Obinutuzumab as consolidation after chemo-immunotherapy: Results of the UK National Cancer Research Institute phase II/III GALACTIC trial

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.

Minimal Residual Disease After Autologous Stem-Cell Transplant for Patients With Myeloma: Prognostic Significance and the Impact of Lenalidomide Maintenance and Molecular Risk

PURPOSE

Minimal residual disease (MRD) can predict outcomes in patients with multiple myeloma, but limited data are available on the prognostic impact of MRD when assessed at serial time points in the context of maintenance therapy after autologous stem-cell transplant (ASCT) and the interaction between MRD and molecular risk.

METHODS

Data from a large phase III trial (Myeloma XI) were examined to determine the relationship between MRD status, progression-free survival (PFS), and overall survival (OS) in post-ASCT patients randomly assigned to lenalidomide maintenance or no maintenance at 3 months after ASCT. MRD status was assessed by flow cytometry (median sensitivity 0.004%) before maintenance random assignment (ASCT + 3) and 6 months later (ASCT + 9).

RESULTS

At ASCT + 3, 475 of 750 (63.3%) patients were MRD-negative and 275 (36.7%) were MRD-positive. MRD-negative status was associated with improved PFS (hazard ratio [HR] = 0.47; 95% CI, 0.37 to 0.58 P < .001) and OS (HR = 0.59; 95% CI, 0.40 to 0.85; P = .0046). At ASCT + 9, 214 of 326 (65.6%) were MRD-negative and 112 (34.4%) were MRD-positive. MRD-negative status was associated with improved PFS (HR = 0.20; 95% CI, 0.13 to 0.31; P < .0001) and OS (HR = 0.33; 95% CI, 0.15 to 0.75; P = .0077). The findings were very similar when restricted to patients with complete response/near complete response. Sustained MRD negativity from ASCT + 3 to ASCT + 9 or the conversion to MRD negativity by ASCT + 9 was associated with the longest PFS/OS. Patients randomly assigned to lenalidomide maintenance were more likely to convert from being MRD-positive before maintenance random assignment to MRD-negative 6 months later (lenalidomide 30%, observation 17%). High-risk molecular features had an adverse effect on PFS and OS even for those patients achieving MRD-negative status. On multivariable analysis of MRD status, maintenance therapy and molecular risk maintained prognostic impact at both ASCT + 3 and ASCT + 9.

CONCLUSION

In patients with multiple myeloma, MRD status at both ASCT + 3 and ASCT + 9 is a powerful predictor of PFS and OS.

OP0190 COMPREHENSIVE GENETIC AND FUNCTIONAL ANALYSES OF Fc GAMMA RECEPTORS EXPLAIN RESPONSE TO RITUXIMAB THERAPY FOR AUTOIMMUNE RHEUMATIC DISEASES

Background

Rituximab is widely used to treat rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) but clinical response varies. Efficacy is determined by the efficiency of depletion, which may depend on a variety of Fc gamma receptor (FcγR)-dependent mechanisms. Previous research was limited by complexity of the FCGR locus, not integrating copy number variation with functional SNP, and small sample size.

Objectives

The study objectives were to assess the effect of the full range of FcγRs variants on depletion, clinical response and functional effect on NK-cell-mediated killing in two rheumatic diseases with a view to personalised B-cell depleting therapies.

Methods

A prospective longitudinal cohort study was conducted in 873 patients [RA=611; SLE=262] from four cohorts (BSRBR-RA and BILAG-BR registries, Leeds RA and Leeds SLE Biologics). For RA, the outcome measures were 3C-DAS28CRP and 2C-DAS28CRP at 6 (+/-3) months post-rituximab (adjusted for baseline DAS28). For SLE, major clinical response (MCR) was defined as improvement of active BILAG-2004 domains to grade C/better at 6 months. B-cell depletion was evaluated by highly-sensitive flow cytometry. Qualitative and quantitative polymorphisms for five major FcγRs were measured using a commercial multiplex ligation-dependent probe amplification. Median NK cell FcγRIIIa expression (CD3-CD56+CD16+) and NK-cell degranulation (CD107a) in the presence of rituximab-coated Daudi/Raji B-cell lines were assessed using flow cytometry.

Results

In RA, for FCGR3A, carriage of V allele (coefficient -0.25 (SE 0.11); p=0.02) and increased copies of V allele (-0.20 (0.09); p=0.02) were associated with greater 2C-DAS28 response. Irrespective of FCGR3A genotype, increased gene copies were associated with a better response. In SLE, 177/262 (67.6%) achieved BILAG response [MCR=34.4%; Partial=33.2%]. MCR was associated with increased copies of FCGR3A-158V allele, OR 1.64 (95% CI 1.12-2.41) and FCGR2C-ORF allele 1.93 (1.09-3.40). Of patients with B-cells data in the combined cohort, 236/413 (57%) achieved complete depletion post-rituximab. Only homozygosity for FCGR3A-158V and increased FCGR3A-158V copy number were associated with increased odds of complete depletion. Patients with complete depletion had higher NK cell FcγRIIIa expression at rituximab initiation than those with incomplete depletion (p=0.04) and this higher expression was associated with improved EULAR response in RA. Moreover, for FCGR3A, degranulation activity was increased in V allele carriers vs FF genotype in the combined cohort; p=0.02.

