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Despite significant progress in treating chronic lymphocytic leukaemia (CLL), resistance to therapy remains challenging. NOTCH1 activation, common in CLL, confers adverse prognosis. This study explores the impact of NOTCH1 signalling on venetoclax sensitivity in vitro. Although NOTCH1 activation minimally impaired the susceptibility of CLL cells to venetoclax, ex vivo cell competition studies reveal that cells with constitutive NOTCH1 activation outgrew their wild-type counterparts in the presence of ongoing venetoclax exposure. Our findings suggest that while NOTCH1 activation is insufficient to confer venetoclax refractoriness, there is enhanced potential for cells with NOTCH1 activation to escape and thus become fully resistant to venetoclax., (© 2024 The Author(s). British Journal of Haematology published by British Society for Haematology and John Wiley & Sons Ltd.)

Real-world evidence comparing clinical outcomes between venetoclax and Bruton tyrosine kinase inhibitors (BTKis) in patients with frontline (1 L) chronic lymphocytic leukaemia (CLL) is lacking. We compared treatment effectiveness of 1 L venetoclax plus obinutuzumab (VenO) versus BTKi-based regimens. This retrospective observational study using Optum Clinformatics Data Mart® included adult patients with CLL (≥2 outpatient or ≥1 inpatient claim) who received VenO or BTKi-based regimens in 1 L (1/2019-9/2022). Baseline characteristics were balanced using stabilised inverse probability weighting. Outcomes included duration of therapy (DoT), persistence, time to next treatment or death (TTNT-D), and time off-treatment. Among 1506 eligible patients (VenO: 203; BTKi: 1303), the median follow-up duration was 12.6 (VenO) and 16.2 months (BTKi). Median DoT for VenO was 12.3 months; persistence remained higher in VenO versus BTKi through expected 1 L fixed treatment duration. Median TTNT-D was not reached for VenO; however, more VenO- versus BTKi-treated patients had not switched therapies/experienced death through Month 12 (87.1% vs. 75.3%). Among patients that discontinued, median time to discontinuation was 11.7 vs. 5.9 months for VenO versus BTKi and median time off-treatment was 11.3 vs. 4.3 months. In this real-world study, VenO was associated with better effectiveness outcomes than BTKi-based regimens in 1 L CLL., (© 2024 The Author(s). British Journal of Haematology published by British Society for Haematology and John Wiley & Sons Ltd.)

The potential prognostic influence of genetic aberrations on chronic lymphocytic leukaemia (CLL) can vary based on various factors, such as the immunoglobulin heavy variable (IGHV) status. We conducted an integrative analysis on genetic abnormalities identified through cytogenetics and targeted next-generation sequencing in 536 CLL patients receiving first-line chemo(immuno)therapies (CIT) as part of two prospective trials. We evaluated the prognostic implications of the main abnormalities, with specific attention to their relative impact according to IGHV status. In the entire cohort, unmutated (UM)-IGHV, complex karyotype, del(11q) and ATM mutations correlated significantly with shorter progression-free survival (PFS). Focusing on the subset of mutated IGHV (M-IGHV) patients, univariate analysis showed that complex karyotype, del(11q), SF3B1 and SAMHD1 mutations were associated with significant lower PFS. The prognostic influence varied based on the patient's IGHV status, as these abnormalities did not affect outcomes in the UM-IGHV subgroup. TP53 mutations had no significant impact on outcomes in the M-IGHV subgroup. Our findings highlight the diverse prognostic influence of genetic aberrations depending on the IGHV status in symptomatic CLL patients receiving first-line CIT. The prognosis of gene mutations and cytogenetic abnormalities needs to be investigated with a compartmentalized methodology, taking into account the IGVH status of patients receiving first-line BTK and/or BCL2 inhibitors., (© 2024 British Society for Haematology and John Wiley & Sons Ltd.)

Although the unfavourable prognostic role of complex karyotype (CK) in chronic lymphocytic leukaemia (CLL) patients treated with chemoimmunotherapy has been clarified, its impact on the outcome of patients being treated with novel targeted agents, and especially with venetoclax-based regimens, remains to be resolved. In fact, only few studies, utilizing data derived from clinical trials (e.g. MURANO, CLL14, GAIA-CLL13), specifically focus on this topic while real-word evidence is missing. In our real-life retrospective study conducted on 61 patients with CLL and treated with venetoclax-based regimens in any therapeutic line, we documented a remarkable lower progression-free survival in patients harbouring both CK and high CK, while overall response rate (including complete remissions and partial remissions) and overall survival are not affected by CK in our population., (© 2024 British Society for Haematology and John Wiley & Sons Ltd.)

Large-scale next-generation sequencing (NGS) studies revealed extensive genetic heterogeneity, driving a highly variable clinical course of chronic lymphocytic leukaemia (CLL). The evolution of subclonal populations contributes to diverse therapy responses and disease refractoriness. Besides, the dynamics and impact of subpopulations before therapy initiation are not well understood. We examined changes in genomic defects in serial samples of 100 untreated CLL patients, spanning from indolent to aggressive disease. A comprehensive NGS panel LYNX, which provides targeted mutational analysis and genome-wide chromosomal defect assessment, was employed. We observed dynamic changes in the composition and/or proportion of genomic aberrations in most patients (62%). Clonal evolution of gene variants prevailed over the chromosomal alterations. Unsupervised clustering based on aberration dynamics revealed four groups of patients with different clinical behaviour. An adverse cluster was associated with fast progression and early therapy need, characterized by the expansion of TP53 defects, ATM mutations, and 18p- alongside dynamic SF3B1 mutations. Our results show that clonal evolution is active even without therapy pressure and that repeated genetic testing can be clinically relevant during long-term patient monitoring. Moreover, integrative NGS testing contributes to the consolidated evaluation of results and accurate assessment of individual patient prognosis., (© 2023 The Authors. British Journal of Haematology published by British Society for Haematology and John Wiley & Sons Ltd.)

