Abstract Phosphoinositide 3-kinase (PI3K) is a key target in cancer therapy, but first-generation PI3K inhibitors were associated with toxicities limiting their clinical use. Roginolisib, a next-generation PI3Kdelta inhibitor, is currently being investigated across multiple cancer types. In contrast to previous PI3K inhibitors, roginolisib has shown a well-tolerated profile. We hypothesize that this improved safety is in part due to high selectivity, driven by its structural properties. Structural and biophysical analyses—including X-ray crystallography, molecular dynamics simulations, and hydrogen-deuterium exchange mass spectrometry—demonstrate that roginolisib, unlike the first-generation inhibitor idelalisib, stabilizes the catalytic C-terminal helix (k-alpha12) of PI3Kdelta. This stabilization is specific for PI3Kdelta and locks the enzyme in an inactive conformation, resulting in potent and sustained inhibition of PI3Kdelta activity. This inhibition profile is observed in tumor samples from patients with chronic lymphocytic leukemia (CLL) and in lymphoma cell lines. Although roginolisib and idelalisib exhibit similar potency in CLL cells, their effects on immune cells differ. Notably, high concentrations of idelalisib impair the cytotoxic activity of CD8+ T cells and promote the differentiation of CD4+ T cells towards Th17 and Th2 subsets. By contrast, roginolisib preserves CD8+ T-cell function and does not alter CD4+ T-cell differentiation. This mechanism of inhibition, likely based on conformational stabilization of the inactive kinase, is novel for PI3K small-molecule inhibitors. Hence, our findings may enable the development of more effective and better-tolerated PI3K inhibitors. Citation Format: Giusy Di Conza, Oscar Vadas, Simon Tiede, Elise Solli, Maria Chaouki, Laura Tesmer, Shanlin Rao, Remy Visentin, Mathias Wenes, Denis Migliorini, Sigrid S. Skånland, Anne Quillet-Mary, Loïc Ysebaert, Julie Guillermet-Guibert, Alessio Bevilacqua, Lars van der Veen, Michael Lahn, Kjetil Tasken, Gerhard Hummer. Roginolisib stabilizes inactive PI3Kdelta to deliver specific target blockade with reduced immune toxicity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 5763.

In this review, we focus on the pro-oncogene MYC, the modes of deregulation in mouse and human B-cells, its undisputable importance in the evaluation of biological prognostication of patients, but also how it impacts on response to modern therapeutics, and how it should be targeted to improve the overall survival of chronic lymphocytic lymphoma (CLL) patients. After an overview of the current understanding of the molecular dysregulation of c-MYC, we will show how CLL, both in its indolent and transformed phases, has developed among other B-cell lymphomas a tight regulation of its expression through the chronic activation of B-Cell Receptors (among others). This is particularly important if one desires to understand the mechanisms at stake in the over-expression of c-MYC especially in the lymph nodes compartment. So doing, we will show how this oncogene orchestrates pivotal cellular functions such as metabolism, drug resistance, proliferation and histologic transformation (Richter syndrome).

Objective: Ibrutinib has been the first Bruton tyrosine kinase inhibitor (BTKi) authorized for the treatment of B-cell lymphoproliferative disorders (B-LPDs). Numerous publications have confirmed the efficacy of this orally administrated drug in chemo-free regimens for B-LPDs. They also reported several adverse events (AE) associated with ibrutinib treatment. Whether these AEs depended on ibrutinib exposure has however been seldom explored. Methods: In the study reported here, the incidence of AE was recorded in 92 patients with B-LPD (mostly chronic lymphocytic leukemia n = 79) for whom ibrutinib alone was proposed as fist line therapy. Moreover, a pharmacokinetics (PK) exploration was planned over one day after 1 month treatment. PK assays included drug and metabolite (DHD-ibrutinib) mean/median and maximal plasmatic concentrations as well as areas under the curve (AUE) data. Results: This PK evaluation was analyzed regarding AEs recorded over the first year of therapy, which were similar as in published reports. PK data disclosed a significant impact of ibrutinib exposure on infections but mostly on the occurrence of hypertension. The latter was mostly related to dihydrodiol-ibrutinib (DHD-ibrutinib) exposure. Conclusions: These data suggest that a DHD-ibrutinib assay after one month of treatment could be interesting to consider a lower dosage for patients above maximal concentration thresholds for the drug, its metabolite or the sum of both. Whether this can be applied to newer BTKi remains to be explored but it could be important for patients to whom ibrutinib is proposed.

