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Abstract Background: Proteasome inhibition with carfilzomib (CFZ) has shown to be effective therapy in relapsed refractory multiple myeloma (MM).1 Cardiac toxicity induced by CFZ has been reported in a small subset of patients treated in phase 3 clinical trials, including congestive heart failure (CHF) in approximately 2-5% of patients. The natural history or reversibility of cardiac dysfunction with CFZ has not been fully reported. The myocardium constantly contracts in adults and thus, adequate protein metabolism may be essential; and hence, effective proteasome degradation may pose a risk for contractility. Methods and results: We identified 12 patients, who received CFZ at Mayo Clinic in Arizona, and had a drop in ejection fraction (EF) attributable to the use of CFZ. Medical records were reviewed for baseline cardiovascular (CV) risk factors, CV disease reversibility and mortality resulting from CFZ induced cardiac dysfunction. Patients who had a drop in EF attributed to other causes, were not included in this count. The median age at the time of initiation of therapy with CFZ was 62.5 years (range, 55-70 years), median body mass index was 27.65 (range, 21 - 40), with 4 (33%) patients being obese and 6 (50%) in the overweight range. Two (17%) patients had history of coronary artery disease while 9 (75%) had hypertension, and were on medical treatment prior to CFZ initiation. Six (46%) patients had a previous history of CHF. Two of these had symptomatic systolic dysfunction, however at the time of CFZ initiation, EF had improved. The other 4 with prior CHF had sub-normal EFs noted on echocardiograms done prior to initiation of CFZ (median EF of these 4 was 49%). Overall, baseline EF was available for 10 out of these 12 patients and median EF at baseline was 55% (range, 45 - 67%). Other risk factors predisposing to cardiac dysfunction were smoking in 1 patient and history of radiation to the chest in 2 (17%) patients. No patient had received cardiotoxic dose of anthracyclines prior to starting CFZ. Myeloma therapies: All patients had received multiple lines of therapy for MM (median 4, range, 2-7). Ten (83%) patients had previous received bortezomib and 10 (83%) had received autologous stem cell transplant. Cardiac events and CFZ use: Median duration of CFZ therapy received prior to documented systolic dysfunction was 4 months (range, 0.5 - 20 months), with 3 episodes happening with less than one month of total CFZ therapy. Five out of the 12 (42%) patients had previously discontinued CFZ for other reasons when the systolic dysfunction was noted. However they were included since CHF occurred shortly after treatment (median of 2 months, range, 0.5 - 3). The median drop in EF was 22% (range, 9 - 45%). Recovery/ outcomes: Follow-up echocardiograms were available in 8 patients and all of these showed some improvement in EF (table 1). Median improvement in EF noted by the time of last follow up was 16% (range, 7-30%). Median best EF noted after the initial drop was 48% (range, 35 - 67%). Two patients never discontinued CFZ and EF improved spontaneously, to 67% and 64% respectively, after an initial drop. Another patient was rechallenged with CFZ due to progression of MM, 8 months after initial discontinuation, and did not have recurrence of systolic dysfunction. No patients succumbed to CHF. Six (50%) out of these 12 patients had died by the time of last follow-up. Cause of death was progressive MM in 4 (67%) and sepsis secondary to immunosuppression resulting from chemotherapy in 2 (33%). Conclusions: Our data, although with limited number of patients, suggests using caution when treating patients who have underlying cardiac risk factors with CFZ. Nevertheless, the cardiotoxicity was mostly reversible, with the minimal EF after recovery of 35%. In the setting of a life threatening malignancy, the impact and reversibility of cardiotoxicity needs to be understood so as not to prevent the utilization of otherwise effective therapy such as CFZ. Larger studies are needed to confirm these findings. References: 1. Stewart et al. Carfilzomib, Lenalidomide and Dexamethasone for relapsed multiple myeloma. NEJM 2015;372:142-52. Disclosures Mikhael: Celgene: Research Funding; Abbvie: Research Funding; Sanofi: Research Funding; Onyx: Research Funding. Reeder:Novartis, Millennium, BMS and Celgene: Research Funding. Bergsagel:Amgen, BMS, Novartis, Incyte: Consultancy; Novartis: Research Funding. Fonseca:Millennium, a Takeda Company: Consultancy; Sanofi: Consultancy; AMGEN: Consultancy; Patent: Patents & Royalties: Prognostication of MM based on genetic categorization of FISH of the disease; Patent Pending: Patents & Royalties: The use of calcium isotopes as biomarkers for bone metabolisms; Millennium, a Takeda Company: Consultancy; Novartis: Consultancy; AMGEN: Consultancy; Janssen: Consultancy; Janssen: Consultancy; BMS: Consultancy; Millennium, a Takeda Company: Consultancy; Bayer: Consultancy; Millennium, a Takeda Company: Consultancy; Patent: Patents & Royalties: Prognostication of MM based on genetic categorization of FISH of the disease; Celgene: Consultancy; Patent Pending: Patents & Royalties: The use of calcium isotopes as biomarkers for bone metabolisms; AMGEN: Consultancy; Patent: Patents & Royalties: Prognostication of MM based on genetic categorization of FISH of the disease; Patent: Patents & Royalties: Prognostication of MM based on genetic categorization of FISH of the disease; 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; Celgene: Consultancy; BMS: Consultancy; Bayer: Consultancy; Novartis: Consultancy; Sanofi: Consultancy; AMGEN: Consultancy.

