Anti-CD20 monoclonal antibody-dependent phagocytosis of chronic lymphocytic leukaemia cells by autologous macrophages.

Unconjugated monoclonal antibodies (mAbs) are an important component of effective combination therapies for chronic lymphocytic leukaemia (CLL). Antibody-dependent phagocytosis (ADP) is a major mediator of mAb cytotoxicity, but there is limited knowledge of the determinants of ADP efficacy. We used macrophages derived in vitro from autologous circulating monocytes to test the effects of mAb structure and concentration, target : effector cell ratio, duration of co-incubation and CLL cell CD20 expression on ADP. Next-generation anti-CD20 mAbs (ofatumumab, ublituximab, obinutuzumab, ocaratuzumab) were significantly more effective at inducing ADP compared to rituximab, but none were as effective as the anti-CD52 mAb alemtuzumab. Ofatumumab (10 µg/ml) used as a representative next-generation anti-CD20 mAb achieved an ADP plateau at 3 h co-incubation with a target : effector ratio of 10 : 1 (mean = 2.1 CLL cells/macrophage, range = 1.5-3.5). At 0.156 µg/ml (the lowest concentration tested) ofatumumab ADP was significantly higher than alemtuzumab. However, ofatumumab-induced ADP did not increase significantly at higher mAb concentrations. We show that anti-CD20 mAb ADP efficacy is determined by the mAb characteristics, target : effector ratio and incubation time. We suggest that preclinical evaluation of anti-CD20 mAbs to understand the determinants of ADP could be useful in designing future combination therapies for CLL.

A comprehensive review of lenalidomide therapy for B-cell non-Hodgkin lymphoma.

Lenalidomide is an oral non-chemotherapy immunomodulator with direct and indirect effects on non-Hodgkin lymphoma (NHL) cells and with single-agent activity in relapsed/refractory aggressive and indolent B-cell NHL, including mantle cell lymphoma (MCL), diffuse large B-cell lymphoma, and follicular lymphoma. Based on the pivotal phase II MCL-001 trial of lenalidomide in heavily pretreated patients with relapsed/refractory MCL, lenalidomide was approved by the US Food and Drug Administration for the treatment of relapsed/refractory MCL after failure of two prior therapies, one of which includes bortezomib, at a recommended starting dose of 25 mg on days 1-21 of each 28-day cycle. Lenalidomide enhanced the survival benefit in combination with rituximab in preclinical models, prompting clinical evaluation of the lenalidomide-rituximab (R2) combination. In phase II trials, lenalidomide 20 mg on days 1-21 in combination with different standard-dose rituximab schedules exhibited promising activity in both first-line and relapsed/refractory disease across multiple B-cell NHL subtypes. The feasibility of combining lenalidomide with immunochemotherapy, including R-CHOP and rituximab-bendamustine, has been demonstrated in phase I/II trials. These latter regimens are currently being evaluated in ongoing phase II and III trials. The role of lenalidomide monotherapy and R2 in maintenance therapy is also being examined. Based on available evidence, a comprehensive review of lenalidomide in all treatment phases of B-cell NHL-relapsed/refractory disease, first-line, and maintenance-is presented here.

Bowel perforation in intestinal lymphoma: incidence and clinical features.

BACKGROUND: Perforation is a serious life-threatening complication of lymphomas involving the gastrointestinal (GI) tract. Although some perforations occur as the initial presentation of GI lymphoma, others occur after initiation of chemotherapy. To define the location and timing of perforation, a single-center study was carried out of all patients with GI lymphoma. PATIENTS AND METHODS: Between 1975 and 2012, 1062 patients were identified with biopsy-proven GI involvement with lymphoma. A retrospective chart review was undertaken to identify patients with gut perforation and to determine their clinicopathologic features. RESULTS: Nine percent (92 of 1062) of patients developed a perforation, of which 55% (51 of 92) occurred after chemotherapy. The median day of perforation after initiation of chemotherapy was 46 days (mean, 83 days; range, 2-298) and 44% of perforations occurred within the first 4 weeks of treatment. Diffuse large B-cell lymphoma (DLBCL) was the most common lymphoma associated with perforation (59%, 55 of 92). Compared with indolent B-cell lymphomas, the risk of perforation was higher with aggressive B-cell lymphomas (hazard ratio, HR = 6.31, P < 0.0001) or T-cell/other types (HR = 12.40, P < 0.0001). The small intestine was the most common site of perforation (59%). CONCLUSION: Perforation remains a significant complication of GI lymphomas and is more frequently associated with aggressive than indolent lymphomas. Supported in part by University of Iowa/Mayo Clinic SPORE CA97274 and the Predolin Foundation.

