Minimal residual disease-driven treatment intensification with sequential addition of ibrutinib to venetoclax in R/R CLL.

Undetectable measurable residual disease (uMRD) is achievable in patients with chronic lymphocytic leukemia (CLL) with the BCL2-inhibitor venetoclax alone or combined with the Bruton's tyrosine kinase inhibitor ibrutinib. This phase 2, multicenter, MRD-driven study was designed to discontinue treatment upon reaching uMRD4 (<10-4) in patients with relapsed/refractory CLL receiving venetoclax monotherapy or after the addition of ibrutinib. Primary end point of the study was proportion of uMRD4 with venetoclax ± ibrutinib. Secondary end points were overall response rate, partial response, complete response, progression-free survival, duration of response, overall survival, and safety of venetoclax ± ibrutinib. Patients with uMRD4 at Cycle 12 Day 1 discontinued venetoclax. MRD+ patients added ibrutinib and continued both drugs up to Cycle 24 Day 28/uMRD4/progression/toxicity. After Cycle 24 Day 28, MRD+ patients continued ibrutinib. Thirty-eight patients (29% with TP53 aberrations; 79% with unmutated IGHV) started venetoclax. Overall response rate with venetoclax was 36 (95%) of 38 patients (20 complete; 16 partial response). Seventeen patients (45%) with uMRD4 at Cycle 12 Day 1 discontinued venetoclax. Nineteen (55%) MRD+ subjects added ibrutinib. After a median of 7 months (range, 3-10 months) of combined treatment, 16 (84%) of 19 achieved uMRD4, thus stopping both drugs. Two MRD+ patients at Cycle 24 Day 28 continued ibrutinib until progression/toxicity. After a median follow-up of 36.5 months, median progression-free survival was not reached; 10 patients progressed (4 restarted venetoclax, 3 without treatment need, 2 developed Richter transformation, and 1 dropped out). Seven (22%) of 32 patients remain uMRD4 after 3 years of follow-up. Neutropenia was the most frequent grade 3 to 4 adverse event; no grade 5 events occurred on study. This sequential MRD-guided approach led to uMRD4 in 33 (87%) of 38 patients, with venetoclax monotherapy or combined with ibrutinib, delivering treatment combination only in a fraction, and ultimately identifying the few patients benefiting from continuous therapy. This trial was registered at www.clinicaltrials.gov as # NCT04754035.

XPO1 mutations identify early-stage CLL characterized by shorter time to first treatment and enhanced BCR signalling.

Here we evaluated the epigenomic and transcriptomic profile of XPO1 mutant chronic lymphocytic leukaemia (CLL) and their clinical phenotype. By ATAC-seq, chromatin regions that were more accessible in XPO1 mutated CLL were enriched of binding sites for transcription factors regulated by pathways emanating from the B-cell receptor (BCR), including NF-κB signalling, p38-JNK and RAS-RAF-MEK-ERK. XPO1 mutant CLL, consistent with the chromatin accessibility changes, were enriched with transcriptomic features associated with BCR and cytokine signalling. By combining epigenomic and transcriptomic data, MIR155HG, the host gene of miR-155, and MYB, the transcription factor that positively regulates MIR155HG, were upregulated by RNA-seq and their promoters were more accessible by ATAC-seq. To evaluate the clinical impact of XPO1 mutations, we investigated a total of 957 early-stage CLL subdivided into 3 independent cohorts (N = 276, N = 286 and N = 395). Next-generation sequencing analysis identified XPO1 mutations as a novel predictor of shorter time to first treatment (TTFT) in all cohorts. Notably, XPO1 mutations maintained their prognostic value independent of the immunoglobulin heavy chain variable status and early-stage prognostic models. These data suggest that XPO1 mutations, conceivably through increased miR-155 levels, may enhance BCR signalling leading to higher proliferation and shorter TTFT in early-stage CLL.

Active Akt signaling triggers CLL toward Richter transformation via overactivation of Notch1.