Obinutuzumab is a third-generation anti-CD20 monoclonal antibody widely used in the treatment of B-lymphoproliferative disorders but infrequently associated with severe thrombocytopenia, which can be life-threatening. The pathophysiology is unclear, but platelet clearance can be extremely rapid (usually within 24 h). In a retrospective case series, we have identified four cases among 149 recipients of obinutuzumab-containing chemotherapy regimens between 2015 and 2022 treated for haematological malignancies in Canberra, Australia (frequency 2.7%). We illustrate four cases of obinutuzumab-induced thrombocytopenia with a review of the literature. Research is required to identify the pathophysiology and improve early recognition and management of the condition in the context of multiagent chemotherapy., (© 2023 British Society for Haematology and John Wiley & Sons Ltd.)

Patients with chronic lymphocytic leukaemia can have an indolent or aggressive clinical course. Current guidelines recommend performing immunoglobin heavy chain testing, four-colour probe fluorescence in situ hybridization testing and mutational analysis for TP53 mutations as part of routine prognostic testing to determine if high-risk genomic features are present. Rigolin et al. demonstrate that genomic microarray testing can identify high-risk genomic features in patients deemed low risk by current testing standards and is independently associated with shorter time to first treatment in their cohort. Commentary on: Rigolin et al. Additional lesions identified by genomic microarrays are associated with an inferior outcome in low-risk chronic lymphocytic leukaemia patients. Br J Haematol 2023;202:953-959., (© 2023 The Author. British Journal of Haematology published by British Society for Haematology and John Wiley & Sons Ltd.)

The aims of our study were to analyse compliance with the 2014 GELTAMO SMZL Guidelines, in patients with splenic marginal zone lymphoma (SMZL), and to evaluate the outcome according to the HPLLs/ABC-adapted therapeutic strategy. Observational prospective multicenter study of 181 SMZL patients diagnosed between 2014 and 2020. Lymphoma-specific survival (LSS), composite event-free survival (CEFS) and response rates were assessed. 57% of the 168 patients included in the analysis followed the Guidelines. The overall response rate was higher in the rituximab chemotherapy and in the rituximab arms compared with the splenectomy arm (p < 0.001). The 5-year overall survival was 77% and the 5-year LSS of 93%. There were no differences in the 5-year LSS according to the treatment received (p = 0.68). The 5-year CEFS in the overall series was 45%, and there were significant differences between scores A and B (p = 0.036). There were no significant differences when comparing LSS and progression-free survival in patients treated with rituximab or rituximab chemotherapy at diagnosis or after observation. Our data support HPLLs/ABC score as a practical tool for the management of SMZL, observation as the best approach for patients in group A and rituximab as the best treatment for group B., (© 2023 British Society for Haematology and John Wiley & Sons Ltd.)

This retrospective, observational study evaluated patterns of inpatient versus outpatient tumour lysis syndrome (TLS) monitoring during venetoclax ramp-up in 170 patients with chronic lymphocytic leukaemia. The primary outcome was clinical/biochemical TLS. Two clinical and four biochemical TLS occurred (4.1%). Five of the six events occurred in high-risk patients, four occurred at 20 mg dose and three at the 6-h time-point. Inpatient versus outpatient TLS rates within the high-risk subgroup were 15% and 8%. Risk category was the only predictor of TLS events in multivariate analysis. Outpatient escalation did not associate with clinically meaningful TLS events, suggesting outpatient escalation has manageable associated TLS risks, including in high-risk cohorts. These observations require confirmation in larger studies., (© 2023 The Authors. British Journal of Haematology published by British Society for Haematology and John Wiley & Sons Ltd.)

In chronic lymphocytic leukaemia (CLL) the efficacy of SARS-CoV-2 vaccination remains unclear as most studies have focused on humoral responses. Here we comprehensively examined humoral and cellular responses to vaccine in CLL patients. Seroconversion was observed in 55.2% of CLL with lower rate and antibody titres in treated patients. T-cell responses were detected in a significant fraction of patients. CD4 + and CD8 + frequencies were significantly increased independent of serology with higher levels of CD4 + cells in patients under a Bruton tyrosine kinase (BTK) or a B-cell lymphoma 2 (BCL-2) inhibitor. Vaccination skewed CD8 + cells towards a highly cytotoxic phenotype, more pronounced in seroconverted patients. A high proportion of patients showed spike-specific CD4 + and CD8 + cells producing interferon gamma (IFNγ) and tumour necrosis factor alpha (TNFα). Patients under a BTK inhibitor showed increased production of IFNγ and TNFα by CD4 + cells. Vaccination induced a Th1 polarization reverting the Th2 CLL T-cell profile in the majority of patients with lower IL-4 production in untreated and BTK-inhibitor-treated patients. Such robust T-cell responses may have contributed to remarkable protection against hospitalization and death in a cohort of 540 patients. Combining T-cell metrics with seroprevalence may yield a more accurate measure of population immunity in CLL, providing consequential insights for public health., (© 2022 The Authors. British Journal of Haematology published by British Society for Haematology and John Wiley & Sons Ltd.)

