Antibody responses after first and second Covid-19 vaccination in patients with chronic lymphocytic leukaemia.

B-cell chronic lymphocytic leukaemia (CLL) is associated with immunosuppression and patients are at increased clinical risk following SARS-CoV-2 infection. Covid-19 vaccines offer the potential for protection against severe infection but relatively little is known regarding the profile of the antibody response following first or second vaccination. We studied spike-specific antibody responses following first and/or second Covid-19 vaccination in 299 patients with CLL compared with healthy donors. 286 patients underwent extended interval (10-12 week) vaccination. 154 patients received the BNT162b2 mRNA vaccine and 145 patients received ChAdOx1. Blood samples were taken either by venepuncture or as dried blood spots on filter paper. Spike-specific antibody responses were detectable in 34% of patients with CLL after one vaccine (n = 267) compared to 94% in healthy donors with antibody titres 104-fold lower in the patient group. Antibody responses increased to 75% after second vaccine (n = 55), compared to 100% in healthy donors, although titres remained lower. Multivariate analysis showed that current treatment with BTK inhibitors or IgA deficiency were independently associated with failure to generate an antibody response after the second vaccine. This work supports the need for optimisation of vaccination strategy in patients with CLL including the potential utility of booster vaccines.

Extended follow-up and impact of high-risk prognostic factors from the phase 3 RESONATE study in patients with previously treated CLL/SLL.

In the phase 3 RESONATE study, ibrutinib demonstrated superior progression-free survival (PFS), overall survival (OS) and overall response rate (ORR) compared with ofatumumab in relapsed/refractory CLL patients with high-risk prognostic factors. We report updated results from RESONATE in these traditionally chemotherapy resistant high-risk genomic subgroups at a median follow-up of 19 months. Mutations were detected by Foundation One Heme Panel. Baseline mutations in the ibrutinib arm included TP53 (51%), SF3B1 (31%), NOTCH1 (28%), ATM (19%) and BIRC3 (14%). Median PFS was not reached, with 74% of patients randomized to ibrutinib alive and progression-free at 24 months. The improved efficacy of ibrutinib vs ofatumumab continues in all prognostic subgroups including del17p and del11q. No significant difference within the ibrutinib arm was observed for PFS across most genomic subtypes, although a subset carrying both TP53 mutation and del17p had reduced PFS compared with patients with neither abnormality. Reduced PFS or OS was not evident in patients with only del17p. PFS was significantly better for ibrutinib-treated patients in second-line vs later lines of therapy. The robust clinical activity of ibrutinib continues to show ongoing efficacy and acceptable safety consistent with prior reports, independent of various known high-risk mutations.

Results of the randomized phase IIB ARCTIC trial of low-dose rituximab in previously untreated CLL.

ARCTIC was a multicenter, randomized-controlled, open, phase IIB non-inferiority trial in previously untreated chronic lymphocytic leukemia (CLL). Conventional frontline therapy in fit patients is fludarabine, cyclophosphamide and rituximab (FCR). The trial hypothesized that including mitoxantrone with low-dose rituximab (FCM-miniR) would be non-inferior to FCR. A total of 200 patients were recruited to assess the primary end point of complete remission (CR) rates according to IWCLL criteria. Secondary end points were progression-free survival (PFS), overall survival (OS), overall response rate, minimal residual disease (MRD) negativity, safety and cost-effectiveness. The trial closed following a pre-planned interim analysis. At final analysis, CR rates were 76 FCR vs 55% FCM-miniR (adjusted odds ratio: 0.37; 95% confidence interval: 0.19-0.73). MRD-negativity rates were 54 FCR vs 44% FCM-miniR. More participants experienced serious adverse reactions with FCM-miniR (49%) compared to FCR (41%). There are no significant differences between the treatment groups for PFS and OS. FCM-miniR is not expected to be cost-effective over a lifetime horizon. In summary, FCM-miniR is less well tolerated than FCR with an inferior response and MRD-negativity rate and increased toxicity, and will not be taken forward into a confirmatory trial. The trial demonstrated that oral FCR yields high response rates compared to historical series with intravenous chemotherapy.

Results of the randomized phase IIB ADMIRE trial of FCR with or without mitoxantrone in previously untreated CLL.

