Citations

Abstract Introduction A unique biological characteristic of MM plasma cells (PCs) is the substantial production of immunoglobulin proteins. This process requires disulfide bond formations that in turn generate large amounts of H2O2. The Trx-TrxR reductase system exists to combat this oxidative stress; however, cytotoxicity can occur when the cells' antioxidative capacity is overwhelmed. Recently, we demonstrated that IMiDs inhibit peroxidase-mediated decomposition of H2O2, and that lenalidomide sensitivity in MM correlates with the degree of antioxidative capacity (Sebastian et al. 2015 ASH). In this study we sought to better understand this inhibitory process. Methods We used various human MM cell lines with different sensitivity to lenalidomide. Cell viability was assessed by the MTT assay. Antioxidative capacity was measured via the total cellular oxidation of reduced flavin adenine dinucleotide (FADH2) and reduced nicotinamide adenine dinucleotide (NAD(P)H) after H2O2treatment. A CRBN CRISPR/Cas9 KO plasmid was used to generate CRBN knockout cells and lentivirus system was used to over-express CRBN in MM cells. Results We found that IMiDs inhibit TrxR mediated intracellular H₂O₂ decomposition in a CRBN dependent fashion. Unlike lenalidomide, the direct TrxR inhibitor auranofin was very effective in inducing cell death in MM cell lines, in a CRBN independent fashion. By using MM.1R isogeneic cells with and without CRBN, and the CRBN-overexpressing OCIMY-5 cell line (transfected with wt-CRBN) we showed that auranofin treatment caused cytotoxicity irrespective of CRBN level of expression, while lenalidomide was only effective in CRBN expressing cells. Clinically achievable concentrations of auranofin treatment induced cell signals similar to lenalidomide, including degradation of IKZF1, IKZF3. As with lenalidomide, the sensitivity of CRBN expressing cell lines to auranofin correlated with their basal antioxidative capacity (MM.1S cells are sensitive and have with lower anti-oxidative capacity while RPMI-8226 is resistant due to its high anti-oxidative capacity). We also found that targeting Trx (downstream effector of TrxR) with the direct inhibitor PX12 overcame this cellular anti-oxidative capacity and inhibited cell proliferation in both RPMI-8226 and MM.1S in a CRBN independent fashion. Combination of auranofin with bortezomib showed a synergistic effect, but only in cells with lower anti-oxidative capacity. In contrast, PX-12, showed a synergistic effect with bortezomib in all analyzed MM cells lines, irrespective of their anti-oxidative capacity and CRBN expression. Conclusions IMiDs inhibit TrxR-mediated intracellular H2O2decomposition in CRBN expressing MM. While the direct TrxR inhibitor, auranofin, bypassed the CRBN requirement for inducing cytotoxicity in MM, its cytotoxic effect could be overcome by the cells antioxidative capacity. Direct Trx inhibition (such as PX-12) seems like a potent strategy for MM therapy to overcome cellular CRBN requirements and higher anti-oxidative capacity cells. Disclosures Bergsagel: Novartis: Research Funding; Amgen, BMS, Novartis, Incyte: Consultancy. Stewart:celgene: Consultancy. Fonseca:Patent Pending: Patents & Royalties: The use of calcium isotopes as biomarkers for bone metabolisms; Patent Pending: Patents & Royalties: The use of calcium isotopes as biomarkers for bone metabolisms; Janssen: Consultancy; Bayer: Consultancy; Millennium, a Takeda Company: Consultancy; Millennium, a Takeda Company: Consultancy; BMS: Consultancy; Millennium, a Takeda Company: Consultancy; Patent: Patents & Royalties: Prognostication of MM based on genetic categorization of FISH of the disease; Celgene: Consultancy; AMGEN: Consultancy; Patent: Patents & Royalties: Prognostication of MM based on genetic categorization of FISH of the disease; Millennium, a Takeda Company: Consultancy; Novartis: Consultancy; Celgene: Consultancy; Patent: Patents & Royalties: Prognostication of MM based on genetic categorization of FISH of the disease; Janssen: Consultancy; Patent: Patents & Royalties: Prognostication of MM based on genetic categorization of FISH of the disease; Bayer: Consultancy; AMGEN: Consultancy; Patent Pending: Patents & Royalties: The use of calcium isotopes as biomarkers for bone metabolisms; Novartis: Consultancy; AMGEN: Consultancy; Sanofi: Consultancy; AMGEN: Consultancy; Sanofi: Consultancy; BMS: Consultancy; Patent Pending: Patents & Royalties: The use of calcium isotopes as biomarkers for bone metabolisms.

