Early clinical trials in chronic lymphocytic leukaemia in the UK.

This is an historical account of the randomised trials in chronic lymphocytic leukaemia in the UK between the years 1978 to 2004, describing their gestation, the treatments used and the main lessons learnt. Those lessons include: (1) how best to use chlorambucil, which was the first effective treatment for CLL; (2) the significant difference in survival between the sexes; and (3) the value of prognostic markers, both morphological and molecular, which continue to be relevant to current practice.

iwCLL guidelines for diagnosis, indications for treatment, response assessment, and supportive management of CLL.

The previous edition of the consensus guidelines of the International Workshop on Chronic Lymphocytic Leukemia (iwCLL), published in 2008, has found broad acceptance by physicians and investigators caring for patients with CLL. Recent advances including the discovery of the genomic landscape of the disease, the development of genetic tests with prognostic relevance, and the detection of minimal residual disease (MRD), coupled with the increased availability of novel targeted agents with impressive efficacy, prompted an international panel to provide updated evidence- and expert opinion-based recommendations. These recommendations include a revised version of the iwCLL response criteria, an update on the use of MRD status for clinical evaluation, and recommendations regarding the assessment and prophylaxis of viral diseases during management of CLL.

Consensus guidelines for the diagnosis and management of patients with classic hairy cell leukemia.

Hairy cell leukemia is an uncommon hematologic malignancy characterized by pancytopenia and marked susceptibility to infection. Tremendous progress in the management of patients with this disease has resulted in high response rates and improved survival, yet relapse and an appropriate approach to re-treatment present continuing areas for research. The disease and its effective treatment are associated with immunosuppression. Because more patients are being treated with alternative programs, comparison of results will require general agreement on definitions of response, relapse, and methods of determining minimal residual disease. The development of internationally accepted, reproducible criteria is of paramount importance in evaluating and comparing clinical trials to provide optimal care. Despite the success achieved in managing these patients, continued participation in available clinical trials in the first-line and particularly in the relapse setting is highly recommended. The Hairy Cell Leukemia Foundation convened an international conference to provide common definitions and structure to guide current management. There is substantial opportunity for continued research in this disease. In addition to the importance of optimizing the prevention and management of the serious risk of infection, organized evaluations of minimal residual disease and treatment at relapse offer ample opportunities for clinical research. Finally, a scholarly evaluation of quality of life in the increasing number of survivors of this now manageable chronic illness merits further study. The development of consensus guidelines for this disease offers a framework for continued enhancement of the outcome for patients.

Germ line mutations in shelterin complex genes are associated with familial chronic lymphocytic leukemia.

Chronic lymphocytic leukemia (CLL) can be familial; however, thus far no rare germ line disruptive alleles for CLL have been identified. We performed whole-exome sequencing of 66 CLL families, identifying 4 families where loss-of-function mutations in protection of telomeres 1 (POT1) co-segregated with CLL. The p.Tyr36Cys mutation is predicted to disrupt the interaction between POT1 and the telomeric overhang. The c.1164-1G>A splice-site, p.Gln358SerfsTer13 frameshift, and p.Gln376Arg missense mutations are likely to impact the interaction between POT1 and adrenocortical dysplasia homolog (ACD), which is a part of the telomere-capping shelterin complex. We also identified mutations in ACD (c.752-2A>C) and another shelterin component, telomeric repeat binding factor 2, interacting protein (p.Ala104Pro and p.Arg133Gln), in 3 CLL families. In a complementary analysis of 1083 cases and 5854 controls, the POT1 p.Gln376Arg variant, which has a global minor allele frequency of 0.0005, conferred a 3.61-fold increased risk of CLL (P = .009). This study further highlights telomere dysregulation as a key process in CLL development.

The long-term outcome of patients in the LRF CLL4 trial: the effect of salvage treatment and biological markers in those surviving 10 years.

