up in this trial hamper direct translation of these results to routine practice. PATIENTS AND METHODS: We report retrospective data on Dutch ruxolitinib-treated myelofibrosis patients, focusing on those with baseline thrombocytopenia. Additionally, we reviewed current literature regarding ruxolitinib treatment in this subgroup. RESULTS: In our cohort, 12 of 119 patients had a baseline platelet count of < 100 × 109/L. Spleen responses at a mean treatment duration of 25 weeks were documented in 1 of 6 and 15 of 47 patients with and without baseline thrombocytopenia, respectively. Despite a high rate of grade 3 or higher thrombocytopenia in thrombocytopenic versus nonthrombocytopenic patients (42% vs. 15%), no grade 3 or higher hemorrhage was reported. Median doses in thrombocytopenic patients were 15 and 10 mg BID at the start and after 12 weeks of treatment, respectively. Additionally, 238 thrombocytopenic patients were identified in the available literature, of whom 59 were treated in routine practice. Incidences of severe thrombocytopenia reported separately for patients with baseline thrombocytopenia were 30% to 59% (grade 3 or higher) and 4% to 60% (grade 4). Severe bleeding, pooled across our data and evaluable studies, occurred in 2.4%. CONCLUSION: Ruxolitinib treatment appears to be safe for patients with platelet counts of 50 to 100 × 109/L in real-life practice. We did not find any reason to discourage a starting dose of 10 mg BID in this subgroup.

Feasibility and efficacy of addition of individualized-dose lenalidomide to chlorambucil and rituximab as first-line treatment in elderly and FCR-unfit patients with advanced chronic lymphocytic leukemia.

Lenalidomide has been proven to be effective but with a distinct and difficult to manage toxicity profile in the context of chronic lymphocytic leukemia, potentially hampering combination treatment with this drug. We conducted a phase 1-2 study to evaluate the efficacy and safety of six cycles of chlorambucil (7 mg/m2 daily), rituximab (375 mg/m2 cycle 1 and 500 mg/m2 cycles 2-6) and individually-dosed lenalidomide (escalated from 2.5 mg to 10 mg) (induction-I) in first-line treatment of patients with chronic lymphocytic leukemia unfit for treatment with fludarabine, cyclophosphamide and rituximab. This was followed by 6 months of 10 mg lenalidomide monotherapy (induction-II). Of 53 evaluable patients in phase 2 of the study, 47 (89%) completed induction-I and 36 (68%) completed induction-II. In an intention-to-treat analysis, the overall response rate was 83%. The median progression-free survival was 49 months, after a median follow-up time of 27 months. The 2- and 3-year progression-free survival rates were 58% and 54%, respectively. The corresponding rates for overall survival were 98% and 95%. No tumor lysis syndrome was observed, while tumor flair reaction occurred in five patients (9%, 1 grade 3). The most common hematologic toxicity was grade 3-4 neutropenia, which occurred in 73% of the patients. In conclusion, addition of lenalidomide to a chemotherapy backbone followed by a fixed duration of lenalidomide monotherapy resulted in high remission rates and progression-free survival rates, which seem comparable to those observed with novel drug combinations including novel CD20 monoclonal antibodies or kinase inhibitors. Although lenalidomide-specific toxicity remains a concern, an individualized dose-escalation schedule is feasible and results in an acceptable toxicity profile. EuraCT number: 2010-022294-34.

Obinutuzumab pretreatment abrogates tumor lysis risk while maintaining undetectable MRD for venetoclax + obinutuzumab in CLL.

Early data on venetoclax-containing regimens for the treatment of chronic lymphocytic leukemia (CLL) show promising results with deep remissions, but are hampered by potential risk for tumor lysis syndrome (TLS). Whether optimal duration of venetoclax treatment can be guided by minimal residual disease (MRD) is currently unknown. To study whether TLS risk can be mitigated in an unfit population by introducing preinduction, and whether MRD-guided duration of venetoclax treatment is a feasible and efficacious approach, we performed the Dutch-Belgian Cooperative Trial Group for Hemato-oncology (HOVON) 139/GIVE trial. The study treatment consists of 4 treatment phases: preinduction (2 cycles obinutuzumab), induction I (6 cycles obinutuzumab and venetoclax), induction II (6 cycles venetoclax), and a randomization phase (group A: maintenance with 12 additional cycles of venetoclax irrespective of MRD; group B: MRD guided venetoclax maintenance with a maximum of 12 cycles). Here we report on a planned interim safety analysis as well as preliminary efficacy and MRD data of the first 30 patients enrolled. Downgrading of TLS risk after preinduction occurred in 25 patients: 3 from high to medium, 3 from high to low, and 19 from medium to low risk. No patient remained high risk. From these 30 patients, peripheral blood MRD data were obtained for 28 patients at the end of induction II (6 months after the last obinutuzumab dose), of whom 26 had undetectable MRD levels, and for 18 patients who reached the 3-month after-randomization point, of whom 16 had undetectable MRD levels. Obinutuzumab preinduction is tolerated well in these unfit patients and results in abrogating high TLS risk in all patients. Preliminary data indicate that efficacy is maintained with a high proportion of patients with undetectable MRD levels after combination treatment.