Abstract Background Suppression of uninvolved immunoglobulins is a common finding in multiple myeloma and the preservation of uninvolved immunoglobulins at diagnosis is associated with improved progression-free and overall survival. However, little is known about the impact of myeloma treatment on levels of uninvolved immunoglobulins, and the link between changes in uninvolved immunoglobulins during therapy and treatment response, disease progression and survival. Methods We identified patients who received therapy for newly diagnosed multiple myeloma at our institution between 2001 and 2014, and who had data available on absolute lymphocyte count (ALC) and quantitative uninvolved immunoglobulins (Ig) before commencing treatment. The ALC and levels of uninvolved Ig after 4 cycles of therapy were abstracted from the electronic medical record; patients who switched or stopped treatment, or died, before this time point were excluded. To assess change in ALC, the percentage difference in ALC between baseline and 4 cycles was calculated; for uninvolved Ig, the average of the percentage difference between baseline and 4 cycles for each uninvolved Ig (IgA and IgM for IgG myeloma, IgG and IgM for IgA myeloma, IgG and IgA for IgM and IgD myeloma, and IgG, IgM and IgA for light-chain only myeloma) was calculated. Treatment response at 4 cycles was retrospectively assigned according to International Myeloma Working Group criteria. Time to treatment failure (TTF) was defined as time from start of initial therapy to start of next line of therapy or death (if no additional treatment was received). A landmark analysis was used to calculate overall survival (OS) from the date of follow-up after 4 cycles of therapy. The Kruskal-Wallis, Chi-Square, and log rank tests were used to detect differences in medians, proportions, and survival times respectively. Results A total of 421 patients were included in this analysis. The median age was 63 years (range 33-91), 254 patients (60.3%) were male and median follow-up was 6.5 years (95% CI 5.6-7.3); the vast majority of patients had IgG (n=247 [58.7%]), IgA (n=98 [23.3%]) or light-chain only myeloma (n=68 [16.2%]). First line therapy comprised of pulse-dose dexamethasone (DEX, n=92 [21.9%]), lenalidomide-dexamethasone (RD, n=176 [41.8%]), bortezomib-dexamethasone (VD, n=22 [5.2%]), bortezomib-cyclophosphamide-dexamethasone (VCD, n=84 [20.0%]), and bortezomib-lenalidomide-dexamethasone (VRD, n=47 [11.2%]). Across the entire cohort, the median change in ALC and uninvolved Ig after 4 cycles of treatment was -11.0% (range: -92.7 to +718.8) and +9.0% (-77.7 to +1094.4) respectively; treatment with VCD was associated with the greatest median declines in ALC (DEX: -0.1%; RD: -9.9%; VD: -20.8%; VCD: -40.9%; VRD: -15.3%) and uninvolved Ig (DEX: -0.5%; RD: +15.5%; VD: +44.0%; VCD: -14.0%; VRD: +76.0%, both p<0.001). Conversion from suppression to normalization of the primary uninvolved Ig (IgA in IgG myeloma, and IgG in all other myeloma types) after 4 cycles was seen more frequently with the use of RD (13.1%) and VRD (12.8%) compared to DEX (4.7%), VCD (1.3%), or VD (4.8%), χ2=21.8, p=0.040. When considering only patients in whom the primary uninvolved Ig remained suppressed between baseline and 4 cycles, a ≥25% reduction in the primary uninvolved Ig occurred more frequently with the use of DEX (51.5%) and VCD (34.5%) compared to RD (24.8%), VD (23.5%) or VRD (25.7%), χ2=15.1, p=0.005 (Table 1). Although an average reduction in uninvolved Ig between baseline and 4 cycles (ΔIg<0) was independently associated with a lower likelihood of achieving very good partial response (VGPR) of