Oncolytic measles virus targets high CD46 expression on multiple myeloma cells

OBJECTIVE: Multiple myeloma (MM) is an incurable B cell malignancy and novel therapeutics are urgently needed. Live attenuated measles virus (MV) has potent oncolytic activity against MM tumor xenografts. The virus is tumor selective and preferentially targets cells that express high levels of CD46 receptors. However, CD46 levels on MM have not previously been evaluated. In this study, we investigated the potential of CD46 as a target for MM therapy and correlated surface levels of CD46 on MM cells with their susceptibility to MV-induced cytopathic effects. MATERIALS AND METHODS: CD46 expression on neoplastic plasma cells (PCs) and nonplasma cells (NPCs) from 38 MM patients was analyzed by flow cytometry and receptor numbers were quantitated using BD QuantiBRITE PE beads. RESULTS: Results showed that malignant PCs expressed significantly higher levels of CD46 receptors compared to NPCs (p < 0.0001). The mean CD46 receptor numbers on PCs and NPCs were 49,130/cell and 7,340/cell, respectively. Potent cytopathic effects of extensive intercellular fusion were observed in measles-infected PCs but not in NPCs. The extent of MV-induced cytopathic effects of cell fusion correlated with CD46 expression levels on the MM cells. Normal plasma cells do not overexpress CD46 and colony-forming assays demonstrated that MV was not cytotoxic to normal bone marrow progenitor cells. CONCLUSION: The present study establishes CD46 as a surface antigen that is expressed more abundantly on primary MM cells compared to normal hematopoietic cells of various lineages in the bone marrow, making CD46 a promising surface marker for targeted cytoreductive therapy of MM.     

Risk of non-Hodgkin lymphoma in association with germline variation in complement genes

Germline mutations in complement genes have been associated with susceptibility to infections and autoimmune diseases, conditions that are associated with non-Hodgkin lymphoma (NHL) risk. To test the hypothesis that common genetic variation in complement genes affect risk of NHL, we genotyped 167 single nucleotide polymorphisms (SNPs) from 31 genes in 441 NHL cases and 475 controls. Principal components (PC) and haplotype analyses were used for gene-level tests of NHL risk, while individual SNPs were modelled as having a log-additive effect. In gene level PC analyses, C2 ( P =  0·023), C5 ( P =  0·0032) and C9 ( P =  0·020) were associated with NHL risk; haplotype analyses showed similar results, as well as a haplotype association for C7 ( P =  0·046). When all four genes were considered simultaneously, only C5 and C9 remained significant ( P <  0·05). In SNP level results from these genes, 10 SNPs had a P <  0·05. However, after correcting for multiple testing, only the C5 SNPs rs7026551 ( q  = 0·015; OR = 1·54, 95% CI 1·21–1·95) and rs2416810 ( q  = 0·015; OR = 1·57; 95% CI 1·22–2·01), and the C9 SNP rs187875 ( q  = 0·015; OR = 0·68; 95% 0·56–0·84) remained noteworthy. Associations were similar for the common NHL subtypes. In summary, we provide evidence for a role of genetic variation in complement genes, particularly C5 and C9 , and NHL risk.     

Development of a marrow transplant regimen for acute leukemia using targeted hematopoietic irradiation delivered by 131I-labeled anti-CD45 antibody, combined with cyclophosphamide and total body irradiation