Conclusion

FcγRIIIa is the major low affinity FcγR and increased copies of the FCGR3A-158V allele, encoding the allotype with a higher affinity for IgG1, was associated with clinical and biological responses to rituximab in two autoimmune diseases. This was supported by functional data on NK cell-mediated cytotoxicity. In SLE, increased copies of the FCGR2C-ORF allele was also associated with improved response. Our findings indicate that enhancing FcγR-effector functions could improve the next generation of CD20-depleting therapies and genotyping could stratify patients for optimal treatment protocols.

References

None

Acknowledgements

This research was funded/supported by the joint funding from the Medical Research Council (MRC) and Versus Arthritis of MATURA (grant codes 36661 and MR/K015346/1). MASTERPLANS was funded by the MRC (grant code MR/M01665X/1). The Leeds Biologics Cohort was part funded by programme grants from Versus Arthritis (grant codes 18475 and 18387), the National Institute for Health Research (NIHR) Leeds Biomedical Research Centre (BRC) and Diagnostic Evaluation Co-operative and the Ann Wilks Charitable Foundation. The BILAG-BR has received funding support from Lupus UK, and unrestricted grants from Roche and GSK.

The functional studies were in part supported through a NIHR/HEFCE Clinical Senior Lectureship and a Versus Arthritis Foundation Fellowship (grant code 19764) to AWM, the Wellcome Trust Institutional Strategic Support Fund to JIR and MYMY (204825/Z/16/Z), NIHR Doctoral Research Fellowship to MYMY (DRF-2014-07-155) and NIHR Clinician Scientist to EMV (CS-2013-13-032). . AWM, INB, JDI and PE were supported by NIHR Senior Investigator awards. Work in JDI’s laboratory is supported by the NIHR Newcastle BRC, the Research Into Inflammatory Arthritis Centre Versus Arthritis, and Rheuma Tolerance for Cure (European Union Innovative Medicines Initiative 2, grant number 777357). INB is funded by the NIHR Manchester BRC.

This article/paper/report presents independent research funded/supported by the NIHR Leeds BRC and the NIHR Guy’s and St Thomas’ BRC. The views expressed are those of the author(s) and not necessarily those of the NIHR or the Department of Health and Social Care.

Disclosure of Interests

Md Yuzaiful Md Yusof: None declared, James Robinson: None declared, Vinny Davies: None declared, Dawn Wild: None declared, Michael Morgan: None declared, John Taylor: None declared, Yasser El-Sherbiny: None declared, David Morris: None declared, Lu Liu: None declared, Andrew Rawstron: None declared, Maya H Buch: None declared, Darren Plant: None declared, Heather Cordell: None declared, John Isaacs: None declared, Ian N. Bruce: None declared, Paul Emery Speakers bureau: Roche, Consultant of: Roche, Grant/research support from: Roche, Anne Barton: None declared, Timothy Vyse: None declared, Jennifer Barrett: None declared, Edward Vital Consultant of: Roche, Grant/research support from: Roche, Ann Morgan Speakers bureau: Roche/Chugai, Consultant of: GSK, Roche, Chugai, AstraZeneka, Regeneron, Sanofi, Vifor, Grant/research support from: Roche, Kiniksa Pharmaceuticals

AB0293 IDENTIFYING PREDICTORS OF SHORT-TERM RESPONSE TO RITUXIMAB IN PRIMARY SJOGREN’S SYNDROME

Background:

Randomised controlled trials of rituximab (RTX) in primary Sjogren’s syndrome (pSS) have aimed to alleviate glandular symptoms and fatigue with only limited data on efficacy/effectiveness of the initial and repeat cycles of RTX on extra-glandular pSS.

Objectives:

To assess the effectiveness of RTX on extra-glandular symptoms and identify predictors of short-term response with a view to personalised B-cell depleting therapy in patients with pSS.

Methods:

An observational study was conducted in 40 consecutive RTX-treated pSS patients in a single centre for over 15 years. All patients fulfilled the 2002 AEG criteria and were CCP negative. Clinical response at 6 months was defined as ≥3 reduction of ESSDAI from baseline. B-cell subsets were measured using highly sensitive flow cytometry. Predictors of short-term response were analysed using penalised logistic regression.