Richter's transformation (RT) is an aggressive lymphoma that occurs upon progression from chronic lymphocytic leukemia (CLL). Transformation has been associated with genetic aberrations in the CLL phase involving TP53, CDKN2A, MYC, and NOTCH1; however, a significant proportion of RT cases lack CLL phase-associated events. Here, we report that high levels of AKT phosphorylation occur both in high-risk CLL patients harboring TP53 and NOTCH1 mutations as well as in patients with RT. Genetic overactivation of Akt in the murine Eµ-TCL1 CLL mouse model resulted in CLL transformation to RT with significantly reduced survival and an aggressive lymphoma phenotype. In the absence of recurrent mutations, we identified a profile of genomic aberrations intermediate between CLL and diffuse large B-cell lymphoma. Multiomics assessment by phosphoproteomic/proteomic and single-cell transcriptomic profiles of this Akt-induced murine RT revealed an S100 protein-defined subcluster of highly aggressive lymphoma cells that developed from CLL cells, through activation of Notch via Notch ligand expressed by T cells. Constitutively active Notch1 similarly induced RT of murine CLL. We identify Akt activation as an initiator of CLL transformation toward aggressive lymphoma by inducing Notch signaling between RT cells and microenvironmental T cells.

The immunomodulatory molecule TIGIT is expressed by chronic lymphocytic leukemia cells and contributes to anergy.

T-cell immunoreceptor with Ig and ITIM domains (TIGIT) is an inhibitory checkpoint receptor that negatively regulates Tcell responses. CD226 competes with TIGIT for binding to the CD155 ligand, delivering a positive signal to the T cell. Here we studied the expression of TIGIT and CD226 in a cohort of 115 patients with chronic lymphocytic leukemia (CLL) and report expression of TIGIT and CD226 by leukemic cells. By devising a TIGIT/CD226 ratio, we showed that CLL cells favoring TIGIT over CD226 are typical of a more indolent disease, while those favoring CD226 are characterized by a shorter time to first treatment and shorter progression-free survival after first treatment. TIGIT expression was inversely correlated to the B-cell receptor (BCR) signaling capacity, as determined by studying BTK phosphorylation, cell proliferation and interleukin- 10 production. In CLL cells treated with ibrutinib, in which surface IgM and BCR signaling capacity are temporarily increased, TIGIT expression was downmodulated, in line with data indicating transient recovery from anergy. Lastly, cells from patients with Richter syndrome were characterized by high levels of CD226, with low to undetectable TIGIT, in keeping with their high proliferative drive. Together, these data suggest that TIGIT contributes to CLL anergy by downregulating BCR signaling, identifying novel and actionable molecular circuits regulating anergy and modulating CLL cell functions.

Lymphadenopathy as a predictor of progression during venetoclax treatment in chronic lymphocytic leukemia. A campus chronic lymphocytic leukemia study.

Clinical or biological parameters useful to predict progression during treatment in real-life setting with ibrutinib, idelalisib and venetoclax in relapsed/refractory chronic lymphocytic leukemia (CLL) are still debated. We conducted a multi-center retrospective study on CLL patients treated with ibrutinib and/or idelalisib who were switched to venetoclax for progression or due to adverse events to identify any clinical and/or biological parameters useful to predict progression during treatment with venetoclax. Of all the 128 evaluable patients, 81 had received ibrutinib prior to switching to venetoclax, 35 had received idelalisib and 12 both. When comparing the three subgroups, we did not notice any statistical difference in terms of clinical or biological features. No variable at baseline and at different time points during the follow-up (at 6, 12, 18 and 24 months) was found to predict progression nor to have significance for Progression Free Survival (PFS) in the ibrutinib group and in the idelalisib group and in subgroups according to the line of treatment. Analyzing the data of the venetoclax treatment, after a median follow up of 14.3 months, median PFS was not reached and estimated 3-year PFS was 54%. Of the 128 patients treated with venetoclax, 28 (22%) experienced progressive disease. At multivariate analysis for predictive factors for progression, lymph node diameter >56.5 mm before starting treatment emerged as an independent risk factor for progression. The lymph node predictive role for progression during venetoclax treatment could be a new parameter that deserves to be investigate in future studies.

