Idelalisib therapy of indolent B-cell malignancies: chronic lymphocytic leukemia and small lymphocytic or follicular lymphomas

Chronic lymphocytic leukemia, small lymphocytic lymphoma, and follicular lymphoma are indolent B-cell lymphoproliferative disorders that mainly affect an older population. Although the majority of patients in need of treatment derive significant benefit from conventional chemotherapeutic agents as well as monoclonal antibodies, less toxic and more effective treatments are needed. Novel agents that inhibit the B-cell receptor signaling pathway have shown promising outcomes in these disorders. Idelalisib is a potent selective oral inhibitor of phosphatidylinositol 3-kinase delta and has shown significant clinical activity in B-cell malignancies. In this review, we summarize the clinical trial data using idelalisib as monotherapy or in combination with rituximab for the treatment of relapsed/refractory disease. The adverse effect profile includes autoimmune disorders such as transaminitis, colitis, and pneumonitis. Given the efficacy and manageable toxicity profile of idelalisib, it is being increasingly incorporated into the management of indolent B-cell malignancies.

Observation of Gravitational Waves from a Binary Black Hole Merger

On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0×10(-21). It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203,000 years, equivalent to a significance greater than 5.1σ. The source lies at a luminosity distance of 410(-180)(+160)  Mpc corresponding to a redshift z=0.09(-0.04)(+0.03). In the source frame, the initial black hole masses are 36(-4)(+5)M⊙ and 29(-4)(+4)M⊙, and the final black hole mass is 62(-4)(+4)M⊙, with 3.0(-0.5)(+0.5)M⊙c(2) radiated in gravitational waves. All uncertainties define 90% credible intervals. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.

Abstract B58: BIM, a key player in apoptosis induction and acquired venetoclax resistance in follicular lymphoma cells

The chromosomal translocation t(14;18) in follicular lymphoma (FL) cells is a primary oncogenic event resulting in BCL-2 over-expression. BCL-2 is not directly responsible for growth of tumor cells, but it protects them against death by binding pro-apoptotic proteins. This study investigates in vitro and in vivo activity of the BH3 mimetic venetoclax (ABT-199) and mechanisms of acquiring resistance in FL.

Primary FL cells with similar expression of anti-apoptotic proteins, such as BCL-2 and MCL-1, showed variable sensitivity to treatment, which correlated with expression of BIM. To further study this correlation we used two t(14;18)+ cell lines, WSU-FSCCL and FC-TxFL2. As with primary cells, FC-TxFL2 cells with higher expression of BIM protein were more sensitive to venetoclax-induced apoptosis. The treatment caused dissociation of BCL-2/ BIM complexes, decreased mitochondrial potential, activation of caspase-3 and caspase-7, and PARP cleavage. Interestingly the population of cells that survived venetoclax treatment showed an increase of phospho-ERK1/2 and phospho-BIM (S69), as well as a decrease of total BIM levels.

Venetoclax treatment of murine xenografts of FC-TxFL2 cells resulted in significant delay in tumor growth. However, viable cells isolated from treated tumors showed a decrease of sensitivity to venetoclax exposure (IC50 increased almost 10 times) in comparison with the cells from the mice treated with vehicle only. These cells contained higher levels of MCL-1 and lower levels of BIM protein compared to control cells. BCL-2 levels remained unchanged.

Venetoclax resistant cells prepared in vitro by continuous treatment with increasing concentrations of venetoclax initially showed elevated levels of p-AKT, p-FOX01/3a, MCL-1, dissociation of BIM/BCL-2/BECLIN1 complex, decrease of p62 level (a sign of an increased autophagy) together with a slight decline of BIM expression. After a stable resistant cell line was established, a significant reduction of BCL-2 levels and almost total absence of BIMEL, BIML and BIMS isoforms was observed.

Detailed knowledge of venetoclax action and the mechanisms for acquired resistance in t(14;18)+ cells may help inform biomarker strategies and dosing schedules in future clinical trials. Inhibition of pathways activated in order to protect the FL cells (e.g. by down-regulating BIM (ERK or AKT pathway) or by autophagy) can significantly augment venetoclax potency and decrease incidence of acquired resistance.

Citation Format: Juraj Bodo, Xiaoxian Zhao, Andrew J. Souers, Darren C. Phillips, Mitchell R. Smith, Eric D. Hsi. BIM, a key player in apoptosis induction and acquired venetoclax resistance in follicular lymphoma cells. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr B58.

Azacitidine with or without Entinostat for the treatment of therapy-related myeloid neoplasm: further results of the E1905 North American Leukemia Intergroup study

Therapy-related myeloid neoplasms (tMN) are serious late effects of the treatment of cancer with poor response to conventional treatment. Azacitidine (AZA) has been used to treat patients with tMN but current data are retrospective. We present here 47 tMN patients prospectively enrolled as a specific cohort in the E1905 study. TheE1905 study was a randomized phase 2 study (NCT00313586) testing 10 d of AZA (50 mg/m(2) /d) +/- the histone deacetylase inhibitor entinostat (4 mg/m(2) /d PO day-3 and day-10). A total of 47 patients [29 therapy-related myelosyspastic syndrome (t-MDS) and 18 therapy-related acute myeloid leukaemia (t-AML)] were recruited to the study. 24 patients were treated with AZA monotherapy and 23 with AZA+entinostat. The median number of administered cycles was 4, significantly higher in patients treated with AZA (6 cycles vs. 3 cycles, P = 0·008). Haematological normalization rates were 46% in monotherapy and 17% in the combination arm. Median overall survivals were 13 and 6 months, respectively. The novel 50 * 10 schedule of azacitidine appears effective, with response rates, when given as single agent, comparable to those for patients with de novo MDS/AML treated on the same protocol. However, the combination of AZA and entinostat was associated with increased toxicity and could not be recommended for treatment of tMN.

Phase I Study of the Novel Investigational NEDD8-Activating Enzyme Inhibitor Pevonedistat (MLN4924) in Patients with Relapsed/Refractory Multiple Myeloma or Lymphoma

PURPOSE

Evaluate the safety, pharmacokinetic profile, pharmacodynamic effects, and antitumor activity of the first-in-class investigational NEDD8-activating enzyme (NAE) inhibitor pevonedistat (TAK-924/MLN4924) in patients with relapsed/refractory lymphoma or multiple myeloma.

EXPERIMENTAL DESIGN

Patients with relapsed/refractory myeloma (n = 17) or lymphoma (n = 27) received intravenous pevonedistat 25 to 147 mg/m(2) on days 1, 2, 8, 9 (schedule A; n = 27) or 100 to 261 mg/m(2) on days 1, 4, 8, 11 (schedule B; n = 17) of 21-day cycles.

