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People with advanced melanoma face an uncertain trajectory as new treatments now have the potential to provide longer-term survival for some. However, the disease course is variable and unpredictable, with many expressing a need for better supportive care. This study aimed to investigate the acceptability and feasibility of extending an existing melanoma-specific self-referral or 'passive' telephone consultation support service to an 'active' outreach call to offer a supportive care program tailored to the needs of the patient. Participants were enrolled by their oncology nurse into a single group pre-post intervention study. Participants received an outreach telephone call focused on knowledge and skill development. Participants completed questionnaires at baseline and four weeks post-intervention. Post-intervention interviews with patients and involved staff were used to explore acceptability and feasibility of the outreach service call. Of 18 participants approached, 15 enrolled and 14 received the intervention. Staff time required for intervention delivery provided evidence for feasibility. Participants perceived the intervention as acceptable, and beneficial. In interviews, having someone with melanoma-specific knowledge to talk with was a key benefit of the outreach call program. Many participants expressed that they would have wished to receive the outreach call at an earlier stage, for example at the time of recurrence of/progression to advanced melanoma. Extending an existing self-referral support service model to use a more 'active' outreach approach is acceptable and feasible. The next step in the evaluation process for this intervention is a randomised controlled trial to determine effectiveness and cost-effectiveness.

This commentary highlights the publishing revolution achieved by Robert Edwards in founding Reproductive Biomedicine Online. It corrects some inaccuracies in the account given by Roger Gosden in his recently published book Let There Be Life: An Intimate Portrait of Robert Edwards and His IVF Revolution.

Objective: Treatment with immunotherapy has positively changed the long-term outlook of many patients with advanced melanoma; however, fatigue is a common and debilitating side effect. Evidence indicates exercise can improve treatment-related fatigue for patients receiving chemotherapy and radiotherapy. However, currently little is known about exercise behaviors and preferences of patients receiving immunotherapy. This project aimed to describe self-reported levels of fatigue related to immunotherapy; patient perspectives of exercise behaviors; and barriers and facilitators to engagement in exercise for patients receiving, or recently completed immunotherapy for unresectable stage III and stage IV melanoma. Method: A cross-sectional purpose-built survey was distributed to members of the Melanoma Patients Australia closed Facebook group via an online survey platform. The survey remained active for 1 month, with 3 posts during this time inviting members to participate. Results: A total of 55 responses were collected. Just over half the participants (n = 31; 56%) described exercising while receiving immunotherapy, with walking as the most common activity (n = 24; 77%). Participants described a range of physical and emotional benefits of exercise, the most predominant being fatigue reduction. Barriers to exercise also included fatigue and competing physical demands at home or work. Patient understanding of what constitutes exercise appeared to differ from clinical classifications. Conclusions: Results from this study indicate that patients are engaging in exercise while receiving immunotherapy, with the intent of mediating treatment-related fatigue. Identification of preferred exercise activities and barriers will assist in developing tailored exercise interventions for this cohort.

Chronic lymphocytic leukemia (CLL) is a clonal disease of B lymphocytes manifesting as an absolute lymphocytosis in the blood. However, not all lymphocytoses are leukemic. In addition, first-degree relatives of CLL patients have an ~15 % chance of developing a precursor condition to CLL termed monoclonal B cell lymphocytosis (MBL), and distinguishing CLL and MBL B lymphocytes from normal B cell expansions can be a challenge. Therefore, we selected FMOD, CKAP4, PIK3C2B, LEF1, PFTK1, BCL-2, and GPM6a from a set of genes significantly differentially expressed in microarray analyses that compared CLL cells with normal B lymphocytes and used these to determine whether we could discriminate CLL and MBL cells from B cells of healthy controls. Analysis with receiver operating characteristics and Bayesian relevance determination demonstrated good concordance with all panel genes. Using a random forest classifier, the seven-gene panel reliably distinguished normal polyclonal B cell populations from expression patterns occurring in pre-CLL and CLL B cell populations with an error rate of 2 %. Using Bayesian learning, the expression levels of only two genes, FMOD and PIK3C2B, correctly distinguished 100 % of CLL and MBL cases from normal polyclonal and mono/oligoclonal B lymphocytes. Thus, this study sets forth effective computational approaches that distinguish MBL/CLL from normal B lymphocytes. The findings also support the concept that MBL is a CLL precursor.