Pediatric B-cell acute lymphoblastic leukemia (B-ALL) is effectively controlled with contemporary multi-agent chemotherapy, resulting to 5-year survival rates above 90%. However, relapse occurs in 15-20% of patients due to minimal residual disease (MRD), characterized by the presence of persisting and resistant leukemic cells, and associated with a poor clinical outcome. Despite its prognostic relevance, the molecular features driving MRD are poorly characterized. In this study, we developed patient-derived xenograft (PDX) models from matched diagnosis and relapse B-ALL samples combined to chemotherapy to mimic MRD in vivo . Drug-tolerant leukemic cells were profiled using single-cell RNA sequencing and we identified a transcriptionally distinct MRD-like population enriched for cell-quiescence, inflammatory stress, and B-cell receptor pathway signatures. Strikingly, the B-lymphocyte surface antigen CD20, encoding by MS4A1 gene, emerged as a consistent upregulated marker in MRD cells from PDXs and patients with diverse oncogenic subtypes. We further demonstrated that CD20 expression is induced by glucocorticoid exposure, creating a therapeutic opportunity where anti-CD20 monoclonal antibodies selectively eradicated MRD cells in vivo . Our data highlight CD20 not only as a biomarker but as an actionable vulnerability in B-ALL MRD, supporting clinical evaluation of anti-CD20 immunotherapy during induction treatment to kill drug-resistant cells and reduce relapse risk.

Background One of the first clinical observations of ibrutinib activity in the treatment of chronic lymphocytic leukemia (CLL) is a rapid decline in lymph nodes size. This phenomenon is accompanied by an hyperlymphocytosis, either transient or prolonged, which is associated with distinct clinical responses and thus has an impact on long-term outcomes. Understanding which factors determine distinct disease courses upon ibrutinib treatment remains a scientific challenge. Methods and findings From 2016 to 2021, we conducted a longitudinal and observational study in 2 cohorts of patients with chronic lymphocytic leukemia (CLL) (cohort 1, n = 41; cohort 2, n = 81). These cohorts reflect the well-known clinical features of CLL patients, such as Male/Female sex ratio of 2/1, a median age of 70 years at diagnosis, and include patients in first-line therapy (27%) or relapsed/refractory patients (73%). Blood cell counts were followed for each patient during 2 years of ibrutinib treatment. In addition, immunophenotyping and whole-body magnetic resonance imaging (MRI) were assessed in patients from cohort 1. These data were integrated in a newly built mathematical model, inspired by previous mathematical works on CLL treatment and combining dynamical and statistical models, leading to the identification of biological mechanisms associated with the 2 types of clinical responses. This multidisciplinary approach allowed to identify baseline parameters that dictated lymphocytes kinetics upon ibrutinib treatment. Indeed, ibrutinib-induced lymphocytosis defined 2 CLL patient subgroups, transient hyperlymphocytosis (tHL) or prolonged hyperlymphocytosis (pHL), that can be discriminated, before the treatment, by absolute counts of CD4+ T lymphocytes (p = 0.026) and regulatory CD4 T cells (p = 0.007), programmed cell death protein 1 PD1 (p = 0.022) and CD69 (p = 0.03) expression on B leukemic cells, CD19/CD5high/CXCR4low level (p = 0.04), and lymph node cellularity. We also pinpointed that the group of patients identified by the transient hyperlymphocytosis has lower duration response and a poor clinical outcome. The mathematical approach led to the reproduction of patient-specific dynamics and the estimation of associated patient-specific biological parameters, and highlighted that the differences between the 2 groups were mainly due to the production of leukemic B cells in lymph node compartments, and to a lesser extent to T lymphocytes and leukemic B cell egress into bloodstream. Access to additional data, especially longitudinal MRI data, could strengthen the conclusions regarding leukemic B cell dynamics in lymph nodes and the relevance of 2 distinct groups of patients. Conclusions Altogether, our multidisciplinary study provides a better understanding of ibrutinib response and highlights new pharmacodynamic parameters before and along ibrutinib treatment. Since our results highlight a reduced duration response and outcome in patients with transient hyperlymphocytosis, our approach provides support for managing ibrutinib therapy after 3 months of treatment. Trial registration ClinicalTrials.gov NCT02824159.

