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The phase III GALLIUM trial assessed the safety and efficacy of obinutuzumab-based versus rituximab-based immunochemotherapy in patients with previously untreated follicular lymphoma (FL) or marginal zone lymphoma (MZL). At the primary analysis, the trial met its primary end point, demonstrating improvement in investigator-assessed progression-free survival (PFS) with obinutuzumab-based versus rituximab-based immunochemotherapy in patients with FL. We report the results of the final analysis in the FL population, with an additional exploratory analysis in the MZL subgroup. Overall, 1202 patients with FL were randomized 1:1 to obinutuzumab- or rituximab-based immunochemotherapy followed by maintenance with the same antibody for up to 2 years. After a median 7.9 (range, 0.0–9.8) years of follow-up, PFS remained improved with obinutuzumab- versus rituximab-based immunochemotherapy, with 7-year PFS rates of 63.4% versus 55.7% (P = 0.006). Time-to-next antilymphoma treatment was also improved (74.1% versus 65.4% of patients had not started their next antilymphoma treatment at 7 y; P = 0.001). Overall survival was similar between the arms (88.5% versus 87.2%; P = 0.36). Irrespective of the treatment received, PFS and OS were higher in patients with a complete molecular response (CMR) versus those with no CMR (P < 0.001). Serious adverse events were reported in 48.9% and 43.4% of patients in the obinutuzumab and rituximab arms, respectively; there was no difference in the rate of fatal adverse events (4.4% and 4.5%, respectively). No new safety signals were reported. These data demonstrate the long-term benefit of obinutuzumab-based immunochemotherapy and confirm its role as a standard-of-care for the first-line treatment of advanced-stage FL, taking into account patient characteristics and safety considerations.

The BCL-2-specific inhibitor, ABT-199 (venetoclax) has exhibited remarkable clinical activity in nearly all cases of chronic lymphocytic leukemia. In contrast, responses are usually much less in diffuse large B-cell lymphoma (DLBCL), despite high level expression of BCL-2 in over 40% of cases, indicating that co-expression of related anti-apoptotic BCL-2 family proteins may limit the activity of ABT-199. We have investigated the roles of BCL-2 proteins in DLBCL cells using a panel of specific BCL-2 homology 3 (BH3)-mimetics and identified subgroups of these cells that exhibited marked and specific dependency on either BCL-2, BCL-XL or MCL-1 for survival. Dependency was associated with selective sequestration of the pro-apoptotic proteins BIM, BAX and BAK by the specific anti-apoptotic BCL-2 protein which was important for cellular survival. Sensitivity to BH3-mimetics was independent of genetic alterations involving the BCL-2 family and only partially correlated with protein expression levels. Treatment with ABT-199 displaced BAX and BIM from BCL-2, subsequently leading to BAK activation and apoptosis. In contrast, apoptosis induced by inhibiting BCL-XL with A1331852 was associated with a displacement of both BAX and BAK from BCL-XL and occurred independently of BIM. Finally, the MCL-1 inhibitor S63845 induced mainly BAX-dependent apoptosis mediated by a displacement of BAK, BIM and NOXA from MCL-1. In conclusion, our study indicates that in DLBCL, the heterogeneous response to BH3-mimetics is mediated by selective interactions between BAX, BAK and anti-apoptotic BCL-2 proteins.

BH3 mimetics are novel targeted drugs with remarkable specificity, potency and enormous potential to improve cancer therapy. However, acquired resistance is an emerging problem. We report the rapid development of resistance in chronic lymphocytic leukemia cells isolated from patients exposed to increasing doses of navitoclax (ABT-263), a BH3 mimetic. To mimic such rapid development of chemoresistance, we developed simple resistance models to three different BH3 mimetics, targeting BCL-2 (ABT-199), BCL-XL (A-1331852) or MCL-1 (A-1210477), in relevant hematologic cancer cell lines. In these models, resistance could not be attributed to either consistent changes in expression levels of the anti-apoptotic proteins or interactions among different pro- and anti-apoptotic BCL-2 family members. Using genetic silencing, pharmacological inhibition and metabolic supplementation, we found that targeting glutamine uptake and its downstream signaling pathways, namely glutaminolysis, reductive carboxylation, lipogenesis, cholesterogenesis and mammalian target of rapamycin signaling resulted in marked sensitization of the chemoresistant cells to BH3 mimetic-mediated apoptosis. Furthermore, our findings highlight the possibility of repurposing widely used drugs, such as statins, to target intermediary metabolism and improve the efficacy of BH3 mimetic therapy.

The GAUDI study assessed safety and preliminary efficacy of induction therapy with obinutuzumab plus chemotherapy, followed by maintenance therapy with obinutuzumab alone, in previously untreated patients with follicular lymphoma. Assignment to chemotherapy was decided on a per-center basis before the patients’ enrollment. Patients (n=81) received four to six cycles of obinutuzumab plus bendamustine every 4 weeks or six to eight cycles of obinutuzumab plus CHOP every 3 weeks. Patients with an end-of-treatment response were eligible for obinutuzumab maintenance therapy every 3 months for 2 years or until disease progression. Induction treatment was completed by 90% of patients in the obinutuzumab plus bendamustine group and 95% in the obinutuzumab plus CHOP group, while maintenance was completed by 81% and 72% of patients, respectively. All patients experienced at least one adverse event during induction, most commonly infusion-related reactions (58%), the majority of which were grade 1/2. The most common hematologic adverse event was grade 3/4 neutropenia (36% during induction and 7% during maintenance). One treatment-related death occurred during the maintenance phase. At the end of induction, 94% of patients had achieved an overall response, with complete response based on computed tomography in 36%. The progression-free survival rate at 36 months was 90% in the obinutuzumab plus bendamustine group and 84% in the obinutuzumab plus CHOP group. These results demonstrate that induction therapy with obinutuzumab plus bendamustine or obinutuzumab plus CHOP, followed by obinutuzumab maintenance, is associated with tolerable safety and promising efficacy. This study is registered at ClinicalTrials.gov as NCT00825149.