Abstract Chemo-refractory acute myeloid leukemia (AML) is associated with poor prognosis and treatment options are extremely limited. Most of these patients are ineligible for allogeneic stem cell transplantation. Chemo-refractory AML is thought to arise due to selection pressure of resistant clones from prior use of chemotherapy or in some cases pre-exist due to properties of the leukemic stem cells (LSC). CLEC12A (also known as CLL1) has previously been described as being selectively over expressed in LSCs. Successful modalities to target CLEC12A and eradicate the LSC would overcome chemo-refractoriness in AML and would represent a vertical advance in the field. In this study, we confirm that CLEC12A is heterogenously expressed on AML blasts and over-expressed on AML LSC. We also show that CLEC12A is overexpressed on bone marrows from patients with AML that fail to achieve a complete remission after induction chemotherapy, suggesting that it could be a marker for residual disease that is refractory to chemotherapy. We then separated AML blasts into CLEC12A positive or negative cells by magnetic sorting. CLEC12A positive blasts selected from AML patients were more resistant to chemotherapy compared to CLEC12A negative blasts (20% killing of CLEC12A positive AML cells versus 43% of CLEC12A negative AML cells when cultured with cytarabine 10 µg/ml, P=0.01). This finding was confirmed by using the AML MOLM14 cell line engineered to overexpress CLEC12A. CLEC12Ahigh MOLM14 cells were more resistant to chemotherapy compared to wild type MOLM14 cells (P=0.003). We then evaluated CLEC12A resistance to chemotherapy in a patient derived AML xenograft model. We found a relative increase in CLEC12A positive cells post Ara-C induction chemotherapy in AML xenograft models (Figure 1). The observation that CLEC12A positive cells are more resistant to chemotherapy provided a solid rationale to target CLEC12A with chimeric antigen receptor T (CART) cells. We therefore developed a second generation CLEC12A directed CAR construct using CD3z and 41BB costimulatory domains and generated CLEC12A CART cells by lentiviral transduction with this construct. Upon incubation with primary AML samples or AML cell lines, CLEC12A CART cells resulted in modest effector functions, due to the heterogeneity of CLEC12A expression on AML blasts. However when CLEC12A overexpressed MOLM14 cell line or CLEC12Apos selected leukemic cells were used as targets, CLEC12A-CART cells resulted in potent cytotoxicity, proliferation and cytokine production, indicating that CLEC12A-CART cells are more specific for LSC. To test the in vivo anti-leukemic activity of CLEC12A CARTs, we used primary human AML blasts xenografted into NSG-S mice (NOD-SCID-γc-/-, additionally transgenic for human stem cell factor, IL3 and GM-CSF). Treatment with CLEC12A CART (single dose, 1x105 total T cells via tail vein injection) resulted in modest activity against AML when employed as monotherapy. To investigate the potential role of CLEC12A CART cells in eradication of MRD and LSC, mice were treated first with chemotherapy (cytarabine 60 mg/kg intraperitoneal injection daily for 5 days) followed by a single dose (1x105 total T cells via tail vein injection) of either CLEC12A CARTs or control untransduced T cells (UTD). Treatment with CLEC12A CART cells resulted in eradication of leukemia and prolonged survival in these mice (overall survival at 200 days of 100% after CLEC12A CARTs compared to 20% after UTD, p=0.01, Figure 2). In conclusion, our preclinical studies reveal that CLEC12A positive cells in leukemia are resistant to chemotherapy and can be successfully targeted with CART cells. CLEC12A CART cells can potentially be employed as a consolidation regimen after induction chemotherapy to eradicate LSC and MRD in AML. Disclosures Kenderian: Novartis: Patents & Royalties, Research Funding. Ruella:novartis: Patents & Royalties: Novartis, Research Funding. Singh:Novartis: Employment. Richardson:Novartis: Employment, Patents & Royalties, Research Funding. June:Tmunity: Equity Ownership, Other: Founder, stockholder ; Immune Design: Consultancy, Equity Ownership; Novartis: Honoraria, Patents & Royalties: Immunology, Research Funding; University of Pennsylvania: Patents & Royalties; Celldex: Consultancy, Equity Ownership; Johnson & Johnson: Research Funding; Pfizer: Honoraria. Gill:Novartis: Patents & Royalties, Research Funding.