RESULTS

Maximum tolerated doses were 110 mg/m(2) (schedule A) and 196 mg/m(2) (schedule B). Dose-limiting toxicities included febrile neutropenia, transaminase elevations, muscle cramps (schedule A), and thrombocytopenia (schedule B). Common adverse events included fatigue and nausea. Common grade ≥3 events were anemia (19%; schedule A), and neutropenia and pneumonia (12%; schedule B). Clinically significant myelosuppression was uncommon. There were no treatment-related deaths. Pevonedistat pharmacokinetics exhibited a biphasic disposition phase and approximate dose-proportional increases in systemic exposure. Consistent with the short mean elimination half-life of approximately 8.5 hours, little-to-no drug accumulation in plasma was seen after multiple dosing. Pharmacodynamic evidence of NAE inhibition included increased skin levels of CDT-1 and NRF-2 (substrates of NAE-dependent ubiquitin ligases), and increased NRF-2-regulated gene transcript levels in whole blood. Pevonedistat-NEDD8 adduct was detected in bone marrow aspirates, indicating pevonedistat target engagement in the bone marrow compartment. Three lymphoma patients had partial responses; 30 patients achieved stable disease.

CONCLUSIONS

Pevonedistat demonstrated anticipated pharmacodynamic effects in the clinical setting, a tolerable safety profile, and some preliminary evidence that may be suggestive of the potential for activity in relapsed/refractory lymphoma.

miR-377-dependent BCL-xL regulation drives chemotherapeutic resistance in B-cell lymphoid malignancies

Background

BCL-xL is an anti-apoptotic BCL-2 family protein that inhibits apoptosis and is overexpressed in many cancers. We have reported that acquired resistance to the BCL-2 inhibitor ABT-199 (venetoclax) is associated with increased BCL-xL expression. Yet, how BCL-xL mediates chemoresistance in hematopoietic malignancies is not clear. This finding may help in design of new strategies for therapeutic intervention to overcome acquired chemoresistance mediated by BCL-xL.

Results

We now show that the increased BCL-xL expression was inversely correlated with that of miR-377 in ABT-199-resistant cells. This finding was also extended to a panel of B-cell lymphoid lines and primary chronic lymphocytic leukemia (CLL) cells. miR-377 suppressed BCL-xL expression by recognizing two binding sites in the BCL-xL 3’-UTR. Mutation of these two miR-377 consensus-binding sites completely abolished its regulatory effect. Expression of a miR-377 mimic downregulated BCL-xL protein expression and significantly increased apoptotic cell death. Expression of a miR-377 inhibitor restored BCL-xL protein expression and limited cell death caused by the hypomethylating agent 5-azacytidine. Thus, miR-377-dependent BCL-xL regulation drives acquired therapeutic resistance to ABT-199. We further show that CLL patients who received a diverse array of chemotherapy regimens also had significantly higher BCL-xL and lower miR377 expression, indicating that exposure to chemotherapy might trigger transcriptional silencing of miR-377, which results in high levels of BCL-xL. Importantly, CLL patients with high BCL-xL/low miR-377 expression had an advanced tumor stage. Moreover, the high BCL-xL expression correlated with short treatment-free survival in 76 CLL patients. miR-377 is located at 14q32 in the DLK1-DIO3 region, which encodes the largest tumor suppressor miRNA cluster in humans. Examination of five additional 14q32 miRNAs revealed that the majority were significantly down-regulated in most CLL patients as well as in ABT-199-resistant cell lines. Remarkably, four of these miRNAs had significantly decreased expression in chemotherapy-treated CLL patients as compared to those untreated. These findings indicate a reduced expression of multiple miRNAs that may reflect a global silencing of this miRNA cluster in therapy-resistant lymphoid cells.

Conclusions

These findings reveal a novel mechanism by which down-regulation of miR-377 increases BCL-xL expression, promoting chemotherapy resistance in B-cell lymphoid malignancies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-015-0460-8) contains supplementary material, which is available to authorized users.

Management of patients with advanced prostate cancer: recommendations of the St Gallen Advanced Prostate Cancer Consensus Conference (APCCC) 2015

The first St Gallen Advanced Prostate Cancer Consensus Conference (APCCC) Expert Panel identified and reviewed the available evidence for the ten most important areas of controversy in advanced prostate cancer (APC) management. The successful registration of several drugs for castration-resistant prostate cancer and the recent studies of chemo-hormonal therapy in men with castration-naïve prostate cancer have led to considerable uncertainty as to the best treatment choices, sequence of treatment options and appropriate patient selection. Management recommendations based on expert opinion, and not based on a critical review of the available evidence, are presented. The various recommendations carried differing degrees of support, as reflected in the wording of the article text and in the detailed voting results recorded in supplementary Material, available at Annals of Oncology online. Detailed decisions on treatment as always will involve consideration of disease extent and location, prior treatments, host factors, patient preferences as well as logistical and economic constraints. Inclusion of men with APC in clinical trials should be encouraged.

Ibrutinib in B lymphoid malignancies

INTRODUCTION

Most lymphomas and lymphoid leukemias are of B cell origin. Indolent B cell lymphomas, most commonly follicular lymphoma but including Waldenstrom's macroglobulinemia and mantle cell lymphoma, as well as chronic lymphocytic leukemia, are incurable with standard therapy. New treatments are needed. Survival of normal and many abnormal B cells depends on signals through the B-cell receptor, and a key element of this pathway is Bruton's tyrosine kinase (BTK). The oral BTK inhibitor ibrutinib is already US FDA approved in four different indications based on marked treatment benefit in indolent B cell lymphoma/leukemia.

AREAS COVERED

This review covers the clinical pharmacology of ibrutinib, its efficacy in clinical trials in chronic lymphocytic leukemia, mantle cell lymphoma, and Waldenstrom's macroglobulinemia, as well as safety and toxicity. Future directions are discussed.

EXPERT OPINION

Ibrutinib is a well-tolerated once-daily oral BTK inhibitor with impressive activity in treating indolent B cell lymphoproliferative disorders. As a single agent, it is already altering treatment paradigms in its approved indications. Ongoing studies will determine its movement to the front-line setting in these and other B cell disorders, as well as combination approaches.

Progression and Transformation of Clonally Heterogeneous B-cell Lymphoma

Indolent B- cell non-Hodgkin lymphoma can transform into aggressive lymphoma. We extend our prior mathematical model to analyze and predict transformation. To provide additional confidence in our model, we compare it with SCID mouse data for combination therapy of Diffuse Large B-cell Lymphoma, an aggressive form of the disease. We develop a two cell model that includes indolent and aggressive clones but no immune response and use it to predict transformation. An approximate model for the time to transformation is derived that provides insight regarding scaling effects. We then add an immune response and therapeutic measures, and illustrate the complex interactions among the various processes, with a focus on transformation. The implications for initial diagnosis and treatment of non-Hodgkin lymphoma are discussed.

