Abstract 6208: Targeting DNA polymerase theta and ATM leads to synergistic killing of mantle cell lymphoma cells

Introduction: Rapid cell proliferation requires intact and faithful DNA damage repair mechanisms. DNA polymerase theta (POLQ) plays a key role in repairing DNA double-strand breaks through the microhomology-mediated end-joining (MMEJ), which is one of the three main pathways involved in repairing replication-induced double-strand breaks. Limited data have suggested that concurrent depletion of POLQ and ataxia-telangiectasia mutated (ATM) could be embryonic lethal. Hence, this phenomenon has the potential to be exploited for therapeutic benefit in cancers where ATM mutations are commonly seen. Mantle cell lymphoma (MCL) is a non-Hodgkin lymphoma marked by (11;14) translocation with ATM alterations seen in 40-50% of patients. There is an unmet need to find novel therapeutic strategies, especially in relapsed and/or refractory (R/R) MCL. Here, we investigated whether targeting POLQ and ATM could be a potential therapeutic strategy in MCL.

Methods: In vitro studies were conducted by using MCL cell lines. CRISPR-Cas9 system was used to genetically deplete POLQ and ATM genes and sgRNAs co-expressing fluorescence markers were used to track the cell population with respective genotypes over time. Cell viability was assessed by CellTiter-Glo assay and flow cytometry. All cell lines were profiled for ATM expression and activity. A p-value of < 0.05 was considered statistically significant. The combination index of <1 was defined as synergistic.

Results: CRISPR-Cas9-mediated depletion of POLQ significantly decreased cell proliferation in multiple MCL cell lines. In particular, Granta-519, which possesses a single copy of kinase-dead ATM that is reduced in expression, was most sensitive to POLQ depletion. Concurrent genetic depletion of ATM and POLQ resulted in a synergistic antiproliferative effect in ATM-proficient MCL cell lines. Subsequently, this cellular phenotype caused by the genetic intervention was recapitulated by using two POLQ inhibitors (novobiocin and ART558) and an ATM inhibitor (AZD0156). In vitro, single-agent treatment with novobiocin or ART558 caused a significant cytotoxic effect at physiologically relevant concentrations in ATM-deficient cells and co-treatment of novobiocin or ART558 with AZD0156 was synergistic in killing ATM-proficient MCL cells. Importantly, POLQ inhibitors significantly decreased the cell viability of MCIR1, which is an ibrutinib-resistant MCL cell line. Mechanistically, novobiocin or ART558 treatment induced gH2AX and cleaved PARP upregulation, which was further enhanced by ATM depletion, suggesting that co-inhibition of POLQ and ATM caused apoptosis due to the accumulation of unrepaired DNA damage.

Conclusion: POLQ is a promising target in MCL, especially in ATM-deficient setting. In ATM-proficient MCL, targeting ATM and POLQ is synergistic. Our data has the potential to uncover novel biomarker-driven drug therapy of POLQ inhibitors in R/R MCL.

Citation Format: Jithma Prasad Abeykoon, Shuhei Asada, Kalindi Parmar, Xiaosheng Wu, Thomas Witzig, Geoffrey Shapiro, Alan D. D'Andrea. Targeting DNA polymerase theta and ATM leads to synergistic killing of mantle cell lymphoma cells. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6208.

Central nervous system involvement by mantle cell lymphoma

Involvement of the central nervous system (CNS) is a rare complication of mantle cell lymphoma (MCL) with limited treatment options. We report the outcomes of 36 patients with CNS involvement compared to 72 matched control MCL patients without CNS involvement. Four patients (11%) with CNS MCL were diagnosed with CNS involvement at time of MCL diagnosis. Median OS from MCL diagnosis was 50.3 months (95% CI: 22.8-79.6) for the CNS MCL group compared to 97.1 months (95% CI: 82.8-NR; p= <0.001) for the control group. Median OS from CNS involvement was 4.7 months (95% CI: 2.3-6.7). CNS involvement by MCL has dismal outcomes as evident by a short median OS and PFS after CNS involvement. Advanced stage, blastoid variant, elevated LDH, and elevated Ki67 at MCL diagnosis were features more commonly seen in the CNS MCL cohort.

PET-CR as a potential surrogate endpoint in untreated DLBCL: meta-analysis and implications for clinical trial design

This study's focus is the association of end-of-therapy (EOT) PET results with progression-free (PFS) and overall survival (OS) in patients with diffuse large B-cell lymphoma receiving first-line chemoimmunotherapy. We develop a Bayesian hierarchical model for predicting PFS and OS from EOT PET-complete response (PET-CR) using a literature-based meta-analysis of 20 treatment arms and a substudy of 4 treatment arms in 3 clinical trials for which we have patient-level data. The PET-CR rate in our substudy was 72%. The modeled estimates for hazard ratio (PET-CR/non-PET-CR) were 0.13 for PFS (95% CI 0.10, 0.16) and 0.10 for OS (CI 0.07, 0.12). Hazard ratios varied little by patient subtype and were confirmed by the overall meta-analysis. We link these findings to designing future clinical trials and show how our model can be used in adapting the sample size of a trial to accumulating results regarding treatment benefits on PET-CR and a survival endpoint.

Patient Experience in Clinical Trials: Quality of Life, Financial Burden, and Perception of Care in Patients With Multiple Myeloma or Lymphoma Enrolled on Clinical Trials Compared With Standard Care

PURPOSE

Patients' concerns regarding clinical trial (CT) participation include apprehension about side effects, quality of life (QoL), financial burden, and quality of care.

METHODS

We prospectively evaluated the experience of patients with multiple myeloma or lymphoma who were treated on CTs (CT group, n = 35) versus patients treated with standard approaches (non-CT group, n = 88) focusing on QoL, financial burden of care, and patients' perception of quality of care over a 1-year period.

RESULTS

There were no significant differences in any of the patient-reported outcomes in CT versus non-CT groups. We observed an initial decline in overall QoL in the first 3 months across both groups, driven primarily by physical and functional well-being. QoL gradually improved and was above baseline by month 12. Patients reported highest improvement in the functional well-being subdomain. Patients in both groups reported high satisfaction with the quality of care received, and there were no differences in overall satisfaction, communication with team, or access to care. At baseline, 16%-19% of patients reported financial burden, which increased to a peak of 33% in the CT group and to 49% in the non-CT group over the course of 1 year. There was no significant difference in financial burden in the two groups overall. Most of the patients reported getting all the care that was deemed medically necessary in both groups. However, a significant proportion of patients reported having to make other kinds of financial sacrifices because of their cancer (CT group: 33% of patients at baseline and 21%-40% over 1 year; non-CT group: 19% at baseline and 25%-36% over 1 year).

CONCLUSION

Patients treated on CTs reported comparable QoL and quality of care with the non-CT group. A high proportion of patients reported financial burden over time in both groups. Our findings can serve as a guide to educate patients regarding CT participation and highlight the need to address the significant financial burden experienced by patients with cancer.

Durvalumab as monotherapy and in combination therapy in patients with lymphoma or chronic lymphocytic leukemia: The FUSION NHL 001 trial

BACKGROUND

Studies suggest that immune checkpoint inhibitors may represent a promising strategy for boosting immune responses and improving the antitumor activity of standard therapies in patients with relapsed/refractory hematologic malignancies.

AIMS

Phase 1/2 FUSION NHL 001 was designed to determine the safety and efficacy of durvalumab, an anti-programmed death ligand 1 (PD-L1) antibody, combined with standard-of-care therapies for lymphoma or chronic lymphocytic leukemia (CLL).