Antibody-drug conjugates (ADCs) are potent cytotoxic drugs linked to antibodies through chemical linkers, and allow specific targeting of drugs to neoplastic cells. The expression of CD22 is limited to B-cells, and we show that CD22 is expressed on the vast majority of non-Hodgkin's lymphomas (NHLs). An ideal target for an ADC for the treatment of NHL would have limited expression outside the B-cell compartment and be highly effective against NHL. We generated an ADC consisting of a humanized anti-CD22 antibody conjugated to the anti-mitotic agent maytansine with a stable linker (anti-CD22-MCC-DM1). Anti-CD22-MCC-DM1 was broadly effective in in vitro killing assays on NHL B-cell lines. We did not find a strong correlation between in vitro potency and CD22 surface expression, internalization of ADC or sensitivity to free drug. We show that anti-CD22-MCC-DM1 was capable of inducing complete tumor regression in NHL xenograft mouse models. Further, anti-CD22-MCC-DM1 was well tolerated in cynomolgus monkeys and substantially decreased circulating B-cells as well as follicle size and germinal center formation in lymphoid organs. These results suggest that anti-CD22-MCC-DM1 has an efficacy, safety and pharmacodynamic profile that support its use as a treatment for NHL.

Here we describe the generation of an antibody–drug conjugate (ADC) consisting of a humanized anti-CD79b antibody that is conjugated to monomethylauristatin E (MMAE) through engineered cysteines (THIOMABs) by a protease cleavable linker. By using flow cytometry, we detected the surface expression of CD79b in almost all non-Hodgkin lymphoma (NHL) and chronic lymphocytic leukemia patients, suggesting that anti–CD79b-vcMMAE could be widely used in these malignancies. By using NHL cell lines to simulate a patient population we discovered that a minimal cell-surface expression level of CD79b was required for in vitro activity. Within the subpopulation of cell lines above this minimal threshold, we found that sensitivity to free MMAE, mutation of cancer genes, and cell doubling time were poorly correlated with in vitro activity; however, the expression level of BCL-XL was correlated with reduced sensitivity to anti–CD79b-vcMMAE. This observation was supported by in vivo data showing that a Bcl-2 family inhibitor, ABT-263, strikingly enhanced the activity of anti–CD79b-vcMMAE. Furthermore, anti–CD79b-vcMMAE was significantly more effective than a standard-of-care regimen, R-CHOP (ie, rituximab with a single intravenous injection of 30 mg/kg cyclophosphamide, 2.475 mg/kg doxorubicin, 0.375 mg/kg vincristine, and oral dosing of 0.15 mg/kg prednisone once a day for 5 days), in 3 xenograft models of NHL. Together, these data suggest that anti–CD79b-vcMMAE could be broadly efficacious for the treatment of NHL.