Results:

38/40 (95%) patients were female, mean (SD) Age 54 (13.7) years, median (IQR) disease duration 5 (2-9) years, 39/40 (98%) had positive ANA, 26/40 (65%) were on concomitant immunosuppressant (IS). Mean (SD) ESSDAI at RTX initiation was 11.5 (6.7); main domains for RTX were articular (73%), skin (23%), PNS (15%) and muscular (15%). 169 RTX cycles were administered with a total follow-up of 165PY. In Cycle 1 (C1) RTX, the proportion of patient achieving ESSDAI response from baseline was 29/40 (73%; 95% CI 58-87). There were significant reductions in ESSDAI, daily prednisolone dose and IgG levels at 6 months (all p<0.05). Of C1 responders, 23/29 received retreatment on clinical relapse; of which 8/23 (35%) lost response [secondary non-depletion non response (2NDNR) associated with anti-RTX antibodies=4 (17%) as we previously observed in SLE[1], side effects=2, ineffective=2]. Of C1 non-responders, 9/11 were retreated but only 2/9 responded in C2. Overall, 13/40 (33%) discontinued RTX within two cycles. In multivariable analysis, concomitant IS and achieving compete B-cell depletion in C1 reduced non-response to RTX (Table 1).

Conclusion:

All pSS patients should be prescribed concomitant immunosuppressant with RTX and therapy should aim to achieve complete depletion. About 1 in 6 pSS patients lose response in repeat cycles which is associated with 2NDNR phenomenon. The use of humanised or type 2 anti-CD20mAbs should overcome these issues and improve the clinical response of extra-glandular pSS.

References:

[1]Md Yusof et al. ARD 2017 (2520 characters – allowed around 2600 as Table 1 is included too)

Table 1.

MVA logistic regression of risk factors for RTX non-response

PredictorsContinued Response (N=27)Non-response within 2 RTX Cycles (N=13)UnivariableOR (95% CI); p-valueMultivariableOR (95% CI); p-valueAge, mean (SD) per 10 years55 (14)52 (12)0.87 (0.53-1.41); 0.572Excluded from final modelDisease duration, median (IQR)5 (2-9)6 (3-9)0.97 (0.87-1.08); 0.565Excluded from final modelConcomitant IS, %81.5%30.8%0.10 (0.02-0.46); 0.0030.07 (0.01-0.52); 0.010IgG, mean (SD), g/L15.5 (6.3)18.4 (5.8)1.08 (0.97-1.20); 0.1751.13 (0.97-1.32); 0.116Clinical ESSDAI, median (IQR)10 (6-16)8 (6-10)0.96 (0.85-1.08); 0.4870.91 (0.79-1.05); 0.185Baseline Plasmablast (x1000),109 cells/L, median(IQR)2.6 (1 -5.2)2.3 (1.6-9.5)1.00 (0.94-1.07); 0.885Excluded from final modelComplete B-cell depletion post-RTX, %55.6%8.5%0.07 (0.01-0.64); 0.0180.04 (0.02-0.82); 0.036

Disclosure of Interests:

Sophanit Pepple: None declared, Jack Arnold: None declared, Edward Vital Grant/research support from: Dr Vital has received honoraria and research grant support from Roche, Andrew Rawstron: None declared, Colin Pease: None declared, Shouvik Dass Grant/research support from: Dr Dass has received honoraria from Roche, Paul Emery Consultant of: Professor Emery has received consultant fees from Roche., Grant/research support from: Professor Emery has received research grants paid to his employer from Roche., Md Yuzaiful Md Yusof: None declared

OP0057 A PERSONALISED RITUXIMAB RETREATMENT APPROACH BASED ON CLINICAL AND B-CELL BIOMARKERS IN ANCA-ASSOCIATED VASCULITIS

Background:

Time-to-relapse after rituximab for ANCA-associated vasculitis (AAV) is variable and optimal retreatment strategy has been unclear. We previously showed that repopulation of naïve B-cells at 6 months predicts sustained response [1].

Objectives:

In AAV following rituximab induction, to evaluate clinical and B-cell predictors of relapse in order to develop a retreatment algorithm.

Methods:

An observational study was conducted in 60 rituximab-treated AAV patients followed for over 10 years. Complete response (CR) was defined as Birmingham Vasculitis Activity Score v3.0 = 0. Retreatment was given on clinical relapse, defined as new features or worsening of persistent disease (not by biomarker status). Peripheral B-cell subsets were measured using highly sensitive flow cytometry. Predictors were tested using multivariable Cox-Regression.

Results:

Median times-to-retreatment for rituximab cycles 1-5 were 87, 71, 65, 59 and 86 weeks. Over 417 patient-years follow-up, 137 relapses occurred in 50 patients; 16 (in 14 patients) were major (renal=7, neurological=4, ENT=3 and respiratory=2). The major-relapse rate was 3.8/100 patient-years. In multivariable analysis, concomitant immunosuppressant [HR 0.48 (95% CI 0.24–0.94)], achieving CR [0.24 (0.12–0.50)] and naïve B-cell repopulation at 6 months [0.43 (0.22–0.84)] were associated with longer time-to-relapse. Higher baseline memory B-cells [1.01 (1.00–1.02)] were associated with a shorter time-to-relapse. AUROC for prediction of time-to-relapse was greater if guided by naïve B-cell repopulation than if ANCA and/or CD19+ return at 6 months had been used, 0.82 and 0.52 respectively.

Conclusion:

These data suggest that all patients should receive concomitant oral immunosuppressant. Those with incomplete response or with absent naïve B-cells should be retreated at 6 months. Patients with complete response and naïve repopulation at 6 months should not receive fixed retreatment. This algorithm could reduce hypogammaglobulinaemia due to unnecessary retreatment.