Historically, invasive procedures and surgeries were deferred in patients with haematological malignancies including advanced stage chronic lymphocytic leukaemia (CLL) because of limited life expectancy. However, novel, and often continuous, treatments have markedly improved outcomes in CLL. Some patients may expect years of treatment response and disease control, overcoming the short life expectancy that deters interventionalists. Such patients now often undergo various invasive procedures including major surgery. To inform peri-operative management, we summarize the relevant side effects and drug interactions of continuous CLL therapies, highlight potential surgical risks, and provide recommendations on withholding specific CLL drugs around invasive procedures., (© 2023 British Society for Haematology and John Wiley & Sons Ltd.)

The GA101 (obinutuzumab) monocLonal Antibody as Consolidation Therapy In chronic lymphocytic leukaemia (CLL) (GALACTIC) was a seamless phase II/III trial designed to test whether consolidation with obinutuzumab is safe and eradicates minimal residual disease (MRD) and, subsequently, whether this leads to prolonged progression-free survival (PFS) in patients with CLL who have recently responded to chemo-immunotherapy. Patients with a response 3-24 months after chemotherapy were assessed for MRD. MRD-positive patients were randomised to receive consolidation therapy with obinutuzumab or no consolidation. The trial closed after the phase II part due to slow recruitment. In all, 48 patients enrolled of whom 19 were MRD negative and were monitored. Of the 29 MRD-positive patients, 14 were randomised to receive consolidation and 15 to no consolidation. At 6 months after randomisation, 10 and 13 consolidated patients achieved MRD negativity by flow cytometry (sensitivity 10 -4 ) in bone marrow and peripheral blood respectively. PFS was significantly better in consolidated patients compared to non-consolidated patients (p = 0.001). No difference was observed in PFS, overall survival or duration of MRD negativity when comparing the 10 MRD-negative patients after consolidation with the 19 MRD-negative patients in the monitoring group. Common adverse events in the consolidation arm were thrombocytopenia, infection, and cough. Only 1% of events were infusion-related reactions. This observation provides further evidence that consolidation to achieve MRD negativity improves outcomes in CLL and that obinutuzumab is well tolerated in patients with low levels of disease., (© 2022 The Authors. British Journal of Haematology published by British Society for Haematology and John Wiley & Sons Ltd.)

Idelalisib, a reversible inhibitor of PI3Kδ (phosphoinositide-3 kinase delta), showed remarkable activity in the phase II DELTA trial, leading to its approval by the European Medicines Agency (EMA) in patients with relapsed/refractory (R/R) follicular lymphoma (FL). However, real-life data on idelalisib are scarce. We treated 55 double-refractory FL patients with idelalisib in a real-life setting. With a median exposure to idelalisib of 10 months (range 1-43), overall response rate was 73%, the highest ever reported. Non-haematological toxicities were mild and manageable. At 12 months, 80% of patients were alive, and 72% disease-free. The efficacy and safety of idelalisib was confirmed in a real-life setting., (© 2022 British Society for Haematology and John Wiley & Sons Ltd.)

Acalabrutinib, a Bruton tyrosine kinase inhibitor, demonstrated greater selectivity and improved safety versus ibrutinib in a head-to-head trial in relapsed/refractory (R/R) chronic lymphocytic leukaemia. In the R/R marginal zone lymphoma (MZL) cohort (phase 2) of a phase 1b/2 trial (NCT02180711), 43 patients with MZL and at least one prior therapy received acalabrutinib 100 mg twice daily until disease progression or unacceptable toxicity [median age 69 years (range 42-84); median one (1-4) prior systemic regimens]. Median follow-up was 13.3 months (range 0.5-45.5). Among 40 patients evaluable for response, investigator-assessed overall response rate was 53% [95% confidence interval (CI) 36%-69%] with five (13%) complete responses. Tumour reduction occurred in 40 (93%) of the treated patients. Median time to response was 2.9 months (median duration of response not estimable). Estimated median progression-free survival (PFS) was 27.4 months (12-month PFS rate, 67%). Five patients died (disease progression, n = 4; septic shock, n = 1). Seventeen patients (40%) had grade 3 or higher adverse events (AEs), most commonly neutropenia (14%), anaemia, dyspnoea (7% each), fatigue and thrombocytopenia (5% each). Hypertension occurred in 5%; atrial fibrillation/flutter and major haemorrhage were not reported. AEs led to treatment discontinuation in three (7%) patients. Acalabrutinib was active and well tolerated in patients with R/R MZL., (© 2022 The Authors. British Journal of Haematology published by British Society for Haematology and John Wiley & Sons Ltd.)

Patients with chronic lymphocytic leukaemia (CLL) disease progression on ibrutinib or after sequential ibrutinib and venetoclax-based treatments (double-refractory) have poor outcomes. In this retrospective study, we analysed outcomes with combined ibrutinib and venetoclax treatment in these groups of patients. The median treatment-free and overall survival for 22 patients with prior progression on ibrutinib (venetoclax-naïve) were 23.7 and 47.1 months respectively. In 11 patients with double-refractory CLL, the median treatment-free and overall survival were 11.2 and 27.0 months respectively. The combination of ibrutinib and venetoclax may help bridge the current gap in options for patients with disease refractory to the most commonly used novel agents., (© 2022 British Society for Haematology and John Wiley & Sons Ltd.)