Identification of Ezrin-Radixin-Moesin proteins as novel regulators of pathogenic B-cell receptor signaling and tumor growth in diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) is a hematological cancer associated with an aggressive clinical course. The predominant subtypes of DLBCL display features of chronic or tonic B-cell antigen receptor (BCR) signaling. However, it is not known whether the spatial organization of the BCR contributes to the regulation of pro-survival signaling pathways and cell growth. Here, we show that primary DLBCL tumors and patient-derived DLBCL cell lines contain high levels of phosphorylated Ezrin-Radixin-Moesin (ERM) proteins. The surface BCRs in both activated B cell and germinal B cell subtype DLBCL cells co-segregate with phosphoERM suggesting that the cytoskeletal network may support localized BCR signaling and contribute to pathogenesis. Indeed, ablation of membrane-cytoskeletal linkages by dominant-negative mutants, pharmacological inhibition and knockdown of ERM proteins disrupted cell surface BCR organization, inhibited proximal and distal BCR signaling, and reduced the growth of DLBCL cell lines. In vivo administration of the ezrin inhibitor retarded the growth of DLBCL tumor xenografts, concomitant with reduction in intratumor phosphoERM levels, dampened pro-survival signaling and induction of apoptosis. Our results reveal a novel ERM-based spatial mechanism that is coopted by DLBCL cells to sustain tumor cell growth and survival.

Denosumab for the prevention of skeletal complications in metastatic castration-resistant prostate cancer: comparison of skeletal-related events and symptomatic skeletal events

In this analysis of a phase III trial in patients with castration-resistant prostate cancer and bone metastases, treatment with denosumab reduced the risk of skeletal complications vs zoledronic acid regardless of whether the end point was defined as SSE or SRE. Both SSEs and SREs were associated with development of moderate/severe pain among patients with no/mild pain at baseline.

Background

In a phase III trial in patients with castration-resistant prostate cancer (CRPC) and bone metastases, denosumab was superior to zoledronic acid in reducing skeletal-related events (SREs; radiation to bone, pathologic fracture, surgery to bone, or spinal cord compression). This study reassessed the efficacy of denosumab using symptomatic skeletal events (SSEs) as a prespecified exploratory end point.

Patients and methods

Patients with CRPC, no previous bisphosphonate exposure, and radiographic evidence of bone metastasis were randomized to subcutaneous denosumab 120 mg plus i.v. placebo every 4 weeks (Q4W), or i.v. zoledronic acid 4 mg plus subcutaneous placebo Q4W during the blinded treatment phase. SSEs were defined as radiation to bone, symptomatic pathologic fracture, surgery to bone, or symptomatic spinal cord compression. The relationship between SSE or SRE and time to moderate/severe pain was assessed using the Brief Pain Inventory Short Form.

Results

Treatment with denosumab significantly reduced the risk of developing first SSE [HR, 0.78; 95% confidence interval (CI) 0.66–0.93; P = 0.005] and first and subsequent SSEs (rate ratio, 0.78; 95% CI 0.65–0.92; P = 0.004) compared with zoledronic acid. The treatment differences in the number of patients with SSEs or SREs were similar (n = 48 and n = 45, respectively). Among patients with no/mild pain at baseline, both SSEs and SREs were associated with moderate/severe pain development (P < 0.0001). Fewer patients had skeletal complications, particularly fractures, when defined as SSE versus SRE.

Conclusion

In patients with CRPC and bone metastases, denosumab reduced the risk of skeletal complications versus zoledronic acid regardless of whether the end point was defined as SSE or SRE.

Targeting mTORC1-mediated metabolic addiction overcomes fludarabine resistance in malignant B cells

MTOR complex-1(mTORC1) activation occurs frequently in cancers, yet clinical efficacy of rapalogs is limited because of the associated activation of upstream survival pathways. An alternative approach is to inhibit downstream of mTORC1; therefore, acquired resistance to fludarabine (Flu), a purine analogue and antimetabolite chemotherapy, active agent for chronic lymphocytic leukemia (CLL) was investigated. Elevated phospho-p70S6K, also known as RPS6KB1 (ribosomal protein S6 kinase, 70kDa, polypeptide 1) (T389), an mTORC1 activation marker, predicted Flu resistance in a panel of B-cell lines, isogenic Flu-resistant (FluR) derivatives, and primary human CLL cells. Consistent with the anabolic role of mTORC1, FluR cells had higher rates of glycolysis and oxidative phosphorylation than Flu-sensitive (FluS) cells. Rapalogs (everolimus and rapamycin) induced moderate cell death in FluR and primary CLL cells, and everolimus significantly inhibited glycolysis and oxidative phosphorylation in FluR cells. Strikingly, the higher oxidative phosphorylation in FluR cells was not coupled to higher ATP synthesis. Instead, it contributed primarily to an essential, dihydroorotate dehydrogenase catalyzed, step in de novo pyrimidine biosynthesis. mTORC1 promotes pyrimidine biosynthesis by p70S6 kinase-mediated phosphorylation of CAD (carbamoyl-phosphate synthetase 2, aspartate transcarbamylase, and dihydroorotase; Ser1859) and favors S-phase cell-cycle progression. We found increased phospho-CAD (S1859) and higher S-phase population in FluR cells. Pharmacological inhibition of de novo pyrimidine biosynthesis using N-phosphonacetyl-l-aspartate and leflunomide, RNAi-mediated knockdown of p70S6K, and inhibition of mitochondrial respiration were selectively cytotoxic to FluR, but not FluS, cells. These results reveal a novel link between mTORC1-mediated metabolic reprogramming and Flu resistance identifying mitochondrial respiration and de novo pyrimidine biosynthesis as potential therapeutic targets.

IMPLICATIONS

This study provides the first evidence for mTORC1/p70S6K-dependent regulation of pyrimidine biosynthesis in a relevant disease setting.

Phase 1/2 study of ocaratuzumab, an Fc-engineered humanized anti-CD20 monoclonal antibody, in low-affinity FcγRIIIa patients with previously treated follicular lymphoma

This phase 2 study assessed the safety and efficacy of ocaratuzumab, a humanized anti-CD20 monoclonal antibody. Fifty patients with previously treated follicular lymphoma (FL) and a low-affinity genotype of FcγRIIIa received ocaratuzumab 375 mg/m(2) weekly for 4 weeks. Grade 3/4/5 adverse events (AEs) were reported in 11/1/1 patients, respectively. Serious AEs were reported by 11/50 patients, and three discontinued due to AEs. One patient died from aspiration pneumonia due to possibly drug-related nausea and vomiting. Investigator-assessed response rate was 30% (15/50), including four complete responses (CR), three CR unconfirmed (CRu) and eight partial responses (PR). Investigator-assessed median Progression-free survivial (PFS) was 38.3 weeks. Ocaratuzumab's pharmacokinetic profile was similar to that reported for rituximab. Lymphocyte subset analysis showed significant, selective reduction of B-cells during and after ocaratuzumab treatment. Ocaratuzumab at this dose and schedule is active and well tolerated in patients with previously treated FL with low affinity FcγRIIIa genotypes. ClinTrials registry number: NCT00354926.