ADMIRE was a multicenter, randomized-controlled, open, phase IIB superiority trial in previously untreated chronic lymphocytic leukemia. Conventional front-line therapy in fit patients is fludarabine, cyclophosphamide and rituximab (FCR). Initial evidence from non-randomized phase II trials suggested that the addition of mitoxantrone to FCR (FCM-R) improved remission rates. Two hundred and fifteen patients were recruited to assess the primary end point of complete remission (CR) rates according to International Workshop on Chronic Lymphocytic Leukemia criteria. Secondary end points were progression-free survival (PFS), overall survival (OS), overall response rate, minimal residual disease (MRD) negativity and safety. At final analysis, CR rates were 69.8 FCR vs 69.3% FCM-R (adjusted odds ratio (OR): 0.97; 95% confidence interval (CI): (0.53-1.79), P=0.932). MRD-negativity rates were 59.3 FCR vs 50.5% FCM-R (adjusted OR: 0.70; 95% CI: (0.39-1.26), P=0.231). During treatment, 60.0% (n=129) of participants received granulocyte colony-stimulating factor as secondary prophylaxis for neutropenia, a lower proportion on FCR compared with FCM-R (56.1 vs 63.9%). The toxicity of both regimens was acceptable. There are no significant differences between the treatment groups for PFS and OS. The trial demonstrated that the addition of mitoxantrone to FCR did not increase the depth of response. Oral FCR was well tolerated and resulted in impressive responses in terms of CR rates and MRD negativity compared with historical series with intravenous chemotherapy.

Genomic disruption of the histone methyltransferase SETD2 in chronic lymphocytic leukaemia.

Histone methyltransferases (HMTs) are important epigenetic regulators of gene transcription and are disrupted at the genomic level in a spectrum of human tumours including haematological malignancies. Using high-resolution single nucleotide polymorphism (SNP) arrays, we identified recurrent deletions of the SETD2 locus in 3% (8/261) of chronic lymphocytic leukaemia (CLL) patients. Further validation in two independent cohorts showed that SETD2 deletions were associated with loss of TP53, genomic complexity and chromothripsis. With next-generation sequencing we detected mutations of SETD2 in an additional 3.8% of patients (23/602). In most cases, SETD2 deletions or mutations were often observed as a clonal event and always as a mono-allelic lesion, leading to reduced mRNA expression in SETD2-disrupted cases. Patients with SETD2 abnormalities and wild-type TP53 and ATM from five clinical trials employing chemotherapy or chemo-immunotherapy had reduced progression-free and overall survival compared with cases wild type for all three genes. Consistent with its postulated role as a tumour suppressor, our data highlight SETD2 aberration as a recurrent, early loss-of-function event in CLL pathobiology linked to aggressive disease.

Changing prognosis in paroxysmal nocturnal haemoglobinuria disease subcategories: an analysis of the International PNH Registry.

BACKGROUND: Paroxysmal nocturnal haemoglobinuria (PNH) is a rare disease. Although much progress has been made in the understanding of the pathophysiology of the disease, far less is known with respect to the clinical outcomes of patients with PNH. Few retrospective studies provide survival estimates, and even fewer have explored the clinical heterogeneity of the disease. Haemolytic and aplastic anaemia (AA) forms of the disease have been recognised as main disease categories, with the haemolytic form being associated with the worst prognosis by the largest studied cohort some years ago. AIMS: To describe mortality and causes of death in PNH overall and by PNH classification and to evaluate risk factors associated with mortality. METHODS: We analysed data of 2356 patients enrolled in the International PNH Registry with multivariate analyses, using time-dependent covariates. Patients were classified into haemolytic, AA/PNH syndrome or intermediate PNH. RESULTS: Overall, 122 (5.2%) patients died after enrolment, the incidence according to subcategories being 5.1, 11.7, 2.0 and 4.8% for patients with haemolytic PNH, AA-PNH, intermediate and insufficient data respectively. Older age and decreased performance status also affected survival in multivariate analysis. Improved outcome of patients with haemolytic PNH suggests that eculizumab treatment in PNH may be associated with improved survival. CONCLUSION: A detailed analysis of clinical presentations and causes of death in patients with PNH, overall and by disease subcategories, provide evidence that in the current era, patients with haemolytic PNH are no longer those who harbour the worst prognosis. This finding differs sharply from what has been previously reported.

An ultra-deep sequencing strategy to detect sub-clonal TP53 mutations in presentation chronic lymphocytic leukaemia cases using multiple polymerases.