Hodgkin variant Richter transformation (HvRT) is a rare and challenging complication of chronic lymphocytic leukaemia (CLL) for which information on prognostic factors and treatment approaches remain limited. We analysed characteristics and survival outcomes of a population-based cohort of 32 patients with HvRT identified in British Columbia over a 40-year period. Median interval from CLL diagnosis to HvRT was 5.6 years (range, 0-33.6), with five cases diagnosed concurrently. Most patients (80%) had treatment for CLL prior to HvRT. Median age at HvRT was 71 years (range, 51-86) and the majority of patients had high-risk disease, including stage 3-4 in 87% and International Prognostic Score (IPS) ≥ 4 in 65%. Two-year progression-free (PFS) and overall survival (OS) from HvRT were 47% (95% CI: 29%-64%) and 57% (95% CI: 38%-72%), respectively. OS from HvRT was significantly worse in those with anaemia (p = 0.02), elevated lactate dehydrogenase (p = 0.04), high IPS (p = 0.04), and worse performance status (p = 0.001). For those treated with curative-intent ABVD/ABVD-like therapy, 2-year PFS and OS were 70% (95% CI: 45%-85%) and 74% (95% CI: 49%-89%), respectively. In this real-world population-based cohort, HvRT was associated with poor clinical outcomes overall; however, those able to tolerate curative-intent therapy had similar survival to older patients with de novo HL., (© 2022 British Society for Haematology and John Wiley & Sons Ltd.)

Clonal haematopoiesis of indeterminate potential (CHIP) may predispose for the development of therapy-related myeloid neoplasms (t-MN). Using target next-generation sequencing (t-NGS) panels and digital droplet polymerase chain reactions (ddPCR), we studied the myeloid gene mutation profiles of patients with chronic lymphocytic leukaemia (CLL) who developed a t-MN after treatment with chemo-(immuno)therapy. Using NGS, we detected a total of 30 pathogenic/likely pathogenic (P/LP) variants in 10 of 13 patients with a t-MN (77%, median number of variants for patient: 2, range 0-6). The prevalence of CHIP was then backtracked in paired samples taken at CLL diagnosis in eight of these patients. Six of them carried at least one CHIP-variant at the time of t-MN (median: 2, range: 1-5), and the same variants were present in the CLL sample in five cases. CHIP variants were present in 34 of 285 patients from a population-based CLL cohort, which translates into a significantly higher prevalence of CHIP in patients with a CLL who developed a t-MN, compared to the population-based cohort (5/8, 62.5% vs. 34/285, 12%, p = 0.0001). Our data show that CHIP may be considered as a novel parameter affecting treatment algorithms in patients with CLL, and highlight the potential of using chemo-free therapies in CHIP-positive cases., (© 2022 British Society for Haematology and John Wiley & Sons Ltd.)

Phosphatidylinositol 3 kinase (PI3K) inhibitors such as idelalisib have been associated with potentially severe autoimmune toxicity. In the present study, we demonstrate that relapsed refractory patients with chronic lymphocytic leukaemia treated with idelalisib rituximab on the phase III registration trial show uniform decrease in regulatory T cells (Tregs) and increase in CD8 T cells with treatment. Patients who do not develop toxicity show enrichment for T cells expressing multiple chemokine receptors, while those who do develop toxicity have an activated CD8 T cell population with T helper 17 cell differentiation at baseline, which then increases, leading to an increased CD8:Treg ratio that likely triggers autoimmune toxicity., (© 2022 British Society for Haematology and John Wiley & Sons Ltd.)

The phase I/II AU-003 study in patients with treatment-naïve (TN) or relapsed/refractory (R/R) chronic lymphocytic leukaemia/small lymphocytic lymphoma demonstrated that zanubrutinib therapy results in clinically meaningful and durable responses with acceptable safety and tolerability. We report updated safety and efficacy data for 123 patients with a median follow-up of 47·2 months. Patients received zanubrutinib 160 mg twice daily (81 patients), 320 mg once daily (40), or 160 mg once daily (two). Discontinuations due to adverse events or disease progression were uncommon. The overall response rate (ORR) was 95·9% (TN, 100%; R/R, 95%) with 18·7% achieving complete response (CR). Ongoing response at 3 years was reported in 85·7%. The ORR in patients with del(17p)/tumour protein p53 mutation was 87·5% (CR 16·7%). The 2- and 3-year progression-free survival estimates were 90% (TN, 90%; R/R, 91%) and 83% (TN, 81%; R/R, 83%) respectively. The most reported Grade ≥3 adverse events were neutropenia (15·4%), pneumonia (9·8%), hypertension (8·9%) and anaemia (6·5%). The annual incidence of atrial fibrillation, major haemorrhage, Grade ≥3 neutropenia and Grade ≥3 infection decreased over time. With a median follow-up of ~4 years, responses remain clinically meaningful and durable and long-term tolerability to zanubrutinib therapy continues., (© 2021 The Authors. British Journal of Haematology published by British Society for Haematology and John Wiley & Sons Ltd.)

TP53 aberrations [del(17p) or TP53 mutation] predict poor survival with chemoimmunotherapy in patients with chronic lymphocytic leukaemia (CLL). We evaluated long-term efficacy and safety of first-line ibrutinib-based therapy in patients with CLL bearing TP53 aberrations in a pooled analysis across four studies: PCYC-1122e, RESONATE-2 (PCYC-1115/16), iLLUMINATE (PCYC-1130) and ECOG-ACRIN E1912. The pooled analysis included 89 patients with TP53 aberrations receiving first-line treatment with single-agent ibrutinib (n = 45) or ibrutinib in combination with an anti-CD20 antibody (n = 44). All 89 patients had del(17p) (53% of 89 patients) and/or TP53 mutation (91% of 58 patients with TP53 sequencing results available). With a median follow-up of 49·8 months (range, 0·1-95·9), median progression-free survival was not reached. Progression-free survival rate and overall survival rate estimates at four years were 79% and 88%, respectively. Overall response rate was 93%, including complete response in 39% of patients. No new safety signals were identified in this analysis. Forty-six percent of patients remained on ibrutinib treatment at last follow-up. With median follow-up of four years (up to eight years), results from this large, pooled, multi-study data set suggest promising long-term outcomes of first-line ibrutinib-based therapy in patients with TP53 aberrations. Registered at ClinicalTrials.gov (NCT01500733, NCT01722487, NCT02264574 and NCT02048813)., (© 2021 The Authors. British Journal of Haematology published by British Society for Haematology and John Wiley & Sons Ltd.)