Figure 1.

A personalised retreatment algorithm for rituximab in ANCA-associated vasculitis

References:

[1]Md Yusof et al. Annals of rheumatic diseases (2015) PMID: 25854586.

Disclosure of Interests:

Jack Arnold: None declared, Edward Vital Speakers bureau: Roche, GSK and AstraZeneca, Consultant of: Roche, GSK and AstraZeneca, Grant/research support from: Roche, GSK and AstraZeneca, Shouvik Dass Speakers bureau: Roche and GSK, Aamir Aslam: None declared, Andrew Rawstron: None declared, Sinisa Savic: None declared, Paul Emery Speakers bureau: BMS, Abbott, Pfizer, MSD, Novartis, Roche and UCB, Consultant of: BMS, Abbott, Pfizer, MSD, Novartis, Roche and UCB, Grant/research support from: Abbott, BMS, Pfizer, MSD and Roche., Md Yuzaiful Md Yusof: None declared

Early Emergence of CD19-Negative Human Antibody-Secreting Cells at the Plasmablast to Plasma Cell Transition

Long-lived human plasma cells (PCs) play central roles in immunity and autoimmunity and are enriched among the subpopulation of CD19neg human PCs. However, whether human CD19neg PCs are necessarily aged cells that have gradually lost CD19 expression is not known. Assessing peripheral blood samples at steady-state and during the acute response to influenza vaccination in healthy donors, we identify the presence of phenotypic CD19neg plasmablasts, the proliferative precursor state to mature PCs, and demonstrate by ELISPOT that these are Ab-secreting cells (ASCs). During the acute response to influenza vaccination, CD19pos, CD19low, and CD19neg ASCs secrete vaccine-specific Abs and show linked IGHV repertoires. To address precursor/product relationships, we use in vitro models that mimic T-dependent and T-independent differentiation, finding that the CD19neg state can be established at the plasmablast to PC transition, that CD19neg PCs increase as a percentage of surviving PCs in vitro, and that CD19neg and CD19pos PCs can be maintained independently. These data provide proof-of-principle for the view that newly generated ASCs can acquire a mature PC phenotype that is accompanied by loss of CD19 expression at an early stage of differentiation and that aging is not an obligate requirement for a CD19neg state to be established.

Rituximab plus chlorambucil as first-line treatment for chronic lymphocytic leukemia: Final analysis of an open-label phase II study

PURPOSE

Most patients with chronic lymphocytic leukemia (CLL) are elderly and/or have comorbidities that may make them ineligible for fludarabine-based treatment. For this population, chlorambucil monotherapy is an appropriate therapeutic option; however, response rates with chlorambucil are low, and more effective treatments are needed. This trial was designed to assess how the addition of rituximab to chlorambucil (R-chlorambucil) would affect safety and efficacy in patients with CLL.

PATIENTS AND METHODS

Patients with first-line CLL were treated with rituximab (375 mg/m(2) on day 1, cycle one, and 500 mg/m(2) thereafter) plus chlorambucil (10 mg/m(2)/d all cycles; day 1 through 7) for six 28-day cycles. For patients not achieving complete response (CR), six additional cycles of chlorambucil alone could be administered. The primary end point of the study was safety.

RESULTS

A total of 100 patients were treated with R-chlorambucil, with a median follow-up of 30 months. Median age of patients was 70 years (range, 43 to 86 years), with patients having a median of seven comorbidities. Hematologic toxicities accounted for most grade 3/4 adverse events reported, with neutropenia and lymphopenia both occurring in 41% of patients and leukopenia in 23%. Overall response rates were 84%, with CR achieved in 10% of patients. Median progression-free survival was 23.5 months; median overall survival was not reached.

CONCLUSION

These results compare favorably with previously published results for chlorambucil monotherapy, suggesting that the addition of rituximab to chlorambucil may improve efficacy with no unexpected adverse events. R-chlorambucil may improve outcome for patients who are ineligible for fludarabine-based treatments.

DCDT2980S, an anti-CD22-monomethyl auristatin E antibody-drug conjugate, is a potential treatment for non-Hodgkin lymphoma

Antibody-drug conjugates (ADC), potent cytotoxic drugs linked to antibodies via chemical linkers, allow specific targeting of drugs to neoplastic cells. We have used this technology to develop the ADC DCDT2980S that targets CD22, an antigen with expression limited to B cells and the vast majority of non-Hodgkin lymphomas (NHL). DCDT2980S consists of a humanized anti-CD22 monoclonal IgG1 antibody with a potent microtubule-disrupting agent, monomethyl auristatin E (MMAE), linked to the reduced cysteines of the antibody via a protease cleavable linker, maleimidocaproyl-valine-citrulline-p-aminobenzoyloxycarbonyl (MC-vc-PAB). We describe the efficacy, safety, and pharmacokinetics of DCDT2980S in animal models to assess its potential as a therapeutic for the treatment of B-cell malignancies. We did not find a strong correlation between in vitro or in vivo efficacy and CD22 surface expression, nor a correlation of sensitivity to free drug and in vitro potency. We show that DCDT2980S was capable of inducing complete tumor regression in xenograft mouse models of NHL and can be more effective than rituximab plus combination chemotherapy at drug exposures that were well tolerated in cynomolgus monkeys. These results suggest that DCDT2980S has an efficacy, safety, and pharmacokinetics profile that support potential treatment of NHL.