Lenalidomide plus R-CHOP21 in newly diagnosed diffuse large B-cell lymphoma (DLBCL): long-term follow-up results from a combined analysis from two phase 2 trials.

Lenalidomide-RCHOP (R2-CHOP21) has been shown to be safe and effective in patients with untreated diffuse large B-cell lymphoma (DLBCL). The aim of this analysis is to report long-term outcome and toxicities in newly diagnosed DLBCL patients who received R2-CHOP21 in two independent phase 2 trials, conducted by Mayo Clinic (MC) and Fondazione Italiana Linfomi (FIL). All patients received R-CHOP21 plus lenalidomide. Long-term progression-free survival (PFS), time to progression (TTP), overall survival (OS) and late toxicities and second tumors were analyzed. Hundred and twelve patients (63 MC, 49 FIL) were included. Median age was 69 years, 88% were stage III-IV. At a median follow-up of 5.1 years, 5y-PFS was 63.5%, 5y-TTP 70.1% and 5y-OS 75.4%; according to cell of origin (COO): 5y-PFS 52.8% vs 64.5%, 5y-TTP 61.6% vs 69.6% and 5y-OS 68.6% vs 74.1% in germinal center (GCB) vs non-GCB respectively. Four patients experienced grade 4-5 late toxicities. Grade ≤ 3 toxicities were infections (N = 4), thrombosis (N = 1) and neuropathy (N = 3). Seven seconds tumors were observed. Long-term follow-up demonstrates that R2-CHOP21 efficacy was maintained with high rates of PFS, TTP, and OS. Lenalidomide appears to mitigate the negative prognosis of non-GCB phenotype. Incidence of therapy-related secondary malignancies and late toxicities were low.

Histone deacetylase inhibitors interrupt HSP90•RASGRP1 and HSP90•CRAF interactions to upregulate BIM and circumvent drug resistance in lymphoma cells.

Histone deacetylase (HDAC) inhibitors, which are approved for the treatment of cutaneous T-cell lymphoma and multiple myeloma, are undergoing evaluation in other lymphoid neoplasms. How they kill susceptible cells is incompletely understood. Here, we show that trichostatin A, romidepsin and panobinostat induce apoptosis across a panel of malignant B cell lines, including lines that are intrinsically resistant to bortezomib, etoposide, cytarabine and BH3 mimetics. Further analysis traces the pro-apoptotic effects of HDAC inhibitors to increased acetylation of the chaperone heat shock protein 90 (HSP90), causing release and degradation of the HSP90 client proteins RASGRP1 and CRAF, which in turn leads to downregulation of mitogen-activated protein kinase pathway signaling and upregulation of the pro-apoptotic BCL2 family member BIM in vitro and in vivo. Importantly, these pro-apoptotic effects are mimicked by RASGRP1 small interfering RNA (siRNA) or HSP90 inhibition and reversed by overexpression of constitutively active MEK1 or siRNA-mediated downregulation of BIM. Collectively, these observations not only identify a new HSP90 client protein, RASGRP1, but also delineate a complete signaling pathway from HSP90 acetylation through RASGRP1 and CRAF degradation to BIM upregulation that contributes to selective cytotoxicity of HDAC inhibitors in lymphoid malignancies.

Vitamin D insufficiency is associated with an increased risk of early clinical failure in follicular lymphoma.