Statin use has been associated with reduced mortality from several cancers but also suggested, in vitro, to diminish the effectiveness of lymphoma treatments including rituximab. The present study aimed to assess the association of statin use with mortality in patients with non-Hodgkin lymphoma (NHL) and chronic lymphocytic leukaemia (CLL). We identified all incident NHLs and CLLs in Sweden from 2007 to 2013 with subtype information in the Swedish Lymphoma and Cancer Registers. Using Cox regression, we estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for the association of pre- or post-diagnosis statin use (yes/no, intensity) with lymphoma-specific, cardiovascular, or all-cause mortality; and for follicular lymphoma (FL) by initial treatment strategy (active/watch-and-wait). Among 16 098 incident NHL/CLL patients, 20% used statins at diagnosis. Pre- and post-diagnosis statin use, and statin intensity were not consistently associated with any mortality outcome in patients with NHL, overall or for any subtype. For actively treated patients with FL, statin use did not appear to increase lymphoma-specific mortality (vs. non-users, HR [95% CI] after diagnosis 0·87 [0·45-1·67]). For CLL, statin use was associated with all-cause and cardiovascular but not consistently with lymphoma-specific mortality. In conclusion, statin use was not associated with improved lymphoma survival but appears safe to use during lymphoma treatment., (© 2021 The Authors. British Journal of Haematology published by British Society for Haematology and John Wiley & Sons Ltd.)

Richter syndrome (RS), an aggressive lymphoma occurring in the context of chronic lymphocytic leukaemia/small lymphocytic lymphoma, is associated with poor prognosis when treated with conventional immunochemotherapy, therefore, improved treatments are required. Immune checkpoint blockade has shown efficacy in some B-cell malignancies and modest responses in early clinical trials for RS. We investigated the immune checkpoint profile of RS as a basis to inform rational therapeutic investigations in RS. Formalin-fixed, paraffin-embedded biopsies of RS (n = 19), de novo diffuse large B-cell lymphoma (DLBCL; n = 58), transformed indolent lymphomas (follicular [tFL], n = 16; marginal zone [tMZL], n = 24) and non-transformed small lymphocytic lymphoma (SLL; n = 15) underwent gene expression profiling using the NanoString Human Immunology panel. Copy number assessment was performed using next-generation sequencing. Immunohistochemistry (IHC) for LAG3 and PD-1 was performed. LAG3 gene expression was higher in RS compared to DLBCL (P = 0·0002, log2FC 1·96), tFL (P < 0·0001, log2FC 2·61), tMZL (P = 0·0004, log2FC 1·79) and SLL (P = 0·0057, log2FC 1·45). LAG3 gene expression correlated with the gene expression of human leukocyte antigen Class I and II, and related immune genes and immune checkpoints. IHC revealed LAG3 protein expression on both malignant RS cells and tumour-infiltrating lymphocytes. Our findings support the investigation of LAG3 inhibition to enhance anti-tumour responses in RS., (© 2021 British Society for Haematology and John Wiley & Sons Ltd.)

Idelalisib (IDL) is an oral first-in-class phosphatidylinositol 3-kinase delta (PI3Kδ) inhibitor approved for chronic lymphocytic leukaemia (CLL) alongside rituximab (R) since 2014. However, little data exist on routine practice. The RETRO-idel was a protocol-led, retrospective study of 110 patients [n = 27 front-line (1L)] who received IDL-R. The primary end-point was clinical overall response rate (ORR). The median (range) follow-up of the whole cohort was 30·2 (0·1-51·9) months. The median (range) age was 72 (48-89) years. Tumour protein p53-disruption was common [100% 1L, 32·5% relapsed/refractory (R/R)]. The best ORR (intention-to-treat) was 88·2% (1L 96·3%, R/R 85·5%). Overall, the median event-free survival (mEFS) was 20·3 months and time-to-next treatment was 29·2 months. The mEFS for 1L patients was 18·7 months and R/R patients was 21·7 months. The 3-year overall survival was 56·1% (95% confidence interval 45·7-65·3). IDL was discontinued in 87·3% (n = 96). More patients discontinued due to adverse events in the front-line setting (1L 63·0% vs. R/R 44·6%) and due to progressive disease in R/R patients (20·5% vs. 3·7% in 1L). Lower respiratory tract infection/pneumonia were reported in 34·5% (Grade ≥3, 19·1%), diarrhoea in 30·9% (Grade ≥3, 6·4%), and colitis in 9·1% (Grade ≥3, 5·5%). Overall, these data describe clear efficacy for IDL-R in routine practice. No new safety signals were identified, although careful management of known toxicities is required., (© 2021 Gilead Sciences Ltd. British Journal of Haematology published by John Wiley & Sons Ltd and British Society for Haematology.)