METHODS AND RESULTS

The primary endpoints were to determine the recommended phase 2 dose of the drugs used in combination with durvalumab (durvalumab was administered at the previously recommended dose of 1500 mg every 4 weeks) and to assess safety and tolerability. Patients were enrolled into one of four arms: durvalumab monotherapy (Arm D) or durvalumab in combination with lenalidomide ± rituximab (Arm A), ibrutinib (Arm B), or rituximab ± bendamustine (Arm C). A total of 106 patients with relapsed/refractory lymphoma were enrolled. All but two patients experienced at least one treatment-emergent adverse event (TEAE); those not experiencing a TEAE were in Arm C (diffuse large B-cell lymphoma [DLBCL]) and Arm D (DLBCL during the durvalumab monotherapy treatment period). No new safety signals were identified, and TEAEs were consistent with the respective safety profiles for each study treatment. Across the study, patients with follicular lymphoma (FL; n = 23) had an overall response rate (ORR) of 59%; ORR among DLBCL patients (n = 37) was 18%. Exploratory biomarker analysis showed that response to durvalumab monotherapy or combination therapy was associated with higher interferon-γ signature scores in patients with FL (p = .02).

CONCLUSION

Durvalumab as monotherapy or in combination is tolerable but requires close monitoring. The high rate of TEAEs during this study may reflect on the difficulty in combining durvalumab with full doses of other agents. Durvalumab alone or in combination appeared to add limited benefit to therapy.

Nivolumab in patients with relapsed or refractory peripheral T-cell lymphoma: modest activity and cases of hyperprogression

Peripheral T-cell lymphomas (PTCL), a heterogeneous group of mature aggressive non-Hodgkin's lymphomas, carry a worse prognosis for most subtypes when compared with their B-cell counterparts. Despite recent approval of newer therapies, the outlook for patients with relapsed/refractory (RR) PTCL remains poor and new treatment strategies are clearly needed. Targeting the profoundly immunosuppressive tumor microenvironment in PTCL is one such approach. To determine whether immune checkpoint blockade targeting program death receptor 1 would be effective in PTCL, we conducted an investigator-initiated phase 2 prospective study of single-agent nivolumab for RR PTCL. We report here results of the pre-specified interim analysis.

METHODS

The primary objective was to assess the overall response rate (ORR). Secondary objectives were to assess safety and tolerability of nivolumab in PTCL and to assess progression-free survival (PFS), duration of response (DOR) and overall survival (OS). Hyperprogressive disease (HPD) was defined as time-to-treatment failure of less than or equal to one month from initiation of therapy.

RESULTS

Twelve patients who received at least one cycle of nivolumab were included in this interim analysis. Half (6/12) of the patients had angioimmunoblastic T-cell lymphoma (AITL), 3/12 had PTCL, not otherwise specified. Most (11/12) were advanced stage, had extranodal disease (97.1%) and had received a prior autologous stem cell transplant (50%). The ORR was 33% (95% CI: 12.3 to 63.7%) with two complete response and two partial response. The median PFS was however short at 2.7 months (95% CI: 1.5 to NE); and the median OS was 6.7 months (95% CI: 3.4 to NE). The median DOR was also short at 3.6 months (95% CI: 1.9 to NE). HPD occurred in four patients, three of whom had AITL. Observed grade 3 and higher adverse events (AEs) were non-hematologic in 5/12 (42%), while hematologic AEs were seen in 3/12 (25%).

CONCLUSIONS

Nivolumab had modest clinical activity in R/R PTCL. Due to a high number of hyperprogression and short DOR, a decision was made to halt the study. These findings likely reflect the distinct biology of PTCL and should be considered when designing future studies using checkpoint inhibitors in these diseases.

TRIAL REGISTRATION NUMBER

NCT03075553.

Ibritumomab Tiuxetan Radioimmunotherapy for Primary Gastrointestinal Follicular Lymphoma

Primary gastrointestinal follicular lymphoma (PGIFL) is characterized by localized involvement of the gastrointestinal (GI) tract. PGIFL usually runs an indolent course. External beam radiation therapy is curative in a substantial proportion of localized follicular lymphomas, but GI toxicities may discourage its use in PGIFL. Ibritumomab tiuxetan radioimmunotherapy (RIT) is a radioimmunoconjugate of anti-CD20 monoclonal antibody linked to chelator tiuxetan and radioisotope. RIT delivers confined high-intensity radiation with short path length specifically targeting lymphoma cells and sparing normal tissue. In this case series report, we included six cases of PGIFL treated with RIT. All patients had low-risk, localized, and nonbulky disease. All patients responded completely and were relapse-free for the duration of follow-up. Hematologic toxicities were seen, but none were serious. RIT is a potentially curative treatment option in PGIFL with a tolerable toxicity profile.

RAS mutations drive proliferative chronic myelomonocytic leukemia via a KMT2A-PLK1 axis

Proliferative chronic myelomonocytic leukemia (pCMML), an aggressive CMML subtype, is associated with dismal outcomes. RAS pathway mutations, mainly NRASG12D, define the pCMML phenotype as demonstrated by our exome sequencing, progenitor colony assays and a Vav-Cre-NrasG12D mouse model. Further, these mutations promote CMML transformation to acute myeloid leukemia. Using a multiomics platform and biochemical and molecular studies we show that in pCMML RAS pathway mutations are associated with a unique gene expression profile enriched in mitotic kinases such as polo-like kinase 1 (PLK1). PLK1 transcript levels are shown to be regulated by an unmutated lysine methyl-transferase (KMT2A) resulting in increased promoter monomethylation of lysine 4 of histone 3. Pharmacologic inhibition of PLK1 in RAS mutant patient-derived xenografts, demonstrates the utility of personalized biomarker-driven therapeutics in pCMML.

Abstract S06-03: Outcomes of COVID-19 in patients with cancer: Results of a prospective observational comparison of routine screening strategy versus testing based on clinical suspicion

Abstract Importance: The benefit of routine screening for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in patients with cancer before cancer-directed therapies is unclear. Herein, we characterize the outcomes of a cohort of cancer patients diagnosed with Coronavirus Disease 2019 (COVID-19) by routine screening in comparison with those diagnosed based on clinical suspicion or exposure history (non-routine screening). Objective: To describe and compare the outcomes of cancer patients diagnosed with COVID-19 on routine screening vs. non-routine screening at a multi-site tertiary cancer center. To identify risk factors for COVID-19-related hospital admission. Design: A multi-site prospective observational study was conducted between March 18 and July 31, 2020. Setting: Three major and 5 satellite campuses of the Mayo Clinic Cancer Center. Participants: Adult patients diagnosed with active cancer within the past five years and confirmed SARS-CoV-2 infection were included. Primary Outcomes and Measures: Clinical and laboratory data were assessed as independent variables. The primary outcome was COVID-19-related hospital admission. Secondary outcomes included intensive care unit (ICU) admissions and all-cause mortality. Results: Between March 18 and July 31, 2020, 5452 patients underwent routine screening in the outpatient setting, 44 (0.81%) were diagnosed with COVID-19. Routine screening detected additional 19 patients from inpatient and pre-procedural settings; 161 patients were diagnosed with COVID-19 based on non-routine screening. The median age of the entire cohort at diagnosis was 54 years, and 95 patients (42.2%) were female. COVID-19 related-hospitalization rate (17.5% vs. 26.7%, p=0.14), ICU admission (1.6% vs. 5.6%, p=0.19), and mortality (4.8% vs. 3.7%, p=0.72) were not significantly different between routine screening and non-routine screening groups. In the multivariable analysis, age ≥ 60 years (odds ratio: 4.4, p=0.023) and an absolute lymphocyte count ≤1.4 × 109/L (odds ratio: 9.2, p=0.002) were independent predictors of COVID-19-related hospital admission. Conclusions and Relevance: The COVID-19 positivity rate was low based on routine screening. Comparing the outcome with the non-routine screening cohort, there was no significant difference. These results led to an important practice change at our cancer center. We currently follow a testing strategy based on symptoms, exposure, risk factors, and clinical judgment.