In an attempt to decrease the relapse rate after bone marrow transplantation (BMT) for advanced acute leukemia, we initiated studies using 131I-labeled anti-CD45 antibody (BC8) to deliver radiation specifically to hematopoietic tissues, followed by a standard transplant preparative regimen. Biodistribution studies were performed in 23 patients using 0.5 mg/kg trace 131I-labeled BC8 antibody. The BC8 antibody was cleared rapidly from plasma with an initial disappearance half-time of 1.5 +/- 0.2 hours, presumably reflecting rapid antigen- specific binding. The mean radiation absorbed doses (cGy/mCi131I administered) were as follows: marrow, 7.1 +/- 0.8; spleen, 10.8 +/- 1.4; liver, 2.7 +/- 0.2; lungs, 2.1 +/- 0.1; kidneys, 0.7 +/- 0.1; and total body, 0.4 +/- 0.03. Patients with acute myelogenous leukemia (AML) in relapse had a higher marrow dose (11.4 cGy/mCi) than those in remission (5.2 cGy/mCi; P = .001) because of higher uptake and longer retention of radionuclide in marrow. Twenty patients were treated with a dose of 131I estimated to deliver 3.5 Gy (level 1) to 7 Gy (level 3) to liver, with marrow doses of 4 to 30 Gy and spleen doses of 7 to 60 Gy, followed by 120 mg/kg cyclophosphamide (CY) and 12 Gy total body irradiation (TBI). Nine of 13 patients with AML or refractory anemia with excess blasts (RAEB) and two of seven with acute lymphocytic leukemia (ALL) are alive disease-free at 8 to 41 months (median, 17 months) after BMT. Toxicity has not been measurably greater than that of CY/TBI alone, and the maximum tolerated dose has not been reached. This study demonstrates that with the use of 131I-BC8 substantially greater doses of radiation can be delivered to hematopoietic tissues as compared with liver, lung, or kidney, which may improve the efficacy of marrow transplantation.     

Early event status informs subsequent outcome in newly diagnosed follicular lymphoma

Recent advances in follicular lymphoma (FL) have resulted in prolongation of overall survival (OS). Here we assessed if early events as defined by event‐free survival (EFS) at 12 and 24 months from diagnosis (EFS12/EFS24) can inform subsequent OS in FL. 920 newly diagnosed grade 1‐3A FL patients enrolled on the University of Iowa/Mayo Clinic Lymphoma SPORE Molecular Epidemiology Resource (MER) from 2002‐2012 were initially evaluated. EFS was defined as time from diagnosis to progression, relapse, re‐treatment, or death due to any cause. OS was compared to age‐and‐sex‐matched survival in the general US population using standardized mortality ratios (SMR) and 95% confidence intervals (CI). We used a cohort of 412 FL patients from two Lyon, France hospital registries for independent replication. Patients who failed to achieve EFS12 had poor subsequent OS (MER SMR = 3.72, 95%CI: 2.78‐4.88; Lyon SMR = 8.74, 95%CI: 5.41‐13.36). Conversely, patients achieving EFS12 had no added mortality beyond the background population (MER SMR = 0.73, 95%CI: 0.56‐0.94, Lyon SMR = 1.02, 95%CI: 0.58‐1.65). Patients with early events after immunochemotherapy had especially poor outcomes (EFS12 failure: MER SMR = 17.63, 95%CI:11.97‐25.02, Lyon SMR = 19.10, 95%CI:9.86‐33.36; EFS24 failure: MER SMR = 13.02, 95%CI:9.31‐17.74, Lyon SMR = 7.22, 95%CI:4.13‐11.74). In a combined dataset of all patients from both cohorts, baseline FLIPI was no longer informative in EFS12 achievers. Reassessment of patient status at 12 months from diagnosis in follicular lymphoma patients, or at 24 months in patients treated with immunochemotherapy, is a strong predictor of subsequent overall survival in FL. Early event status provides a simple, clinically relevant endpoint for studies assessing outcome in FL. Am. J. Hematol. 91:1096–1101, 2016. © 2016 Wiley Periodicals, Inc.     

Mechanisms of regulation of CXCR4/SDF-1 (CXCL12)-dependent migration and homing in multiple myeloma

The mechanisms by which multiple myeloma (MM) cells migrate and home to the bone marrow are not well understood. In this study, we sought to determine the effect of the chemokine SDF-1 (CXCL12) and its receptor CXCR4 on the migration and homing of MM cells. We demonstrated that CXCR4 is differentially expressed at high levels in the peripheral blood and is down-regulated in the bone marrow in response to high levels of SDF-1. SDF-1 induced motility, internalization, and cytoskeletal rearrangement in MM cells evidenced by confocal microscopy. The specific CXCR4 inhibitor AMD3100 and the anti-CXCR4 antibody MAB171 inhibited the migration of MM cells in vitro. CXCR4 knockdown experiments demonstrated that SDF-1-dependent migration was regulated by the P13K and ERK/ MAPK pathways but not by p38 MAPK. In addition, we demonstrated that AMD3100 inhibited the homing of MM cells to the bone marrow niches using in vivo flow cytometry, in vivo confocal microscopy, and whole body bioluminescence imaging. This study, therefore, demonstrates that SDF-1/CXCR4 is a critical regulator of MM homing and that it provides the framework for inhibitors of this pathway to be used in future clinical trials to abrogate MM trafficking.     