A diagnosis of chronic lymphocytic leukemia (CLL) requires a count of over 5000 circulating CLL-phenotype cells per cubic millimeter. Asymptomatic persons with fewer CLL-phenotype cells have monoclonal B-cell lymphocytosis (MBL). The goal of this study was to investigate the relation between MBL and CLL.We investigated 1520 subjects who were 62 to 80 years of age with a normal blood count and 2228 subjects with lymphocytosis (4000 lymphocytes per cubic millimeter) for the presence of MBL, using flow cytometry. Monoclonal B cells were further characterized by means of cytogenetic and molecular analyses. A representative cohort of 185 subjects with CLL-phenotype MBL and lymphocytosis were monitored for a median of 6.7 years (range, 0.2 to 11.8).Monoclonal CLL-phenotype B cells were detected in 5.1% of subjects (78 of 1520) with a normal blood count and 13.9% (309 of 2228) with lymphocytosis. CLL-phenotype MBL had a frequency of 13q14 deletion and trisomy 12 similar to that of CLL and showed a skewed repertoire of the immunoglobulin heavy variable group (IGHV) genes. Among 185 subjects presenting with lymphocytosis, progressive lymphocytosis occurred in 51 (28%), progressive CLL developed in 28 (15%), and chemotherapy was required in 13 (7%). The absolute B-cell count was the only independent prognostic factor associated with progressive lymphocytosis. During follow-up over a median of 6.7 years, 34% of subjects (62 of 185) died, but only 4 of these deaths were due to CLL. Age above 68 years and hemoglobin level below 12.5 g per deciliter were the only independent prognostic factors for death.The CLL-phenotype cells found in the general population and in subjects with lymphocytosis have features in common with CLL cells. CLL requiring treatment develops in subjects with CLL-phenotype MBL and with lymphocytosis at the rate of 1.1% per year.

Summary A CD5+23+ monoclonal B-cell population is detectable in approximately 3% of the general adult population. The phenotype of the monoclonal CD5+23+ B cells is identical to chronic lymphocytic leukaemia (CLL) with respect to a large number of proteins in addition to the standard diagnostic markers used to identify CLL. Studies in CLL families and direct assessment of genetic features indicate a close biological association between indolent CLL and the CLL-phenotype cells detected in individuals with a normal blood count. Patients with a CLL-phenotype monoclonal B-cell lymphocytosis (MBL) often have increasing CLL cell counts with time and some progress to a stage requiring treatment. Analysis of intraclonal variation in the immunoglobulin heavy chain gene suggests a process of clonal diversification rather than clonal selection in the early stages of disease progression. CLL-phenotype MBL is detectable in approximately 10% of cases referred for investigation of a lymphocytosis and future studies should be directed towards the detection of factors which identify MBL patients at risk of disease progression.

Chronic lymphocytic leukemia (CLL) -like monoclonal B-cell lymphocytosis (MBL) shares common immunophenotype and cytogenetic abnormalities with CLL, from which it is discriminated by a cutoff value of 5 × 10(9)/L circulating clonal B cells. However, the clonal size in MBL is extremely variable and allows discrimination of two distinct entities (high-count [HC] and low-count [LC]-MBL) based on a cutoff value of 0.5 × 10(9)/L clonal B cells. HC-MBL is associated with lymphocytosis and progresses to CLL requiring treatment at a rate of 1.1% per year, whereas LC-MBL is found in the general population only through high-sensitivity techniques and carries limited, if any, risk of progression. We performed an immunogenetic profiling of 333 cases with CLL-like MBL supplemented by detailed comparisons with CLL, focusing especially on CLL Rai stage 0 (CLL-0). LC- and HC-MBL had similar somatic hypermutation status, yet different IGHV gene repertoires and frequencies of B-cell receptor (BcR) stereotypy. In particular, stereotyped BcRs were infrequent in LC-MBL and were often not CLL specific. In contrast, HC-MBL exhibited clear immunogenetic similarities to CLL-0. These findings indicate that LC-MBL may not represent a true preleukemic condition, thus differing from HC-MBL/CLL-0 in which the identification of factors endowing malignant potential is strongly warranted.