We evaluated whether vitamin D insufficiency (VDI; 25(OH)D <20 ng/ml) was associated with adverse outcomes among follicular lymphoma (FL) patients using an observational prospective cohort study of 642 FL patients enrolled from 2002-2012. The median age at diagnosis was 60 years. At a median follow-up of 59 months, 297 patients (46%) had an event (progression, treatment failure), 78 had died and 42 (6.5%) had a lymphoma-related death. VDI was associated with inferior event-free survival (EFS) at 12 months (EFS12, odds ratio (OR)=2.05; 95% confidence interval (CI) 1.18-3.54), overall survival (OS, hazards ratio (HR)=2.35; 95%CI 1.37-4.02), and lymphoma-specific survival (LSS, HR=2.97; 95% CI 1.52-5.80) for the full cohort. Among patients treated with immunochemotherapy (IC), VDI was associated with inferior EFS12 (OR=3.00; 95% CI 1.26-7.13), OS (HR=2.86; 95% CI 1.39-5.85), and LSS (HR=2.96; 95% CI 1.29-6.79). For observed patients, VDI was associated with inferior OS (HR=2.85; 95% CI 1.20-6.76). For other therapies, VDI was associated with inferior OS (HR=3.06; 95% CI 1.01-9.24). Our work is the first to reveal an association of VDI with early clinical failure, and to demonstrate an association of VDI with adverse outcomes among patients who are observed or treated with therapies other than IC. Our findings suggest a potentially modifiable prognostic factor to address in patients with FL.

Clinical effects of oral green tea extracts in four patients with low grade B-cell malignancies.

Green tea or its constituents have long been touted as a health promoting substance including claims it may have cancer prevention properties. We previously reported the in vitro ability of one tea polyphenol, epigallocatechin gallate (EGCG), to induce apoptotic cell death in the leukemic B-cells from a majority of patients with chronic lymphocytic leukemia (CLL). After the publication of our findings many patients with CLL and other low grade lymphomas began using over-the-counter products containing tea polyphenols despite the absence of evidence to suggest clinical benefit, definition of possible toxicities, or information on optimal dose and schedule. We have become aware of four patients with low grade B-cell malignancies seen in our clinical practice at Mayo Clinic who began, on their own initiative, oral ingestion of EGCG containing products and subsequently appeared to have an objective clinical response. Three of these four patients met criteria for partial response (PR) by standard response criteria. Although spontaneous remission/regression is occasionally observed in individuals with low grade B-cell malignancies, such events are rare. Several patients presented here had documented steady clinical, laboratory, and/or radiographic evidence of progression immediately prior to initiation of over-the-counter green tea products and then developed objective responses shortly after self-initiating this therapy. Such anecdotes highlight the need for clinical trials of tea polyphenols to define the optimal dosing, schedule, toxicities, and clinical efficacy before widespread use can be recommended. An NCI sponsored phase I/II trial of de-caffeinated green tea extracts for patients with asymptomatic, early stage CLL opened at Mayo Clinic in August 2005.

Whole-exome analysis reveals novel somatic genomic alterations associated with outcome in immunochemotherapy-treated diffuse large B-cell lymphoma.

Lack of remission or early relapse remains a major clinical issue in diffuse large B-cell lymphoma (DLBCL), with 30% of patients failing standard of care. Although clinical factors and molecular signatures can partially predict DLBCL outcome, additional information is needed to identify high-risk patients, particularly biologic factors that might ultimately be amenable to intervention. Using whole-exome sequencing data from 51 newly diagnosed and immunochemotherapy-treated DLBCL patients, we evaluated the association of somatic genomic alterations with patient outcome, defined as failure to achieve event-free survival at 24 months after diagnosis (EFS24). We identified 16 genes with mutations, 374 with copy number gains and 151 with copy number losses that were associated with failure to achieve EFS24 (P<0.05). Except for FOXO1 and CIITA, known driver mutations did not correlate with EFS24. Gene losses were localized to 6q21-6q24.2, and gains to 3q13.12-3q29, 11q23.1-11q23.3 and 19q13.12-19q13.43. Globally, the number of gains was highly associated with poor outcome (P=7.4 × 10(-12)) and when combined with FOXO1 mutations identified 77% of cases that failed to achieve EFS24. One gene (SLC22A16) at 6q21, a doxorubicin transporter, was lost in 54% of EFS24 failures and our findings suggest it functions as a doxorubicin transporter in DLBCL cells.

The role of front-line anthracycline-containing chemotherapy regimens in peripheral T-cell lymphomas.