Bendamustine and rituximab (BR) versus dexamethasone,rituximab, and cyclophosphamide (DRC) in patients with Waldenström macroglobulinemia

The treatment approaches for Waldenstrom macroglobulinemia (WM) are largely based upon information from single-arm phase II trials, without comparative data. We compared the efficacy of two commonly used regimens in routine practice (bendamustine-rituximab (BR) and dexamethasone, rituximab plus cyclophosphamide (DRC)) and evaluated their activity with respect to the patients’ MYD88^L265P mutation status. Of 160 consecutive patients, 60 received BR (43 with relapsed/refractory WM) and 100 received DRC (50 had relapsed/refractory WM). In the treatment-naïve setting, overall response rate (ORR) was 93% with BR versus 96% with DRC (p?=?0.55). Two-year progression-free survival (PFS) with BR and DRC was 88 and 61%, respectively (p?=?0.07). In salvage setting, ORR was 95% with BR versus 87% with DRC, p?=?0.45; median PFS with BR was 58 versus 32 months with DRC (2-year PFS was 66 versus 53%; p?=?0.08). Median disease-specific survival was not reached with BR versus 166 months with DRC (p?=?0.51). The time-to-event endpoints and depth of response were independent of the MYD88 mutation status. Grade ≥?3 adverse events of both regimens were comparable. A trend for longer PFS was observed with BR although the regimens have comparable toxicities. The activity of BR and DRC appears to be unaffected by patients’ MYD88 mutation status.     

A phase 2 study of lenalidomide,rituximab, cyclophosphamide,and dexamethasone (LR‐CD) for untreated low‐grade non‐Hodgkin lymphoma requiring therapy

Patients with indolent non‐Hodgkin lymphoma (NHL) have multiple treatment options yet there is no consensus as to the best initial therapy. Lenalidomide, an immunomodulatory agent, has single agent activity in relapsed lymphoma. This trial was conducted to assess feasibility, efficacy, and safety of adding lenalidomide to rituximab, cyclophosphamide, and dexamethasone (LR‐CD) in untreated indolent NHL patients requiring therapy. This was a single institution phase II trial. Treatment consisted of IV rituximab 375 mg/m² day 1; oral lenalidomide 20 mg days 1–21; cyclophosphamide 250 mg/m² days 1, 8, and 15; and dexamethasone 40 mg days 1, 8, 15, and 22 of a 28‐day cycle. Treatment continued 2 cycles beyond best response for a maximum of 12 cycles without rituximab maintenance. Thirty‐three patients were treated. Median age was 68 (43–83 years). 39% had stage IV disease. Histologic subtypes included 8 follicular lymphoma (FL), 7 marginal zone lymphoma (MZL) (1 splenic, 2 extranodal, and 4 nodal), 15 Waldenström's macroglobulinemia (WM), 1 lymphoplasmacytic lymphoma, 1 small lymphocytic lymphoma, and 1 low‐grade B‐cell lymphoma with plasmacytic differentiation (unable to be classified better as MZL or LPL). Hematologic toxicity was the most common adverse event. Median time of follow‐up was 23.4 months (range 1.8–50.9). The overall response rate was 87.9%, with 30.3% complete response. The median duration of response was 38.7 months. The median progression free survival was 39.7 months, while median overall survival (OS) has not yet been reached. Lenalidomide can be safely added to a simple regimen of rituximab, oral cyclophosphamide, and dexamethasone and is an effective combination as initial therapy for low‐grade B‐cell NHL.     