Clinical Practice Guidelines for Diagnosis and Treatment of Chronic Lymphocytic Leukemia (CLL) in The Netherlands.

INTRODUCTION: In recent years, considerable progress has been made in the treatment of patients with chronic lymphocytic leukemia (CLL), and new potent drugs have become available. Therefore, the CLL working party revised the Dutch guidelines. Not only efficacy but also quality of life and socio-economic impact were taken into account in the formulation of treatment recommendations. MATERIALS AND METHODS: The working party discussed a set of questions regarding diagnostic tests and treatment and wrote the draft guideline. This was evidence-based whenever possible, but in cases of low evidence, an expert-based recommendation was formulated with input of the entire working party. The draft guideline was sent to all hematologists in the Netherlands for comment and was subsequently approved. RESULTS: Recommendations were formulated on diagnostic tests and work-up before treatment. Also, recommendations were made for treatment with fludarabine-cyclophosphamide-rituximab, bendamustine-rituximab, chlorambucil with anti-CD20 antibody, ibrutinib, idelalisib-rituximab, venetoclax, and allogeneic stem cell transplantation. CONCLUSION: In the revised Dutch CLL guidelines, chemo-immunotherapy is still the cornerstone of CLL treatment with novel targeted drugs for specific risk groups.

CD40 signaling instructs chronic lymphocytic leukemia cells to attract monocytes via the CCR2 axis.

Chronic lymphocytic leukemia (CLL) cells are provided with essential survival and proliferative signals in the lymph node microenvironment. Here, CLL cells engage in various interactions with bystander cells such as T cells and macrophages. Phenotypically distinct types of tumor infiltrating macrophages can either be tumor supportive (M2) or play a role in tumor immune surveillance (M1). Although recent in vitro findings suggest a protective role for macrophages in CLL, the actual balance between these macrophage subsets in CLL lymphoid tissue is still unclear. Furthermore, the mechanism of recruitment of monocytes towards the CLL lymph node is currently unknown. Both questions are addressed in this paper. Immunofluorescence staining of lymph node samples showed macrophage skewing towards an M2 tumor-promoting phenotype. This polarization likely results from CLL-secreted soluble factors, as both patient serum and CLL-conditioned medium recapitulated the skewing effect. Considering that CLL cell cytokine secretion is affected by adjacent T cells, we next studied CLL-mediated monocyte recruitment in the presence or absence of T-cell signals. While unstimulated CLL cells were inactive, T cell-stimulated CLL cells actively recruited monocytes. This correlated with secretion of various chemokines such as C-C-motif-ligand-2,3,4,5,7,24, C-X-C-motif-ligand-5,10, and Interleukin-10. We also identified CD40L as the responsible T-cell factor that mediated recruitment, and showed that recruitment critically depended on the C-C-motif-chemokine-receptor-2 axis. These studies show that the shaping of a tumor supportive microenvironment depends on cytokinome alterations (including C-C-motif-ligand-2) that occur after interactions between CLL, T cells and monocytes. Therefore, targeted inhibition of CD40L or C-C-motif-chemokine-receptor-2 may be relevant therapeutic options.

Multi-state analysis illustrates treatment success after stem cell transplantation for acute myeloid leukemia followed by donor lymphocyte infusion.

In the field of hematopoietic stem cell transplantation, the common approach is to focus outcome analyses on time to relapse and death, without assessing the impact of post-transplant interventions. We investigated whether a multi-state model would give insight into the events after transplantation in a cohort of patients who were transplanted using a strategy including scheduled donor lymphocyte infusions. Seventy-eight consecutive patients who underwent myeloablative T-cell depleted allogeneic stem cell transplantation for acute myeloid leukemia or myelodysplastic syndrome were studied. We constructed a multi-state model to analyze the impact of donor lymphocyte infusion and graft-versus-host disease on the probabilities of relapse and non-relapse mortality over time. Based on this model we introduced a new measure for outcome after transplantation which we called 'treatment success': being alive without relapse and immunosuppression for graft-versus-host disease. All relevant clinical events were implemented into the multi-state model and were denoted treatment success or failure (either transient or permanent). Both relapse and non-relapse mortality were causes of failure of comparable magnitude. Whereas relapse was the dominant cause of failure from the transplantation state, its rate was reduced after graft-versus-host disease, and especially after donor lymphocyte infusion. The long-term probability of treatment success was approximately 40%. This probability was increased after donor lymphocyte infusion. Our multi-state model helps to interpret the impact of post-transplantation interventions and clinical events on failure and treatment success, thus extracting more information from observational data.