Inducible T-cell co-stimulator (ICOS) and ICOS ligand are novel players in the multiple-myeloma microenvironment.

The inducible T-cell co-stimulator (ICOS) is a T-cell receptor that, once bound to ICOS ligand (ICOSL) expressed on several cell types including the B-cell lineage, plays a decisive role in adaptive immunity by regulating the interplay between B and T cells. In addition to its immunomodulatory functions, we have shown that ICOS/ICOSL signalling can inhibit the activity of osteoclasts, unveiling a novel mechanism of lymphocyte-bone cells interactions. ICOS and ICOSL can also be found as soluble forms, namely sICOS and sICOSL. Here we show that: (i) levels of sICOS and sICOSL are increased in multiple myeloma (MM) compared to monoclonal gammopathy of undetermined significance and smouldering MM; (ii) levels of sICOS and sICOSL variably correlate with several markers of tumour burden; and (iii) sICOS levels tend to be higher in Durie-Salmon stage II/III versus stage I MM and correlate with overall survival as an independent variable. Moreover, surface ICOS and ICOSL are expressed in both myeloma cells and normal plasma cells, where they probably regulate different functional stages. Finally, ICOSL triggering inhibits the migration of myeloma cell lines in vitro and the growth of ICOSL+ MOPC-21 myeloma cells in vivo. These results suggest that ICOS and ICOSL represent novel markers and therapeutic targets for MM.

Prognostic impact of TP53 mutation in newly diagnosed diffuse large B-cell lymphoma patients treated in the FIL-DLCL04 trial.

The prognostic role of TP53 disruption has been established in diffuse large B-cell lymphoma (DLBCL). Aim of this analysis was to correlate TP53 mutations by Sanger sequencing, cell of origin (COO) profile by Lymph2Cx panel on the NanoString platform and MYC, BCL2 and BCL6 overexpression or re-arrangements by immunohistochemistry (IHC) and fluorescent in-situ hybridization (FISH), with outcome in DLBCL patients enrolled into the FIL-DLCL04 trial (NCT00499018). One hundred and twenty-five DLBCL patients with tumour block available were analyzed. TP53 was mutated in 11/125 (9%) cases; 60/125 patients received high-dose chemoimmunotherapy up-front, as for the randomization arm; COO was reported in 88 patients: 48 germinal centre B-cell like, 25 activated B-cell like and 17 unclassified; 26 patients were double expressors in IHC and 11 double hit in FISH. After a median follow-up of 72 months, five-year failure-free survival (FFS) for TP53 mutated versus wild-type was 24% and 72%, and five-year overall survival (OS) was 34% and 83%, respectively. Adjusted hazard ratio (HR) was 2·28 [95% confidence interval (CI) 0·89-5·86, p = 0·086] and 4·05 (95% CI 1·37-11·97, p = 0·011) for FFS and OS, respectively. In this series of young DLBCL patients, TP53 gene mutation identified a poor prognosis subgroup, regardless of treatment and other biological markers.

Clonally unrelated Richter syndrome are truly de novo diffuse large B-cell lymphomas with a mutational profile reminiscent of clonally related Richter syndrome.

Richter syndrome (RS) is mostly due to the direct transformation of the chronic lymphocytic leukaemia (CLL) clone, as documented by the same immunoglobulin heavy-chain variable region (IGHV) rearrangement in both CLL and RS cells. In rare cases characterized by a better outcome, the RS clone harbours a different IGHV rearrangement compared to the CLL phase. We investigated the CLL phase of clonally unrelated RS to test whether the RS clone was already identifiable prior to clinicopathologic transformation, albeit undetectable by conventional approaches. CLL cells of eight patients with unrelated RS were subjected to an ultra-deep next-generation sequencing (NGS) approach with a sensitivity of 10-6 . In 7/8 cases, the RS rearrangement was not identified in the CLL phase. In one case, the RS clone was identified at a very low frequency in the CLL phase, conceivably due to the concomitance of CLL sampling and RS diagnosis. Targeted resequencing revealed that clonally unrelated RS carries genetic lesions primarily affecting the TP53, MYC, ATM and NOTCH1 genes. Conversely, mutations frequently involved in de novo diffuse large B-cell lymphoma (DLBCL) without a history of CLL were absent. These results suggest that clonally unrelated RS is a truly de novo lymphoma with a mutational profile reminiscent, at least in part, of clonally related RS.