Abstract Background: A diagnosis of cancer leads to significant information requirements to facilitate health care decision making, understand management options, and health care system navigation. Many patients demonstrate a knowledge deficit that can lead to decreased quality of life and poor health care compliance. This study sought to evaluate the impact of a patient centered cancer symposium on knowledge level, symptom burden, and desired information in a broad population of cancer patients. Methods: Surveys were distributed to attendees of the Mayo Clinic "Living with and Surviving Cancer" patient symposium in January 2015. A follow up survey was sent to participants 3 months after the symposium. Surveys included demographic data, questionnaire evaluating disease comprehension, symptom burden, desired information and quality of life. Results: Demographics: 113 patients completed the pre-intervention survey. Average age of participants was 64.7 years. Disease types represented included hematologic malignancies (N=50), specifically multiple myeloma (N=24), lymphoma (N=17), leukemia (N=6), MPN/MDS (n=3), as well as solid tumor malignancies (N=77). Highest knowledge topics were disease (80%), screening tests (74%), and monitoring tools (72%). Lowest knowledge topics were financial management (13%), legal issues (13%), and pain management (35%). Pre and Post Analysis: Of the 113 initial participants, 79 patients completed the pre- and post-symposium surveys. In the post-symposium setting significant improvement was noted in understanding of disease (pre 80% vs post 92%), treatment options (pre 60% vs post 76%), nutrition (pre 68% vs post 84%) and legal issues (pre 15% vs post 32%). Non-significant knowledge improvement was noted in areas of risk factors and symptoms, screening/monitoring tools, disease side effects, managing stress/fatigue, end of life decision making and health care navigation. Most patients desired increased understanding regarding disease, screening tests, nutrition, and stress and fatigue management. The level of patient reported desire for information of these topics decreased in the post-symposium setting, statistically significant decrease noted in 4 of 5 topics assessed. In hematology patients who completed pre and post surveys (N=36), a higher level of baseline knowledge was reported regarding disease understanding (89%), tools monitoring response (83%) and recurrence (75%), symptoms (83%), relapse symptoms (64%) and treatment options (72%). In this group the decrease in desire for information was less prominent in the post-symposium setting. Discussion: This data demonstrates improved patient reported understanding on a variety of topics with durable response at 3 months. A majority of patients reported adequate baseline knowledge of many topics prior to the symposium but also a desire of increased cancer specific information. Knowledge deficit in cancer care includes disease specific topics, social stressors and health care navigation. The percentage of participants reporting a high desire for more information remained high but did decrease, suggesting decreased knowledge deficit in the post-symposium setting. Patient education should strive to be accessible, all-inclusive and reactive to patient needs. Table 1.Reported "quite a bit" or "very much" understanding and desired information regarding cancer carePrePostP-valueN=79(%)N=79(%)I understand…How to manage financial considerations of my disease/treatment39(51)41(53)0.85How to manage my pain24(34)23(32)0.81Risk factors that can lead to my disease37 (49)42 (56)0.56How to navigate the health care system43(55)47(60)0.56How to manage fatigue38(50)43(56)0.54Process of making end of life decisions33(47)41(53)0.52Screening tests60 (76)63 (81)0.5Symptoms associated with relapse35(45)42(54)0.27Disease symptoms54(70)60(76)0.2Tools monitoring recurrence49(62)56 (72)0.19Tools monitoring response56(71)63(81)0.15How to manage stress46(60)56(71)0.12Legal issues of my disease11(15)24(32)<0.05Treatment options47(60)60(76)<0.05What to eat49(68)66(84)<0.05My disease62(80)71(92)<0.05I desire increased understanding…Of my disease59(77)53(70)0.4Of managing stress50(65)35(51)<0.05Regarding nutrition64(84)54(70)<0.05Of the screening tests62(79)43(57)<0.05How to manage fatigue54(72)42(54)<0.05 Disclosures Tibes: TetraLogic Pharmaceuticals: Research Funding. Mesa:Novartis. Research- incyte, Gilead, cti, Genentech, promedior, NS Pharma: Consultancy.