With 10+ years follow-up in the Leukaemia Research Fund (LRF) CLL4 trial, we report the effect of salvage therapy, and the clinical/biological features of the 10-year survivors treated for chronic lymphocytic leukaemia (CLL). Overall survival (OS) was similar in the three randomized arms. With fludarabine-plus-cyclophosphamide (FC), progression-free survival (PFS) was significantly longer (P < 0.0001), but OS after progression significantly shorter, than in the chlorambucil or fludarabine arms (P < 0.0001). 614/777 patients progressed; 524 received second-line and 260 third-line therapy, with significantly better complete remission (CR) rates compared to first-line in the chlorambucil arm (7% vs. 13% after second-, 18% after third-line), but worse in the FC arm (38% vs. 15% after both second and third-line). OS 10 years after progression was better after a second-line CR versus a partial response (36% vs. 16%) and better with FC-based second-line therapy (including rituximab in 20%) or a stem cell transplant (28%) versus all other treatments (10%, P < 0.0001). The 176 (24%) 10-year survivors tended to be aged <70 years, with a "good risk" prognostic profile, stage A-progressive, achieving at least one CR, with a first-line PFS >3 years and receiving ≤2 lines of treatment. In conclusion, clinical/biological features and salvage treatments both influence the long-term outcome. Second-line therapies that induce a CR can improve OS in CLL patients.

The morphology of CLL revisited: the clinical significance of prolymphocytes and correlations with prognostic/molecular markers in the LRF CLL4 trial.

Historically, an increase in the percentage and number of circulating prolymphocytes in chronic lymphocytic leukaemia (CLL) has been associated with strong expression of surface immunoglobulin, trisomy 12 and a poor outcome. This study re-examines the biological and clinical significance of increased peripheral blood prolymphocytes in 508 patients at entry into the randomized UK Leukaemia Research Fund CLL4 trial. It also investigates the associations between increased prolymphocytes and a comprehensive array of biomarkers. 270 patients (53%) had <5% prolymphocytes, 167 (33%) had 5-9%, 60 (12%) had 10-14% and 11 (2%) had ≥15% prolymphocytes. We show that a higher proportion of prolymphocytes (≥10%) was independently associated with NOTCH1 mutations (P = 0·006), absence of 13q deletion (P = 0·001), high CD38 expression (P = 0·02) and unmutated IGHV genes (P = 0·01). Deaths due to Richter syndrome were significantly more common amongst patients who had ≥10% vs <10% prolymphocytes (13% vs 2%) respectively (P < 0·0001). ≥10% prolymphocytes was also associated with a shorter progression-free survival (Hazard ratio [HR] 1·50 [95% confidence interval [CI]: 1·16-1·93], P = 0·002) and overall survival (HR 1·99 [95% CI: 1·53-2·59], P < 0·0001). Our data support the routine examination of blood films in CLL and suggest that a finding of an increased proportion of prolymphocytes may be a trigger for further evaluation of clinical and laboratory features of progressive disease.

The outcome of Chronic lymphocytic leukaemia patients with 97% IGHV gene identity to germline is distinct from cases with <97% identity and similar to those with 98% identity.

IGHV gene mutational status has prognostic significance in chronic lymphocytic leukaemia (CLL) but the percentage of mutations that correlates best with clinical outcome remains controversial. We initially studied 558 patients from diagnosis and found significant differences in median time to first treatment (TTFT) among Stage A patients and in overall survival (OS) for the whole cohort, between cases with <97% and 97-98·99% identity and between cases with 97-98·99% and ≥99% identity, when cases from the IGHV3-21 Stereotype Subset #2 were excluded. A significant difference in progression-free survival (PFS) and OS between those with <97% and 97-98·99% identity, but not between those with 97-98·99% and ≥99% identity was also observed in a validation cohort comprising 460 patients in the UK CLL4 trial. Cox Regression analyses in the Stage A cohort revealed that a model which incorporated <97%, 97-98·99% and ≥99% identity as subgroups, was a better predictor of TTFT in CLL than using the 98% cut-off. Multivariate analysis selected the three mutational subgroups as independent predictors of TTFT in Stage A patients, and of OS in the diagnostic cohort. This study highlights that cases with 97% identity should not be considered to have the same prognosis as other cases with mutated IGHV genes defined as <98% identity to germline.