Search for gravitational waves associated with γ-ray bursts detected by the interplanetary network

We present the results of a search for gravitational waves associated with 223 γ-ray bursts (GRBs) detected by the InterPlanetary Network (IPN) in 2005-2010 during LIGO's fifth and sixth science runs and Virgo's first, second, and third science runs. The IPN satellites provide accurate times of the bursts and sky localizations that vary significantly from degree scale to hundreds of square degrees. We search for both a well-modeled binary coalescence signal, the favored progenitor model for short GRBs, and for generic, unmodeled gravitational wave bursts. Both searches use the event time and sky localization to improve the gravitational wave search sensitivity as compared to corresponding all-time, all-sky searches. We find no evidence of a gravitational wave signal associated with any of the IPN GRBs in the sample, nor do we find evidence for a population of weak gravitational wave signals associated with the GRBs. For all IPN-detected GRBs, for which a sufficient duration of quality gravitational wave data are available, we place lower bounds on the distance to the source in accordance with an optimistic assumption of gravitational wave emission energy of 10(-2)M⊙c(2) at 150 Hz, and find a median of 13 Mpc. For the 27 short-hard GRBs we place 90% confidence exclusion distances to two source models: a binary neutron star coalescence, with a median distance of 12 Mpc, or the coalescence of a neutron star and black hole, with a median distance of 22 Mpc. Finally, we combine this search with previously published results to provide a population statement for GRB searches in first-generation LIGO and Virgo gravitational wave detectors and a resulting examination of prospects for the advanced gravitational wave detectors.

Search for gravitational waves associated with γ-ray bursts detected by the interplanetary network

We present the results of a search for gravitational waves associated with 223 γ-ray bursts (GRBs) detected by the InterPlanetary Network (IPN) in 2005-2010 during LIGO's fifth and sixth science runs and Virgo's first, second, and third science runs. The IPN satellites provide accurate times of the bursts and sky localizations that vary significantly from degree scale to hundreds of square degrees. We search for both a well-modeled binary coalescence signal, the favored progenitor model for short GRBs, and for generic, unmodeled gravitational wave bursts. Both searches use the event time and sky localization to improve the gravitational wave search sensitivity as compared to corresponding all-time, all-sky searches. We find no evidence of a gravitational wave signal associated with any of the IPN GRBs in the sample, nor do we find evidence for a population of weak gravitational wave signals associated with the GRBs. For all IPN-detected GRBs, for which a sufficient duration of quality gravitational wave data are available, we place lower bounds on the distance to the source in accordance with an optimistic assumption of gravitational wave emission energy of 10(-2)M⊙c(2) at 150 Hz, and find a median of 13 Mpc. For the 27 short-hard GRBs we place 90% confidence exclusion distances to two source models: a binary neutron star coalescence, with a median distance of 12 Mpc, or the coalescence of a neutron star and black hole, with a median distance of 22 Mpc. Finally, we combine this search with previously published results to provide a population statement for GRB searches in first-generation LIGO and Virgo gravitational wave detectors and a resulting examination of prospects for the advanced gravitational wave detectors.

Platelet count doubling after the first cycle of azacitidine therapy predicts eventual response and survival in patients with myelodysplastic syndromes and oligoblastic acute myeloid leukaemia but does not add to prognostic utility of the revised IPSS

Reliable clinical or molecular predictors of benefit from azacitidine therapy in patients with myelodysplastic syndromes (MDS) are not defined. Doubling of platelet count at start of second cycle of azacitidine therapy compared to baseline was associated with achieving response and survival advantage in a Dutch cohort. To validate this observation, we analysed a larger cohort of North American patients, whose data was collected in a prospective clinical trial with a longer median follow-up. We found a significant association between platelet count doubling after first cycle of azacitidine therapy and probability of achieving objective response. Among patients with MDS or oligoblastic acute myeloid leukaemia (<30% bone marrow blasts, n = 102), there was a statistically significant reduction in risk of death for patients who achieved platelet count doubling (n = 23, median OS, 21·0 months) compared to those who did not (n = 79, median OS, 16·7 months, adjusted hazard ratio (no/yes)=1·88, 95% confidence interval, 1·03-3·40, P = 0·04). Nonetheless, the addition of this platelet count doubling variable did not improve the survival prediction provided by the revised International Prognostic Scoring System or the French Prognostic Scoring System. Identification of reliable and consistent predictors for clinical benefit for azacitidine therapy remains an unmet medical need and a top research priority.

Frontline bortezomib and rituximab for the treatment of newly diagnosed high tumour burden indolent non-Hodgkin lymphoma: a multicentre phase II study

There is a lack of published data examining non-cytotoxic options for the frontline treatment of patients with high-tumour burden (HTB) indolent non-Hodgkin lymphoma (iNHL). We completed a multicentre phase II study for patients with untreated HTB iNHL (NCT00369707) consisting of three induction cycles of weekly bortezomib and rituximab followed by an abbreviated consolidation. Forty-two patients were treated and all were evaluable; the most common histology was follicular lymphoma (FL) (n = 33, 79%). Patient characteristics included median age 62 years (40-86); 38% bulky disease; 19% malignant effusions; 91% advanced-stage disease; and median FL International Prognostic Index (FLIPI) score was 3. Therapy was well tolerated with few grade 3/4 toxicities including minimal neurotoxicity. On intent-to-treat, the overall response rate (ORR) at end of therapy was 70% with a complete remission (CR) rate of 40% (FL: ORR 76%, CR 44%). With 50-month median follow-up, 4-year progression-free survival (PFS) was 44% with 4-year overall survival (OS) of 87% (FL: 44% and 97%, respectively). Four-year PFS for FLIPI 0-2 vs. 3-5 was 60% vs. 26% respectively (P = 0·02), with corresponding OS rates of 92% and 81% respectively (P = 0·16). Collectively, bortezomib/rituximab is a non-cytotoxic therapeutic regimen that was well tolerated and resulted in long-term survival rates approximating prior rituximab/cytotoxic chemotherapy series for untreated HTB FL.

Comparison of the prognostic utility of the revised International Prognostic Scoring System and the French Prognostic Scoring System in azacitidine-treated patients with myelodysplastic syndromes

The revised International Prognostic Scoring System (IPSS-R) was developed in a cohort of untreated myelodysplastic syndromes (MDS) patients. A French Prognostic Scoring System (FPSS) was recently reported to identify differential survival among azacitidine-treated patients with high-risk MDS. We applied the FPSS and IPSS-R to 150 patients previously randomized to azacitidine monotherapy or a combination of azacitidine with entinostat (a histone deacetylase inhibitor). Neither score predicted response but both discriminated patients with different overall survival (OS; median OS, FPSS: 9·7, 14·7, and 25·3 months, P = 0·018; IPSS-R: 12·5, 11·3, 20·8, and 36 months, P = 0·005). Statistical analysis suggested no improvement in OS prediction for the FPSS over the IPSS-R in azacitidine-treated patients.