Citation Format: Zhuoer Xie, Antoine N. Saliba, Jithma Abeykoon, Umair Majeed, Daniel Almquist, Julia Wiedmeier-Nutor, Evandro Bezerra, Xavier Andrade-Gonzalez, Ashley Hickman, Karl Sorenson, Sagar Rakshit, Christopher Wee, Sri Tella, Anuhya Kommalapati, Nadine Abdallah, Joshua Pritchett, Mariza De Andrade, Dipesh Uprety, Andrew Badley, Joleen Hubbard, Naseema Gangat, Carrie A. Thompson, Thomas Witzig, Robert R. McWilliams, Konstantinos Leventakos, Thorvardur R. Halfdanarson. Outcomes of COVID-19 in patients with cancer: Results of a prospective observational comparison of routine screening strategy versus testing based on clinical suspicion [abstract]. In: Proceedings of the AACR Virtual Meeting: COVID-19 and Cancer; 2021 Feb 3-5. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(6_Suppl):Abstract nr S06-03.

Magnesium: The overlooked electrolyte in blood cancers?

Magnesium is an important element that has essential roles in the regulation of cell growth, division, and differentiation. Mounting evidence in the literature suggests an association between hypomagnesemia and all-cause mortality. In addition, epidemiologic studies have demonstrated that a diet poor in magnesium increases the risk of developing cancer, highlighting its importance in the field of hematology and oncology. In solid malignancies, hypomagnesemia at diagnosis portends a worse prognosis. However, little is known about prognosis in patients with hypomagnesemia and blood cancers in general; lymphoma more specifically. Hypomagnesemia has been associated with a higher viral load of the Epstein Barr virus, a virus associated with a multitude of hematologic malignancies. The role of magnesium in the immune system has been further elucidated in studies of patients with a rare primary immunodeficiency known as XMEN disease (X-linked immunodeficiency with Magnesium defect, Epstein-Barr virus (EBV) infection, and Neoplasia disease). These patients have a mutation in the MAGT1 gene, which codes for a magnesium transporter. The mutation leads to impaired T cell activation and an increased risk of developing hematologic malignancies. In this review we discuss the relevance of magnesium as an electrolyte, current measurement techniques, and the known data related to cause and prognosis of blood cancers. The goal is to use these data to stimulate additional high-quality and well powered studies to further investigate the role of magnesium in preventing cancer and improving outcomes of patients with malignancy and concomitant magnesium deficiency.

Abstract CT191: Mechanism of action of the farnesyltransferase inhibitor, tipifarnib, and its clinical applications

Background: CXCL12 is a negative prognostic factor for head & neck (HNSCC) and pancreatic (PDCA) cancers, among others. Its receptor, CXCR4, is a negative prognostic factor in lymphoma/leukemia. CXCR4 signals in part through RAS species, and the expression of CXCL12 and CXCR4 appears to be itself regulated by farnesylated proteins. We provide evidence that targeting the CXCL12/CXCR4 pathway with the farnesyltransferase inhibitor tipifarnib translates to long term clinical benefit.

Methods: Next generation sequencing and analyses of gene expression were conducted in tumor samples from squamous cell carcinoma, lymphoma, and acute myeloid leukemia (AML) patients treated in tipifarnib trials (studies KO-TIP-001, KO-TIP-002, CTEP20), and complemented with analyses of related tumor gene expression databases in TCGA and GEO.

Results: Activating HRAS mutations in HNSCC and KRAS mutations in PDCA were mutually exclusive with CXCL12 expression, consistent with a role for RAS downstream from CXCR4. Contrary to KRAS and NRAS, HRAS is exclusively farnesylated, and treatment with tipifarnib in patients (pts) with advanced HNSCC tumors with a HRAS mutation variant allele frequency (VAF) &gt;20% resulted in 8 partial responses (PR) in 14 pts. Two complete responses (CR), 3 PRs and 4 disease stabilizations (90% clinical benefit) were observed in 10 pts with relapsed/refractory peripheral T cell lymphoma overexpressing CXCL12. Decreases in plasma CXCL12 levels during treatment were observed. Seven CRs were observed in 11 elderly/unfit AML pts overexpressing CXCL12 in bone marrow (NRAS wt or unknown). Ex vivo treatment of bone marrow stromal cell cultures with tipifarnib decreased secretion of CXCL12. Finally, based on the reported relationship between CXCL12 expression and the suppression of pain in PDCA, we conducted a retrospective analysis of a phase 3 study of gemcitabine plus tipifarnib (GT) in advanced PDCA. Notably, absence of abdominal pain at study entry was associated with higher median survival in the GT arm (no pain, pain): 10.2 vs 5.9 months, HR=0.52, p&lt;0.0001, whereas no significant effect was observed in the control arm: 6.1 vs 6.1 months. PDCA with &lt;7% VAF of KRAS mutation (~30% PDCA pts) overexpressed CXCL12.

Conclusions: The mechanism of action of tipifarnib appears to involve targeting the CXCL12/CXCR4 pathway and demonstrates a crucial association with the tumor microenvironment and objective clinical responses.

Citation Format: Antonio Gualberto, Catherine Scholz, Vishnu Mishra, Matthew R. Janes, Linda Kessler, Eric Van Cutsem, Alan L. Ho, Thomas Witzig. Mechanism of action of the farnesyltransferase inhibitor, tipifarnib, and its clinical applications [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT191.

Citron Rho-interacting kinase silencing causes cytokinesis failure and reduces tumor growth in multiple myeloma

Citron Rho-interacting serine/threonine kinase (CIT) is a serine/threonine kinase that acts as a key component of the midbody and is essential for cytokinesis. CIT has been reported to be highly expressed in some tumor tissues and to play a role in cancer proliferation; however, the significance of CIT has not been investigated in multiple myeloma (MM). Here, we identified, by protein microarray and immunohistochemistry, that CIT is 1 of the upregulated proteins in the plasma cells of MM patients compared with healthy controls. Analysis of a gene expression profile data set showed that MM patients with high CIT gene expression had significantly worse overall survival compared with MM patients with low CIT gene expression. CIT silencing in MM cell lines induced cytokinesis failure and resulted in decreased MM cell proliferation in vitro and in vivo. TP53 expression was found to be an independent predictor of CIT dependency, with low-TP53 cell lines exhibiting a strong dependency on CIT. This study provides the rationale for CIT being a potential therapeutic target in MM in future trials.

Ascorbic acid-induced TET activation mitigates adverse hydroxymethylcytosine loss in renal cell carcinoma

Although clear cell renal cell carcinoma (ccRCC) has been shown to result in widespread aberrant cytosine methylation and loss of 5-hydroxymethylcytosine (5hmC), the prognostic impact and therapeutic targeting of this epigenetic aberrancy has not been fully explored. Analysis of 576 primary ccRCC samples demonstrated that loss of 5hmC was strongly associated with aggressive clinicopathologic features and was an independent adverse prognostic factor. Loss of 5hmC also predicted reduced progression-free survival after resection of nonmetastatic disease. The loss of 5hmC in ccRCC was not due to mutational or transcriptional inactivation of ten eleven translocation (TET) enzymes, but to their functional inactivation by l-2-hydroxyglutarate (L2HG), which was overexpressed due to the deletion and underexpression of L2HG dehydrogenase (L2HGDH). Ascorbic acid (AA) reduced methylation and restored genome-wide 5hmC levels via TET activation. Fluorescence quenching of the recombinant TET-2 protein was unaffected by L2HG in the presence of AA. Pharmacologic AA treatment led to reduced growth of ccRCC in vitro and reduced tumor growth in vivo, with increased intratumoral 5hmC. These data demonstrate that reduced 5hmC is associated with reduced survival in ccRCC and provide a preclinical rationale for exploring the therapeutic potential of high-dose AA in ccRCC.

Ascorbic Acid in Cancer Treatment: Let the Phoenix Fly

Vitamin C (ascorbic acid, ascorbate), despite controversy, has re-emerged as a promising anti-cancer agent. Recent knowledge of intravenous ascorbate pharmacokinetics and discovery of unexpected mechanisms of ascorbate action have spawned many investigations. Two mechanisms of anti-cancer activity with ascorbate have gained prominence: hydrogen peroxide-induced oxidative stress and DNA demethylation mediated by ten-eleven translocation enzyme activation. Here, we highlight salient aspects of the evolution of ascorbate in cancer treatment, provide insights into the pharmacokinetics of ascorbate, describe mechanisms of its anti-cancer activity in relation to the pharmacokinetics, outline promising preclinical and clinical evidence, and recommend future directions.