An unusual indication for splenectomy in hairy cell leukaemia: a report of three cases with persistent splenomegaly after chemoimmunotherapy.

We describe three cases of relapsed hairy cell leukaemia (HCL) treated with pentostatin plus rituximab. All three achieved bone marrow complete remission but had persistent splenomegaly and hypersplenism. Because of the clinical uncertainty of its significance, they were all splenectomized. The spleen histology showed no evidence of HCL, but a five-fold thickening of the splenic capsule and areas of fibrosis in the red pulp. This process may have contributed to the lack of elasticity and caused the persistent splenomegaly. We discuss the clinical implications for future patient management. The three patients remain in remission at 1 + , 5 + and 9 + years.

The clinical significance of NOTCH1 and SF3B1 mutations in the UK LRF CLL4 trial.

NOTCH1 and SF3B1 mutations have been previously reported to have prognostic significance in chronic lymphocytic leukemia but to date they have not been validated in a prospective, controlled clinical trial. We have assessed the impact of these mutations in a cohort of 494 patients treated within the randomized phase 3 United Kingdom Leukaemia Research Fund Chronic Lymphocytic Leukemia 4 (UK LRF CCL4) trial that compared chlorambucil and fludarabine with and without cyclophosphamide in previously untreated patients. We investigated the relationship of mutations in NOTCH1 (exon 34) and SF3B1 (exon 14-16) to treatment response, survival and a panel of established biologic variables. NOTCH1 and SF3B1 mutations were found in 10% and17% of patients, respectively. NOTCH1 mutations correlated with unmutated IGHV genes, trisomy 12, high CD38/ ZAP-70 expression and were associated with reduced overall (median 54.8 vs 74.6 months, P = .02) and progression-free (median 22.0 vs 26.4 months, P = .02) survival. SF3B1 mutations were significantly associated with high CD38 expression and with shorter overall survival (median 54.3 vs 79.0 months, P < .001). Furthermore, multivariate analysis, including baseline clinical variables, treatment, and adverse prognostic factors demonstrated that although TP53 alterations remained the most informative marker of dismal survival in this cohort, NOTCH1 (HR 1.58, P = .03) and SF3B1 (HR 1.52, P = .01) mutations have added independent prognostic value.

CYP2B6*6 is an independent determinant of inferior response to fludarabine plus cyclophosphamide in chronic lymphocytic leukemia.

Fludarabine plus cyclophosphamide (FC) is the chemotherapy backbone of modern chronic lymphocytic leukemia (CLL) treatment. CYP2B6 is a polymorphic cytochrome P450 isoform that converts cyclophosphamide to its active form. This study investigated the possible impact of genetic variation in CYP2B6 on response to FC chemotherapy in CLL. Available DNA samples from the LRF CLL4 trial, which compared chlorambucil, fludarabine, and FC, were screened by TaqMan real-time polymerase chain reaction assays for CYP2B6 SNPs c.516G>T and c.785A>G, which define the most common variant allele (*6). Among the 455 samples successfully genotyped, 265 (58.2%), 134 (29.5%), and 29 (6.4%) were classified as *1/*1, *1/*6, and *6/*6, respectively. Patients expressing at least one *6 allele were significantly less likely to achieve a complete response (CR) after FC (odds ratio 0.27; P = .004) but not chlorambucil or fludarabine. Analysis of individual response indicators confirmed that this inferior response resulted from impaired cytoreduction rather than delayed hemopoietic recovery. Multivariate analysis controlling for age, gender, stage, IGHV mutational status, 11q deletion, and TP53 deletion/mutation identified CYP2B6*6 and TP53 mutation/deletion as the only independent determinants of CR attainment after FC. Our study provides the first demonstration that host pharmacogenetics can influence therapeutic response in CLL. This trial is registered as an International Standard Randomised Control Trial, number NCT 58585610 at www.clinicaltrials.gov.