Peripheral T-cell lymphomas (PTCLs) are a heterogenous group of aggressive non-Hodgkin's lymphomas that are incurable in the majority of patients with current therapies. Outcomes associated with anthracycline-based therapies are suboptimal, but remain the standard of care for most patients, even though the benefits of this approach remain uncertain. This study retrospectively examined outcomes in a cohort of North American PTCL patients treated with both anthracycline- and nonanthracycline-containing regimens. The incorporation of anthracycline-containing regimens was associated with improved progression-free survival (PFS) and overall survival (OS). Patients treated with nonanthracycline-containing regimens were more likely to have high-risk features and were less likely to undergo high-dose therapy and stem cell transplantation. However, anthracycline use remained an independent predictor of improved PFS and OS when adjusting for these confounding variables. Anthracycline-based regimens and consolidation with high-dose therapy and autologous stem cell transplantation in appropriately selected patients remains a viable option for patients unable to participate in a clinical trial. Long-term disease-free survival is not optimal, highlighting the need for an improved understanding of disease pathogenesis, and the development of novel therapeutic strategies.

Denileukin diftitox in combination with rituximab for previously untreated follicular B-cell non-Hodgkin's lymphoma.

Follicular lymphoma exhibits intratumoral infiltration by non-malignant T lymphocytes, including CD4+CD25+ regulatory T (T(reg)) cells. We combined denileukin diftitox with rituximab in previously untreated, advanced-stage follicular lymphoma patients anticipating that denileukin diftitox would deplete CD25+ T(reg) cells while rituximab would deplete malignant B cells. Patients received rituximab 375 mg/m(2) weekly for 4 weeks and denileukin diftitox 18 mcg/kg/day for 5 days every 3 weeks for 4 cycles; neither agent was given as maintenance therapy. Between August 2008 and March 2010, 24 patients were enrolled. One patient died before treatment was given and was not included in the analysis. Eleven of 23 patients (48%; 95% confidence interval (CI): 27-69%) responded; 2 (9%) had complete responses and 9 (39%) had partial responses. The progression-free rate at 2 years was 55% (95%CI: 37-82%). Thirteen patients (57%) experienced grade ≥3 adverse events and one patient (4%) died. In correlative studies, soluble CD25 and the number of CD25+ T cells decreased after treatment; however, there was a compensatory increase in IL-15 and IP-10. We conclude that although the addition of denileukin diftitox to rituximab decreased the number of CD25+ T cells, denileukin diftitox contributed to the toxicity of the combination without an improvement in response rate or time to progression.

Lenalidomide can be safely combined with R-CHOP (R2CHOP) in the initial chemotherapy for aggressive B-cell lymphomas: phase I study.

Lenalidomide was shown to have significant single-agent activity in relapsed aggressive non-Hodgkin's lymphoma (NHL). We conducted a phase I trial to establish the maximum tolerated dose of lenalidomide that could be combined with R-CHOP (rituximab-cyclophosphamide, doxorubicin, vincristine, and prednisone). Eligible patients were adults with newly diagnosed, untreated CD20 positive diffuse large cell or follicular grade III NHL. Patients received oral lenalidomide on days 1-10 with standard dose R-CHOP every 21 days. All patients received pegfilgrastim on day 2 of the cycle and aspirin prophylaxis. The lenalidomide dose levels tested were 15, 20 and 25 mg. A total of 24 patients were enrolled. The median age was 65 (35-82) years and 54% were over 60 years. Three patients received 15 mg, 3 received 20 mg and 18 received 25 mg of lenalidomide. No dose limiting toxicity was found, and 25 mg on days 1-10 is the recommended dose for phase II. The incidence of grade IV neutropenia and thrombocytopenia was 67% and 21%, respectively. Febrile neutropenia was rare (4%) and there were no toxic deaths. The overall response rate was 100% with a complete response rate of 77%. Lenalidomide at the dose of 25 mg/day administered on days 1 to 10 of 21-day cycle can be safely combined with R-CHOP in the initial chemotherapy of aggressive B-cell lymphoma.

The absolute monocyte and lymphocyte prognostic score predicts survival and identifies high-risk patients in diffuse large-B-cell lymphoma.