Abstract Abstract 873 Introduction: Clonal chromosomal anomalies have been well-characterized in the blood cells of patients with Chronic Lymphocytic Leukemia (CLL) and other hematological malignancies. However, the frequencies and types of chromosomal anomalies found in “normal” people (i.e. no history of hematological cancer) are much less well known. Here we compare chromosomal anomalies in untreated CLL patients with those found in a large sample of people (n>50,000) recruited for genome-wide association studies in the Gene Environment Association Studies (GENEVA) consortium. This comparison provides information about the extent to which people without a prior history of hematological cancer have chromosomal anomalies that are characteristic of CLL. Methods and Results: The anomaly detection method focused on acquired, rather than inherited, chromosomal anomalies identified in whole blood samples. The method and results for the GENEVA subjects were published recently (Laurie et al. 2012, Nat. Gen. 44:642–650). The same method was applied to pre-treatment samples from 220 CLL patients from US Intergroup Trial E2997 of the Eastern Cooperative Oncology Group (ECOG). Acquired anomalies were detected as mosaic mixtures of normal disomic cells along with cells containing autosomal anomalies consisting of large (generally > 1 Mb) deletions, duplications and/or acquired uniparental disomy (UPD). Detection requires a large fraction of cells with the same abnormal karyotype (>5–10%), which is presumably of clonal origin. The subjects (of all ages) came from 12 different GENEVA studies, which addressed a variety of health conditions not directly related to hematological cancer (e.g. addiction and glaucoma). DNA was extracted mainly from blood samples (or, in 8% of subjects, from buccal/saliva samples) and genotyped on Illumina SNP mircroarrays. Clonal mosaic anomalies were detected from change points in intensity and genotype data (B Allele Frequency and Log R Ratio). We found 514 anomalies in 404 GENEVA subjects out of 50,222 examined (0.8% of subjects), although the prevalence increased with age. Clinical data from about 75% of subjects with a clonal chromosomal abnormality revealed that only a small fraction (2.8%, 95% CI=1.0 – 4.7%) had a record of prior hematological cancer. In the ECOG study, blood samples from 220 CLL patients enrolled in protocol E2997 were genotyped on the Illumina HumanOmni1-Quad_v1 array and clonal mosaic chromosome anomalies were detected using the GENEVA method. Chromosomal anomalies typical of CLL also were identified using interphase FISH (i.e. 6q23.3-, 11q22-, 12q15+, 13q14-, 17p13-) as previously reported (Grever, JCO 25:799-804). We found 489 anomalies in 148 patients of the 220 examined (67% of patients). The anomalies detected by FISH and SNP microarray were highly concordant (>98%). Although, the most common recurrent anomalies occurred on chromosomes 6, 11, 12, 13 and 17 in regions that span the FISH probes (except for chromosome 6), a majority of the anomalies detected by SNP data (74% of 489) were not detected by the CLL FISH panel. The frequency of large chromosomal anomalies was much higher in CLL patients than in GENEVA (67% versus 0.8% of subjects) and the overall composition of anomaly types found was also different. The fraction of anomalies consisting of acquired UPD was substantially higher in GENEVA subjects than in ECOG (34.0% versus 10.6%), while deletions were less