In vitro generation of long-lived human plasma cells

Plasma cells (PCs), the terminal effectors of humoral immunity, are short-lived unless supported by niche environments in which they may persist for years. No model system has linked B cell activation with niche function to allow the in vitro generation of long-lived PCs. Thus, the full trajectory of B cell terminal differentiation has yet to be investigated in vitro. In this article, we describe a robust model for the generation of polyclonal long-lived human PCs from peripheral blood B cells. After a proliferative plasmablast phase, PCs persist in the absence of cell division, with viability limited only by elective culture termination. Conservative predictions for PC life expectancy are 300 d, but with the potential for significantly longer life spans for some cells. These long-lived PCs are preferentially derived from memory B cells, and acquire a CD138(high) phenotype analogous to that of human bone marrow PCs. Analysis of gene expression across the system defines clusters of genes with related dynamics and linked functional characteristics. Importantly, genes in these differentiation clusters demonstrate a similar overall pattern of expression for in vitro and ex vivo PCs. In vitro PCs are fully reprogrammed to a secretory state and are adapted to their secretory load, maintaining IgG secretion of 120 pg/cell/day in the absence of XBP1 mRNA splicing. By establishing a set of conditions sufficient to allow the development and persistence of mature human PCs in vitro, to our knowledge, we provide the first platform with which to sequentially explore and manipulate each stage of human PC differentiation.

EuroFlow antibody panels for standardized n-dimensional flow cytometric immunophenotyping of normal, reactive and malignant leukocytes

Most consensus leukemia & lymphoma antibody panels consist of lists of markers based on expert opinions, but they have not been validated. Here we present the validated EuroFlow 8-color antibody panels for immunophenotyping of hematological malignancies. The single-tube screening panels and multi-tube classification panels fit into the EuroFlow diagnostic algorithm with entries defined by clinical and laboratory parameters. The panels were constructed in 2-7 sequential design-evaluation-redesign rounds, using novel Infinicyt software tools for multivariate data analysis. Two groups of markers are combined in each 8-color tube: (i) backbone markers to identify distinct cell populations in a sample, and (ii) markers for characterization of specific cell populations. In multi-tube panels, the backbone markers were optimally placed at the same fluorochrome position in every tube, to provide identical multidimensional localization of the target cell population(s). The characterization markers were positioned according to the diagnostic utility of the combined markers. Each proposed antibody combination was tested against reference databases of normal and malignant cells from healthy subjects and WHO-based disease entities, respectively. The EuroFlow studies resulted in validated and flexible 8-color antibody panels for multidimensional identification and characterization of normal and aberrant cells, optimally suited for immunophenotypic screening and classification of hematological malignancies.

Is MRD eradication a desirable goal in CLL?

Among chronic lymphocytic leukaemia (CLL) patients who require therapy, their response to therapy is the most important prognostic factor, with a better response predicting longer progression-free and overall survival. In this context, patients who achieve minimal residual disease (MRD)-negative status have better prognosis than those with inferior response to therapy, including those with MRD-positive complete response (CR). MRD can be assessed by either allele-specific polymerase chain reaction (PCR) or four-colour cytofluorometry. Importantly, methods to determine MRD in CLL have been standardised. Nevertheless, MRD status should not be used as a goal of therapy outside clinical studies. This is because the issue of the benefits of achieving MRD-negative status in patients with CLL requires further investigation in large controlled trials, in which patients should be stratified according to not only clinical variables but also biological parameters such as cytogenetics, IGHV mutations or ZAP-70 expression.

CD4(+)CD25(+)FoxP3(+) regulatory T cells are increased whilst CD3(+)CD4(-)CD8(-)alphabetaTCR(+) Double Negative T cells are decreased in the peripheral blood of patients with multiple myeloma which correlates with disease burden

Increased levels of naturally occurring regulatory T cells (T(Reg) cells) have been found in a variety of solid tumours and haematological malignancies. In multiple myeloma (MM), evidence suggests that T(Reg) cells are increased though controversy exists with regards to their function and no relationship to disease stage and treatment has been demonstrated. Here, we demonstrate significantly elevated levels of functional CD4(+)CD25(+)FoxP3(+) T(Reg) cells in a large cohort of patients with MM as well as monoclonal gammopathy of uncertain significance (MGUS) in comparison to age-matched, healthy controls. The frequency of Double Negative T(Reg) cells was also evaluated, demonstrating that these cells were reduced in patients with MM. Furthermore, a characteristic profile of immunomodulatory cytokines in the peripheral blood and bone marrow of patients with MM and MGUS was demonstrated, compared with healthy controls. This data adds further evidence to the understanding of the role of T(Reg) cell subsets in tumour immunology and the fundamentals of the host/tumour immune conflict.