The Bruton tyrosine kinase (BTK) inhibitor ibrutinib is widely used for treatment of patients with relapsed/refractory or treatment-naïve chronic lymphocytic leukemia (CLL). A prominent effect of ibrutinib is to disrupt the retention of CLL cells from supportive lymphoid tissues, by altering BTK-dependent adhesion and migration. To further explore the mechanism of action of ibrutinib and its potential impact on non-leukemic cells, we quantified multiple motility and adhesion parameters of human primary CLL cells and non-leukemic lymphoid cells. In vitro, ibrutinib affected CCL19-, CXCL12- and CXCL13-evoked migration behavior of CLL cells and non-neoplastic lymphocytes, by reducing both motility speed and directionality. De-phosphorylation of BTK induced by ibrutinib in CLL cells was associated with defective polarization over fibronectin and inability to assemble the immunological synapse upon B-cell receptor engagement. In patients' samples collected during a 6-month monitoring of therapy, chemokine-evoked migration was repressed in CLL cells and marginally reduced in T cells. This was accompanied by profound modulation of the expression of chemokine receptors and adhesion molecules. Remarkably, the relative expression of the receptors governing lymph node entry (CCR7) versus exit (S1PR1) stood out as a reliable predictive marker of the clinically relevant treatment-induced lymphocytosis. Together, our data reveal a multifaceted modulation of motility and adhesive properties of ibrutinib on both CLL leukemic cell and T-cell populations and point to intrinsic differences in CLL recirculation properties as an underlying cause for variability in treatment response.

Biological hallmarks of splenic marginal zone lymphoma (SMZL) remain poorly described. Herein, we performed in-depth SMZL characterization through multimodal single-cell analyses of paired blood/spleen samples. The 3'-single-cell RNA-sequencing, Cellular Indexing of Transcriptomes and Epitopes by sequencing, and 5'-V(D)J single-cell RNA-sequencing datasets were integrated to characterize SMZL transcriptome profiles, including B-cell receptor and T-cell receptor repertoires. Hyperexpanded B-cell clones in the spleen were at a memory-like stage, whereas recirculating tumor B-cells in blood encompassed multiple differentiation stages, indicating an unexpected desynchronization of the B-cell maturation program in SMZL cells. Spatial transcriptomics showed the enrichment of T-effector and T-follicular helper (TFH) signatures in the nodular subtype of SMZL. This latter also exhibited gene-based cell-cell interactions suggestive of dynamic crosstalk between TFH and cancer cells in transcriptomics, further substantiated by using imaging mass cytometry. Our findings provide a comprehensive high-resolution description of SMZL biological hallmarks and characterize, for the first time in situ, inter- and intra-patient heterogeneity at both transcriptomic and protein levels. (c) 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

γδ T lymphocytes diverge from conventional T CD8 lymphocytes for ontogeny, homing, and antigen specificity, but whether their differentiation in tumors also deviates was unknown. Using innovative analyses of our original and ~150 published single-cell RNA sequencing datasets validated by phenotyping of human tumors and murine models, here we present the first high-resolution view of human γδ T cell differentiation in cancer. While γδ T lymphocytes prominently encompass TCRVγ9 cells more differentiated than T CD8 in healthy donor's blood, a different scenario is unveiled in tumors. Solid tumors and lymphomas are infiltrated by a majority of TCRVγnon9 γδ T cells which are quantitatively correlated and remarkably aligned with T CD8 for differentiation, exhaustion, gene expression profile, and response to immune checkpoint therapy. This cancer-wide association is critical for developing cancer immunotherapies.

High-definition transcriptomic studies through single-cell RNA sequencing (scRNA-Seq) have revealed the heterogeneity and functionality of the various microenvironments across numerous solid tumors. Those pioneer studies have highlighted different cellular signatures correlated with clinical response to immune checkpoint inhibitors. scRNA-Seq offers also a unique opportunity to unravel the intimate heterogeneity of the ecosystems across different lymphoma entities. In this review, we will first cover the basics and future developments of the technology, and we will discuss its input in the field of translational lymphoma research, from determination of cell-of-origin and functional diversity, to monitoring of anti-cancer targeted drugs response and toxicities, and how new improvements in both data collection and interpretation will further foster precision medicine in the upcoming years.