Introduction: The aim of this study was to screen for cell surface markers that could discriminate CLL-type MBL from CLL or identify CLL cases likely to have stable disease. Methods: Six color flow cytometry was performed on CLL-type MBL (n = 94) and CLL (n = 387) at diagnosis or relapse; 39 cases had poor-risk chromosomal abnormalities (17p and/or 11q deletion). Expression of 30 markers was analysed: CCR6, CD10, CD103, CD11c, CD138, CD200, CD22, CD23, CD24, CD25, CD27, CD31, CD38, CD39, CD43, CD49d, CD5, CD52, CD62L, CD63, CD79b, CD81, CD86, CD95, CXCR5, HLADR, IgD, IgG, IgM, LAIR1. Results: There was no difference in expression between CLL-type MBL and CLL for the majority of markers. Differential expression was observed for several markers, mainly between MBL and CLL cases with adverse-risk chromosomal abnormalities. These differences included lower expression of CD38 (9.4-fold lower, P = 0.007) and CD49d (3.2-fold lower, P = 0.008) and higher expression of LAIR-1 (3.7-fold higher, P = 0.003), CXCR5 (1.25-fold higher, P = 0.002), and CCR6 (1.9-fold higher P < 0.001) on CLL-type MBL compared to CLL with adverse chromosomal abnormalities. CD62L (L-selectin) which mediates lymphocyte adhesion to endothelial venules of lymphoid tissue, was expressed at a significantly different level between CLL-type MBL and both CLL sub-groups, with 1.3-fold lower (P = 0.04) expression levels on the MBL cases. However, there was broad overlap in expression levels. Conclusions: CLL-type MBL is phenotypically identical to CLL for a very broad range of markers. Differential expression is predominantly related to known prognostic markers and proteins involved in homing to lymphoid tissue. © 2010 International Clinical Cytometry Society

The proliferating component in chronic lymphocytic leukaemia (CLL) is usually small (

Abstract 1736 The distinction between Acute Myeloid Leukaemia (AML) and Myelodysplastic Syndrome (MDS), together with its prognostic assessment, depends on the proportion of bone marrow blast cells. The International Prognostic Scoring System (IPSS) uses this value to predict survival in conjunction with cytogenetic and blood count parameters. Current practice in most centres is to count blast cells manually on stained smears and to assign patients to one of 4 bands (20%). This approach has two major disadvantages. Firstly, the evaluation of cellular morphology is subjective and the standard error of a manual count is sufficiently large that many patients cannot be assigned with reasonable accuracy to a category - which can critically impact on their care. Secondly, assigning patients into broad groups, instead of retaining blast cell count as a continuous variable, may be degrading important prognostic information. Modern flow cytometric techniques allow blast cells to be counted with high levels of accuracy. In this study we used a standard five colour assay including CD34, CD117, CD15, CD3, CD19 and physical characteristics to count bone marrow blast cells. Bone marrows from 271 patients with AML/MDS treated with curative intent (median age, 59 yrs; M: F,1.22) and 684 patients treated with supportive therapy (median age, 77 yrs; M: F,1: 1.8) were evaluated. Patients with acute promyelocytic leukaemia (APML), AML with t(8;21) or inv 16 were excluded. All patients were from a population-based cohort (www.hmrn.org), and all diagnostic studies were performed using standard protocols in a single laboratory. A prognostic model was constructed using age, flow cytometric blast cell count and gender. In non-intensively treated patients survival declined rapidly with blast counts up to 10% and then decreases much more slowly. Age had a minimal effect on survival under the age of 70, but prognosis declined rapidly in older patients. Male gender was a significant adverse risk factor (hazard ratio = 1.47). In contrast, patients who were treated intensively showed only a modest relationship between blast count and prognosis but a much more marked effect of age. Survival declined progressively from 20 years with the trend accelerating in those over 60 years. There was also a smaller effect of gender in those receiving intensive treatment (hazard ratio = 1.09). In MDS patients, a complex relationship between blast cell count, standard cytogenetic risk factors and the degree of cytopenia was observed. Using age and flow cytometric blast count as continuous variables, modelled using restricted cubic splines, together with gender enabled more accurate outcome prediction in patients with AML and MDS across the full range of blast counts. This is possible because of the much higher levels of accuracy of flow cytometry compared to manual counting methods. The main practical advantage of a unified prognostic model is that it allows the relative benefits of intensive and non-intensive treatment to be readily compared for an individual patient. The predictive power of this core model can be improved further by the inclusion of additional clinical and molecular data. MDS and most forms of AML are part of a continuous spectrum of disease. A more unified approach to classification avoiding arbitrary subdivision may improve clinical decision making in this complex group of patients. Figure: The interrelationship between survival, age and blast cell count in patients with myelodysplastic syndrome. Figure:. The interrelationship between survival, age and blast cell count in patients with myelodysplastic syndrome. Disclosures: No relevant conflicts of interest to declare.