Evaluation of ZAP-70 expression by flow cytometry in chronic lymphocytic leukemia: A multicentric international harmonization process

The clinical course of patients with chronic lymphocytic leukemia (CLL) is heterogeneous with some patients requiring early therapy whereas others will not be treated for years. The evaluation of an individual CLL patient's prognosis remains a problematic issue. The presence or absence of somatic mutations in the IgVH genes is currently the gold-standard prognostic factor, but this technique is labor intensive and costly. Genomic studies uncovered that 70 kDa zeta-associated protein (ZAP-70) expression was associated with unmutated IgVH genes and ZAP-70 protein expression was proposed as a surrogate for somatic mutational status. Among the available techniques for ZAP-70 detection, flow cytometry is most preferable as it allows the simultaneous quantification of ZAP-70 protein expression levels in CLL cells and residual normal lymphocyte subsets. However, several factors introduce variability in the results reported from different laboratories; these factors include the anti-ZAP-70 antibody clone and conjugate, the staining procedure, the gating strategy, and the method of reporting the results. The need for standardization of the approach led to the organization of an international working group focused on harmonizing all aspects of the technique. During this workshop, a technical consensus was reached on the methods for cell permeabilization and immunophenotyping procedures. An assay was then designed that allowed comparison of two clones of anti-ZAP-70 antibody and the identification of the expression of this molecule in B, T, and NK cells identified in a four multicolor analysis. This procedure was applied to three stabilized blood samples, provided by the UK NEQAS group to all participating members of this study, in order to minimize variability caused by sample storage and shipment. Analysis was performed in 20 laboratories providing interpretable data from 14 centers. Various gating strategies were used and the ZAP-70 levels were expressed as percentage positive (POS) relative to isotype control or normal B-cells or normal T-cells; in addition the levels were reported as a ratio of expression in CLL cells relative to T-cells. The reported level of ZAP-70 expression varied greatly depending on the antibody and the method used to express the results. The CLL/T-cell ZAP-70 expression ratio showed a much lower interlaboratory variation than other reporting strategies and is recommended for multicenter studies. Stabilization results in decreased expression of CD19 making gating more difficult and therefore stabilized samples are not optimal for multicentric analysis of ZAP-70 expression. We assessed the variation of ZAP-70 expression levels in fresh cells according to storage time, which demonstrated that ZAP-70 is labile but sufficiently stable to allow comparison using fresh samples distributed between labs in Europe. These studies have demonstrated progress toward a consensus reporting procedure, and further work is underway to harmonize the preparation and analysis procedures.

Thalidomide maintenance following high-dose therapy in multiple myeloma: a UK myeloma forum phase 2 study

Thalidomide maintenance has unresolved issues regarding dosage and toxicity. We evaluated this in five dose cohorts in 100 patients. At a median follow-up of 32.3 months, 23 patients had stopped thalidomide for disease progression, 54 for side effects. 3-year overall and progression-free survival was 76% and 41% respectively. Dosage did not influence disease outcome but greatly affected toxicity. Fifteen patients converted from partial remission to complete remission on thalidomide at a median of 13.5 months. Maintenance doses >200 mg were largely unachievable and peripheral neuropathy was the main toxicity. Lower doses enabled more patients to stay on the drug for a useful period of time.

Eradication of minimal residual disease in B-cell chronic lymphocytic leukemia after alemtuzumab therapy is associated with prolonged survival

PURPOSE

To test whether eradication of minimal residual disease (MRD) in B-cell chronic lymphocytic leukemia (CLL) by alemtuzumab is associated with a prolongation of treatment-free and overall survival.

PATIENTS AND METHODS

Ninety-one previously treated patients with CLL (74 men and 17 women; median age, 58 years [range, 32 to 75 years]; 44 were refractory to purine analogs) received a median of 9 weeks of alemtuzumab treatment between 1996 and 2003. Regular bone marrow assessments by MRD flow cytometry were performed with the aim of eradicating detectable MRD (< 1 CLL cell in 10(5) normal cells).

RESULTS

Responses according to National Cancer Institute-sponsored working group response criteria were complete remission (CR) in 32 patients (36%), partial remission (PR) in 17 patients (19%), and no response (NR) in 42 patients (46%). Twenty-two (50%) of 44 purine analog-refractory patients responded to alemtuzumab. Detectable CLL was eradicated from the blood and marrow in 18 patients (20%). Median survival was significantly longer in MRD-negative patients compared with those achieving an MRD-positive CR, PR, or NR. Patients achieving an MRD-negative CR had a longer treatment-free survival than patients with MRD-positive CRs, PR, or NR: MRD-negative CRs, not reached; MRD-positive CRs, 20 months; PRs, 13 months; NR, 6 months (P < .0001). Overall survival for the 18 patients with MRD-negative remissions was 84% at 60 months. Eight (47%) of the MRD-negative patients converted to MRD positivity at a median of 28 months.