CD49d promotes disease progression in chronic lymphocytic leukemia: new insights from CD49d bimodal expression.

CD49d is a remarkable prognostic biomarker of chronic lymphocytic leukemia (CLL). The cutoff value for the extensively validated 30% of positive CLL cells is able to separate CLL patients into 2 subgroups with different prognoses, but it does not consider the pattern of CD49d expression. In the present study, we analyzed a cohort of 1630 CLL samples and identified the presence of ∼20% of CLL cases (n = 313) characterized by a bimodal expression of CD49d, that is, concomitant presence of a CD49d+ subpopulation and a CD49d- subpopulation. At variance with the highly stable CD49d expression observed in CLL patients with a homogeneous pattern of CD49d expression, CD49d bimodal CLL showed a higher level of variability in sequential samples, and an increase in the CD49d+ subpopulation over time after therapy. The CD49d+ subpopulation from CD49d bimodal CLL displayed higher levels of proliferation compared with the CD49d- cells; and was more highly represented in the bone marrow compared with peripheral blood (PB), and in PB CLL subsets expressing the CXCR4dim/CD5bright phenotype, known to be enriched in proliferative cells. From a clinical standpoint, CLL patients with CD49d bimodal expression, regardless of whether the CD49d+ subpopulation exceeded the 30% cutoff or not, experienced clinical behavior similar to CD49d+ CLL, both in chemoimmunotherapy (n = 1522) and in ibrutinib (n = 158) settings. Altogether, these results suggest that CD49d can drive disease progression in CLL, and that the pattern of CD49d expression should also be considered to improve the prognostic impact of this biomarker in CLL.

International prognostic score for asymptomatic early-stage chronic lymphocytic leukemia.

Most patients with chronic lymphocytic leukemia (CLL) are diagnosed with early-stage disease and managed with active surveillance. The individual course of patients with early-stage CLL is heterogeneous, and their probability of needing treatment is hardly anticipated at diagnosis. We aimed at developing an international prognostic score to predict time to first treatment (TTFT) in patients with CLL with early, asymptomatic disease (International Prognostic Score for Early-stage CLL [IPS-E]). Individual patient data from 11 international cohorts of patients with early-stage CLL (n = 4933) were analyzed to build and validate the prognostic score. Three covariates were consistently and independently correlated with TTFT: unmutated immunoglobulin heavy variable gene (IGHV), absolute lymphocyte count higher than 15 × 109/L, and presence of palpable lymph nodes. The IPS-E was the sum of the covariates (1 point each), and separated low-risk (score 0), intermediate-risk (score 1), and high-risk (score 2-3) patients showing a distinct TTFT. The score accuracy was validated in 9 cohorts staged by the Binet system and 1 cohort staged by the Rai system. The C-index was 0.74 in the training series and 0.70 in the aggregate of validation series. By meta-analysis of the training and validation cohorts, the 5-year cumulative risk for treatment start was 8.4%, 28.4%, and 61.2% among low-risk, intermediate-risk, and high-risk patients, respectively. The IPS-E is a simple and robust prognostic model that predicts the likelihood of treatment requirement in patients with early-stage CLL. The IPS-E can be useful in clinical management and in the design of early intervention clinical trials.

Multiregional sequencing and circulating tumour DNA analysis provide complementary approaches for comprehensive disease profiling of small lymphocytic lymphoma.

We aimed at molecularly dissecting the anatomical heterogeneity of small lymphocytic lymphoma (SLL), by analysing a cohort of 12 patients for whom paired DNA from a lymph node biopsy and circulating cells, as well as plasma-circulating tumour DNA (ctDNA) was available. Notably, the analyses of the lymph node biopsy and of circulating cells complement each other since a fraction of mutations (20·4% and 36·4%, respectively) are unique to each compartment. Plasma ctDNA identified two additional unique mutations. Consistently, the different synchronous sources of tumour DNA complement each other in informing on driver gene mutations in SLL harbouring potential prognostic and/or predictive value.