Despite the use of modern immunochemotherapy regimens, almost 50% of patients with diffuse large-B-cell lymphoma will relapse. Current prognostic models, including the International Prognostic Index, incorporate patient and tumor characteristics. In contrast, recent observations show that variables related to host adaptive immunity and the tumor microenvironment are significant prognostic variables in non-Hodgkin lymphoma. Therefore, we retrospectively examined the absolute monocyte and lymphocyte counts as prognostic variables in a cohort of 366 diffuse large-B-cell lymphoma patients who were treated between 1993 and 2007 and followed at a single institution. The absolute monocyte and lymphocyte counts in univariate analysis predicted progression-free and overall survival when analyzed as continuous and dichotomized variables. On multivariate analysis performed with factors included in the IPI, the absolute monocyte and lymphocyte counts remained independent predictors of progression-free and overall survival. Therefore, the absolute monocyte and lymphocyte counts were combined to generate a prognostic score that identified patients with an especially poor overall survival. This prognostic score was independent of the IPI and added to its ability to identify high-risk patients.

Lymphopenia assessed during routine follow-up after immunochemotherapy (R-CHOP) is a risk factor for predicting relapse in patients with diffuse large B-cell lymphoma.

A specific predictor during routine follow-up to ascertain risk for relapse after standard chemotherapy in non-Hodgkin's lymphoma (NHL) has not been identified. Thus, we studied absolute lymphocyte count (ALC) as a marker of poststandard chemotherapy (rituximab, cyclophosphamide, adriamycin, vincristine and prednisone (R-CHOP)) NHL relapse in patients with diffuse large B-cell lymphoma (DLBCL). ALC was obtained at the time of confirmed relapse and at last follow-up. From 2000 until 2006, 149 consecutive DLBCL patients, originally diagnosed, treated with R-CHOP and followed up at Mayo Clinic, Rochester, were included in this study. Patients at last follow-up without relapse (N=112) had a higher ALC compared with those with relapsed lymphoma ((N=37) median ALC x 10(9)/l of 1.43 (range: 0.33-4.0) versus 0.67 (range: 0.18-1.98), P<0.0001, respectively). ALC at the time of confirmed relapse was a strong predictor for relapse with an area under the curve =0.91 (P<0.0001). An ALC <0.96 x 10(9)/l at the time of confirmed relapse had a positive predictive value of 72% and a positive likelihood ratio of 7.4 to predict relapse after R-CHOP in DLBCL. Patients with an ALC>or=0.96 x 10(9)/l (N=103) had a cumulative incidence of relapse of 6 versus 79% with an ALC <0.96 x 10(9)/l (N=46) (P<0.0001). This study suggests that lymphopenia measured by ALC can be used as a marker to assess risk of DLBCL relapse during routine follow-up after standard chemotherapy.

Interphase fluorescence in situ hybridization with an IGH probe is important in the evaluation of patients with a clinical diagnosis of chronic lymphocytic leukaemia.

Translocations involving IGH are common in some lymphoid malignancies but are believed to be rare in chronic lymphocytic leukaemia (CLL). To study the clinical utility of fluorescence in situ hybridization (FISH) for IGH translocations, we reviewed 1032 patients with a presumptive diagnosis of CLL. Seventy-six (7%) patients had IGH translocations. Pathology and clinical data were available for the 24 patients evaluated at the Mayo Clinic. Ten (42%) patients had IGH/cyclin D1 fusion and were diagnosed with mantle cell lymphoma (MCL). The immunophenotype was typical of MCL in three of these patients and atypical for MCL in seven patients. One patient had biclonal disease with typical MCL and CLL with IGH/BCL-2. Eleven (46%) patients had IGH/BCL-2 fusion including the patient with biclonal disease. Two of these patients had leukaemic phase follicular lymphoma and nine patients had CLL. The median progression-free survival of patients with CLL and IGH/BCL-2 translocation was 20.6 months. The two patients with IGH/BCL-3 fusion (one of these also had IGH/BCL-11a) had rapid disease progression. The IGH partner gene was not identified in two patients. We conclude that use of an IGH probe in FISH analysis of monoclonal B-cell lymphocytosis improves diagnostic precision and could have prognostic value in patients with CLL.