CONCLUSION

MRD-negative remission in CLL is achievable with alemtuzumab, leading to an improved overall and treatment-free survival.

Clonal lymphocytes in persons without known chronic lymphocytic leukemia (CLL): implications of recent findings in family members of CLL patients

Several genetic abnormalities have been characterized in chronic lymphocytic leukemia (CLL) but these are predominantly secondary events and the initiating phenomena in the etiology of the disease are yet to be established. Studies of inherited susceptibility have identified the early oncogenic events in both familial and "sporadic" forms of several malignant disorders, and this may also be possible in CLL. However, the utility of linkage analysis in identifying a predisposition locus for the disease is limited because large multigenerational families segregating CLL are rare, while the more frequent small nuclear CLL families contain insufficient numbers of affected individuals. The power to detect predisposition gene(s) could be greatly increased by extending the number of affected individuals within a particular family, for example, by identifying family members with subclinical levels of disease. High-sensitivity flow cytometry techniques, developed to monitor disease in CLL patients undergoing treatment, have allowed accurate enumeration of subclinical levels of CLL cells in healthy individuals from the general population and CLL families. Emerging evidence confirms the phenotypic, genotypic, and clinical associations between the aberrant cells in healthy individuals and those in CLL patients. The data suggest that inherited factors increase the susceptibility to both indolent and aggressive CLL, and they provide unbiased demonstration that the age of onset in CLL families is younger than in the general population.

Campath-1H and fludarabine in combination are highly active in refractory chronic lymphocytic leukemia

Campath-1H (alemtuzumab) is the most effective monoclonal antibody in single-agent use in B-cell chronic lymphocytic leukemia (CLL) with reported response rates of 33% to 70%. Combination therapy is now the conventional treatment for most hematologic malignancies. Monoclonal antibody treatments may sensitize tumor cells to subsequent chemotherapy. We report the combination of Campath-1H with fludarabine in patients with CLL refractory to each agent used singly. Six patients who had received a median of 8 courses of fludarabine (range, 4-10 courses) and 16 weeks of Campath-1H (range, 8-32 weeks) were treated. Five patients responded, including one who had a complete response by National Cancer Institute criteria. The responses observed were better in each patient than responses after each agent used singly. Complete morphologic bone marrow responses were seen in 3 patients, including eradication of disease measured by sensitive flow cytometry in 2. Campath-1H combined with fludarabine is a highly promising novel therapy for refractory CLL.

Distribution of myeloma plasma cells in peripheral blood and bone marrow correlates with CD56 expression

There is a wide variation in the degree of marrow and blood involvement between patients with multiple myeloma. Both of these parameters are known to be highly significant prognostic factors, and the differences between patients may be due to variable expression of adhesion molecules. To test this we used three-colour flow cytometry to study three adhesion molecules associated with myeloma, namely CD38, CD56 and CD138. The level of expression of these molecules was compared with the distribution of myeloma plasma cells in bone marrow (n=59) and peripheral blood (n=26) in patients at presentation or relapse. The extent of marrow infiltration on the trephine biopsy correlated inversely with CD56 expression (Mann-Whitney U Test, P=0.022); there was no difference in CD38 or in CD138 expression. CD56 expression also correlated inversely with the number of circulating plasma cells (linear regression, R2=0.4268, slope=-0.58, P=0.0003). Peripheral blood plasma cell numbers correlated weakly with bone marrow plasmacytosis, and inversely with CD38 expression. The level of CD56 expression by neoplastic plasma cells was assessed in 37 patients over a median of 11 months (range 6-25). There was no significant change in expression (Wilcoxon Signed Rank, P=0.6271). We conclude that plasma cell CD56 expression is constant over the course of the disease; unlike CD138 expression, it is significantly linked to the degree of both bone marrow and peripheral blood involvement.

A phase 1 study to address the safety and efficacy of granulocyte colony-stimulating factor for the mobilization of hematopoietic progenitor cells in active rheumatoid arthritis

OBJECTIVE

To examine the safety and efficacy of granulocyte colony-stimulating factor (G-CSF) alone for the mobilization of peripheral blood progenitor cells in patients with resistant active rheumatoid arthritis (RA).

METHODS

Five patients with resistant active RA were studied. A dose of 5 microg/kg of G-CSF (Filgrastim) was given subcutaneously each day for 5 days, and the number of stem cells mobilized into the peripheral blood was assessed by daily CD34 counts. RA disease activity was assessed by standard clinical methods.

RESULTS

The absolute numbers of peripheral blood CD34+ cells peaked on day 4, with a mean value of 0.025 x 10(9)/liter (range 0.013-0.048 x 10(9)/liter). There was no significant change in disease activity during the study or in the month following therapy.

CONCLUSION

Using G-CSF alone, CD34+ progenitor peripheral blood cells were mobilized in numbers suitable for leukopheresis. G-CSF therapy was well-tolerated in patients with active RA, and was not associated with a flare during treatment or in the month following treatment.