A First-in-Human Phase I Study of OPB-111077, a Small-Molecule STAT3 and Oxidative Phosphorylation Inhibitor, in Patients with Advanced Cancers

Lessons Learned.

OPB‐111077 is a novel inhibitor of STAT3 and mitochondrial oxidative phosphorylation that exhibited promising anticancer activity in preclinical models.

In this first‐in‐human phase I study of OPB‐111077 in unselected advanced cancers, treatment‐emergent adverse events, most frequently nausea, fatigue, and vomiting, were generally mild to moderate in intensity and could be medically managed.

Overall, only modest clinical activity was observed after OPB‐111077 given as monotherapy. Notable antitumor activity was seen in a subject with diffuse large B‐cell lymphoma.

Background.

OPB‐111077 is a novel inhibitor of STAT3 and mitochondrial oxidative phosphorylation with promising anticancer activity in preclinical models.

Methods.

Open‐label, phase I trial of OPB‐111077 in advanced cancers with no available therapy of documented benefit. Initial dose escalation in unselected subjects was followed by dose expansion. Patients received oral OPB‐111077 daily in 28‐day cycles until loss of clinical benefit.

Results.

Eighteen subjects enrolled in dose escalation, and 127 in dose expansion. Dose‐limiting toxicities were observed at 300 mg and 400 mg QD; maximum tolerated dose was defined as 250 mg QD. Frequently reported treatment‐emergent adverse events (TEAEs) included nausea, fatigue, and vomiting. TEAEs were generally mild to moderate and could be medically managed. OPB‐111077 reached micromolar drug concentrations, had an elimination half‐life of approximately 1 day, and reached steady‐state by day 8. A durable partial response was observed in one subject with diffuse large B‐cell lymphoma. Seven subjects with diverse tumor types had stable disease or minor responses for at least eight treatment cycles (224 days).

Conclusion.

OPB‐111077 is generally well tolerated, and its pharmacokinetic profile is sufficient for further clinical development. Notable clinical activity was observed in a subject with diffuse large B‐cell lymphoma. Overall, modest efficacy was observed against unselected tumors.

Low hypoxia inducible factor-1α (HIF-1α) expression in testicular germ cell tumors - a major reason for enhanced chemosensitivity?

The molecular basis for enhanced chemosensitivity of testicular germ cell tumors (GCT) has been an area of great interest, as it could potentially give us therapeutic leads in other resistant malignancies. Thus far, however, the increased sensitivity of GCT has been variously attributed to multiple factors — an inability to detoxify cisplatin, a lack of export pumps, an inability to repair the DNA damage, an intact apoptotic cascade and lack of p53 mutation; but a unifying underlying etiology leading to the aforementioned processes and having a translational implication has so far been elusive. Herein, we offer evidence to support a potential significant role for the previously demonstrated low hypoxia inducible factor-1α (HIF-1α) expression in mediating the general exquisite chemosensitivity of testicular GCT, through the aforementioned processes. This molecular mechanism based hypothesis could have a significant translational implication in platinum refractory GCT as well as other platinum resistant malignancies.

Coinhibition of the deubiquitinating enzymes, USP14 and UCHL5, with VLX1570 is lethal to ibrutinib- or bortezomib-resistant Waldenstrom macroglobulinemia tumor cells

The survival of Waldenstrom macroglobulinemia (WM) tumor cells hinges on aberrant B-cell receptor (BCR) and MYD88 signaling. WM cells upregulate the proteasome function to sustain the BCR-driven growth while maintaining homeostasis. Clinically, two treatment strategies are used to disrupt these complementary yet mutually exclusive WM survival pathways via ibrutinib (targets BTK/MYD88 node) and bortezomib (targets 20 S proteasome). Despite the success of both agents, WM patients eventually become refractory to treatment, highlighting the adaptive plasticity of WM cells and underscoring the need for development of new therapeutics. Here we provide a comprehensive preclinical report on the anti-WM activity of VLX1570, a novel small-molecule inhibitor of the deubiquitinating enzymes (DUBs), ubiquitin-specific protease 14 (USP14) and ubiquitin carboxyl-terminal hydrolase isozyme L5 (UCHL5). Both DUBs reside in the 19 S proteasome cap and their inhibition by VLX1570 results in rapid and tumor-specific apoptosis in bortezomib- or ibrutinib-resistant WM cells. Notably, treatment of WM cells with VLX1570 downregulated BCR-associated elements BTK, MYD88, NFATC, NF-κB and CXCR4, the latter whose dysregulated function is linked to ibrutinib resistance. VLX1570 administered to WM-xenografted mice resulted in decreased tumor burden and prolonged survival (P=0.0008) compared with vehicle-treated mice. Overall, our report demonstrates significant value in targeting USP14/UCHL5 with VLX1570 in drug-resistant WM and carries a high potential for clinical translation.

Translation initiation complex eIF4F is a therapeutic target for dual mTOR kinase inhibitors in non-Hodgkin lymphoma

Deregulated mRNA translation has been implicated in disease development and in part is controlled by a eukaryotic initiation complex eIF4F (composed of eIF4E, eIF4G and eIF4A). We demonstrate here that the cap bound fraction from lymphoma cells was enriched with eIF4G and eIF4E indicating that lymphoma cells exist in an activated translational state. Moreover, 77% (110/142) of diffuse large B cell lymphoma tumors expressed eIF4E and this was associated with an inferior event free survival. Over-expression of wild-type eIF4E (eIF4E(WT)) but not cap-mutant eIF4E (eIF4E(cap mutant)) increased the activation of the eIF4F complex. Treatment with the active-site dual mTOR inhibitor CC214-1 reduced the level of the eIF4F complex by decreasing the cap bound fraction of eIF4G and increasing the levels of 4E-BP1. CC214-1 inhibited both the cap dependent and global protein translation. CC214-1 inhibited c-Myc, and cyclin D3 translation by decreasing polysomal fractions from lymphoma cells. Inhibition of eIF4E with shRNA further decreased the CC214-1 induced inhibition of the eIF4F complex, c-Myc, cyclin D3 translation, and colony formation. These studies demonstrate that the eIF4F complex is deregulated in aggressive lymphoma and that dual mTOR therapy has therapeutic potential in these patients.

Abstract B118: A phase 1, open-label multiple dose escalation trial to determine safety and tolerability of once daily OPB-111077 in subjects with advanced cancer

Background: OPB-111077 is a new chemical entity with anticancer activity in vitro and in human tumor xenograft models. The compound modulates STAT3 phosphorylation but has no marked effect on activity of any of 69 tested human tyrosine or serine/threonine kinases. This P1 study evaluated safety, pharmacokinetics, and antitumor activity of OPB-111077 in subjects with advanced cancers.

Methods: Primary objectives determined safety, tolerability, and maximum tolerated dose (MTD) of OPB-111077 given orally once daily to subjects with advanced cancer. Secondary objectives included pharmacokinetics (PK) and antitumor activity. In the first 2 cycles of dose escalation, Day 1 dose was followed by 2 days off study therapy for PK. The starting dose was 100 mg once daily. Single subject cohorts with dose level doublings were studied until the first ≥ Grade 2 AE that was possibly drug-related. Then a 3+3 design was used. After MTD determination, expansion cohorts were opened for subjects with malignancies possibly susceptible to inhibition by OPB-111077, including breast, cervical, colorectal, gastric, kidney, myeloma, non-small cell lung, non-Hodgkin's lymphoma, ovarian, and prostate cancers, as well as “rare tumors” for which STAT3 inhibition might generate clinical activity.