Abstract 59 Monoclonal B-cell Lymphocytosis with a CLL-phenotype (CLL-type MBL) is detected in over 10% of individuals undergoing investigation of a lymphocytosis. The risk of developing progressive CLL requiring treatment is approximately 1% per year. However, monoclonal B-cells can now be readily detected at a level above 1 cell/μL in over 3.5% of adults with normal blood counts, & using highly sensitive techniques in over 20% of elderly individuals. There is currently no reported outcome data for such individuals. The aim of this study was to determine whether individuals with normal blood counts and very low count MBL had any increase in mortality or risk of developing a haematological malignancy. We obtained ethical approval to undertake a linked anonymised investigation of low count MBL cases identified in previous studies. In 2003, 1520 peripheral blood samples from haematologically normal 60–80 year old hospital outpatients were screened & MBL was detected in 105 individuals (78 CLL-type, 27 CD5-negative). Follow-up data is available for 40 CLL-type MBL, 17 CD5-negative MBL & 126 age-matched controls screened for MBL at the same time from the same source with no evidence of abnormal B-cells. After a median follow-up of 65 months (range 0.2–72 months) there have been 51 deaths: 23% (9/40) CLL-type MBL, 35% (6/17) CD5-negative MBL & 29% (36/126) controls. The presence of MBL was not associated with a significantly different overall survival (Log-rank P=0.82). The yearly mortality rate (with 95% CI) was 4.8% (2.5–9.2%) for patients with CLL-type MBL vs. 6.8% (4.7–9.8%, P=0.76) for matched controls. The yearly mortality rate (with 95% CI) was 5.2 % (2.6–10.3%) for patients with a CD5-negative MBL vs. 6.4% (2.6–15.3%) for matched controls. A non-haematological malignancy was detected in 30 cases: 20% (8/40) CLL-type MBL, 6% (1/17) CD5-negative MBL & 17% (21/126) controls. The presence of MBL was also not associated with a significantly risk of developing a non-haematological malignancy (Log-rank P=0.65). Three individuals who had a low level of CLL-type MBL detectable with a normal blood count have been subsequently referred for investigation of a haematological malignancy at 8, 21 and 50 months after initial testing. Two were for referred for investigation of a paraprotein: in both cases the paraprotein isotype was different to the immunoglobulin expressed by the CLL-phenotype cells and neoplastic plasma cells were detected. The third was referred for investigation of a lymphocytosis. In all cases CLL cells were detectable, representing 5-25% of leucocytes. All three individuals are alive with a stable B-lymphocyte count below 5,000/μL and none have required treatment for progressive CLL or myeloma where applicable. One individual who had CD5-negative MBL detected was investigated for a suspected lymphoproliferative disorder 41 months after screening but bone marrow & peripheral blood investigation did not demonstrate any abnormality & the CD5-negative MBL was no longer detectable. One individual from the control group developed MDS. We therefore demonstrate that the presence of a low level of MBL in hospital patients with a normal blood count has no influence on survival or development of non-haematological malignancies compared to age-matched controls. None of the individuals have developed progressive CLL but 7.5% (3/40) cases of low-count CLL-type MBL have shown an expansion of CLL cells over time and been identified clinically through independent referral. The higher rate of detection of MBL or a paraprotein in this group may reflect the closer monitoring applied to regular hospital attenders. These represent the first data concerning outcome for individuals with low levels ( Disclosures: No relevant conflicts of interest to declare.