better on multivariate analysis adjusting for age, sex and treatment regimen (OR=0.40 [0.24-0.63], p<0.001), there were no differences in TTF (2.0yrs vs. 2.0yrs, p=0.783) or OS (8.0yrs vs. 8.0yrs, p=0.721) between patients with ΔIg<0 (n=169) and those with ΔIg≥0 (n=222). Conclusions Myeloma treatments produce differential impacts on immune parameters, with VCD causing the greatest reduction in lymphocytes and uninvolved Ig, implying general targeting of plasma cells, in comparison to lenalidomide, which appeared to be more tumor-specific with relative sparing of lymphocytes and uninvolved Ig. While an average decrease in uninvolved Ig was an independent predictor of a lower likelihood of achieving VGPR or better after 4 cycles of therapy, it was not associated with a shorter TTF or poorer OS. Disclosures Kumar: BMS: Consultancy; Glycomimetics: Consultancy; Onyx: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Kesios: Consultancy; Millennium: Consultancy, Research Funding; Noxxon Pharma: Consultancy, Research Funding; Array BioPharma: Consultancy, Research Funding; Skyline: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; AbbVie: Research Funding. Dispenzieri:GSK: Membership on an entity's Board of Directors or advisory committees; Prothena: Membership on an entity's Board of Directors or advisory committees; pfizer: Research Funding; Jannsen: Research Funding; Alnylam: Research Funding; Celgene: Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding. Kapoor:Amgen: Research Funding; Celgene: Research Funding; Takeda: Research Funding. Bergsagel:Amgen, BMS, Novartis, Incyte: Consultancy; Novartis: Research Funding.

Abstract Background: Pomalidomide has demonstrated excellent activity in patients with relapsed, lenalidomide refractory, multiple myeloma (MM). Between November 2007 and March 2012, we enrolled 285 patients with relapsed MM on 5 sequential phase 2 trials; patients received pomalidomide at 2mg or 4 mg daily with weekly dexamethasone (Pom/dex). The approved dose of pomalidomide is 4 mg for 21 of 28 days. We wished to compare efficacy, tolerability and long-term outcomes between cohorts treated with 2 mg or 4mg daily continuously and 4mg daily for 21/28 days. Methods: After excluding two ineligible patients, 283 patients with lenalidomide refractory, relapsed MM from 5 sequential cohorts were analyzed. These patients were divided into 3 groups: Group1 received Pom 2mg for 28/28 day cycle (N= 69), Group 2 received Pom 4 mg for 28/28 day cycle (N= 95) and Group 3 received Pom 4mg for 21/28 day cycle (N= 119). All patients received oral dexamethasone given 40 mg daily on days 1, 8, 15, and 22. Response was assessed by the IMWG Uniform Response criteria. All patients received aspirin 325 mg daily for DVT prophylaxis or full dose anticoagulation. Results: The median age was 63 years (32-85); 35% were female. The median time from diagnosis was 53 months and the median number of prior regimens was 4. 127 (46%) had high-risk molecular markers. Prior therapies (% received) included lenalidomide (100%), thalidomide (46%), bortezomib (78%), autologous stem cell transplant (71%), and allogeneic transplant (4%). The median follow-up is 16.4 months (3.2-64.4). Forty eight percent are alive and 26% remain progression free; 15 patients are continuing to receive treatment. Frequency of AEs by groups are shown in Table 1. The most notable difference is grade 3+ neutropenia seen in 39% of group 1 and 56% and 57% of groups 2 and 3. Confirmed responses of PR or better were seen in 29% (group1), 35% (group2) and 24% (group3). Median duration of response (DOR) was 14.1 months (group1), 14.5 months (group2) and 