Constraints on cosmic strings from the LIGO-Virgo gravitational-wave detectors

Cosmic strings can give rise to a large variety of interesting astrophysical phenomena. Among them, powerful bursts of gravitational waves (GWs) produced by cusps are a promising observational signature. In this Letter we present a search for GWs from cosmic string cusps in data collected by the LIGO and Virgo gravitational wave detectors between 2005 and 2010, with over 625 days of live time. We find no evidence of GW signals from cosmic strings. From this result, we derive new constraints on cosmic string parameters, which complement and improve existing limits from previous searches for a stochastic background of GWs from cosmic microwave background measurements and pulsar timing data. In particular, if the size of loops is given by the gravitational backreaction scale, we place upper limits on the string tension Gμ below 10(-8) in some regions of the cosmic string parameter space.

Prolonged administration of azacitidine with or without entinostat for myelodysplastic syndrome and acute myeloid leukemia with myelodysplasia-related changes: results of the US Leukemia Intergroup trial E1905

PURPOSE

Although azacitidine (AZA) improves survival in patients with high-risk myelodysplastic syndrome, the overall response remains approximately 50%. Entinostat is a histone deacetylase inhibitor that has been combined with AZA with significant clinical activity in a previous phase I dose finding study.

DESIGN

Open label phase II randomized trial comparing AZA 50 mg/m(2)/d given for 10 days ± entinostat 4 mg/m(2)/d day 3 and day 10. All subtypes of myelodysplasia, chronic myelomonocytic leukemia, and acute myeloid leukemia with myelodysplasia-related changes were eligible for the study. The primary objective was the rate of hematologic normalization (HN; complete remission + partial remission + trilineage hematological improvement).

RESULTS

One hundred forty-nine patients were analyzed, including 97 patients with myelodysplastic syndrome and 52 patients with acute myeloid leukemia. In the AZA group, 32% (95% CI, 22% to 44%) experienced HN and 27% (95% CI, 17% to 39%) in the AZA + entinostat group. Both arms exceeded the HN rate of historical control (Cancer and Leukemia Group B 9221 trial), but only the AZA group fulfilled the primary objective of the study. Rates of overall hematologic response were 46% and 44%, respectively. Median overall survivals were 18 months for the AZA group and 13 months for the AZA + entinostat group. The combination arm led to less demethylation compared with the monotherapy arm, suggesting pharmacodynamic antagonism.

CONCLUSION

Addition of entinostat to AZA did not increase clinical response as defined by the protocol and was associated with pharmacodynamic antagonism. However, the prolonged administration of AZA by itself seems to increase HN rate compared with standard dosing and warrants additional investigation.

Phase 2 study of VcR-CVAD with maintenance rituximab for untreated mantle cell lymphoma: an Eastern Cooperative Oncology Group study (E1405)

Rituximab, bortezomib, modified hyper-cyclophosphamide, doxorubicin, vincristine, dexamethasone (VcR-CVAD) induction chemoimmunotherapy and maintenance rituximab (MR) were evaluated for efficacy and safety in Eastern Cooperative Oncology Group protocol E1405. Patients with previously untreated mantle cell lymphoma received VcR-CVAD chemotherapy every 21 days for 6 cycles, followed by MR for 2 years. Transplant-eligible patients had the option of autologous stem cell transplantation (ASCT) consolidation instead of MR. The primary end point was the complete response (CR) rate to VcR-CVAD. The secondary end points were overall response rate (ORR), progression-free survival (PFS), overall survival (OS), and toxicities. Seventy-five eligible patients with a median age of 62 (range 40-76) were enrolled. The ORR was 95% and a CR was achieved in 68% of patients. After a median follow-up of 4.5 years, 3-year PFS and OS were 72% and 88%, respectively. No substantial difference in PFS or OS was observed between patients treated with MR (n = 44) vs ASCT (n = 22). There were no unexpected toxicities. VcR-CVAD produced high ORR and CR rates in mantle cell lymphoma. MR after VcR-CVAD induction performed similarly to ASCT and may improve response duration. Randomized clinical trials comparing MR against ASCT should be considered and randomized clinical trials evaluating bortezomib's contribution to conventional therapy are under way. This study was registered at www.clinicaltrials.gov as #NCT00433537.

New agents for the treatment of lymphoid leukemia and lymphoma: focus on recent FDA approvals

Leukemia and lymphoma are systemic malignancies that represent half of all childhood cancers, though 90% occur in adults. Various treatment options are available, but therapy is mainly systemic chemotherapy plus appropriate monoclonal antibodies. In certain situations radiotherapy and bone marrow transplantation play a role. Some types/subtypes of these diseases are potentially curable, yet many leukemias and lymphomas do not properly respond to current therapies. Although the FDA (US Food and Drugs Administration) approvals of new drugs have shown a small increasing trend between 2007-2012, overall, the trend of new approvals remains relatively steady between 2006-2013, with a peak of 39 new drugs approved in 2012 and a drop in the new FDA drug approvals in 2013, to 27. Drugs approved for cancer treatment have shown a similar trend. Between 2006-2013, at least one drug was approved every year for the treatment of particular types of lymphoma or leukemia, except in 2010, with a peak of 5 new approvals in 2012. Between January 2013-March 2014, several important new approvals were made: ibrutinib for the treatment of CLL and mantle cell lymphoma (MCL), obinutuzumab for the treatment of CLL (in combination with chlorambucil), and lenalidomide for the treatment of mantle cell lymphoma. The results, importance, adverse effects and mechanisms of action of these agents are discussed in this review. These results held promise and their discovery and approval for the treatment of CLL and MCL is a major step forward. However, the emergence of resistance and the lack of cures need to be addressed by rational development of combination therapy, as well as development of novel drugs with enhanced potency or different mechanism of action, to achieve better overall and complete response rates with decreased toxicity.

Noninvasive phosphorus magnetic resonance spectroscopic imaging predicts outcome to first-line chemotherapy in newly diagnosed patients with diffuse large B-cell lymphoma

RATIONALE AND OBJECTIVES

Based on their association with malignant proliferation, using noninvasive phosphorus MR spectroscopic imaging ((31)P MRSI), we measured the tumor content of the phospholipid-related phosphomonoesters (PME), phosphoethanolamine and phospholcholine, and its correlation with treatment outcome in newly diagnosed patients with diffuse large B-cell lymphoma (DLBCL) receiving standard first-line chemotherapy.

EXPERIMENTAL DESIGN

The PME value normalized to nucleoside triphosphates (PME/NTP) was measured using (31)P MRSI in tumor masses of 20 patients with DLBCL before receiving standard first-line chemotherapy. Response at 6 months was complete in 13 patients and partial in seven. Time to treatment failure (TTF) was ≤11 months in eight patients, from 18 to 30 months in three, and ≥60 months in nine.

