Background Endogenous or iatrogenic antitumor immune responses can improve the course of follicular lymphoma (FL), but may be diminished by immune checkpoints in the tumor microenvironment. These may include effects of programmed death (PD)-1, a co-inhibitory receptor that impairs T-cell function and is highly expressed on intratumoral T cells. In a Phase II trial, we determined the activity of pidilizumab, a humanized anti-PD-1 monoclonal antibody, with rituximab in patients with relapsed FL. Methods FL patients with rituximab-sensitive disease relapsing after 1–4 prior therapies were eligible. Pidilizumab was administered at 3 mg/kg every 4 weeks for 4 infusions, plus 8 optional infusions every 4 weeks for patients with stable disease or better. Starting 2 weeks after the first infusion of pidilizumab, rituximab was given at 375 mg/m2 weekly for 4 weeks. The primary endpoint was to assess the overall response rate. Analysis was by intention to treat. Peripheral blood and tumor biopsies were studied to assess immunological effects of pidilizumab. This trial has been completed and was registered at www.clinicaltrials.gov as NCT00904722. Findings The combination was well-tolerated, with no autoimmune or therapy-related grade 3/4 toxicities. The most common grade 1 adverse events were anemia (14 patients) and fatigue (13 patients), and the most common grade 2 adverse event was respiratory infection (5 patients). Overall 19/29 (66%) and complete 15/29 (52%) response rates in 29 evaluable patients were high, with tumor regression in 25/29 (86%) of patients. Median progression-free survival was 18.8 months (95% CI: 14.7 months to not reached). The median response duration for the 19 responders was 20.2 months (95% CI: 13.9 months to not reached). Correlative studies of blood and tumor provided insights into predicting response and understanding mechanisms involved. Interpretation Pidilizumab with rituximab is well-tolerated and its activity compared favorably to historical retreatment with rituximab monotherapy in patients with relapsed FL. Our results establish that immune checkpoint blockade is worthy of further study in FL. Funding National Institutes of Health, Leukemia and Lymphoma Society, Cure Tech Ltd, and UT MD Anderson Cancer Center.

Summary Background Standard treatments for indolent non-Hodgkin lymphomas (iNHLs) are frequently toxic, and most patients ultimately relapse. Lenalidomide, an immunomodulatory agent, is effective as monotherapy for relapsed iNHL. The aim of this phase 2 trial (NCT00695786) was to evaluate the efficacy and safety of lenalidomide plus rituximab in untreated, advanced-stage iNHL and determine the combinaton’s effect on the immune system and tumour microenvironment. The primary objective was to determine the number of complete and partial responses. Methods For follicular lymphoma (FL) and marginal zone lymphoma (MZL), lenalidomide was given orally at 20 mg/day on days 1–21 of all 28-day cycles. Dosing for small lymphocytic lymphoma (SLL) began at 10 mg/day to avoid tumour flare. Rituximab was given at 375 mg/m2 body surface area on day 1 of each cycle. Patients responding after 6 cycles could continue therapy for up to 12 cycles. Patients were evaluated for response analysis if they had any post-baseline tumor assessment. Findings The study enrolled 110 patients, and 103 were evaluable for efficacy analysis. All patients were eligible for safety analysis. The most common grade 3 or 4 adverse events were neutropenia (35%), muscle pain (9%), rash (7%), cough/dyspnea (7%), fatigue (5%), thrombosis (5%), and thrombocytopenia (4%). The overall response rate was 90% (93/103) (95% confidence interval [CI] 83–95%). Complete and partial response rates were 63% (95% CI 53–72%) and 27% (95% CI 19–37%), respectively. Eighty-seven percent (95% CI 74–95%) and 11% (95% CI 4–24%) of FL patients achieved complete and partial responses, respectively. Seventy-nine percent of evaluable FL patients remained in remission at 36 months. Interpretation Lenalidomide plus rituximab is well tolerated and highly effective as initial treatment for iNHL. Durable response rates obtained without cytotoxic agents suggest this regimen could replace chemotherapy as the frontline treatment of iNHL. An international phase 3 study (NCT01476787) is ongoing comparing this regimen to chemotherapy in untreated follicular lymphoma. Funding The study was funded by Celgene Corporation and the Richard Spencer Lewis Memorial Foundation.