Common variation at 6p21.31 (BAK1) influences the risk of chronic lymphocytic leukemia.

We performed a meta-analysis of 3 genome-wide association studies to identify additional common variants influencing chronic lymphocytic leukemia (CLL) risk. The discovery phase was composed of genome-wide association study data from 1121 cases and 3745 controls. Replication analysis was performed in 861 cases and 2033 controls. We identified a novel CLL risk locus at 6p21.33 (rs210142; intronic to the BAK1 gene, BCL2 antagonist killer 1; P = 9.47 × 10(-16)). A strong relationship between risk genotype and reduced BAK1 expression was shown in lymphoblastoid cell lines. This finding provides additional support for polygenic inheritance to CLL and provides further insight into the biologic basis of disease development.

The clinical significance of patients' sex in chronic lymphocytic leukemia.

We examined the prognostic influence of gender in chronic lymphocytic leukemia. Data from four randomized trials (involving 1821 patients) and three registration studies of stage-A disease (involving 1299 patients) were analyzed. Overall survival at 10 years was better for women than men in all trials (27% versus 15%; P=0.0001) and in the registration series (55% versus 43%; P<0.0001). More women than men in the trials were Binet stage A-progressive (26% versus 15%), but gender was an independent predictor of survival in multivariate analysis of clinical variables (P<0.0001). Women responded better to treatment (overall response 83%) than men (71%; P<0.0001), within each stage and age group, although fewer women than men received the full treatment dose (79% versus 85%; P=0.01). Women were more likely than men to experience toxicity (85% versus 78%, P=0.01), particularly gastro-intestinal toxicity (57% versus 42%, P<0.0001). Laboratory markers in the LRF CLL4 trial showed a significantly lower incidence in women than men of unmutated IGHV genes, raised beta-2 microglobulin, CD38 and Zap-70 positivity and TP53 deletions/mutations and/or 11q deletions. We also highlight the higher male:female ratios in randomized trials versus studies of early chronic lymphocytic leukemia and monoclonal B-cell lymphocytosis. Chronic lymphocytic leukemia in women runs a more benign clinical course than in men. Gender was also an independent predictor of response, suggesting that pharmacokinetic differences between the sexes and a possible effect of estrogens may contribute to the better outcome. Understanding the reasons for the different outcome by gender may improve patients' management. (LRF CLL4 controlled-trials.com identifier: ISRCTN58585610).

ATM mutation rather than BIRC3 deletion and/or mutation predicts reduced survival in 11q-deleted chronic lymphocytic leukemia: data from the UK LRF CLL4 trial.

ATM mutation and BIRC3 deletion and/or mutation have independently been shown to have prognostic significance in chronic lymphocytic leukemia. However, the relative clinical importance of these abnormalities in patients with a deletion of 11q encompassing the ATM gene has not been established. We screened a cohort of 166 patients enriched for 11q-deletions for ATM mutations and BIRC3 deletion and mutation and determined the overall and progression-free survival among the 133 of these cases treated within the UK LRF CLL4 trial. SNP6.0 profiling demonstrated that BIRC3 deletion occurred in 83% of 11q-deleted cases and always co-existed with ATM deletion. For the first time we have demonstrated that 40% of BIRC3-deleted cases have concomitant deletion and mutation of ATM. While BIRC3 mutations were rare, they exclusively occurred with BIRC3 deletion and a wild-type residual ATM allele. In 11q-deleted cases, we confirmed that ATM mutation was associated with a reduced overall and progression-free survival comparable to that seen with TP53 abnormalities, whereas BIRC3 deletion and/or mutation had no impact on overall and progression-free survival. In conclusion, in 11q-deleted patients treated with first-line chemotherapy, ATM mutation rather than BIRC3 deletion and/or mutation identifies a subgroup with a poorer outcome.

rs2072135, a low-penetrance variant for chronic lymphocytic leukaemia?