The Bruton's tyrosine kinase (BTK) inhibitor ibrutinib has revolutionised the therapeutic landscape of chronic lymphocytic leukaemia (CLL). Acquired mutations emerging at position C481 in the BTK tyrosine kinase domain are the predominant genetic alterations associated with secondary ibrutinib resistance. To assess the correlation between disease progression, and the emergence and temporal dynamics of the most common resistance mutation BTK C481S , sensitive (10 -4 ) time-resolved screening was performed in 83 relapsed/refractory CLL patients during single-agent ibrutinib treatment. With a median follow-up time of 40 months, BTK C481S was detected in 48·2% (40/83) of the patients, with 80·0% (32/40) of them showing disease progression during the examined period. In these 32 cases, representing 72·7% (32/44) of all patients experiencing relapse, emergence of the BTK C481S mutation preceded the symptoms of clinical relapse with a median of nine months. Subsequent Bcl-2 inhibition therapy applied in 28/32 patients harbouring BTK C481S and progressing on ibrutinib conferred clinical and molecular remission across the patients. Our study demonstrates the clinical value of sensitive BTK C481S monitoring with the largest longitudinally analysed real-world patient cohort reported to date and validates the feasibility of an early prediction of relapse in the majority of ibrutinib-treated relapsed/refractory CLL patients experiencing disease progression., (© 2021 The Authors. British Journal of Haematology published by British Society for Haematology and John Wiley & Sons Ltd.)

Chronic lymphocytic leukaemia (CLL) rarely presents in adolescent and young adult (AYA) patients (patients aged 15-39 years). Disease characteristics and outcomes of AYA patients with CLL are not well understood, particularly in the era of novel oral targeted therapies. We analysed outcomes of 227 AYA patients with CLL diagnosed in the last two decades and evaluated at our institution. Median time to first treatment (TTFT) was 2·2 years, and five- and 10-year overall survival (OS) were 90% and 78%, respectively. Pre-treatment elevated beta 2-microglobulin, advanced Rai stage, del(11q) or del(17p) by FISH, unmutated IGHV and CD38 positivity were associated with both shorter TTFT and OS. Within the subgroup of patients who received oral targeted therapy at any time, del(11q) or del(17p) and complex karyotype were associated with shorter OS. First-line treatment choice was significantly associated with time to second treatment (P < 0·001). Patients harbouring del(11q) or del(17p) experienced shorter time to Richter transformation and were more likely to undergo an allogeneic stem cell transplant. There was a significant association between age and both OS and time to Richter transformation. Our study is the first analysis of AYA patients with CLL with a large number of patients treated with oral targeted therapies., (© 2021 British Society for Haematology and John Wiley & Sons Ltd.)

Therapeutic options used to be very limited for treatment-naïve elderly/comorbid patients with chronic lymphocytic leukaemia/small lymphocytic lymphoma (CLL/SLL) before the introduction of chemo-immunotherapy. Because dose-reduced fludarabine-based regimens yielded promising results, the Czech CLL Study Group initiated a prospective observational study to assess safety and efficacy of low-dose fludarabine and cyclophosphamide combined with rituximab (FCR) in elderly/comorbid patients. Between March 2009 and July 2012, we enrolled 107 patients considered ineligible for full-dose FCR (median age, 70 years; median Cumulative Illness Rating Scale score, 5; median creatinine clearance, 69 ml/min). Notably, 77% patients had unfavourable biological prognosis [unmutated immunoglobulin heavy-chain variable-region gene (IGHV), 74%; deletion 17p, 9%). Fludarabine was reduced to 12 mg/m 2 intravenously (iv) or 20 mg/m 2 orally on days 1-3 and cyclophosphamide to 150 mg/m 2 iv/orally on days 1-3. Grade 3-4 neutropenia occurred in 56% of the patients, but there were serious infections in only 15%. The median progression-free survival was 29 months, but was markedly longer in patients with mutated IGHV (median 53 months), especially in absence of del 11q or 17p (median 74 months). Low-dose FCR is a well-tolerated and effective first-line regimen for selected elderly/comorbid patients with CLL/SLL with favourable biology. The study was registered at clinicaltrials.gov (NCT02156726)., (© 2021 British Society for Haematology and John Wiley & Sons Ltd.)

Clinical research of chronic lymphocytic leukaemia (CLL) has been advancing at an unprecedented pace. Several randomized studies in the current era of oral targeted agents seem to have skipped one step and proceeded directly to combinations with antibodies, omitting the testing of novel-agent monotherapy. Thus, the ibrutinib + rituximab combination was used as the experimental arm in a major trial for untreated fit patients while two other trials subsequently showed that addition of rituximab to ibrutinib does not produce any meaningful benefit. Similarly, two large trials omitted venetoclax monotherapy and proceeded directly to venetoclax + rituximab or obinutuzumab versus chemoimmunotherapy. While such trials are undoubtedly cheaper, quicker and easier to manage, they leave the CLL community with uncertainty regarding the real role of the monoclonal antibody components. Thus, we are left with regimens which are undoubtedly effective, but might actually be unnecessarily toxic and expensive. The solution to this problem is simple: future randomized trials should be carefully designed in a 'step by step' fashion which would provide the CLL community with simple yet robust answers regarding efficacy of novel regimens so that these can be introduced to practice following the best principles of evidence-based medicine., (© 2020 British Society for Haematology and John Wiley & Sons Ltd.)