Proteasome inhibition with bortezomib is a validated approach to the treatment of multiple myeloma, but drug resistance often emerges and limits its utility in the retreatment setting. To begin to identify some of the mechanisms involved, we developed bortezomib-resistant myeloma cell lines that, unlike previously reported models, showed no ␤5 subunit mutations. Instead, up-regulation of the insulinlike growth factor (IGF)-1 axis was identified, with increased autocrine and paracrine secretion of IGF-1, leading to increased activation of the IGF-1 receptor (IGF-1R). Exogenous IGF-1 reduced cellular sensitivity to bortezomib, whereas pharmacologic or small hairpin RNAmediated IGF-1R suppression enhanced bortezomib sensitivity in cell lines and patient samples. In vitro studies with OSI-906, a clinically relevant dual IGF-1R and insulin receptor inhibitor, showed it acted synergistically with bortezomib, and potently resensitized bortezomib-resistant cell lines and patient samples to bortezomib. Importantly, OSI-906 in combination with bortezomib also overcame bortezomib resistance in an in vivo model of myeloma. Taken together, these data support the hypothesis that signaling through the IGF-1/IGF-1R axis contributes to acquired bortezomib resistance, and provide a rationale for combining bortezomib with IGF-1R inhibitors like OSI-906 to overcome or possibly prevent the emergence of bortezomib-refractory disease in the clinic. (Blood. 2012;120(16):3260-3270) IntroductionMultiple myeloma is a malignancy of immunoglobulin-secreting clonal plasma cells that is most often found in the bone marrow. 1,2 Modulation of the activity of the ubiquitin-proteasome pathway with the small molecule proteasome inhibitor bortezomib (VEL-CADE) has been validated as a rational therapeutic strategy for this disease 3,4 both in the front-line and relapsed/refractory settings. Despite these and other advances, myeloma remains an incurable disease characterized by decreasing response durations with each subsequent salvage therapy. 5 This is mediated in part through both intrinsic and acquired drug resistance, the latter of which emerges during and after bortezomib therapy. 6 Response rates in patients with previously bortezomib-sensitive disease are typically decreased on drug rechallenge 7-9 and may be as low as 23% among patients who had achieved at least a partial remission previously. 7 These findings indicate a need for an understanding of the molecular basis for bortezomib resistance.Proteasome inhibition acutely activates multiple inducible chemoresistance pathways that reduce the efficacy of bortezomib. One example is the antiapoptotic Akt pathway that can be activated by proteasome inhibitors, 10 and suppression of this pathway can induce chemosensitization to bortezomib. [11][12][13] Another possible mechanism aiding in acquired resistance to bortezomib may be the development of mutations in the bortezomib-binding pocket of the ␤5 proteasome subunit, or increased expression of ␤5 itself. [14][15][16] However, ␤5 proteasome sub...