γδ T lymphocytes represent ∼1% of human peripheral blood mononuclear cells and even more cells in most tissues of vertebrates. Although they have important anticancer functions, most current single-cell RNA sequencing (scRNA-seq) studies do not identify γδ T lymphocytes because their transcriptomes at the single-cell level are unknown. Here we show that high-resolution clustering of large scRNA-seq datasets and a combination of gene signatures allow the specific detection of human γδ T lymphocytes and identification of their T cell receptor (TCR)Vδ1 and TCRVδ2 subsets in large datasets from complex cell mixtures. Int-distributed stochastic neighbor embedding plots from blood and tumor samples, the few γδ T lymphocytes appear collectively embedded between cytotoxic CD8 T and NK cells. Their TCRVδ1 and TCRVδ2 subsets form close yet distinct subclusters, respectively neighboring NK and CD8 T cells because of expression of shared and distinct cytotoxic maturation genes. Similar pseudotime maturation trajectories of TCRVδ1 and TCRVδ2 γδ T lymphocytes were discovered, unveiling in both subsets an unattended pool of terminally differentiated effector memory cells with preserved proliferative capacity, a finding confirmed by in vitro proliferation assays. Overall, the single-cell transcriptomes of thousands of individual γδ T lymphocytes from different CMV+and CMV−donors reflect cytotoxic maturation stages driven by the immunological history of donors. This landmark study establishes the rationale for identification, subtyping, and deep characterization of human γδ T lymphocytes in further scRNA-seq studies of complex tissues in physiological and disease conditions.

gamma delta T lymphocytes represent similar to 1% of human peripheral blood mononuclear cells and even more cells in most tissues of vertebrates. Although they have important anticancer functions, most current single-cell RNA sequencing (scRNA-seq) studies do not identify gamma delta T lymphocytes because their transcriptomes at the single-cell level are unknown. Here we show that high-resolution clustering of large scRNA-seq datasets and a combination of gene signatures allow the specific detection of human gamma delta T lymphocytes and identification of their T cell receptor (TCR)V delta 1 and TCRV delta 2 subsets in large datasets from complex cell mixtures. In t-distributed stochastic neighbor embedding plots from blood and tumor samples, the few gamma delta T lymphocytes appear collectively embedded between cytotoxic CD8 T and NK cells. Their TCRV delta 1 and TCRV delta 2 subsets form close yet distinct subclusters, respectively neighboring NK and CD8 T cells because of expression of shared and distinct cytotoxic maturation genes. Similar pseudotime maturation trajectories of TCRV delta 1 and TCRV delta 2 gamma delta T lymphocytes were discovered, unveiling in both subsets an unattended pool of terminally differentiated effector memory cells with preserved proliferative capacity, a finding confirmed by in vitro proliferation assays. Overall, the single-cell transcriptomes of thousands of individual gamma delta T lymphocytes from different CMV+ and CMV- donors reflect cytotoxic maturation stages driven by the immunological history of donors. This landmark study establishes the rationale for identification, subtyping, and deep characterization of human gamma delta T lymphocytes in further scRNA-seq studies of complex tissues in physiological and disease conditions.

Eradication of minimal residual disease (MRD), at the end of Fludarabine-Cyclophosphamide-Rituximab (FCR) treatment, is a validated surrogate marker for progression-free and overall survival in chronic lymphocytic leukaemia. But such deep responses are also associated with severe immuno-depletion, leading to infections and the development of secondary cancers. We assessed, blood MRD and normal immune cell levels at the end of treatment, in 162 first-line FCR patients, and analysed survival and adverse event. Multivariate Landmark analysis 3 months after FCR completion identified unmutated IGHV status (HR, 2.03, p = 0.043), the level of MRD reached (intermediate versus low, HR, 2.43, p = 0.002; high versus low, HR, 4.56, p = 0.002) and CD4 > 200/mm3 (HR, 3.30, p <  0.001) as factors independently associated with progression-free survival (PFS); neither CD8 nor NK counts were associated with PFS. The CD4 count was associated with PFS irrespective of IGHV mutational status, but only in patients with detectable MRD (HR, 3.51, p = 0.0004, whereas it had no prognostic impact in MRD < 10− 4 patients: p = 0.6998). We next used a competitive risk model to investigate whether immune cell subsets could be associated with the risk of infection and found no association between CD4, CD8 and NK cells and infection. Consolidation/maintenance trials based on detectable MRD after FCR should investigate CD4 T-cell numbers both as a selection and a response criterion, and consolidation treatments should target B-cell/T-cell interactions.