Chronic lymphocytic leukaemia (CLL) is the most common clonal B-cell disorder characterized by clonal diversity, a relapsing and remitting course, and in its aggressive forms remains largely incurable. Current front-line regimes include agents such as fludarabine, which act primarily via the DNA damage response pathway. Key to this is the transcription factor p53. Mutations in the TP53 gene, altering p53 functionality, are associated with genetic instability, and are present in aggressive CLL. Furthermore, the emergence of clonal TP53 mutations in relapsed CLL, refractory to DNA-damaging therapy, suggests that accurate detection of sub-clonal TP53 mutations prior to and during treatment may be indicative of early relapse. In this study, we describe a novel deep sequencing workflow using multiple polymerases to generate sequencing libraries (MuPol-Seq), facilitating accurate detection of TP53 mutations at a frequency as low as 0.3%, in presentation CLL cases tested. As these mutations were mostly clustered within the regions of TP53 encoding DNA-binding domains, essential for DNA contact and structural architecture, they are likely to be of prognostic relevance in disease progression. The workflow described here has the potential to be implemented routinely to identify rare mutations across a range of diseases.

Lenalidomide treatment and prognostic markers in relapsed or refractory chronic lymphocytic leukemia: data from the prospective, multicenter phase-II CLL-009 trial.

Efficacy of lenalidomide was investigated in 103 patients with relapsed/refractory chronic lymphocytic leukemia (CLL) treated on the prospective, multicenter randomized phase-II CLL-009 trial. Interphase cytogenetic and mutational analyses identified TP53 mutations, unmutated IGHV, or del(17p) in 36/96 (37.5%), 68/88 (77.3%) or 22/92 (23.9%) patients. The overall response rate (ORR) was 40.4% (42/104). ORRs were similar irrespective of TP53 mutation (36.1% (13/36) vs 43.3% (26/60) for patients with vs without mutation) or IGHV mutation status (45.0% (9/20) vs 39.1% (27/68)); however, patients with del(17p) had lower ORRs than those without del(17p) (21.7% (5/22) vs 47.1% (33/70); P=0.049). No significant differences in progression-free survival and overall survival (OS) were observed when comparing subgroups defined by the presence or absence of high-risk genetic characteristics. In multivariate analyses, only multiple prior therapies (⩾3 lines) significantly impacted outcomes (median OS: 21.2 months vs not reached; P=0.019). This analysis indicates that lenalidomide is active in patients with relapsed/refractory CLL with unfavorable genetic profiles, including TP53 inactivation or unmutated IGHV. (ClinicalTrials.gov identifier: NCT00963105).

A complementary role of multiparameter flow cytometry and high-throughput sequencing for minimal residual disease detection in chronic lymphocytic leukemia: an European Research Initiative on CLL study.

In chronic lymphocytic leukemia (CLL) the level of minimal residual disease (MRD) after therapy is an independent predictor of outcome. Given the increasing number of new agents being explored for CLL therapy, using MRD as a surrogate could greatly reduce the time necessary to assess their efficacy. In this European Research Initiative on CLL (ERIC) project we have identified and validated a flow-cytometric approach to reliably quantitate CLL cells to the level of 0.0010% (10(-5)). The assay comprises a core panel of six markers (i.e. CD19, CD20, CD5, CD43, CD79b and CD81) with a component specification independent of instrument and reagents, which can be locally re-validated using normal peripheral blood. This method is directly comparable to previous ERIC-designed assays and also provides a backbone for investigation of new markers. A parallel analysis of high-throughput sequencing using the ClonoSEQ assay showed good concordance with flow cytometry results at the 0.010% (10(-4)) level, the MRD threshold defined in the 2008 International Workshop on CLL guidelines, but it also provides good linearity to a detection limit of 1 in a million (10(-6)). The combination of both technologies would permit a highly sensitive approach to MRD detection while providing a reproducible and broadly accessible method to quantify residual disease and optimize treatment in CLL.

Oncolytic reovirus enhances rituximab-mediated antibody-dependent cellular cytotoxicity against chronic lymphocytic leukaemia.

The naturally occurring oncolytic virus (OV), reovirus, replicates in cancer cells causing direct cytotoxicity, and can activate innate and adaptive immune responses to facilitate tumour clearance. Reovirus is safe, well tolerated and currently in clinical testing for the treatment of multiple myeloma, in combination with dexamethasone/carfilzomib. Activation of natural killer (NK) cells has been observed after systemic delivery of reovirus to cancer patients; however, the ability of OV to potentiate NK cell-mediated antibody-dependent cellular cytotoxicity (ADCC) is unexplored. This study elucidates the potential of oncolytic reovirus for the treatment of chronic lymphocytic leukaemia (CLL), both as a direct cytotoxic agent and as an immunomodulator. We demonstrate that reovirus: (i) is directly cytotoxic against CLL, which requires replication-competent virus; (ii) phenotypically and functionally activates patient NK cells via a monocyte-derived interferon-α (IFNα)-dependent mechanism; and (iii) enhances ADCC-mediated killing of CLL in combination with anti-CD20 antibodies. Our data provide strong preclinical evidence to support the use of reovirus in combination with anti-CD20 immunotherapy for the treatment of CLL.