Recent multi-stage genome-wide association studies (GWAS) have identified single nucleotide polymorphisms (SNPs) that are robustly associated with chronic lymphocytic leukaemia (CLL) risk. Given that most of these SNPs map to non-coding regions of the genome, it suggests that the functional basis of many GWAS signals will be through differential gene expression. By referencing publically accessible expression quantitative trait loci (eQTL) data on lymphoblastoid cells lines (LCLs) we have globally demonstrated an association between GWAS P-values and eQTLs, consistent with much of the variation in CLL risk being defined by variants impacting on gene expression. To explore using eQTL data to select GWAS SNPs for replication, we genotyped rs2072135 (GWAS P-value = 0·0024, eQTL P-value = 1·510(-19)) in five independent case-control series totalling 1968 cases and 3538 controls. While not attaining statistical significance (combined P-value = 1 × 10(-4)), rs2072135 defines a promising risk locus for CLL. Incorporating eQTL information offers an attractive strategy for selecting SNPs from GWAS for validation.

Alemtuzumab therapy in T-cell prolymphocytic leukemia: comparing efficacy in a series treated intravenously and a study piloting the subcutaneous route.

Intravenous alemtuzumab is an effective and well-tolerated treatment for T-cell prolymphocytic leukemia (T-PLL). Alemtuzumab given intravenously as first-line treatment in 32 patients resulted in an overall response rate of 91% with 81% complete responses. Studies in B-cell chronic lymphocytic leukemia have shown subcutaneous alemtuzumab to be equally as effective as intravenous alemtuzumab. The UKCLL05 pilot study examined the efficacy and toxicity of this more convenient method of administration in 9 previously untreated patients with T-PLL. Only 3 of 9 patients (33%) responded to treatment. Furthermore, 2 of 9 patients (22%) died while on treatment. Recruitment was terminated because of these poor results. After rescue therapy with intravenous alemtuzumab and/or pentostatin, median progression-free survival and overall survival were similar to the intravenous group. Alemtuzumab delivered intravenously, but not subcutaneously, remains the treatment of choice for previously untreated T-PLL.

Autologous hematopoietic stem cell transplantation in chronic lymphocytic leukemia: results of European intergroup randomized trial comparing autografting versus observation.

We present results of a phase 3 randomized trial of autografting in chronic lymphocytic leukemia versus observation for responding patients after first- or second-line treatment. The primary objective was to demonstrate that autografting improves the 5-year event-free survival (EFS) from 30% to 50%. There were 223 enrolled patients, 72% men and 28% women, 83% after first and 17% after second-line treatment. Binet stages were progressive A 13%, B 67%, C 20%; at randomization, 59% were in complete remission, and 41% in less than complete remission. Patients were randomized between autografting (n = 112) and observation (n = 111). Median EFS was 24.4 months (range, 16.7-32 months) in the observation group and 51.2 months (39.8-62.5 months) in the autografting group; the 5-year EFS was 24% and 42%, respectively (P < .001). Accordingly, the 5-year relapse incidence was 76% versus 54% (P < .001). Median time to relapse requiring therapy or death was 40 months (25-56 months) in the observation arm and 65 months (59-71 months) after autografting (P = .002). Cox modeling confirmed that autografting significantly improved EFS (hazard ratio 0.44, 95% confidence interval 0.30-0.65; P < .001). At 5 years, the probability of OS was 85.5% and 84.3% for autografting and observation, respectively (P = .77). In chronic lymphocytic leukemia, consolidating autografting reduces the risk of progression by more than 50% but has no effect on overall survival.

CLLU1 expression has prognostic value in chronic lymphocytic leukemia after first-line therapy in younger patients and in those with mutated IGHV genes.