RESULTS

On a t test, the pretreatment tumor PME/NTP mean value (SD, n) of patients with a complete response at 6 months was 1.42 (0.41, 13), which was significantly different from the value of 2.46 (0.40, 7) in patients with partial response (P < .00001). A Fisher test significantly correlated the PME/NTP values with response at 6 months (sensitivity and specificity at 0.85, P < .004) while a Cox proportional hazards regression significantly correlated the PME/NTP values with TTF (hazard ratio = 5.21, P < .02). A Kaplan-Meier test set apart a group entirely composed of patients with TTF ≤ 11 months (hazard ratio = 8.66, P < .00001).

CONCLUSIONS

The pretreatment tumor PME/NTP values correlated with response to treatment at 6 months and time to treatment failure in newly diagnosed patients with DLBCL treated with first-line chemotherapy, and therefore they could be used to predict treatment outcome in these patients.

Low NK cell counts in peripheral blood are associated with inferior overall survival in patients with follicular lymphoma

Host immune responses influence follicular lymphoma (FL) outcomes. To test our hypothesis that immune cells in blood reflect that response, we assessed by peripheral blood flow cytometry in 75 untreated FL patients the absolute counts of: lymphocytes (ALC), CD4(+)T (ACD4C), CD8(+)T (ACD8C) and natural killer (ANKC) cells. Low ANKC was the only parameter associated with inferior overall survival by univariate analysis (p=0.02), and trended to significance in multivariable analysis with ACD4C (p=0.08). Five (24%) patients with low initial ANKC died, while one (2%) with normal/high ANKC has died. In conclusion, evaluation of blood ANKC may be a useful indicator of outcome in previously untreated FL patients.

Novel targeted therapies in peripheral T cell lymphoma

Peripheral T cell lymphomas (PTCL), non-Hodgkin lymphomas characterized by having features of T cells that have matured in the thymus, are a heterogeneous group of clinical entities. Compared with B cell lymphomas, they are less common, more difficult to diagnose and classify, more aggressive, and have inferior outcomes with current treatment paradigms. They are also less completely understood in terms of how different PTCL types correspond to normal T cell development, and in identifying cell signaling pathways as targets for new therapies. Recent studies with novel targeted therapies as single agents or in combination with other drugs have illustrated promising outcomes both for relapsed and frontline PTCL. We first briefly review classification, prognostic indices, and results of initial therapy of various T cell lymphomas. We then review recent studies of chemotherapy, monoclonal antibody-based therapy directed at cell surface targets, small molecule inhibitors of intracellular targets such as histone deacetylases and the proteasome, and agents that disrupt stromal interactions. Investigations that enhance our knowledge of T cell molecular biology and integrate novel targeted agents into the treatment algorithm for PTCL will be keys to improved outcomes for patients with PTCL.

Therapies for mantle cell lymphoma: current challenges and a brighter future

Mantle cell lymphoma (MCL), which accounts for about 6% of non-Hodgkin lymphoma (NHL), is characterized by the chromosomal translocation t(11;14)(q13;q32), resulting in de-regulated expression of cyclin D1. Managing MCL is challenging, because it is incurable with conventional chemotherapy as with indolent NHL, but has a more aggressive natural history. Therapeutic advances have been made in the past decade with the incorporation of targeted therapies into the frontline setting, use of aggressive combination regimens followed by consolidation with high dose therapy and autologous stem cell rescue for a younger population, use of less aggressive combinations in the elderly, and translation of pre-clinical findings to the clinical trial realm with novel agents that hold significant promise in the treatment of this disease. The authors review current standard approaches in the treatment of MCL, and novel findings in the pathogenesis of this disease that may guide the way for further development of modern therapeutic approaches.

Safety and clinical activity of a combination therapy comprising two antibody-based targeting agents for the treatment of non-Hodgkin lymphoma: results of a phase I/II study evaluating the immunoconjugate inotuzumab ozogamicin with rituximab

PURPOSE

Inotuzumab ozogamicin (INO) is an antibody-targeted chemotherapy agent composed of a humanized anti-CD22 antibody conjugated to calicheamicin, a potent cytotoxic agent. We performed a phase I/II study to determine the maximum-tolerated dose (MTD), safety, efficacy, and pharmacokinetics of INO plus rituximab (R-INO) for treatment of relapsed/refractory CD20(+)/CD22(+) B-cell non-Hodgkin lymphoma (NHL).

PATIENTS AND METHODS

A dose-escalation phase to determine the MTD of R-INO was followed by an expanded cohort to further evaluate the efficacy and safety at the MTD. Patients with relapsed follicular lymphoma (FL), relapsed diffuse large B-cell lymphoma (DLBCL), or refractory aggressive NHL received R-INO every 4 weeks for up to eight cycles.

RESULTS

In all, 118 patients received one or more cycles of R-INO (median, four cycles). Most common grade 3 to 4 adverse events were thrombocytopenia (31%) and neutropenia (22%). Common low-grade toxicities included hyperbilirubinemia (25%) and increased AST (36%). The MTD of INO in combination with rituximab (375 mg/m(2)) was confirmed to be the same as that for single-agent INO (1.8 mg/m(2)). Treatment at the MTD yielded objective response rates of 87%, 74%, and 20% for relapsed FL (n = 39), relapsed DLBCL (n = 42), and refractory aggressive NHL (n = 30), respectively. The 2-year progression-free survival (PFS) rate was 68% (median, not reached) for FL and 42% (median, 17.1 months) for relapsed DLBCL.

CONCLUSION

R-INO demonstrated high response rates and long PFS in patients with relapsed FL or DLBCL. This and the manageable toxicity profile suggest that R-INO may be a promising option for CD20(+)/CD22(+) B-cell NHL.

A multicenter phase II trial to determine the safety and efficacy of combination therapy with denileukin diftitox and cyclophosphamide, doxorubicin, vincristine and prednisone in untreated peripheral T-cell lymphoma: the CONCEPT study

This phase II study to determine the safety and efficacy of denileukin diftitox (DD) and cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP) enrolled patients with newly diagnosed peripheral T-cell lymphoma (PTCL). Forty-nine received DD 18 μg/kg/day (days 1, 2) with CHOP (day 3) every 21 days for ≤ 6-8 cycles. Intent-to-treat (ITT) and safety populations comprised all patients. In the ITT population, the overall response rate was 65%, median duration of response was 30 months and median progression-free survival was 12 months. Median overall survival was not attained at the end of the study, and the overall survival rate was 63.3%. The two most frequent treatment-related adverse events (AEs) were fatigue and nausea. Most frequent AEs ≥ grade 3 within the hematologic system were lymphopenia (24.5%), neutropenia (20.4%) and leukopenia (18.4%). Three treatment-related deaths occurred. DD plus CHOP was well tolerated, and progression-free and overall survival improved versus historical comparison with CHOP alone. Confirmation in larger trials is warranted.