A neuploidy (aberrant chromosome number) is a hallmark feature of human malignancies (1, 2) and has also been proposed as a necessary event for tumorigenesis (2). Although there have been many proposed hypotheses, there is no general agreement as to why aneuploidy is so highly prevalent in cancer cells, and how it contributes to tumor progression (3, 4). Importantly, if aneuploidy forms an underlying cause of human cancer, it has not been fully substantiated. The mechanisms of aneuploidy also remain a fundamental unresolved problem in cancer biology.To understand how aneuploidy might originate in mammalian tissues, we have focused on the elements that regulate chromosomal segregation, particularly those involved in sister chromatid cohesion and separation, because chromosome missegregation, for example during mitosis, can lead to aneuploidy. A key gene in our analysis is ESPL1, which encodes an endopeptidase called Separase that separates sister chromatids by cleaving cohesin Rad21/Mcd1/Scc1 during the metaphase to anaphase transition. The hypothesis we tested is that hormonal stimulation of the p53-null mouse mammary gland results in misexpression of the ESPL1 gene, thus promoting aneuploidy and breast cancer formation. Dysregulation of the mitotic machinery that helps maintain chromosomal stability in mammary cells can result in aneuploidy and subsequently, cancer formation. We focused on Separase for the following reasons that have important implications for breast cancer: (i) Separase plays a central role in promoting faithful chromosome segregation; (ii) our previous studies strongly indicated that hormonal stimulation of p53-null mice mammary gland results in overexpression of the ESPL1 and Separase protein, which may be a direct cause of aneuploidy (5); and (iii) siRNA-mediated knockdown of Separase and Separase deficient mouse embryonic fibroblasts results in genomic instability (6-8).An evolutionarily conserved protein complex called cohesin and an endopeptidase named Separase play pivotal roles in the accurate segregation of sister chromatids into two daughter cells. Cohesion along the length of the sister chromatids is formed during DNA replication in S phase. Cohesion along the chromosomal arms is removed during prophase and from centromeric regions at the metaphase-to-anaphase transition when Separase is activated after its inhibitory chaperone securin is degraded (9, 10).To understand how aberration in sister chromatid separation may contribute to chromosomal missegregation, we investigated the role of Separase overexpression in mouse mammary cells by using a mammary epithelial transplant model (11) as well as various biochemical and functional assays. Our results indicate that conditional overexpression of Separase alone in mammary epithelial cells with a p53 mutant background is sufficient to induce aneuploidy and tumorigenesis in vitro and in vivo. Results Conditional Expression of Mouse Separase (mSeparase) Results inAneuploidy in Mouse Mammary Epithelial Cells. To examine the direct effect of ...

BackgroundTumor suppressor gene TUSC2/FUS1 (TUSC2) is frequently inactivated early in lung cancer development. TUSC2 mediates apoptosis in cancer cells but not normal cells by upregulation of the intrinsic apoptotic pathway. No drug strategies currently exist targeting loss-of–function genetic abnormalities. We report the first in-human systemic gene therapy clinical trial of tumor suppressor gene TUSC2.MethodsPatients with recurrent and/or metastatic lung cancer previously treated with platinum-based chemotherapy were treated with escalating doses of intravenous N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium chloride (DOTAP):cholesterol nanoparticles encapsulating a TUSC2 expression plasmid (DOTAP:chol-TUSC2) every 3 weeks.ResultsThirty-one patients were treated at 6 dose levels (range 0.01 to 0.09 milligrams per kilogram). The MTD was determined to be 0.06 mg/kg. Five patients achieved stable disease (2.6–10.8 months, including 2 minor responses). One patient had a metabolic response on positron emission tomography (PET) imaging. RT-PCR analysis detected TUSC2 plasmid expression in 7 of 8 post-treatment tumor specimens but not in pretreatment specimens and peripheral blood lymphocyte controls. Proximity ligation assay, performed on paired biopsies from 3 patients, demonstrated low background TUSC2 protein staining in pretreatment tissues compared with intense (10–25 fold increase) TUSC2 protein staining in post-treatment tissues. RT-PCR gene expression profiling analysis of apoptotic pathway genes in two patients with high post-treatment levels of TUSC2 mRNA and protein showed significant post-treatment changes in the intrinsic apoptotic pathway. Twenty-nine genes of the 82 tested in the apoptosis array were identified by Igenuity Pathway Analysis to be significantly altered post-treatment in both patients (Pearson correlation coefficient 0.519; p<0.01).ConclusionsDOTAP:chol-TUSC2 can be safely administered intravenously in lung cancer patients and results in uptake of the gene by human primary and metastatic tumors, transgene and gene product expression, specific alterations in TUSC2-regulated pathways, and anti-tumor effects (to our knowledge for the first time for systemic DOTAP:cholesterol nanoparticle gene therapy).Trial RegistrationClinicalTrials.gov NCT00059605