Improving efficiency and sensitivity: European Research Initiative in CLL (ERIC) update on the international harmonised approach for flow cytometric residual disease monitoring in CLL.

Detection of minimal residual disease (MRD) in chronic lymphocytic leukaemia (CLL) is becoming increasingly important as treatments improve. An internationally harmonised four-colour (CLR) flow cytometry MRD assay is widely used but has limitations. The aim of this study was to improve MRD analysis by identifying situations where a less time-consuming CD19/CD5/κ/λ analysis would be sufficient for detecting residual CLL, and develop a six-CLR antibody panel that is more efficient for cases requiring full MRD analysis. In 784 samples from CLL patients after treatment, it was possible to determine CD19/CD5/κ/λ thresholds that identified cases with detectable MRD with 100% positive predictive value (PPV). However, CD19/CD5/κ/λ analysis was unsuitable for predicting iwCLL/NCI response status or identifying cases with no detectable MRD. For the latter cases requiring a full MRD assessment, a six-CLR assay was designed comprising CD19/CD5/CD20 with (1) CD3/CD38/CD79b and (2) CD81/CD22/CD43. There was good correlation between four-CLR and six-CLR panels in dilution studies and clinical samples, with 100% concordance for detection of residual disease at the 0.01% (10(-4)) level (n=59) and good linearity even at the 0.001-0.01% (10(-5)-10(-4)) level. A six-CLR panel therefore provides equivalent results to the four-CLR panel but it requires fewer reagents, fewer cells and a much simpler analysis approach.

Cross-sectional validation study of patient-reported outcomes in patients with paroxysmal nocturnal haemoglobinuria.

BACKGROUND: Paroxysmal nocturnal haemoglobinuria (PNH) is a rare, acquired, clonal haemopoietic stem cell disorder that causes chronic intravascular haemolysis, increases the risk of thrombosis and results in significant patient morbidity and mortality. The symptoms of PNH may have a major impact on patient quality of life. AIMS: To assess patient fatigue and health-related quality of life in 29 patients with PNH using the Functional Assessment of Chronic Illness Therapy Fatigue subscale version 4 (FACIT-Fatigue) and the European Organization for Research and Treatment of Cancer Quality-of-Life Questionnaire-C30, version 3 (EORTC QLQ-C30). METHODS: Following completion of the questionnaires, patients were interviewed to assess the validity, clarity, relevance and comprehensiveness of the assessments. RESULTS: Overall, patients considered both the FACIT-Fatigue and EORTC QLQ-C30 instruments to be relevant and adequate in assessing the level of PNH-associated fatigue and other quality-of-life measures. The FACIT-Fatigue questionnaire was considered to be clear and to comprehensively cover PNH-related fatigue. The EORTC QLQ-C30 instrument was considered to be easy to understand, but of an overall lower relevance, although some differences between countries were observed. Patients suggested additional questions that could be incorporated into future EORTC QLQ-C30 versions to make it more relevant to PNH. CONCLUSIONS: This study confirms the validity of the FACIT-Fatigue and the EORTC QLQ-C30 questionnaires in this patient population and their routine use should be considered in the management of patients with PNH.

ERIC recommendations on TP53 mutation analysis in chronic lymphocytic leukemia.

Recent evidence suggests that - in addition to 17p deletion - TP53 mutation is an independent prognostic factor in chronic lymphocytic leukemia (CLL). Data from retrospective analyses and prospective clinical trials show that ∼5% of untreated CLL patients with treatment indication have a TP53 mutation in the absence of 17p deletion. These patients have a poor response and reduced progression-free survival and overall survival with standard treatment approaches. These data suggest that TP53 mutation testing warrants integration into current diagnostic work up of patients with CLL. There are a number of assays to detect TP53 mutations, which have respective advantages and shortcomings. Direct Sanger sequencing of exons 4-9 can be recommended as a suitable test to identify TP53 mutations for centers with limited experience with alternative screening methods. Recommendations are provided on standard operating procedures, quality control, reporting and interpretation. Patients with treatment indications should be investigated for TP53 mutations in addition to the work-up recommended by the International workshop on CLL guidelines. Patients with TP53 mutation may be considered for allogeneic stem cell transplantation in first remission. Alemtuzumab-based regimens can yield a substantial proportion of complete responses, although of short duration. Ideally, patients should be treated within clinical trials exploring new therapeutic agents.