A number of single nucleotide polymorphisms have been associated with disease predisposition in chronic lymphocytic leukemia. A single nucleotide polymorphism in the MDM2 promotor region, MDM2SNP309, was shown to soothe the p53 pathway. In the current study, we aimed to clarify the effect of the MDM2SNP309 on chronic lymphocytic leukemia characteristics and outcome. We performed a meta-analysis of data from 2598 individual patients from 10 different cohorts. Patients’ data and genetic analysis for MDM2SNP309 genotype, immunoglobulin heavy chain variable region mutation status and fluorescence in situ hybridization results were collected. There were no differences in overall survival based on the polymorphism (log rank test, stratified by study cohort; P=0.76; GG genotype: cohort-adjusted median overall survival of 151 months; TG: 153 months; TT: 149 months). In a multivariable Cox proportional hazards regression analysis, advanced age, male sex and unmutated immunoglobulin heavy chain variable region genes were associated with inferior survival, but not the MDM2 genotype. The MDM2SNP309 is unlikely to influence disease characteristics and prognosis in chronic lymphocytic leukemia. Studies investigating the impact of individual single nucleotide polymorphisms on prognosis are often controversial. This may be due to selection bias and small sample size. A meta-analysis based on individual patient data provides a reasonable strategy for prognostic factor analyses in the case of small individual studies. Individual patient data-based meta-analysis can, therefore, be a powerful tool to assess genetic risk factors in the absence of large studies.

Ataxia telangiectasia patients, with constitutional bi-allelic ATM mutations, have a marked risk of lymphoid tumors and ATM mutation carriers have a smaller risk of cancer. Sporadic ATM mutations occur in 10–20% of chronic lymphocytic leukemia and are often associated with chromosome 11q deletions which cause loss of an ATM allele. The role of constitutional ATM mutations in the pathogenesis of chronic lymphocytic leukemia is unknown. Here we investigated the frequency of constitutional ATM mutations in either of two chronic lymphocytic leukemia cohorts, those with and without a chromosome 11q deletion. We found that in comparison to controls, constitutional pathogenic ATM mutations were increased in patients with chromosome 11q deletions (6 of 140 vs. 0 of 281, P=0.001) but not in those without 11q deletions (2 of 178 vs. 0 of 281, P=0.15). These results suggest that ATM germline heterozygosity does not play a role in chronic lymphocytic leukemia initiation but rather influences rapid disease progression through ATM loss.

Background Bortezomib has been successfully used in the treatment of multiple myeloma and has been proposed as a potential treatment for chronic lymphocytic leukemia. In this study we investigated the mechanism by which bortezomib induces apoptosis in chronic lymphocytic leukemia cells.Design and Methods Using western blot analysis, we monitored the regulation of BCL2 family members, proteins of the unfolded protein response (endoplasmic reticulum stress response) and activation of caspases in relation to induction of apoptosis (measured by annexin-propidium iodide staining and loss of mitochondrial membrane potential) by bortezomib in chronic lymphocytic leukemia cells.Results Bortezomib induced apoptosis through activation of the mitochondrial pathway independently of changes associated with endoplasmic reticulum stress. Perturbation of mitochondria was regulated by a rapid and transcription-independent increase of NOXA protein, which preceded release of cytochrome c, HtrA2, Smac and activation of caspase-9 and −3. NOXA had a short half life (~ 1–2 h) and was ubiquitinated on at least three primary lysine residues, resulting in proteasomal-dependent degradation. Down-regulation of NOXA, using short interfering RNA in chronic lymphocytic leukemia cells, decreased bortezomib-induced apoptosis. Finally bortezomib when combined with seliciclib resulted in a stronger and earlier increase in NOXA protein, caspase-3 cleavage and induction of apoptosis in chronic lymphocytic leukemia cells.Conclusions These results highlight a critical role for NOXA in bortezomib–induced apoptosis in chronic lymphocytic leukemia cells and suggest that this drug may become more efficient for the treatment of chronic lymphocytic leukemia if combined with other agents able to interfere with the basal levels of MCL1.

In a subset of B-cell malignancies, the genes encoding members of the cyclin D familiy are juxtaposed to immunoglobulin loci through recurrent chromosomal translocations. Here, we identified the gene encoding cyclin E1 as novel translocation partner of the immunoglobulin heavy chain (IGH) locus involved in a t(14;19)(q32;q12) in a case of t(8;14)(q24;q32) IGH-MYC-positive leukemic diffuse large B-cell lymphoma. The translocation breakpoints were cloned and mapped to the switch region Sα1 of IGH in 14q32 and approximately 60kb centromeric to CCNE1 in 19q12. Immunohistochemical analysis revealed overexpression of the cyclin E1 protein in this case, which to a comparable extent was observed in 3/41 independent DLBCL. These data indicate that cyclin E1 may act as a novel oncogene in B-cell lymphomagenesis.