common in GENEVA (50.1% versus 72.4%) and duplications were similar (15.6% versus 17.0%) (Chi-squared test p-value=3 × 10−18). We compared the most commonly deleted regions (CDR) on each chromosome across studies. In the ECOG CLL patients, four chromosomes each had 10 or more overlapping deletions in their top CDR (6, 11, 13 and 17), which span the FISH probes (except for chromosome 6). The GENEVA subjects also had CDR on chromosomes 11, 13 and 17, which overlap those in ECOG. In addition, GENEVA had CDR spanning genes or regions implicated in myeloid malignancies, including DNMT3a on 2p, TET2 on 4q, PRAME on 22q, and a region on 20q13. Conclusions: These genotyping results of >50,000 subjects suggest clonal chromosomal anomalies may represent precursor states, or perhaps undiagnosed or unrecorded cases, of a variety of hematological malignancies. Further studies to validate these findings and explore the natural history of these genetic defects in individuals without hematologic malignancy are warranted. Disclosures: Shanafelt: Genentech: Research Funding; Glaxo-Smith-Kline: Research Funding; Cephalon: Research Funding; Hospira: Research Funding; Celgene: Research Funding; Polyphenon E International: Research Funding.

Abstract Abstract 4055 Introduction: Approximately 15% of patients (pts) with multiple myeloma (MM) exhibit a t(4;14) translocation that results in constitutive activation of the receptor tyrosine kinase (RTK) fibroblast growth factor receptor 3 (FGFR3) in the absence of ligand. This translocation has been strongly linked with a poor prognosis and short survival compared with pts without this translocation. Dovitinib (TKI258) is an RTK inhibitor that has demonstrated in vitro inhibitory activity against FGFR (including FGFR3), vascular endothelial growth factor receptor (VEGFR), and platelet-derived growth factor receptor (PDGFR), with IC50values of approximately 10 nM. Tumor growth inhibition was observed in xenograft tumor models of MM treated with dovitinib. This study was designed to evaluate the efficacy and safety of dovitinib in pts with relapsed or refractory MM that is either t(4;14) positive or negative. Patients and Methods: Adult pts who had received at least 2 prior antimyeloma regimens and who had relapsed or were refractory to their last treatment regimen were enrolled in this multicenter, open-label, 2-stage, phase 2 trial. Pts were evaluated for t(4;14) status at the baseline visit and classified according to the result into either a t(4;14)-positive or a t(4;14)-negative group. Dovitinib was administered at a dose of 500 mg/day on a 5-days-on/2-days-off schedule. Response was characterized as per the International Myeloma Working Group (IMWG) criteria. The primary endpoint was extended overall response rate as defined by the rate of pts with best overall response of complete response, very good partial response, partial response, or minor response. Secondary endpoints included safety, overall response rate, progression-free survival, and pharmacokinetics. After disease progression, pts had the option to continue treatment with the addition of low-dose dexamethasone (40 mg every 7 days) with M-protein levels at the time of progression considered as the new baseline. Results: A total of 43 pts were enrolled in this study; 26 pts were t(4;14) negative, 13 were t(4;14) positive, and 4 pts had unknown/indeterminate t(4;14) status. Median age was 63 years. Most pts (86%; n = 37) had received ≥ 3 prior lines of therapy. No objective responses were observed in either group of pts. Due to the apparent lack of efficacy, the study did not proceed to stage 2. The following observations are based on the preliminary data. In the t(4;14)-negative group, median duration of exposure to the study drug was 4.0 weeks, and 9 of the 26 pts (35%) had stable disease, 13 (50.0%) had progressive disease, and 4 (15%) were not evaluable. Due to slow enrollment and lack of efficacy among the earlier enrolled