Phase II study of rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone immunochemotherapy followed by yttrium-90-ibritumomab tiuxetan in untreated mantle-cell lymphoma: Eastern Cooperative Oncology Group Study E1499

PURPOSE

To test the hypothesis that consolidation therapy with yttrium-90 ((90)Y) -ibritumomab tiuxetan after brief initial therapy with four cycles of rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) in patients with previously untreated mantle-cell lymphoma would be a well-tolerated regimen that would improve outcomes compared with historical R-CHOP data.

PATIENTS AND METHODS

Patients ≥ 18 years old with histologically confirmed mantle-cell lymphoma expressing CD20 and cyclin D1 who had not received any previous therapy and had an Eastern Cooperative Oncology Group performance status of 0 to 2 and adequate organ function were eligible. The study enrolled and treated 57 patients, of whom 56 patients were eligible. Fifty-two patients (50 eligible patients) received (90)Y-ibritumomab tiuxetan. The study design required 52 eligible patients to detect a 50% improvement in the median time to treatment failure (TTF) compared with that reported for six cycles of R-CHOP.

RESULTS

With 56 analyzed patients (median age, 60 years; men, 73%), the overall response rate was 82% (55% complete response/complete response-unconfirmed). With a median follow-up of 72 months, the median TTF was 34.2 months. The median overall survival (OS) has not been reached, with an estimated 5-year OS of 73% (79% for patients ≤ age 65 years v 62% for patients > age 65 years; P = .08 [log-rank test]). There were no unexpected toxicities.

CONCLUSION

R-CHOP given for four cycles followed by (90)Y-ibritumomab tiuxetan compared favorably with historical results with six cycles of R-CHOP in patients with previously untreated mantle-cell lymphoma. This regimen was well tolerated and should be applicable to most patients with this disease.

Radioimmunotherapy in mantle cell lymphoma

Mantle cell lymphoma (MCL), though characterized by the chromosomal translocation t(11; 14) (q13; q32), is a heterogeneous disease. Often termed an aggressive lymphoma in the U.S., but included in indolent lymphoma trials in Europe, MCL is not curable with standard immuno-chemotherapy. There is no single standard initial therapy for this disease. Although standard lymphoma therapies yield high response rates, relapse is inevitable. Unmet needs in MCL include better induction therapy, consolidation treatments to prolong first remission and better therapeutic options for relapsed disease. In this review, we evaluate the role of radioimmunotherapy (RIT) in MCL, a novel strategy combining monoclonal antibodies with radioisotopes to deliver radiation directly to tumour tissue, both in the frontline and relapsed setting.

Tetanus toxoid reactive lymphadenopathy masquerading as T-cell lymphoma

We report a case in which a patient with persistent reactive lymphadenopathy post-tetanus toxoid vaccination was initially diagnosed as having T-cell lymphoma/leukemia. A florid CD4+ T-cell proliferation and pathology interpretation, in the absence of complete clinical information, that these cells co-expressed CD8 led to the initial diagnosis. Better integration of the clinical and pathologic data may have led more rapidly to the final diagnosis. Postvaccination responses can mimic lymphoma.

Efficacy of ocaratuzumab (AME-133v) in relapsed follicular lymphoma patients refractory to prior rituximab

8081

Background: Ocaratzumab, previously known as AME-133v, is a humanized next-generation anti-CD20 monoclonal antibody. It has been optimized with a 13 to 20-fold increase in binding affinity to CD20 and improved binding to the low-affinity (F/F and F/V) polymorphisms of FcγRIIIa (CD16), which are thought to predict lower response rates and shorter duration of responses to rituximab. Methods: In a phase I dose escalation study in relapsed follicular lymphoma (FL) patients, ocaratuzumab was well-tolerated at doses up to 375 mg/m2 (Forero-Torres et al. CCR 2012). In a follow-on phase II trial, 44 patients with relapsed FL following prior rituximab and the low-affinity FcγRIIIa polymorphism (F-carriers) received 375 mg/m2 of ocaratuzumab weekly for 4 doses. In this study, overall response rate (ORR) was 36% and median progression free survival (PFS) was 91 weeks (Ganjoo et al. Haematologica 2011). Results: Amongst the 56 patients receiving 100 and 375 mg/m2 of ocaratuzumab, 8 patients had a previous time to progression of ≤ 180 days following their last rituximab treatment. These patients had a median of 2 prior rituximab treatments, (range 1-6 treatments), and median PFS following last treatment of 159 days. Five of the 8 patients showed a longer PFS after ocaratuzumab administration, compared with last rituximab treatment. All 5 patients expressed the homozygous low-affinity genotype of FcγRIIIa (F/F). At the time of study closure, 3 of the patients were still in remission (indicated by * in the table). Conclusions: This retrospective analysis suggests that ocaratuzumab may be non-cross-resistant to rituximab in patients with the low-affinity FcγRIIIa polymorphism. Prolonged PFS in selected patients following ocaratuzumab suggests that the increased binding affinity to CD16 and improved antibody-dependent cell-mediated cytotoxicity (ADCC) of this antibody is clinically relevant. As a single agent, ocaratuzumab may provide prolonged clinical benefit in relapsed FL patients and a clinical trial comparing ocaratuzumab to rituximab is in preparation. [Table: see text]

Multicenter phase II study of trabectedin in patients with metastatic castration-resistant prostate cancer

BACKGROUND

This multicenter phase II trial evaluated the efficacy and safety of trabectedin in metastatic castration-resistant prostate cancer (CRPC).

PATIENTS AND METHODS

Two schedules were evaluated in three cohorts: weekly as 3-h i.v. infusion at 0.58 mg/m(2) for 3 out of 4 weeks (Cohort A, n = 33), and every 3 weeks (q3wk) as 24-h infusion at 1.5 mg/m(2) (Cohort B1, n = 5) and 1.2 mg/m(2) (Cohort B2, n = 20). The primary end point was prostate-specific antigen (PSA) response; secondary end points included safety, tolerability and time to progression (TTP).

RESULTS

Trabectedin resulted in PSA declines ≥ 50% in 12.5% (Cohort A) and 10.5% (Cohort B2) of patients. Among men pretreated with taxane-based chemotherapy, PSA response was 13.6% (Cohort A) and 15.4% (Cohort B2). PSA responses lasted 4.1-8.6 months, and median TTP was 1.5 months (Cohort A) and 1.9 months (Cohort B2). The dose of 1.5 mg/m(2) (approved for soft tissue sarcoma) given as 24-h infusion q3wk was not tolerable in these patients. At 1.2 mg/m(2) q3wk and 0.58 mg/m(2) weekly, the most common adverse events were nausea, fatigue and transient neutropenia and transaminase increase.

CONCLUSIONS

Two different trabectedin schedules showed modest activity in metastatic CRPC. Further studies may require identification of predictive factors of response in prostate cancer.