Comparison of ibrutinib and idelalisib plus rituximab in real-life relapsed/resistant chronic lymphocytic leukemia cases.

OBJECTIVES: To compare the capacity of ibrutinib (IB) and idelalisib-rituximab (IDELA-R) of prolonging overall survival (OS) as in CLL patients, previously treated with chemotherapy only. METHODS: A real-life cohort of 675 cases has been identified and investigated in the database of the groups participating in the study. RESULTS: At an unadjusted univariate analysis, a significant death risk reduction was observed favoring IB (IDELA-R vs IB HR = 0.5, 95% CI = 0.36-0.71) although with some limitations due to the non-randomized and retrospective nature of the study and to the lower number of patients in the IDELA-R group (112 cases) related to the current prescribing practice. To overcome the potential problem of confounding by indication, we adjusted the association between the type of therapy and mortality for all variables significantly associated with OS at Cox univariate analysis. Furthermore, those variables, differently distributed between the two study groups, were introduced into the multivariate Cox model to improve the effectiveness of the analysis. By introducing all these variables into the multiple Cox regression model, we confirmed the protective effect of IB vs IDELA-R (HR = 0.67, 95% CI = 0.45-0.98, P = .04) independent of potential confounders. CONCLUSIONS: Although our analysis presents some constraints, that is, the unavailability of additional potential confounders, and the retrospective nature of the study, this observation may be of help for the daily clinical practice, particularly in the absence of randomized trials comparing the two schedules.

Redefining the prognostic likelihood of chronic lymphocytic leukaemia patients with borderline percentage of immunoglobulin variable heavy chain region mutations.

In chronic lymphocytic leukaemia (CLL), caution is warranted regarding the clinical implications of immunoglobulin variable heavy chain region (IGHV) rearrangements with a 'borderline' (BL) percentage of mutations (i.e. 97-97·9% IGHV identity). We analysed the IGHV mutational status in 759 untreated CLL patients (cohort 1). BL-CLL (n = 36, 5%) showed a time to first treatment (TFT) similar to that of M-CLL (n = 338) and significantly longer than that of UM-CLL (n = 385), despite the enrichment in subset #2 cases. In fact, CLLs belonging to subset #2 (n = 15/759, 2%) were significantly more frequent among BL-CLLs (n = 5/36, 14%), with a brief TFT. TFT of BL-CLL remained comparable to that of M-CLL also considering the 327 CLL patients evaluated at diagnosis. These findings were then validated in an independent cohort 2 of 759 newly diagnosed CLL patients (BL-CLL: n = 11, 1·4%) and in all newly diagnosed patients from cohorts 1 and 2 (n = 1 086, 84% stage A; BL-CLL: n = 47, 4·3%). BL-CLL at diagnosis showed a biological profile comparable to that of M-CLL with a low frequency of unfavourable prognostic markers, except for a significant enrichment in subset #2. Our data suggest that the prognosis of BL-CLL is good and similar to that of M-CLL, with the exception of subset #2 cases.

KMT2D mutations and TP53 disruptions are poor prognostic biomarkers in mantle cell lymphoma receiving high-dose therapy: a FIL study.