Introduction: Therapeutic drug monitoring (TDM) entails the measurement of drug concentrations and the individualization of drug dosages or schedules to maximize therapeutic effects and minimize toxicity. Ibrutinib (IBR), the first-in-class inhibitor of BTK (Bruton tyrosine kinase) is approved for the therapy of relapsed/refractory chronic lymphocytic leukemia (R/R CLL), mantle cell lymphoma (MCL) and Waldenström's disease (WM), at the dose of 420-560mg/d.

Alteration in the DNA replication, repair or recombination processes is a highly relevant mechanism of genomic instability. Despite genomic aberrations manifested in hematologic malignancies, such a defect as a source of biomarkers has been underexplored. Here, we investigated the prognostic value of expression of 82 genes involved in DNA replication-repair-recombination in a series of 99 patients with chronic lymphocytic leukemia without detectable 17p deletion or TP53 mutation. We found that expression of the POLN gene, encoding the specialized DNA polymerase ν (Pol ν) correlates with time to relapse after first-line therapy with fludarabine. Moreover, we found that POLN was the only gene up-regulated in primary patients' lymphocytes when exposed in vitro to proliferative and pro-survival stimuli. By using two cell lines that were sequentially established from the same patient during the course of the disease and Pol ν knockout mouse embryonic fibroblasts, we reveal that high relative POLN expression is important for DNA synthesis and cell survival upon fludarabine treatment. These findings suggest that Pol ν could influence therapeutic resistance in chronic lymphocytic leukemia. (Patients' samples were obtained from the CLL 2007 FMP clinical trial registered at: clinicaltrials.gov identifer: 00564512).

Background: Bruton's tyrosine kinase (BTK), a mediator of B cell receptor signaling, has been effectively exploited as a therapeutic target in Chronic lymphocytic leukemia (CLL). Ibrutinib is a BTK inhibitor that has shown excellent efficacy in treatment-naïve, relapsed/refractory, and high-risk CLL. However, concerns regarding ibrutinib resistance have emerged and characterizing the underlying mechanisms may aid in identifying patients with increased risk of resistance/disease progression. Moreover, understanding the interplay between determinants of ibrutinib resistance may reveal alternate therapeutic targets. Using a computational biology modeling (CBM) simulation-based method, we reverse-engineered the salient molecular architecture of a CLL patient progressing on ibrutinib to identify potential drug combinations to overcome drug resistance and induce remission.

Introduction: The Btk inhibitor ibrutinib is now a standard therapy for the treatment of CLL. Its daily and prolonged use results in a highly complex illness, the management of which poses multiple challenges. By impairing B-cell receptor signaling, survival, and homing of leukemic cells, ibrutinib purges CLL cells out of the lymphoid organs and/or induces their apoptosis. However, important inter-patient variability in the redistribution of the leukemic cells, the rate of leukemic cell elimination and the disparity of relapses call for an in-depth (i.e. systemic) analysis of the parameters influencing the dynamical behavior of the leukemic cell population in individual patients. In CompuTreatCLL project we consider treatment of CLL with ibrutinib as a prototypical showcase to implement an original systems biology approach in the management of this disease.

In the tumoral micro-environment (TME) of chronic lymphocytic leukemia (CLL), nurse-like cells (NLC) are tumor-associated macrophages which play a critical role in the survival and chemoresistance of tumoral cells. This pro-survival activity is known to involve soluble factors, but few data are available on the relative role of cells cross-talk. Here, we used a transcriptome-based approach to systematically investigate the expression of various receptor/ligand pairs at the surface of NLC/CLL cells. Their relative contribution to CLL survival was assessed both by fluorescent microscopy to identify cellular interactions and by the use of functional tests to measure the impact of uncoupling these pairs with blocking monoclonal antibodies. We found for the first time that lymphocyte function-associated antigen 3 (LFA-3), expressed in CLL at significantly higher levels than in healthy donor B-cells, and CD2 expressed on NLC, were both key for the specific pro-survival signals delivered by NLC. Moreover, we found that NLC/CLL interactions induced the shedding of soluble LFA-3. Importantly, in an exploratory cohort of 60 CLL patients receiving frontline immunochemotherapy, increased levels of soluble LFA-3 were found to correlate with shorter overall survival. Altogether, these data suggest that LFA-3/CD2 interactions promote the survival of CLL cells in the tumor microenvironment.