t(4;14)-positive pts, enrollment for the t(4;14)-positive group was closed prematurely. Among the 13 enrolled t(4;14)-positive pts, median duration of exposure to the study drug was 8.7 weeks. Best responses were stable disease for 8 pts (62%), disease progression for 3 pts (23%), and unknown for 2 pts (15%). Among both groups, the most common adverse events of any grade, regardless of study drug, were nausea (67%), diarrhea (58%), vomiting (51%), fatigue (47%), thrombocytopenia (33%), and anemia (28%). Most of the nonhematologic events were mild. The most common grade 3/4 adverse events were thrombocytopenia (26%) and anemia (23%). The principal reasons for discontinuation of dovitinib monotherapy were disease progression (72%) and adverse events (19%). Six pts continued on the dovitinib plus dexamethasone regimen; 1 pt is ongoing, and 5 pts discontinued due to disease progression (n = 4) and adverse events (n = 1). Conclusion: Dovitinib was found to have no or minimal single-agent activity in relapsed/refractory myeloma irrespective of t(4;14) status. Although the patient numbers are small, the rate of patients with stable disease during study treatment who may have had a clinical benefit was higher in the t(4;14)-positive group, suggesting that this subgroup may be a candidate to explore combination treatment of dovitinib with other agents, such as proteasome inhibitors. Gastrointestinal toxicity, while mostly mild, remains a challenge, and timely monitoring and supportive care during dovitinib treatment may alleviate these symptoms. Dovitinib may be a promising agent for combination therapies to improve prognosis of patients with t(4;14)-positive MM. Disclosures: Scheid: Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Novartis: Consultancy, Honoraria. Reece:Millennium Pharmaceuticals: Research Funding; Otsuka: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Bristol Myers Squibb: Honoraria, Research Funding; Merck: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding. Spencer:Celgene: Honoraria; Janssen: Honoraria, Speakers Bureau; Novartis: Honoraria. Callander:Millennium Pharmaceuticals: Research Funding. Sonneveld:Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Millennium Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Onyx: Honoraria, Research Funding. Kalimi:Novartis Pharmaceuticals: Employment. Cai:Novartis: Employment. Shi:Novartis: Employment, Equity Ownership. Scott:Novartis: Employment. Stewart:Millennium Pharmaceuticals: Consultancy, Honoraria, Research Funding; Onyx: Consultancy; Celgene: Consultancy.

Abstract Objective The main purpose of this article is to determine if vestibular schwannoma consistency as determined by tissue intensity on T2-weighted magnetic resonance imagings (MRIs) is predictive of intraoperative experience and postoperative clinical outcomes. Study Design Retrospective chart review. Setting Tertiary referral center. Patients Seventy-seven patients diagnosed with vestibular schwannomas who were treated with microsurgical resection. Intervention Diagnostic. Main Outcome Measures Intraoperative measures include totality of resection, surgical time and cranial nerve VII stimulation and postoperative measures include House–Brackmann grade and perioperative complications. Results Tumor consistency determined via tissue intensity on MRI was only found to correlate with surgical time, with a softer tumor being associated with a longer surgical time (p < 0.0001). However, this was primarily driven by tumor volume with larger tumors being associated with longer surgical time based on multivariate analysis. None of the other intraoperative or postoperative measures considered were found to correlate with tumor consistency. Conclusions Tumor consistency determined by MRI is not predictive of intraoperative experience or postoperative outcomes in vestibular schwannomas. Tumor volume is the strongest driver of these outcome measures as opposed to tumor consistency.