In recent years, the outcome of mantle cell lymphoma (MCL) has improved, especially in younger patients, receiving cytarabine-containing chemoimmunotherapy and autologous stem cell transplantation. Nevertheless, a proportion of MCL patients still experience early failure. To identify biomarkers anticipating failure of intensive chemotherapy in MCL, we performed target resequencing and DNA profiling of purified tumor samples collected from patients enrolled in the prospective FIL-MCL0208 phase 3 trial (high-dose chemoimmunotherapy followed by autologous transplantation and randomized lenalidomide maintenance). Mutations of KMT2D and disruption of TP53 by deletion or mutation associated with an increased risk of progression and death, both in univariate and multivariate analysis. By adding KMT2D mutations and TP53 disruption to the MIPI-c backbone, we derived a new prognostic index, the "MIPI-genetic" ("MIPI- g"). The "MIPI-g" improved the model discrimination ability compared to the MIPI-c alone, defining three risk groups: i) low-risk patients (4-year progression free survival and overall survival of 72.0% and 94.5%); ii) inter-mediate-risk patients (4-year progression free survival and overall survival of 42.2% and 65.8%) and iii) high-risk patients (4-year progression free survival and overall survival of 11.5% and 44.9%). Our results: i) confirm that TP53 disruption identifies a high-risk population characterized by poor sensitivity to conventional or intensified chemotherapy; ii) provide the pivotal evidence that patients harboring KMT2D mutations share the same poor outcome as patients harboring TP53 disruption; and iii) allow to develop a tool for the identification of high-risk MCL patients for whom novel therapeutic strategies need to be investigated. (Trial registered at clinicaltrials.gov identifier: NCT02354313).

Biological and clinical implications of BIRC3 mutations in chronic lymphocytic leukemia.

BIRC3 is a recurrently mutated gene in chronic lymphocytic leukemia (CLL) but the functional implications of BIRC3 mutations are largely unexplored. Furthermore, little is known about the prognostic impact of BIRC3 mutations in CLL cohorts homogeneously treated with first-line fludarabine, cyclophosphamide, and rituximab (FCR). By immunoblotting analysis, we showed that the non-canonical nuclear factor-κB pathway is active in BIRC3-mutated cell lines and in primary CLL samples, as documented by the stabilization of MAP3K14 and by the nuclear localization of p52. In addition, BIRC3-mutated primary CLL cells are less sensitive to flu-darabine. In order to confirm in patients that BIRC3 mutations confer resistance to fludarabine-based chemoimmunotherapy, a retrospective multicenter cohort of 287 untreated patients receiving first-line FCR was analyzed by targeted next-generation sequencing of 24 recurrently mutated genes in CLL. By univariate analysis adjusted for multiple comparisons BIRC3 mutations identify a poor prognostic subgroup of patients in whom FCR treatment fails (median progression-free survival: 2.2 years, P<0.001) similar to cases harboring TP53 mutations (median progression-free survival: 2.6 years, P<0.0001). BIRC3 mutations maintained an independent association with an increased risk of progression with a hazard ratio of 2.8 (95% confidence interval 1.4-5.6, P=0.004) in multivariate analysis adjusted for TP53 mutation, 17p deletion and IGHV mutation status. If validated, BIRC3 mutations may be used as a new molecular predictor to select high-risk patients for novel frontline therapeutic approaches.

Late relapse in patients with diffuse large B-cell lymphoma: impact of rituximab on their incidence and outcome.

Diffuse large B-cell lymphoma (DLBCL) constitutes 25-35% of all non-Hodgkin lymphomas in Western countries. Approximately two thirds of the patients can be cured with standard immuno-chemotherapy. Most relapses occur within 1-2 years from diagnosis, however, the occurrence of relapses after 5 years or more has been described. We aimed at defining the incidence and clinical features of late relapses. Data of 1113 DLBCL patients were analysed. Among the 196 patients relapsing after a first complete remission, 36 (18% of relapses and 3% of all DLBCLs) experienced a recurrence more than 5 years from diagnosis. Late relapsing patients, in comparison with those relapsing earlier, showed a more favourable risk profile at presentation: normal lactate dehydrogenase levels (P = 0·002), early Ann Arbor stage (P = 0·006) and low International Prognostic Index (P = 0·003). The risk of late relapse was lowered by the introduction of rituximab as part of the front-line treatment (P < 0·001). Cause-specific survival (CSS) from the time of relapse was significantly better for late relapsing patients compared to those relapsing early: 5-year CSS rates were 53% and 31%, respectively (P = 0·033). A trend toward a better overall survival was also observed, with 5-year rates after relapse of 47% and 25%, respectively (P = 0·054).