CLLU1, located at chromosome 12q22, encodes a transcript specific to chronic lymphocytic leukemia and has potential prognostic value. We assessed the value of CLLU1 expression in the LRF CLL4 randomized trial. Samples from 515 patients with chronic lymphocytic leukemia were collected immediately before the start of treatment. After RNA extraction and cDNA synthesis, CLLU1 expression was assessed by quantitative polymerase chain reaction. In total, 247 and 268 samples were identified as having low and high CLLU1 expression, respectively. The median follow-up was 88 months. High CLLU1 expression was significantly correlated with unmutated IGHV genes, ZAP-70 and CD38 positivity, and absence of 13q deletion (all r>0.2, P<0.0001). At 6 years, patients with high CLLU1 expression had significantly worse progression-free survival (9% versus 17%; P=0.03) and overall survival (42% versus 57%; P=0.0003) than patients with low CLLU1 expression. Among patients with mutated IGHV genes, overall survival at 6 years was 50% in those with high CLLU1 expression and 76% in those with low CLLU1 expression (P=0.005). However, CLLU1 expression was not an independent predictor of overall survival in a multivariate model including TP53 aberrations, beta-2 microglobulin level, age and IGHV mutation status. Nor did it predict response to treatment. CLLU1 expression analysis helps to refine the prognosis of patients with chronic lymphocytic leukemia who have mutated IGHV genes.

Fine-scale mapping of the 6p25.3 chronic lymphocytic leukaemia susceptibility locus.

A recent genome-wide association study of chronic lymphocytic leukaemia (CLL) has identified a susceptibility locus on 6p25.3 associated with a modest but highly significant increase in CLL risk. Using a set of single nucleotide polymorphism (SNP) markers, we generated a fine-scale map and narrowed the association signal to a 18 kb DNA segment within the 3'-untranslated region (UTR) of the IRF4 (interferon regulatory factor 4) gene. Resequencing this segment in European subjects identified 55 common polymorphisms, including 13 highly correlated candidate causal variants. In a large case-control study, it was shown that all but four variants could be excluded with 95% confidence. These four SNPs map to a 3 kb region of the 3'-UTR of IRF4, consistent with the causal basis of the association being mediated through differential IRF4 expression.

Revised guidelines for the diagnosis and management of hairy cell leukaemia and hairy cell leukaemia variant*.

The British Committee for Standards in Haematology first produced guidelines for the diagnosis and management of hairy cell leukaemia and hairy cell leukaemia variant in 2000. This revision updates those guidelines and covers the areas of diagnosis, treatment and assessment of response to therapy.

The prognostic impact of clinical and molecular features in hairy cell leukaemia variant and splenic marginal zone lymphoma.

Hairy cell leukaemia variant (HCL-variant) and splenic marginal zone lymphoma (SMZL) are disorders with overlapping features. We investigated the prognostic impact in these disorders of clinical and molecular features including IGH VDJ rearrangements, IGHV gene usage and TP 53 mutations. Clinical and laboratory data were collected before therapy from 35 HCL-variant and 68 SMZL cases. End-points were the need for treatment and overall survival. 97% of HCL-variant and 77% of SMZL cases required treatment (P = 0·009). Survival at 5 years was significantly worse in HCL-variant [57% (95% confidence interval 38-73%)] compared with SMZL [84% (71-91%); Hazard Ratio 2·25 (1·20-4·25), P = 0·01]. In HCL-variant, adverse prognostic factors for survival were older age (P = 0·04), anaemia (P = 0·01) and TP 53 mutations (P = 0·02). In SMZL, splenomegaly, anaemia and IGHV genes with >98% homology to the germline predicted the need for treatment; older age, anaemia and IGHV unmutated genes (100% homology) predicted shorter survival. IGHV gene usage had no impact on clinical outcome in either disease. The combination of unfavourable factors allowed patients to be stratified into risk groups with significant differences in survival. Although HCL-variant and SMZL share some features, they have different outcomes, influenced by clinical and biological factors.