INTRODUCTION: CLL is a disorder with a wide variation in outcome. Patients with adverse cellular features are often refractory to treatment and have a short overall survival. Individuals with CLL-type MBL are unlikely to require treatment and in most cases will eventually die of an unrelated cause. Many factors that predict a poor outcome have been identified, including stage, IGHV mutation status, ZAP-70 expression, and deletions of chromosomes 17p (TP53) and/or 11q23 (ATM). Deletions and mutations in TP53 are generally not presenting features and appear to require clonal evolution. One hypothesis is that the degree of intraclonal variation in genes targeted by the somatic hypermutation machinery, e.g. IGHV and BCL6, may predict the potential for clonal evolution. We have previously tested 66 antigens for their capacity to differentiate proliferating CLL cells, resting CLL cells and normal B-cells and identified 30 potentially relevant markers, including common markers such as CD38 and less frequently used markers such as the Leukocyte-associated immunoglobulin-like receptor 1 (LAIR1). AIM: To compare the expression of relevant cell surface markers with the degree of intraclonal variation in the IGHV and BCL6 genes and to determine if these markers can be used to differentiate CLL-type MBL and CLL with or without adverse biological features. METHODS: The cell surface phenotype was assessed by 6-colour cytometry in 133 patients: 22 CLL with deletion 17p or 11q23, 69 CLL with no adverse prognostic chromosomal abnormalities, and 42 MBL. Surface phenotype was also compared with IGHV mutation status in a cohort of 29 CLL patients (16 ≤2% IGHV mutation, 13 >2% IGHV mutation). These antigens were also assessed using 4-colour flow cytometry in 20 cases (4 MBL, 16 CLL) and compared with IGHV & BCL6 mutation status and degree of intraclonal variation (defined as the proportion of mutations that were detected in a single clone only), and with ZAP-70 (AF488-1E7.2) expression. RESULTS: CLL cases with ≤2% IGHV mutation showed increased expression of CD38 (6.8 fold, p 0.02), CD49d (4.9-fold, P = 0.04), IgD (2.0-fold, P = 0.05), ZAP-70 (1.5-fold, P=0.04) and decreased expression of LAIR-1 (6.2-fold, P = 0.003) in comparison to CLL cases with >2% IGHV mutation. CLL cases with deletions of 17p and 11q23 showed decreased expression of CCR6 (1.7-fold, P = 0.0001), IgD (1.3-fold, P = 0.03) and LAIR-1 (7.1-fold, P2% overall IGHV mutation in both IGHV (median 0.075% vs. 0.049% unique mutations, P>0.05) and BCL6 (median 0.10% vs. 0.095% unique mutations, P>0.05). However, there was an inverse relationship between BCL6 and IGHV intraclonal variation and cases with the highest levels of BCL6 intraclonal variation showed significantly decreased expression of CD39 (1.9-fold, P = 0.04) and LAIR1 (4.7-fold, P = 0.019). CONCLUSIONS: There were no markers or marker combinations that could discriminate MBL from CLL. The key differences were decreased expression of markers that are expressed during cell cycle, i.e. CD23, and adhesion markers such as CD62L and CD49d. These markers show sequential changes with disease stage, supporting the hypothesis that cellular interactions are central to the accumulation and expansion of CLL cells. However, the marker most consistently associated with adverse biological features is LAIR1, which is weak or negative in CLL with ≤2% IGHV mutation, high levels of intraclonal variation and TP53 or ATM deletions. LAIR-1 is an inhibitory receptor involved in regulating classs-witching. LAIR1 is strongly expressed in normal circulating peripheral B-cells. As with other prognostic markers, expression is a continuous variable and therefore a suitable cutoff will need to be identified. However, fluorochrome-conjugated antibodies are readily available and expression on CLL cells is stable for several days in EDTA samples which should minimise inter-laboratory analytical variation. LAIR1 expression in CLL is more closely associated with IGHV mutation status than CD38 or ZAP-70 expression. LAIR1 is a promising prognostic marker that appears to be central to the development of aggressive CLL as there is a strong association between downregulation of LAIR1, intraclonal heterogeneity in BCL6 and development of TP53 and ATM deletions.