Results: Overall 145 subjects received OPB-111077. Mean age was 61 years (range 21-88), and 51% of subjects were female. Dose escalation occurred in 18 subjects. Four DLTs were observed: 2 at 400 mg QD (G3 nausea/vomiting), and 2 at 300 mg QD (G3 vertigo and G3 nausea/vomiting). The MTD was 250 mg QD. All subjects recovered from DLTs after drug discontinuation. Adverse events (AEs) that may be attributable to OPB-111077 include nausea (71%), vomiting (46%), fatigue (44%), dizziness/vertigo (26%), and hypothyroidism (19%). Most AEs were CTCAE Grades 1 or 2 and manageable with supportive treatment. OPB-111077 exposures increase dose proportionally and linearly with increasing single and multiple doses up to 250 mg. Median time to peak plasma concentration (tmax) is about 4 hours. Mean maximum plasma concentration (Cmax) is 16 μmol/L and mean trough concentration is 6 μmol/L after multiple doses of 250 mg QD. Terminal half-life is about 23 hours and steady state was reached by about 1 week. The major metabolites in plasma are pharmacologically inactive and unlikely to contribute to efficacy. Administration with a high fat meal did not significantly alter OPB-111077 bioavailability. Expansion cohorts enrolled 127 subjects, including NSCLC (13), breast (13), ovarian (11), kidney (11), colorectal (10), prostate (8), lymphoma (8), gastric (7), cervical (3) cancers, and myeloma (1). Rare tumors with STAT rationale included sarcomas (13), neuroendocrine tumors (7), squamous cell carcinomas (5), other carcinomas (12), and other malignant tumors (5). One RECIST Partial Response occurred in a subject with Diffuse Large B Cell Lymphoma. In addition, 7 subjects with had stable disease for at least 8 treatment cycles, including gastric (2), cholangiocarcinoma, kidney, prostate, K-Ras mutant colon cancer, and esthesioneuroblastoma.

Conclusions: OPB-111077 can be given safely and achieves clinically active drug levels in humans. Single agent clinical activity was observed. Translational work is ongoing to determine factors driving clinical activity

Citation Format: Gregory Cote, Kyriakos Papadopoulos, Amita Patnaik, Drew Rascoe, Lon Smith, Andrea Bullock, Keith Flaherty, Geoffrey Shapiro, Jordan Berlin, Manish Monga, Thomas Habermann, Thomas Witzig, Chester Lin, Lin-Feng Tsai, Agnes Elekes, Naoto Ohi, Kunihiko Tatsumi, Anthony Tolcher. A phase 1, open-label multiple dose escalation trial to determine safety and tolerability of once daily OPB-111077 in subjects with advanced cancer. [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 B118.

Impact of Alemtuzumab Therapy and Route of Administration in T-Prolymphocytic Leukemia: A Single-Center Experience

OBJECTIVE

We conducted a single-center retrospective analysis to determine the impact of the anti-CD52 monoclonal antibody alemtuzumab including route of administration compared to non-alemtuzumab-containing regimens in T-prolymphocytic leukemia (T-PLL).

PATIENTS AND METHODS

The study was a retrospective analysis of a consecutive cohort of adult patients diagnosed with T-PLL at Mayo Clinic Rochester from January 1, 1997, through September 30, 2014.

RESULTS

A total of 41 patients were diagnosed with T-PLL per the World Health Organization 2008 classification. The median age was 66 years, and 23 (56%) were male. After a median follow-up of 18 months (range, 0.4-66.1 months), 32 patients (78%) had died, with a median overall survival of 16.9 months. Approximately half the cohort was treated with alemtuzumab, almost exclusively after 2004. Median survival for patients receiving intravenous alemtuzumab-based therapy was 40.5 versus 10.3 months for all other therapies (P = .0004). A significant survival difference between intravenous versus subcutaneous alemtuzumab administration of 40.5 versus 13.7 months was noted (P = .0014). Only 4 (14%) of 28 patients aged < 70 years underwent hematopoietic stem cell transplantation, with a median survival after transplantation of 4 months.

CONCLUSION

In this large series of T-PLL patients treated at a single tertiary-care center, we confirmed the prior observation of the superiority of intravenous alemtuzumab over other therapies. Hematopoietic stem cell transplantation was feasible in a minority of potentially eligible patients. Early transplant referral should be considered for all eligible patients.

Longer-term follow-up and outcome by tumour cell proliferation rate (Ki-67) in patients with relapsed/refractory mantle cell lymphoma treated with lenalidomide on MCL-001(EMERGE) pivotal trial

Patients with mantle cell lymphoma (MCL) generally respond to first‐line immunochemotherapy, but often show chemoresistance upon subsequent relapses, with poor outcome. Several studies of the immunomodulator, lenalidomide, have demonstrated its activity in MCL including the MCL‐001 study in relapsed/refractory patients who had failed defined prior therapies of anthracyclines or mitoxantrone, cyclophosphamide, rituximab and also bortezomib. We present here the long‐term efficacy follow‐up of the prospective phase II MCL‐001 study (N = 134), including new exploratory analyses with baseline Ki‐67 (MIB1), a biological marker of tumour proliferation. With longer follow‐up, lenalidomide showed a 28% overall response rate [ORR; 8% complete response (CR)/CR unconfirmed (CRu)]. Median duration of response (DOR), progression‐free survival and overall survival were 16·6, 4·0 and 20·9 months, respectively. Myelosuppression continued to be the most common grade 3/4 toxicity. Several studies of MCL patients treated with chemotherapy, rituximab and bortezomib have shown an inverse association between survival and Ki‐67. Ki‐67 data in 81/134 MCL‐001 patients showed similar ORRs in both low (<30% or <50%) versus high (≥30% or ≥50%) Ki‐67–expressing groups, yet lower Ki‐67 levels demonstrated superior CR/CRu, DOR and survival outcomes. Overall, lenalidomide showed durable efficacy with a consistent safety profile in heavily pretreated, relapsed/refractory MCL post‐bortezomib.

Systemic amyloidosis associated with chronic lymphocytic leukemia/small lymphocytic lymphoma

To clarify the presentation and course of patients with chronic lymphocytic leukemia (CLL) and amyloidosis. Mayo databases were interrogated for patients who carried a diagnosis of amyloidosis and CLL evaluated at Mayo Clinic, Rochester from January 1974 to October 2012. Charts were abstracted and data analyzed. Of the 33 patients identified, 20 (61%) were diagnosed with AL and 13 (39%) with non-AL. Only four patients had immunoglobulin light chain amyloidosis (AL) that could be solely attributed to the CLL clone; another six had both a plasma cell clone and a CLL clone that shared the same light chain. Median overall survival was 15.6 months for patients with AL and 58.1 months for patients with non-AL. For patients with AL management involved chemotherapy targeted toward monoclonal plasma cells, lymphocytes or both, and for patients with non-AL no specific amyloid treatment was administered. AL is a rare complication of CLL, but in this elderly population of patients non-AL is nearly as common. Distinguishing between these two groups is essential since patients with non-AL amyloidosis have better outcomes and they do not require cytotoxic chemotherapy to treat their amyloidosis.

Induction of CD70 is essential for TGF-β-mediated inhibition of T cells (P1019)

Although extensively studied, the exact mechanism by which TGF-β mediates T-cell inhibition is not entirely clear. When we examined the effect of TGF-β on the phenotype and function of T cells, we noted that CD70 was significantly up-regulated by TGF-β. This surprising finding led us to explore the underlying mechanism by which TGF-β upregulates CD70 expression on T cells and to define the function of CD70+ cells in B-cell NHL. Interestingly, we observed that TGF-β preferentially induced CD70 expression on effector memory T cells while it predominantly up-regulated Foxp3 on naïve T cells. CD70 induction is Smad3-dependent and involves Stat5 signaling. CD70+ T cells were highly susceptible to TGF-β-mediated apoptosis and that transfection of Jurkat cells with the CD70 gene led to a significantly reduced survival. TGF-β-induced CD70+ T cells had a diminished response to immune stimulation associated with downregulation of co-stimulatory molecules CD27 and CD28. CD70-expressing T cells from biopsy specimens of patients with B-cell NHL failed to produce cytokines and displayed no signal transduction when stimulated. CD70-expressing T cells were highly represented in follicular NHL biopsy specimens and increased numbers of CD70+ cells correlated with an inferior patient outcome. These novel findings not only revealed a biological role for a TGF-β/CD70 axis in mediating immune inhibition, but also may lead to therapeutic approaches in patients with B-cell NHL.