Introduction: in chronic lymphocytic leukemia (CLL), treatment with FCR is the standard of care for treatment-naive and fit enough patients (pts). threshold assessed 3 months after end of treatment (EOT) is considered as a surrogate for both progression free survival (PFS) and overall survival (OS). On the other hand, antibiotic prophylaxis is often started and maintained until CD4u003e200/mm 3 . We hypothesized that a monitoring of versus normal immune cells recovery kinetics during follow-up (FU) could help refine the predictive power of EOT evaluation, and allow identification of patients with increased risk of either infection and/or relapse. Methods: we prospectively collected fresh peripheral blood (PB) samples of 162 pts from 2 institutions in France (2006-2017) at the end of treatment (EOT), then every 6 months until month 24 (M24). We used 4-color flow cytometry to quantify both (classified as 3 clusters: low ( -4 ), intermediate (≥10 -4 but -2 ) or high (≥10 -2 ) level) and the reconstitution of normal lymphocyte subsets (CD4, CD8, NK). We plotted survival curves using Kaplan-Meier method and landmark analyses at different time points (9-15-21 months from day 1 cycle 1 FCR). Cox proportional model with time-dependent covariates (MRD, CD4, CD8 and NK counts) was also used to evaluate the correlation of covariates with outcomes. Results: one hundred and sixty-two pts (69% male, median age 58y) received a median of 6 courses of FCR. IGHV was mutated in 36.6%, and del13q was the most frequent cytogenetic abnormality (37.4%). Only 7 pts had del17p and/or mutation of TP53. After a median follow-up of 60.5 months, 46.3 % of pts have relapsed and/or died (median PFS estimation: 65.7 months, median OS not reached). At EOT, 65.3%, 27.2% and 7.5 % of pts achieved low, intermediate and high respectively; 64.2% of pts had CD4≤200/mm 3 while 35.8% had CD4u003e200/mm 3 . At landmark analysis of EOT, multivariate Cox model identified IgHV unmutated (HR 2.46), intermediate (HR 3.3) or high (HR 19.57) (Figure 1), CD4 level (HR 1.22) as factors associated with PFS, and only (HR 1.1) and CD4 counts (HR 1.2) were found to be associated with improved OS (Figure 2). In EOT intermediate pts (n=34), those having EOT CD4≤200/mm 3 had better 5-year PFS than those having CD4u003e200/mm 3 (53.5% vs 7.7%, p=0.001) (Figure 3). This difference was not significant for low pts (65% vs 58.9%, p=0.7). In landmark analysis at 21 months (=one year after EOT assessment), intermediate pts (n=44) having CD4≤200/mm 3 had significantly better 5-year PFS (85.7% vs 52.8%, p=0.0138). When performing successive landmark analyses on the whole population, CD4u003e200/mm 3 was associated with worse 5-year PFS at EOT (34.1% vs 59.6%, p=0.016), 6 months (49.5% vs 58.8%, p=0.017) and 12 months (46.7% vs 68.3%, p=0.008) (Figure 4). In total, 20.4% of patients developed opportunistic infections, not correlated to CD4/CD8/NK counts. Conclusion: complementarily with MRD, CD4 count is an independent predictive factor of PFS and OS after FCR. As expected, increase during FU is independently associated with worse PFS and OS, but CD4 counts at EOT and the first year post-FCR refine prognosis of the MRD detectable risk group (independently of CLL associated risk factors such as del17p/IgHV status). This is important in the interpretation and design of clinical trials dedicated to prolong PFS/OS using consolidation regimens based on detectionu003e10 -4 in CLL. On the other hand, CD4u003e200/mm 3 was not predictive of infectious events. Disclosures Recher: Celgene, Sunesis, Amgen, Novartis: Research Funding; Novartis, Celgene, Jazz, Sunesis, Amgen: Consultancy. Ysebaert: Janssen: Consultancy, Research Funding, Speakers Bureau.