Antibody-drug conjugates (ADCs), antibodies linked to potent cytotoxic drugs via specialized chemical linkers, provide a means to increase the effectiveness of chemotherapy by targeting the drug to neoplastic cells while reducing side effects. We have previously shown that ADCs targeted to CD79b are highly effective in xenograft models of non-Hodgkin’s lymphoma. Here we report the development of an ADC consisting of a humanized anti-CD79b antibody (hu-anti-CD79b) conjugated to monomethylauristatin E (MMAE) through engineered cysteines (THIOMABS) by a maleimidocaproyl-valinecitrulline-p-aminobenzyloxycarbonyl (MC-vcPAB) linker (hu-anti-CD79b-thioMAb-MC-vc-PAB-MMAE) that is designed to be cleaved by cathepsins. To determine the potential of this ADC, hu-anti-CD79b-thioMAb-MC-vc-PAB-MMAE (referred to as anti-CD79b-vcMMAE henceforth), as a therapeutic for NHL we interrogated its potency across a large panel of NHL cell lines. Strikingly, anti-CD79b-vcMMAE has very potent activity across a large panel of NHL cell lines in vitro with 68% (23 out of 34) cell lines having greater than 50% reduction in cell viability. Quantitative FACS across the cell line panel revealed that of the 11 insensitive cell lines, 9 had negligible surface CD79b, suggesting a threshold effect in that below a specific level of antigen on the cell surface resulted in cells being insensitive to anti-CD79b-vcMMAE. Within the sensitive cell lines, there was not a direct correlation per se with anti-CD79b-vcMMAE IC50 values and cell surface expression levels and this prompted us to investigate other potential molecular parameters. Gene expression profiling and gene set enrichment analysis revealed that genes predominantly involved in antigen processing and presentation and genes induced by IFN-gamma were significantly enriched in the less sensitive cell lines to CD79b-vcMMAE. Classifying our NHL cell lines as GCB or ABC subtypes by gene expression revealed that both ABC and GCB were responsive. In addition, the activity of anti-CD79b-vcMMAE was very potent in p53 mutant as well as p53 wild-type cell lines. Since the pre-clinical evidence suggests that anti-CD79b-vcMMAE will be a very promising drug candidate for NHL and we have established that cell surface expression is perhaps the best predictor of response, we wished to determine the prevalence of expression of CD79b on the cell surface of primary human lymphoma and CLL samples to estimate a patient population that may gain benefit. Strikingly, CD79b was detected in all cases of CLL, MZL, HCL, DLBCL, FL, and MCL. Furthermore, CD79b expression was detected in all cases that had relapsed from prior chemotherapy regimens, highlighting the clinical relevance of this target and potential therapeutic utility of anti-CD79b-vcMMAE. To assess the potential of anti-CD79b-vcMMAE in vivo we compared its efficacy to R-CHOP in three xenograft models of NHL. In all three models, a single dose of anti-CD79b-vcMMAE resulted in complete sustained tumor remission and was more effective than R-CHOP. These data suggest that anti-CD79b-vcMMAE could be broadly efficacious as a treatment for NHL.

A monoclonal B-cell lymphocytosis (MBL) is detectable in approximately 3% of the general adult population. In most cases the abnormal cells have a phenotype and genotype that is indistinguishable from indolent CLL. Individuals presenting with an MBL count over 500 cells per microlitre progress to CLL requiring treatment at a rate of approximately 1% per year. The relationship between MBL and CLL therefore appears to be similar to that of MGUS and myeloma. Intraclonal variation (ICV) in the immunoglobulin heavy chain gene (IgVH) gene occurs in approximately half of MGUS patients but is not present in myeloma. The majority MGUS patients that progress to myeloma lack intraclonal variation at the MGUS stage suggesting that clonal selection is a critical pathway for disease progression in myeloma. The aim of this study was to compare the rate of intraclonal variation in MBL and CLL and determine whether low rates of ICV are associated with progressive disease. DNA was extracted from ammonium-chloride lysed blood samples from individuals with CLL-phenotype MBL (n=20) and CLL with progressive disease (n=10). IgVH and BCL6 PCR products were directly sequenced and also cloned and at least 10 clones sequenced. Intraclonal variation was defined as the number of unique sequences as a percentage of total clones sequenced. Unmutated CLL was defined as having