Genomic analysis of marginal zone and lymphoplasmacytic lymphomas identified common and disease-specific abnormalities

Lymphoplasmacytic lymphomas and marginal zone lymphomas of nodal, extra-nodal and splenic types account for 10% of non-Hodgkin lymphomas. They are similar at the cell differentiation level, sometimes making difficult to distinguish them from other indolent non-Hodgkin lymphomas. To better characterize their genetic basis, we performed array-based comparative genomic hybridization in 101 marginal zone lymphomas (46 MALT, 35 splenic and 20 nodal marginal zone lymphomas) and 13 lymphoplasmacytic lymphomas. Overall, 90% exhibited copy-number abnormalities. Lymphoplasmacytic lymphomas demonstrated the most complex karyotype (median=7 copy-number abnormalities), followed by MALT (4), nodal (3.5) and splenic marginal zone lymphomas (3). A comparative analysis exposed a group of copy-number abnormalities shared by several or all the entities with few disease-specific abnormalities. Gain of chromosomes 3, 12 and 18 and loss of 6q23-q24 (TNFAIP3) were identified in all entities. Losses of 13q14.3 (MIRN15A-MIRN16-1) and 17p13.3-p12 (TP53) were found in lymphoplasmacytic and splenic marginal zone lymphomas; loss of 11q21-q22 (ATM) was found in nodal, splenic marginal zone and lymphoplasmacytic lymphomas and loss of 7q32.1-q33 was found in MALT, splenic and lymphoplasmacytic lymphomas. Abnormalities affecting the nuclear factor kappa B pathway were observed in 70% of MALT and lymphoplasmacytic lymphomas and 30% of splenic and nodal marginal zone lymphomas, suggesting distinct roles of this pathway in the pathogenesis/progression of these subtypes. Elucidation of the genetic alterations contributing to the pathogenesis of these lymphomas may guide to design-specific therapeutic approaches.

Abstract 2576: STAT3 tyrosine phosphorylation is frequent in diffuse large B cell lymphoma and is independent of molecular subtype: Implications for biomarker

Diffuse Large B cell lymphoma (DLBCL) is the most common form of non-Hodgkin's lymphoma, and is associated with variable clinical presentation as well as variable response to standard chemotherapy regimens. Most significant advances in the treatment of DLBCL over the last 15 years, has been the addition of rituximab to standard chemotherapy. However, still 40% of patients relapse and succumbing to the disease. To improve clinical outcomes for DLBCL patients, it is urgent to identify novel molecular targets and stratify patients according to the expression of specific biomarkers that predict outcomes for the individual patient. Recently, it has been reported that the Signal transducer and activator of transcription 3 (STAT3) is over expressed in DLBCL human cell lines. However, no study has reported the STAT3 expression in DLBCL patient samples or its molecular subtypes (germinal centre B cell type (GCB) and Non-GCB cell type). The phosphorylation of STAT3 (pSTAT3) at its Tyr-705 residue (pSTAT3Tyr705) leads to its activation, followed by dimerization and translocation to the nucleus. Constitutively active STATs (particularly STAT3 and STAT5) contribute to the malignant phenotype in both human cancer cell lines and primary tumors. We hypothesize that constitutive STAT3 activity might be associated with drug resistance and adverse outcome in DLBCL patients. We determined whether STAT3 is constitutively active in patients with DLBCL, and whether activated STAT3 levels correlate with disease severity. Expression of total (tSTAT3) or tyrosine phosphorylated STAT3 (pSTAT3) was determined by in 40 DLBCL tumors. pSTAT3 was found in 52% (21/40) of cases with variable expression {18% low, (+); 25% moderate, (++); and 10% very high (+++)}. However 80% (32/40) of patients expressed tSTAT3. pSTAT3 was expressed in both germinal centre B cells (GCB) (46%) and Non-GCB (69%) DLBCL cases which were molecular subtyped by the Hans method. Furthermore in-vitro inhibition of STAT3 dephosphorylated STAT3 and caused an inhibitory effect on phospho-STAT3 positive DLBCL cells; there was minimal effect on phospho-STAT3 negative cells. Event free survival was lower in pSTAT3 positive compared to pSTAT3 negative DLBCL patients. In summary, our data provide the first evidence that over-expression of pSTAT3 is common in DLBCL, this expression does not clearly relate only to non-GCB tumors and therefore STAT3 inhibitors should be tested in all DLBCL. Pre-treatment assessment of pSTAT3 tumor status will be important to understand whether this IHC marker can preselect patients for response or lack of response to new JAK/STAT targeted agents such as TG101348 (Sanofi Aventis) and BMS-911543 (Bristol-Myers Squibb). Our findings suggest a potential novel therapeutic approach of targeting the inhibition of STAT3 activity in a majority of DLBCL patients.

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 2576. doi:1538-7445.AM2012-2576

Species D adenoviruses as oncolytics against B-cell cancers

PURPOSE

Oncolytic viruses are self-amplifying anticancer agents that make use of the natural ability of viruses to kill cells. Adenovirus serotype 5 (Ad5) has been extensively tested against solid cancers, but less so against B-cell cancers because these cells do not generally express the coxsackie and adenoviral receptor (CAR). To determine whether other adenoviruses might have better potency, we "mined" the adenovirus virome of 55 serotypes for viruses that could kill B-cell cancers.

EXPERIMENTAL DESIGN

Fifteen adenoviruses selected to represent Ad species B, C, D, E, and F were tested in vitro against cell lines and primary patient B-cell cancers for their ability to infect, replicate in, and kill these cells. Select viruses were also tested against B-cell cancer xenografts in immunodeficient mice.

RESULTS

Species D adenoviruses mediated most robust killing against a range of B-cell cancer cell lines, against primary patient marginal zone lymphoma cells, and against primary patient CD138+ myeloma cells in vitro. When injected into xenografts in vivo, single treatment with select species D viruses Ad26 and Ad45 delayed lymphoma growth.

CONCLUSIONS

Relatively unstudied species D adenoviruses have a unique ability to infect and replicate in B-cell cancers as compared with other adenovirus species. These data suggest these viruses have unique biology in B cells and support translation of novel species D adenoviruses as oncolytics against B-cell cancers.

Efficacy and safety of lenalidomide oral monotherapy in patients with relapsed or refractory diffuse large B-cell lymphoma: Results from an international study (NHL-003)

e19504

Background: Patients with diffuse large-B-cell lymphoma (DLBCL) who are not cured with R-CHOP or high-dose chemotherapy with autologous stem cell rescue have a dismal prognosis. A recent phase II trial (NHL-002) of lenalidomide in patients with relapsed or refractory aggressive non-Hodgkin's lymphoma (NHL) demonstrated a 19% overall response rate (ORR) with a 7-month median duration of response (DR) in the subset of patients with DLBCL. A supporting international phase II trial (NHL-003) of single-agent lenalidomide was initiated for patients with relapsed or refractory aggressive NHL that had received at least one prior treatment and had measurable disease. Herein, we report the data from the DLBCL patients enrolled in this trial. Methods: Patients received 25 mg oral lenalidomide once daily on days 1–21 of every 28-day cycle and continued therapy until disease progression or toxicity. The 1999 IWLRC methodology was used to assess response and progression. Results: One hundred-three DLBCL patients were enrolled and were evaluable for response assessment. The median age was 66 years (21–87) and 70 patients (68%) were male. Median time from diagnosis was 2 years (0.4–18.6), patients had received a median of 3 prior treatment regimens (1–10) and 46 of the patients (45%) had received a prior stem cell transplant (DLBCL-stem cell). Response rates are shown in the Table . Grade 3 or 4 adverse events occurring in more than 5% of patients were neutropenia (34%), thrombocytopenia (18%), asthenia (9%), anemia (8%), leucopenia (7%), back pain (6%) and dyspnea (6%). Conclusions: This international study demonstrates that lenalidomide is active in heavily pre-treated patients with relapsed or refractory DLBCL and has manageable side effects.