Assessment of fludarabine plus cyclophosphamide for patients with chronic lymphocytic leukaemia (the LRF CLL4 Trial): a randomised controlled trial.

BACKGROUND: Previous studies of patients with chronic lymphocytic leukaemia reported high response rates to fludarabine combined with cyclophosphamide. We aimed to establish whether this treatment combination provided greater survival benefit than did chlorambucil or fludarabine. METHODS: 777 patients with chronic lymphocytic leukaemia requiring treatment were randomly assigned to fludarabine (n=194) or fludarabine plus cyclophosphamide (196) for six courses, or chlorambucil (387) for 12 courses. The primary endpoint was overall survival, with secondary endpoints of response rates, progression-free survival, toxic effects, and quality of life. Analysis was by intention to treat. This study is registered as an International Standard Randomised Controlled Trial, number NCT 58585610. FINDINGS: There was no significant difference in overall survival between patients given fludarabine plus cyclophosphamide, fludarabine, or chlorambucil. Complete and overall response rates were better with fludarabine plus cyclophosphamide than with fludarabine (complete response rate 38%vs 15%, respectively; overall response rate 94%vs 80%, respectively; p<0.0001 for both comparisons), which were in turn better than with chlorambucil (complete response rate 7%, overall response rate 72%; p=0.006 and 0.04, respectively). Progression-free survival at 5 years was significantly better with fludarabine plus cyclophosphamide (36%) than with fludarabine (10%) or chlorambucil (10%; p<0.00005). Fludarabine plus cyclophosphamide was the best combination for all ages, including patients older than 70 years, and in prognostic groups defined by immunoglobulin heavy chain gene (V(H)) mutation status and cytogenetics, which were tested in 533 and 579 cases, respectively. Patients had more neutropenia and days in hospital with fludarabine plus cyclophosphamide, or fludarabine, than with chlorambucil. There was less haemolytic anaemia with fludarabine plus cyclophosphamide (5%) than with fludarabine (11%) or chlorambucil (12%). Quality of life was better for responders, but preliminary analyses showed no significant difference between treatments. A meta-analysis of these data and those of two published phase III trials showed a consistent benefit for the fludarabine plus cyclophosphamide regimen in terms of progression-free survival. INTERPRETATION: Fludarabine plus cyclophosphamide should now become the standard treatment for chronic lymphocytic leukaemia and the basis for new protocols that incorporate monoclonal antibodies.

Population pharmacokinetics-pharmacodynamics of alemtuzumab (Campath) in patients with chronic lymphocytic leukaemia and its link to treatment response.

AIMS: To characterize alemtuzumab pharmacokinetics and its exposure-response relationship with white blood cell (WBC) count in patients with B-cell chronic lymphocytic leukaemia (CLL). METHODS: Nonlinear mixed effects models were used to characterize plasma concentration-time data and WBC count-time data from 67 patients. Logistic regression was used to relate summary measures of drug exposure to tumour response. RESULTS: Alemtuzumab pharmacokinetics were best characterized by a two-compartment model with nonlinear elimination where V(max) (microg h(-1)) was [1020 x (WBC count/10 x 10(9) l(-1))(0.194)], K(m) was 338 microg l(-1), V(1) was 11.3 l, Q was 1.05 l h(-1) and V(2) was 41.5 l. Intersubject variability (ISV) in V(max), K(m), V(1) and V(2) was 32%, 145%, 84% and 179%, respectively. The reduction in WBC over time was modelled by a stimulatory loss indirect response model with values of 18.2 for E(max), 306 microg l(-1) for EC(50), 1.56 x 10(9) cells l(-1) h(-1) for K(in) and 0.029 per h for K(out). The probability of achieving a complete or partial response was >/=50% when the maximal trough concentration exceeded 13.2 microg ml(-1) or when AUC(0-tau) exceeded 484 microg h(-1) ml(-1). CONCLUSIONS: Alemtuzumab displayed time- and concentration-dependent pharmacokinetics with large interpatient variability, both in pharmacokinetics and pharmacodynamics, which was probably reflective of differences in tumour burden among patients. A direct relationship between maximal trough concentrations and clinical outcomes was observed, with increasing alemtuzumab exposure resulting in a greater probability of positive tumour response.