Greater understanding of the mechanisms involved in the disease progression of haematological malignancies has led to the introduction of novel targeted therapies with reduced toxicity compared with chemotherapy-based regimens, which has expanded the treatment options for patients with mantle cell lymphoma (MCL) and chronic lymphocytic leukaemia/small lymphocytic lymphoma (CLL/SLL). Ibrutinib is a first-in-class Bruton tyrosine kinase (BTK) inhibitor indicated for the treatment of patients with CLL/SLL or relapsed/refractory MCL. However, next-generation BTK inhibitors have been developed with improved specificity and the potential to reduce the off-target toxicity observed with ibrutinib. Acalabrutinib is a highly selective, next-generation BTK inhibitor, which was granted accelerated approval by the US Food and Drug Administration in 2017 for the treatment of adult patients with MCL who have received at least one prior therapy. In November 2019, it was also granted approval for the treatment of adult patients with CLL/SLL on the basis of two phase 3 clinical trials. This review describes the current understanding of acalabrutinib according to clinical study data for the treatment of MCL and CLL/SLL and shares recommendations from our practice on how it should be used when treating patients in the clinic, including dosing, administration and management of adverse events., (© 2020 British Society for Haematology and John Wiley & Sons Ltd.)

Patients with chronic lymphocytic leukaemia (CLL) have an increased risk of new malignancies. However, limited data have been published about the impact of CLL treatment on this risk. Here we followed a Danish population-based cohort of CLL patients for risks of new malignancies. Patients in the Danish CLL registry (2008-2017) were included. Up to 50 CLL-free matched comparators were identified. First-line treatment was categorized into four groups; bendamustine, chlorambucil, fludarabine or other. Patients were followed from CLL diagnosis for individual types of malignancy. Adjusted hazard ratios (HR) for new malignancies and 95% confidence intervals (95% CI) were calculated. Overall, 4286 CLL patients and 214 150 controls developed 594 and 20 565 new malignancies respectively. Risk of new malignancies was increased for CLL patients. Chemotherapy treatment was registered for 1064 (25%) patients with CLL. Chemotherapy was associated with increased HR (1·51, 95% CI: 1·3-1·8) of any new malignancy. Specifically, fludarabine was associated with an increased risk of myelodysplastic syndrome (MDS) (HR 4·93, 95% CI: 1·2-19·8). Patients with CLL are at increased risk of other haematological and solid malignancies compared to the general population. Chemotherapy exposure is associated with increased risk of second malignancies and fludarabine is associated with increased risk of MDS., (© 2021 British Society for Haematology and John Wiley & Sons Ltd.)

The manageable toxicity profile of obinutuzumab (GA101; G) alone or with chemotherapy in first-line (1L; fit and non-fit) and relapsed/refractory (R/R) patients with chronic lymphocytic leukaemia (CLL) was established in the primary analysis of the Phase IIIb GREEN trial (Clinicaltrials.gov: NCT01905943). The final analysis (cut-off, 31 January 2019) is reported here. Patients received G (1000 mg) alone (G-mono; fit and non-fit patients) or with chemotherapy [fludarabine and cyclophosphamide (FC; fit patients); chlorambucil (non-fit patients); bendamustine (any patient)]. Study endpoints were safety (primary) and efficacy (secondary). Subgroup analyses were performed on prognostic biomarkers in 1L CLL. Overall, 630 patients received 1L and 341 received R/R CLL treatment. At the final analysis, no new safety signals were observed [Grade ≥ 3 adverse events (AEs): 1L 82·7%, R/R 84·5%; serious AEs: 1L 58·1%, R/R 62·5%]. Neutropenia (1L 50·5%, R/R 53·4%) and thrombocytopenia (1L 14·6%, R/R 19·1%) were the most common Grade 3-5 AEs. G-mono-, G-bendamustine and G-FC-treated patients with unmutated immunoglobulin heavy chain trended towards shorter progression-free survival. Achievement of minimal residual disease negativity was greatest in 1L patients treated with G-FC. In this final analysis of the GREEN trial, the safety profile of G was consistent with current risk management strategies. Biomarker analyses supported efficacy in the specific subgroups., (© 2021 The Authors. British Journal of Haematology published by British Society for Haematology and John Wiley & Sons Ltd.)

A translocation involving the cyclin-dependent kinase 6 (CDK6) gene [t(CDK6)] is a rare but recurrent abnormality in B-cell neoplasms. To further characterise this aberration, we studied 57 cases; the largest series reported to date. Fluorescence in situ hybridisation analysis confirmed the involvement of CDK6 in all cases, including t(2;7)(p11;q21) immunoglobulin kappa locus (IGK)/CDK6 (n = 51), t(7;14)(q21;q32) CDK6/immunoglobulin heavy locus (IGH) (n = 2) and the previously undescribed t(7;14)(q21;q11) CDK6/T-cell receptor alpha locus (TRA)/T-cell receptor delta locus (TRD) (n = 4). In total, 10 patients were diagnosed with chronic lymphocytic leukaemia, monoclonal B-cell lymphocytosis or small lymphocytic lymphoma, and 47 had small B-cell lymphoma (SmBL) including 36 cases of marginal zone lymphoma (MZL; 34 splenic MZLs, one nodal MZL and one bronchus-associated lymphoid tissue lymphoma). In all, 18 of the 26 cytologically reviewed cases of MZL (69%) had an atypical aspect with prolymphocytic cells. Among the 47 patients with MZL/SmBL, CD5 expression was found in 26 (55%) and the tumour protein p53 (TP53) deletion in 22 (47%). The TP53 gene was mutated in 10/30 (33%); the 7q deletion was detected in only one case, and no Notch receptor 2 (NOTCH2) mutations were found. Immunoglobulin heavy-chain variable-region (IGHV) locus sequencing revealed that none harboured an IGHV1-02*04 gene. Overall survival was 82% at 10 years and not influenced by TP53 aberration. Our present findings suggest that most t(CDK6)+ neoplasms correspond to a particular subgroup of indolent marginal zone B-cell lymphomas with distinctive features., (© 2020 British Society for Haematology and John Wiley & Sons Ltd.)