[Table: see text]

[Table: see text]

Salvage chemotherapy with rituximab, oxaliplatin, cytosine arabinoside, and dexamethasone (ROAD) in patients with relapsed CD20+ aggressive B-cell lymphoma

8556

Background: In the original PARMA trial it was demonstrated that salvage chemotherapy with DHAP followed by autologous bone marrow transplant resulted in increased overall survival over salvage chemotherapy with DHAP alone in patients with aggressive lymphomas. The current study was designed to assess safety and feasibility of ROAD as a salvage chemotherapy regimen which could be administered as an inpatient or outpatient. Methods: Patients received immunochemotherapy on the following schedule: rituximab 375 mg/m2 weekly × 4, oxaliplatin 130 mg/m2 on day 2, Ara C 2000mg/m2 x 2 doses on day 2 and dexamethasone 40 mg on days 2–5, with OAD repeated at 3 week intervals (up to 6 cycles). Patients were considered for autologous stem cell transplantation after 2 cycles if eligible. Eligible histologies included diffuse large B cell lymphoma, mantle cell lymphoma and transformed lymphoma in first relapse. Results: 50 patients were accrued from Aug 2006 through Jul 2008: 5 patients were deemed ineligible after central pathology review. Baseline characteristics of eligible patients included median age 69 (range 23 - 77), 53% were male, 53% had advanced stage at relapse, LDH was elevated in 58% and all patients had an ECOG PS of 2 or less. Patients received a median of 2 cycles of therapy (range 1–6) with 39/45 receiving treatment in cycle 2, with 12 patients continuing beyond 2 cycles. 31 patients experienced grade III/IV hematologic toxicity and 22 patients had grade III/IV non-hematologic toxicity, primarily febrile neutropenia. One patient developed grade III nephrotoxicity due to disease progression. Twenty patients received their treatments exclusively as outpatients. 26 responses were seen in the 45 eligible patients (58%, 95% CI: 44–74%), with 20 responding patients proceeding to autologous SCT. Conclusions: ROAD is a safe and effective salvage chemotherapy regimen for relapsed aggressive lymphoma, including as a preparatory regimen prior to stem cell transplant. It appears to have similar response rates to R-DHAP in a similar patient population, but without the potential nephrotoxicity (data from prior published study from NCCTG). ROAD can be safely administered as an inpatient or outpatient.

No significant financial relationships to disclose.

MicroRNAs 15a and 16–1 regulates tumor proliferation in multiple myeloma

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Background: MicroRNAs (miRNAs) are non-coding RNAs that act as negative regulators of gene expression. They have been described to play roles in solid tumors and hematologic malignancies. However the role of miRNAs in multiple myeloma (MM) has not been yet fully described. Methods: We performed miRNA-profiling of primary bone marrow-derived CD138+ MM cells, compared to their normal cellular counterparts and validated data by qRT-PCR. In vitro and in vivo functional studies were performed on miRNA-15a- and -16–1-precursors-transfected MM cells. Effect of miRNA-15a and -16–1 on signaling cascades have been evaluated by western blot and immunofluorescence. NF-kB activity has been studied using the Active Motif TransAM kit. In vivo MM cell growth has been evaluated by either using an in vivo imaging model or bioluminescence. Angiogenesis has been studied both in vitro and in vivo using the chorioallantoic membrane model. Results: We identified a MM-specific miRNA signature characterized by down-expression of miRNA-15a, -16–1 and over-expression of miRNA-222/-221/-382/-181a/-181b (P<0.01). Data were confirmed by qRT-PCR on matched samples. Predicted targets for the decreased miRNAs in MM patients included pro-angiogenic cytokines, oncogenes, cell cycle regulators, NFkB activators. Conversely, predicted targets for the increased miRNAs included cell cycle inhibitors, suppressors of cytokine signaling, and pro-apoptotic factors. We demonstrated that miRNA-15a and - 16–1 regulate proliferation and growth of MM cells. Indeed, transfected cells showed decreased DNA synthesis; decreased cyclinD1/cyclinD3/CDC25a/pRb protein expression; phase G1 cell cycle arrest. Moreover, transfected cells showed inhibition of NFkB pathway as shown by reduced p65-/p50-/p52-NFkB activities; downregulation of p-p65/p50/p52 nuclear protein level; upregulation of cttosolic phospho-IkB; and inhibited translocation of p-p65 from the cytolplasm to the nucleus. Similarly, inhibition of MM cell growth was confirmed in vivo; and anti-angiogenic properties of miRNA-15a and -16–1 were demonstrated both in vitro and in vivo. Conclusions: These data indicate that miRNAs play a pivotal role in the biology of MM; providing the basis for the development of new miRNA-based targeted therapies in this disease.

No significant financial relationships to disclose.

Novel therapy with 2-methoxyestradiol (2ME2) for the treatment of relapsed and plateau phase multiple myeloma

8108

Background: 2-methoxyestradiol (2ME2) is a natural endogenous product of estradiol metabolism with anti-angiogenic and anti-neoplastic properties that has demonstrated activity against multiple myeloma cell lines and xenografts in immunocompromised mice. We report results of the first phase II clinical trial of 2ME2 in pts with relapsed and plateau phase myeloma. Methods: This trial was designed with a one-stage design to accrue 60 pts in the setting of relapsed and plateau phase myeloma. 2ME2 was administered orally at a dose of 1000 mg daily. After the first 39 pts were accrued, based on the results of ongoing phase I trials, the dose of 2ME2 was increased to 800 mg twice daily for the remaining patients. Pts who were already on study at that point were also allowed to escalate their dose to 800 mg twice daily. The primary endpoint was overall response rate. Responses were assessed using Eastern Cooperative Oncology Group criteria. Results: Sixty patients were treated at Mayo Clinic and Dana Farber Cancer Institute. Median age was 60 years (range, 28–99). Thirty-one patients had relapsed/refractory myeloma and 29 patients had plateau phase myeloma. Median number of prior therapies was 4 including stem cell transplant (48%), thalidomide (62%), bortezomib (6%) and lenalidomide (3%). Therapy was well tolerated. Adverse events were anemia (35%), fatigue (35%), nausea (25%), diarrhea (20%), hot flashes (20%), headache (17%), muscle cramps (15%), and upper respiratory tract infection (15%). Most toxicities were mild (grade 1–2). Estimated progression-free survival rates for all pts at one, two, and three years are 24%, 16%, and 9% respectively. Three pts with plateau phase disease, have been on study for over 4 years without progression at 50, 60, and 63 months. Response assessment is ongoing; so far, whilst no partial responses have been seen, prolonged stable disease has been observed in 3 pts (5%). Conclusions: 2ME2 is a novel agent that appears to be safe and well tolerated. Although no responses have been seen, prolonged stable disease in some pts is promising. Preliminary pharmacokinetic data indicate that the dose of 2ME2 used in this study may be inadequate, and a new formulation with significantly better bioavailability will be tested soon in this patient population.

No significant financial relationships to disclose.

Differential expression of vascular endothelial growth factors and their receptors in multiple myeloma

BACKGROUND AND OBJECTIVES

Bone marrow angiogenesis is increased in patients with multiple myeloma (MM) and correlates with disease stage.

DESIGN AND METHODS

Previous studies of quantifying vascular endothelial growth factor (VEGF) and VEGF receptors (VEGFR) in plasma cells from patients at different stages of MM found no significant difference in expression between overt MM and earlier pre-malignant stages of the disease namely, monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM).

RESULTS

In this report we used quantitative flow cytometry to study cytoplasmic VEGF (cyVEGF) expression (measured as antibody binding capacity) in plasma cells from patients with MM (n = 22), MGUS/SMM (n = 12), and AL-amyloidosis (AL) (n = 9). CyVEGF expression was higher in MM (169,591) than in MGUS/SMM (144,858), or AL (106,011) although these differences were not statistically significant. Using an indirect VEGFR assay that measures VEGF binding, we found VEGF receptors on plasma cells from all groups of patients, with the lowest expression on plasma cells from normal individuals. We detected VEGF R1, VEGF R2, and VEGF R3 on plasma cells from all groups of patients and found receptor expression predominantly in the subset of CD45-positive plasma cells.