Abstract 3857: Smac mimetic TL32711 and TRAIL synergistically induce apoptosis of germinal center B lymphoma cells

TL32711, a Smac mimetic in clinical testing, potently targets Inhibitor of Apoptosis Proteins (IAPs, including cIAPs and XIAP) to unblock intrinsic and extrinsic pathways, enabling caspase-dependent apoptosis via multiple signals including TRAIL (Tumor Necrosis Factor-Related Apoptosis Inducing Ligand). TL32711 also inactivates canonical and activates non-canonical NF-κB signaling through cIAPs. We investigated the pro-apoptotic effects of TL32711, alone and in combination with TRAIL to activate the extrinsic pathway, in a panel of B cell lymphoma cell lines representing germinal center/follicular (GC) vs activated B cell (ABC) histologies. We hypothesized that the efficacy of this potential combination therapeutic strategy might differ between GC and ABC lymphoma types, as ABC are reported to be NF-kB dependent. We used the following EBV negative cell lines: WSU- FSCCL t(14:18)+ follicular lymphoma (FL), FC-TxFL2 t(14:18)+ transformed FL and SU-DHL4 GC-type diffuse large B cell lymphoma (DLBCL) as examples of GC origin lymphomas. U2932 and TMD8 served as ABC-type DLBCL. Apoptosis was determined by annexin V staining after 48 hr incubation (TL32711 added 2-3 hr after TRAIL). The contribution of the different apoptotic pathways was determined by caspase-3 (common), -8 (extrinsic), and-9 (intrinsic) activity, assessed by flow cytometric methods and Western blot. TL32711 had little effect as a single agent on any of these B cell lymphoma cell lines at ≤ 100nM, though apoptosis was induced at 10-20 µM in GC types. TRAIL alone (10-25 ng/ml) induced apoptosis in the 3 GC lines, but had little effect on the 2 ABC lines. Combination of TL32711 and TRAIL at low concentrations showed marked apoptosis in GC lines, with minimal to no effect for each agent alone. In the combination-treated GC types, caspases -3, -8 and -9 were significantly induced, confirming activation of both pathways. We had previously shown in FSCCL and TxFL2 that caspase-8 induction also cleaved tBID, activating the intrinsic apoptotic pathway via caspase-9. GC subtypes, including FL, transformed FL and GC-DLBCL were sensitive to TRAIL and TL32711 at clinically achievable concentrations for TL32711, with supra-additive combination effects. ABC-type DLBCL were not sensitive to either agent alone or in combination. We are investigating whether ABC-DLBCL are truly dependent on canonical NF-κB activation for survival or have other mechanisms of resistance to TRAIL and IAP inhibition. These data suggest that clinical trials of TL32711 may focus on FL and GC lymphoma in combination with TRAIL or TRAIL-agonists.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3857. doi:1538-7445.AM2012-3857

Brentuximab vedotin in anaplastic large cell lymphoma

INTRODUCTION

Brentuximab vedotin , a novel anti-CD30 antibody-drug conjugate, delivers a cytotoxic agent into CD30(+) cells. CD30 expression is characteristic of anaplastic large cell lymphoma (ALCL) and Hodgkin lymphoma (HL).

AREAS COVERED

We reviewed data on brentuximab vedotin, focusing on ALCL and discuss pharmacology, clinical trials leading to approval and future research directions. Systemic ALCL, 3% of adult NHL, is characterized by large anaplastic CD30(+) cells. The fusion protein NPM-ALK, when present in systemic ALCL, confers better prognosis, although even ALK- patients with IPI score ≥ 3 are high-risk. For patients with systemic ALCL, 25 - 45% relapse after frontline therapy, and > 50% of patients will relapse following high-dose chemotherapy with autologous stem-cell support. There has been no standard therapy for relapsed/refractory systemic ALCL. Brentuximab vedotin, combines a monoclonal antibody targeted to CD30 with a microtubule disrupting agent and was recently approved for treatment of patients with systemic ALCL that is refractory or relapsed after at least one multiagent chemotherapy regimen.

EXPERT OPINION

Brentuximab vedotin provides targeted therapy to CD30(+) lymphomas, including ALCL and HL, with high response rates and manageable toxicity, predominantly myelosuppression and peripheral neuropathy.

Results of a phase 1 study of AME-133v (LY2469298), an Fc-engineered humanized monoclonal anti-CD20 antibody, in FcγRIIIa-genotyped patients with previously treated follicular lymphoma

PURPOSE

AME-133v is a humanized monoclonal antibody engineered to have increased affinity to CD20 and mediate antibody-dependent cell-mediated cytotoxicity (ADCC) better than rituximab. Safety, pharmacokinetics, and efficacy were assessed in a phase 1/2 trial in patients with previously treated follicular lymphoma (FL).

PATIENTS AND METHODS

AME-133v was characterized in vitro by ADCC and cell binding assays. A phase 1 study was conducted in which 23 previously treated patients with FL were assigned sequentially to one of five dose-escalation cohorts of AME-133v at 2, 7.5, 30, 100, or 375 mg/m(2) weekly × 4 doses.

RESULTS

AME-133v showed a 13- to 20-fold greater binding affinity for CD20 and was 5- to 7-fold more potent than rituximab in ADCC assays. Cell binding assays showed AME-133v and rituximab competed for an overlapping epitope on the CD20 antigen, and AME-133v inhibited binding of biotinylated rituximab to CD20 in a concentration-dependent manner. AME-133v was well tolerated by patients and common related adverse events included chills and fatigue. One patient experienced a dose-limiting toxicity of neutropenia. AME-133v showed nonlinear pharmocokinetics with properties similar to rituximab. Selective reduction of B cells during and after AME-133v treatment was shown by flow cytometry of peripheral blood. A partial or complete response was observed in 5 of 23 (22%) patients and the median progression-free survival was 25.4 weeks.

CONCLUSIONS

AME-133v was safe and well tolerated at the doses tested. AME-133v showed encouraging results as an anti-CD20 therapy in heavily pretreated FL patients with the less favorable FcγRIIIa F-carrier genotype.

Directional limits on persistent gravitational waves using LIGO S5 science data

The gravitational-wave (GW) sky may include nearby pointlike sources as well as stochastic backgrounds. We perform two directional searches for persistent GWs using data from the LIGO S5 science run: one optimized for pointlike sources and one for arbitrary extended sources. Finding no evidence to support the detection of GWs, we present 90% confidence level (C.L.) upper-limit maps of GW strain power with typical values between 2-20×10(-50)  strain(2) Hz(-1) and 5-35×10(-49)  strain(2) Hz(-1) sr(-1) for pointlike and extended sources, respectively. The latter result is the first of its kind. We also set 90% C.L. limits on the narrow-band root-mean-square GW strain from interesting targets including Sco X-1, SN 1987A and the Galactic center as low as ≈7×10(-25) in the most sensitive frequency range near 160 Hz.