Mobilization of Philadelphia-negative peripheral blood mononuclear cells in chronic myeloid leukaemia using hydroxyurea and G-CSF (filgrastim)

A relatively simple and non-toxic out-patient-based regimen for the mobilization of Philadelphia-negative (Ph-ve) mononuclear cells in chronic myeloid leukaemia (CML) was evaluated in 10 patients, nine in stable chronic phase and one in accelerated phase. They received oral hydroxyurea at a mean dose of 3.5 g/m2 daily for 7 d, followed by 300 micrograms of G-CSF daily until the last day of harvesting. In the nine chronic-phase patients the mean number of days from the end of hydroxyurea to the commencement of harvesting was 14.5 (range 10-18). The patient in accelerated phase recovered and was harvested after 6 d. The mean number of aphereses performed was 3.4. Adequate numbers of stem cells were obtained in 9/10 patients judged by our usual criteria. Side-effects were mild in comparison to published intravenous schedules. No patients lost their hair. Five (50%) patients required admission with neutropenic fever which responded to antibiotics in all cases. Four (40%) patients developed a transient rash and four (40%) experienced mild oral mucostis. This level of toxicity enabled half of the patients to be treated entirely on an out-patient basis. The harvest products were analysed for cells belonging to the leukaemic clone by conventional cytogenetics, FISH and PCR. All were PCR positive. The mean Ph positivities by cytogenetics and FISH were comparable at 18.1% and 15% respectively. Half the patients had > 98% normal metaphases. We conclude that this approach is comparable in efficacy to published intravenous regimens and significantly less toxic. It can be safely used at diagnosis before interferon therapy commences.

Peripheral blood stem cell transplantation in myeloma using CD34 selected cells

We have performed nine CD34 selection procedures on peripheral blood stem cells harvested from eight patients with myeloma using the Cellpro avidin-biotin immunoaffinity column (Ceprate). They all received CVAMP chemotherapy to maximum response prior to mobilisation. Six of the patients have been transplanted using these cells, one receiving successive autografts. Median absolute cell numbers processed and retrieved were: 31.1 x 10(9) pre-column, 2.07 x 10(8) in the final product and 30.4 x 10(9) in the column waste. Mean CD34 positivity in the product was 49% (range 18.4-98) with a median CD34+ yield of 31.4% (range 21-37.8). IgH PCR was performed and seven of the eight patients were amplifiable. Of these, two were positive in the pre-column product and both of these were successfully purged with a negative result in the final, post-column product. Patients were transplanted with a median of 2.0 x 10(6) CD34+ cells/kg (range 1.5-9.4) following conditioning with melphalan 200 mg/m2. The mean time to recovery of neutrophils to > 0.5 x 10(9)/l and platelets to > 20 x 10(9)/l was 16 and 17 days, respectively. At a mean follow-up of 9 months, four of the six patients transplanted are alive, three of them in complete remission and one in a clinically stable relapse. One has died of disease relapse and one of progressive neurological problems the aetiology of which was uncertain but there was no sign of progression of their myeloma. We conclude that PBSCT using CD34 selected cells is safe and practical in myeloma following remission induction with CVAMP chemotherapy.

Immunophenotypic and DNA genotypic analysis of T-cell and NK-cell subpopulations in patients with B-cell chronic lymphocytic leukaemia (B-CLL)

Absolute numbers and distributions of peripheral blood T-cells and NK cells were immunophenotypically determined in 21 patients with B-CLL and compared with those obtained from a series of 13 elderly normal controls with an age range of 60-87 years. For absolute CD3+, CD4+ and CD8+ T-cell, and CD16+ NK subpopulation numbers, there were no consistent differences between the normal and B-CLL groups although some individual patient variation was seen. Immunophenotypic analyses did however reveal that CD3+ T-cells in almost half (10/21) of the B-CLL patients were Ia+ (defined as > 20% positive cells), compared to 0/13 of the elderly control group (p < 0.001), and that the proportions of CD4+ and CD8+ cells expressing membrane CD45RO were significantly increased compared to the control group. Subdivision of the B-CLL cases into those with low (< 20%) and high (> 20%) proportions of CD3+ T-cells co-expressing Ia further showed that CD45RO expression by CD4+ fractions was particularly prominent in the Ia+ subgroup, and that the relative increase of CD4+CD45RO+ cells was primarily a consequence of decreased absolute numbers of CD4+CD45RA+ lymphocytes. This study also examined extracted DNA from enriched CD3+ T-cell fractions (obtained by immunomagnetic bead selection in 9 of the B-CLL cases) by PCR analysis with two primers for the T-cell gamma gene locus. With the V gamma C (consensus) primer, 8/9 cases were polyclonal and the remaining case was oligoclonal. For comparison, 7/9 CD3+ fractions were oligoclonal with the V gamma 9 primer with the other two cases being polyclonal. No monoclonal CD3+ components were found. It is suggested that the observed increased Ia expression by CD3+ cells and the predominance of CD4+ cells expressing membrane CD45RO in patients with B-CLL may be of potential relevance to understanding the pathogenesis and patterns of disease progression.