INTERPRETATION AND CONCLUSIONS

This study supports the concept that VEGF is involved in the pathogenesis of MM, and suggests that VEGF may differentially affect a subset of plasma cells.

Elevated serum levels of IL-10 are associated with inferior progression-free survival in patients with Hodgkin's disease treated with radiotherapy

Elevated pretreatment serum interleukin-10 (IL-10) is associated with inferior progression-free survival (PFS) in patients with Hodgkin's disease (HD) treated with ABVD or equivalent regimens. Therefore, we explored the association of serum IL-10 with presenting features and PFS in HD patients treated only by radiotherapy (RT) with curative intent. Eligible patients were previously untreated, had biopsy-proven HD, were older than 16 years, HIV-negative, and had unthawed pretreatment serum. Serum IL-10 levels were measured with ELISA and were considered high if > or = 10 pg/ml. We identified 69 patients with median age of 34 years (range 16 - 74), of who 52% were males, and 3% had B-symptoms. Ann Arbor Stage was I in 35%, II in 58%, and III in 7% of the patients. Histology was lymphocyte predominance in 26%, and classical HD in 74% of the patients. Serum IL-10 was elevated in 35% of the patients. After a median follow-up of 67 months for survivors, the 5-year PFS of patients with high vs. normal serum IL-10 was 50% vs. 81% (all patients, P = 0.006), and 43% vs. 77% for the subset with classical HD (P = 0.008). Multivariate analysis revealed that high serum IL-10 and beta2-microglobulin were independently associated with inferior PFS. Patients with none, 1, or 2 adverse features comprised 57%, 36%, and 7% of the population, and their 5-year PFS was 80%, 63%, and 0%, respectively (P < 0.0001). In conclusion, high serum IL-10 is independently associated with inferior PFS in patients with HD treated with RT.

Yttrium 90–Labeled Ibritumomab Tiuxetan Radioimmunotherapy Produces High Response Rates and Durable Remissions in Patients with Previously Treated B-Cell Lymphoma

We report updated time-to-event variables of a phase III randomized study comparing yttrium 90-labeled ibritumomab with rituximab standard therapy in 143 rituximab-naive patients with relapsed or refractory low-grade, follicular, or transformed CD20+ non-Hodgkin's lymphoma (NHL). Most patients (79%) had follicular lymphoma. Patients were randomized to receive a single intravenous (I.V.) dose of 90Y ibritumomab tiuxetan 0.4 mCi/kg (n = 73) or rituximab 375 mg/m2 I.V. weekly for 4 doses (n = 70). The radioimmunotherapy group was pretreated with 2 rituximab doses (250 mg/m2) to improve biodistribution and one dose of Indium 111-labeled ibritumomab tiuxetan for imaging. The overall response rate was 80% versus 56% (P = 0.002) and complete response (CR)/CR unconfirmed (CRu) rates were 34% for 90Y ibritumomab tiuxetan versus 20% for rituximab. With a median follow-up of 44 months, the data are mature as all ongoing patients in both groups exceeded the median Kaplan-Meier estimated time to progression (TTP), duration of response (DR), and time to next therapy. Although this study was not powered to detect differences in time-to-event variables, the results from this randomized trial demonstrate trends toward longer median TTP (15 vs. 10.2 months; P = 0.07), DR (16.7 vs. 11.2 months; P = 0.44) and time to next therapy (21.1 vs. 13.8 months; P = 0.27) in follicular NHL patients treated with 90Y ibritumomab tiuxetan compared with the rituximab control arm. In patients achieving a CR/CRu, the median TTP was 24.7 months for patients treated with 90Y ibritumomab tiuxetan compared with 13.2 months for rituximab-treated patients (P = 0.41), and ongoing responses of > 5 years have been observed. These results confirm that 90Y ibritumomab tiuxetan produces high response rates and durable remissions in patients with previously treated low-grade, follicular, and transformed NHL.

Follow-Up Results of a Phase II Study of Ibritumomab Tiuxetan Radioimmunotherapy in Patients with Relapsed or Refractory Low-Grade, Follicular, or Transformed B-Cell Non-Hodgkin's Lymphoma and Mild Thrombocytopenia

This report presents updated time-to-event variables from a multicenter phase II trial of reduced-dose 90Y ibritumomab tiuxetan in patients with relapsed or refractory low-grade, follicular, or transformed B-cell non-Hodgkin's lymphoma (NHL) and mild thrombocytopenia (platelet counts of 100 to 149 x 10(9) platelets/L). Patients received a single course of ibritumomab tiuxetan radioimmunotherapy, with 90Y ibritumomab tiuxetan administered at 0.3 mCi/kg (compared to a standard dose of 0.4 mCi/kg). In 30 patients, the overall response rate was 83%, with complete responses (confirmed [CR] and unconfirmed [CRu]) of 47%. Median follow-up time is currently 36.5 months (range: 7.5-54.9+ months). Median duration of response was 11.5 months (range: 1.0-53.9 months), median time to progression was 9.4 months (range: 1.7-54.8+ months), and median time to next lymphoma therapy was 14.6 months (range: 2.3-54.9 months). Median overall survival time has not yet been reached. Long-term responses, defined as time to progression of 12 months or greater, have been seen in 14 of 30 patients (47%) overall, and 12 of 14 CR/CRu patients (86%). Toxicities were primarily hematologic and reversible. No additional long-term adverse events have been observed in the follow-up period, and treatment did not preclude subsequent lymphoma therapies.

Durable responses after ibritumomab tiuxetan radioimmunotherapy for CD20+ B-cell lymphoma: long-term follow-up of a phase 1/2 study

We previously demonstrated that yttrium-90 (Y-90) ibritumomab tiuxetan (Zevalin) radioimmunotherapy (RIT) was safe and effective for relapsed or refractory CD20+, B-cell, non-Hodgkin lymphoma (NHL). We now provide long-term follow-up data in responding patients based on International Workshop Response Criteria. Complete (CR), CR unconfirmed (CRu), and partial response (PR) rates were 29%, 22%, and 22%, respectively (overall response rate 73%, 51% in CR/CRu). Mean time to progression (TTP) and duration of response (DR) in responders were 12.6 months and 11.7 months, respectively. At the maximum tolerated dose (0.4 mCi/kg [14.8 MBq/kg]), TTP and DR in complete responders (CR/CRu) were 28.3 and 27.5 months, respectively. Nine patients (24% of responding patients) had a TTP of more than 3 years. Long-term responders (&gt; 5 years) have been identified. Ibritumomab tiuxetan produces durable responses in patients with indolent and diffuse large B-cell lymphoma. (Blood. 2004;103:4429-4431)

Radioimmunotherapy: a new treatment modality for B-cell non-Hodgkin's lymphoma

The field of radioimmunotherapy for the treatment of non-Hodgkin's lymphoma (NHL) has advanced significantly over the past decade, and several radioimmunoconjugates are being tested in clinical trials. Two of these antibodies target CD20: yttrium-90 (Y-90)-labeled ibritumomab tiuxetan (Zevalin) and tositumomab/iodine-131 (I-131)-labeled tositumomab (Bexxar). Other agents target either CD22 (Y-90 epratuzumab) or human leukocyte antigen (HLA)-DR (I-131 Lym-1), respectively. In February 2002, Y-90-labeled ibritumomab tiuxetan became the first radioimmunoconjugate to be approved by the US Food and Drug Administration (FDA) for the treatment of cancer. Tositumomab/I-131 tositumomab was approved in June 2003. Thus, two radioimmunoconjugates have been approved for the treatment of NHL. Both agents, when administered as a single dose, have produced impressive tumor response rates with an acceptable toxicity profile. The main side effect is reversible myelosuppression. Radioimmunotherapy produces overall response rates of approximately 80% in patients with low-grade lymphomas, and 25% to 30% of patients achieve a complete remission. Lower response rates (approximately 40%) have been reported in patients with large-cell lymphomas. This review discusses the clinical trials of radioimmunotherapeutic agents for NHL that demonstrated their safety and efficacy and outlines the current status of these agents.