Long‐term analysis of phase II studies of single‐agent lenalidomide in relapsed/refractory mantle cell lymphoma

Mantle cell lymphoma (MCL) is a type of non‐Hodgkin lymphoma (NHL) with aggressive disease characteristics resulting in multiple relapses after initial treatment. Lenalidomide is an immunomodulatory agent approved in the US for patients with relapsed/refractory MCL following bortezomib based on results from 3 multicenter phase II studies (2 including relapsed/refractory aggressive NHL and 1 focusing on MCL post‐bortezomib). The purpose of this report is to provide longer follow‐up on the MCL‐001 study (follow‐ups were 6.8 [NHL‐002], 7.6 [NHL‐003], and 52.2 [MCL‐001] months). The 206 relapsed MCL patients treated with single‐agent lenalidomide (25 mg/day PO, days 1 to 21 every 28‐days) had a median age of 67 years (63% ≥65 years), 91% with stage III/IV disease, and 50% with ≥4 previous treatment regimens. With a median follow‐up of X, the combined best overall response rate (ORR) was 33% (including 11% with complete remission [CR]/CR unconfirmed CRu). Lenalidomide produced rapid and durable responses with a median time to response of 2.2 months and median duration of response (DOR) of 16.6 months (95% CI: 11.1%‐29.8%). The safety profile was consistent and manageable; myelosuppression was the most common adverse event (AE). Overall, single‐agent lenalidomide showed consistent efficacy and safety in multiple phase II studies of heavily pretreated patients with relapsed/refractory MCL, including those previously treated with bortezomib.     

Peripheral blood lymphocyte/monocyte ratio at diagnosis and survival in nodular lymphocyte-predominant Hodgkin lymphoma

The pathological background in nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) consists of lymphocytes and histocytes. This study analysed the peripheral blood absolute lymphocyte count/absolute monocyte count ratio at diagnosis (ALC/AMC-DX) on the impact of survival in NLPHL. One hundred and three consecutive NLPHL patients that were followed at Mayo Clinic from 1974 to 2010 were included in the study. Receiver operating characteristic and area under the curve were used for ALC/AMC-DX cut-off value analysis and proportional-hazards models were used to compare survival based on the ALC/AMC-DX ratio. With a median follow-up of 8·9 years (range: 0·3-31 years), an ALC/AMC-DX ≥2·1 was the best cut-off value for survival with an area under the curve of 0·82, a sensitivity of 70% and specificity of 84%. After adjusting for the International Prognostic Score (IPS), ALC/AMC-DX remained an independent prognostic factor for overall survival [Hazard Ratio (HR), 0·33, 95% confidence interval (CI), 0·15-0·71%, P < 0·004]; lymphoma-specific survival (HR, 0·05; 95%CI, 0·01-0·68%, P < 0·002); progression-free survival (HR, 0·30; 95%CI, 0·14-0·60%, P < 0·006), and time to progression (HR, 0·06, 95%CI, 0·04-0·30%, P < 0·004). ALC/AMC-DX is a low cost, already standarized, biomarker to predict clinical outcomes in NLPHL.     

Analysis of p53 mutations in a large series of lymphoid hematologic malignancies of childhood

p53 mutations are found in a wide variety of cancers, including hematologic malignancies. These alterations apparently contribute to development of the malignant phenotype. We analyzed a large series of lymphoid (330 cases) and a smaller series of myeloid (29 cases) malignancies of childhood for p53 mutations by single-strand conformational polymorphism (SSCP) following polymerase chain reaction. Samples with abnormal SSCP were reamplified and analyzed by direct sequencing method. p53 mutations were detected within the known mutational hotspots (exons 5 to 8) in 8 of 330 lymphoid malignancies, and in none of 29 myeloid malignancies, showing that the frequency of p53 mutations in childhood lymphoid malignancies was very low (8 of 330 cases [2%]). Four of these patients had very aggressive, fatal acute lymphocytic leukemia (ALL). None of 13 infants and none of 48 patients with T-lineage leukemia had detectable p53 mutations in their ALL cells. Exceptionally, p53 mutations were comparatively frequent in a small sample of B-cell non-Hodgkin's lymphomas (2 of 8 cases). Mutations were detected in samples from two patients with ALL at relapse; these were not detected in samples at initial diagnosis from the same patients, suggesting that p53 mutations may be associated with progression to a more malignant phenotype. Seven of eight alterations of p53 were missense mutations, and seven of eight samples may be heterozygous for the mutant p53, indicating that p53 protein may act in a dominant negative fashion.