Comorbidities influence survival in patients with chronic lymphocytic leukaemia (CLL) treated with chemo-immunotherapy or ibrutinib. While idelalisib has been studied in patients with comorbidities, their impact has not been investigated. We analysed 481 patients treated with idelalisib on two randomised trials (NCT01659021 and NCT01539512). Comorbidities were assessed using the Cumulative Illness Risk Scale (CIRS). Patients received idelalisib + anti-CD20 (rituximab or ofatumumab; n = 284) or anti-CD20 alone (n = 197). The median age was 69 years. We found that comorbidities did not significantly affect outcomes of idelalisib therapy. The objective response rate (ORR) was 79·3% versus 85·8%, the median progression-free survival (PFS) was 16·3 versus 19·1 months, and the median overall survival (OS) was 39·8 versus 49·8 months in patients treated with idelalisib who had a CIRS score of >6 versus ≤6, correspondingly. Treatment with idelalisib + anti-CD20 was associated with superior PFS and ORR when compared to anti-CD20 monotherapy in patients who had high comorbidities (CIRS score of >6) or at least one severe comorbidity (median PFS 16·3 vs. 6·9 months and 16·6 vs. 6·5 months; odds ratio 20·1 and 33·2; P < 0·0001). Thus, comorbidities do not portend inferior outcomes in patients with CLL treated with idelalisib in combination with anti-CD20 therapy., (© 2020 British Society for Haematology and John Wiley & Sons Ltd.)

Recently, clinical trial results have established inhibitors of B-cell receptor (BCR)-associated kinase (BAKi), with or without CD20 moniclonal antibodies (mAbs), as the preferred first-line treatment for most chronic lymphocytic leukaemia (CLL) patients. Using phosphospecific flow cytometry, we showed that in leukaemic cells from CLL patients the CD20 therapeutic antibodies - rituximab, ofatumumab, and obinutuzumab - inhibited BCR signalling pathways targeting preferentially pBTK Y551 - but not BTK Y223 - and pAKT. On the contrary, ibrutinib and idelalisib reduced pBTK Y223 to a higher extent than pBTK Y551 . The strong reduction of pAKT induced by idelalisib was enhanced by its combination with rituximab or ofatumumab. Moreover, CD20 mAbs and BAKi induced the death of leukaemia cells that was significantly potentiated by their combination. Analysis of the enhancement of cell death in these combinations revealed an approximately additive enhancement induced by rituximab or obinutuzumab combined with ibrutinib or idelalisib. Taken together, our data identified negative regulatory effects of CD20 mAbs and their combinations with BAKi on BCR signalling and cell survival in CLL. In conclusion, this study advances our understanding of mechanisms of action of CD20 mAbs as single agents or in combination with BAKi and could inform on the potential of combined therapies in ongoing and future clinical trials in patients with CLL., (© 2020 British Society for Haematology and John Wiley & Sons Ltd.)

Bendamustine + rituximab (BR) is the current first-line standard-of-care for chronic lymphocytic leukaemia (CLL) in fit patients aged 66-70 years, whereas chlorambucil + CD20 antibody is recommended in older patients with co-morbidities. This retrospective real-world study investigated whether risk-adapted BR was safe and effective in elderly patients. All 141 CLL patients in the Stockholm region (diagnosed from 2007 to 2016, identified from regional registries) who had received BR as first (n = 84) or later line (n = 57) were analysed. Median age was 72 years, 49% had Binet stage C, 40% had Cumulative Illness Rating Scale (CIRS) score ≥ 6, 20% Eastern Cooperative Oncology Group (ECOG) score 2. None had del(17p). Only 15% of patients aged ≥80 years received full-dose bendamustine and 65% of them postponed rituximab until cycle 2. Corresponding numbers in patients 73-79 years were 21% and 36% and in <73 years, 63% and 33%. Overall response rate was 83% (first line) and 67% (later line) (P < 0·022) equally distributed between age subsets. ECOG, immunoglobulin heavy chain variable region (IGHV) mutational status and cytogenetics, but not treatment line and age, were significant factors on progression-free survival (PFS) in multivariate analysis. Infections and neutropenia/thrombocytopenia (≥grade 3) were similar across age subgroups. In summary, BR was well tolerated even in patients ≥80 years, with similar efficacy and safety as in less old patients, provided that carefully adapted dosing was applied., (© 2020 The Authors. British Journal of Haematology published by British Society for Haematology and John Wiley & Sons Ltd.)

The Complement 1 trial investigated the efficacy and safety of ofatumumab + chlorambucil with chlorambucil monotherapy in patients with previously untreated chronic lymphocytic leukaemia (CLL). On long-term follow-up in the chemoimmunotherapy arm vs. the chemotherapy arm there was an estimated 12% (not significant) and 39% risk reduction in overall survival and progression-free survival, respectively. A high rate (61%) of treatment with next-line therapies in both the treatment arms may dilute any potential OS difference and confound the interpretation of the OS results. Addition of ofatumumab to chlorambucil demonstrated clinical benefit and tolerability as a frontline treatment option in patients unfit for fludarabine-containing therapy, with no new safety concerns., (© 2020 British Society for Haematology and John Wiley & Sons Ltd.)