10.2 months (group3). Median PFS was 5.5 months (group1), 6.9 months (group2) and 4.3 months (group3). Although the dose level cohorts were sequential rather than randomized, we compared OS between the dose levels in an exploratory manner. There was no significant difference in OS between dose levels (p=0.26). Median overall survival (OS) was 16.6 months (group1), 21.9 months (group2) and 16.0 months (group3). Conclusions: Pom/dex is active and well tolerated even in heavily pretreated patients Responses are durable. Response rates and overall toxicity are similar between the 2 mg and 4 mg doses. Neutropenia is more common in those receiving doses of 4mg daily or for 21/28 days compared to those receiving 2 mg daily. Table 1. All Grades Grade 3+ 2mg 28 Day 4mg 28 Day 4mg 21 Day 2mg 28 Day 4mg 28 Day 4mg 21 Day Anemia 68% 58% 74% 14% 15% 27% Lymphopenia 22% 51% 11% 16% 32% 8% Neutropenia 71% 82% 77% 39% 57% 56% Thrombocytopenia 51% 61% 63% 10% 9% 23% Leukopenia 59% 77% 72% 26% 38% 39% Pneumonia 7% 11% 12% 6% 7% 11% Fatigue 51% 65% 60% 9% 5% 8% Neuropathy 28% 32% 28% 0% 3% 0% Elevated Blood Glucose 10% 21% 8% 4% 6% 3% Pneumonitis 3% 2% 3% 3% 1% 1% VTE (Thrombosis) 3% 3% 3% 1% 3% 3% Secondary Malignancy 0% 2% 1% 0% 2% 1% Figure1. Kaplan Meier Overall Survival Curves Figure1. Kaplan Meier Overall Survival Curves Disclosures Lacy: Celgene: Research Funding. Fonseca:Medtronic, Otsuka, Celgene, Genzyme, BMS, Lilly, Onyx, Binding Site, Millennium, AMGEN: Consultancy, patent for the prognostication of MM based on genetic categorization of the disease. He also has sponsored research from Cylene and Onyx Other, Research Funding. Bergsagel:Novartis: Research Funding; Constellation Pharmaceutical: Research Funding; OncoEthix: Research Funding; MundiPharma: Research Funding. Stewart:Novartis: Consultancy; Celgene: Consultancy; Bristol Myers Squibb: Consultancy; Array BioPharma: Consultancy; Sanofi: Consultancy; Takeda Pharmaceuticals International Co.: Research Funding. Reeder:Millennium, Celgene, Novartis: Research Funding. Mikhael:Onyx: Research Funding; Celgene: Research Funding; Sanofi: Research Funding; Novartis: Research Funding.

Abstract Background. Endothelial progenitor cells (EPCs) are circulating precursors with the capacity to differentiate into endothelial lineage cells through a process known as “vasculogenesis” thus contributing to vessel formation. We studied the role of endothelial progenitor cells in multiple myeloma (MM) pathogenesis. Methods. EPC levels were evaluated in peripheral blood (PB) of patients with smoldering MM (SMM), and active myeloma (MM) and in PB of healthy controls, by using flow-cytometry (CD34+VEGFR2+ cells), and by performing endothelial colony forming assays. EPC levels were studied in PB from transgenic Vk*MYC mice harboring either early MM (smoldering-like stage); or late (active MM-like stage); as well as in mice injected intravenously with either murine MM 5TGM1-turboRFP+ cells or human MM1S-GFP+/luc+ cells. Healthy syngeneic mice were used as controls. GFP-bone marrow (BM) transplantation and sub-cutaneous femur implantation were performed in recipient mice to study EPC BM mobilization (GFP+CD34+VEGFR2 cells) and EPC BM recruitment to the implanted femurs during 5TGM1 MM model progression. Transgenic ID1+/-ID3-/- mice (with a defect in EPC mobilization and differentiation ability) were injected with transplantable Vk*MYC cells and followed for survival. Wild type littermates were used as controls. Similar experiments were performed using transgenic ID1+/-ID3-/- mice transplanted with BM of wild type littermates. Therapeutic activity of DC101 anti-murine VEGFR2 Ab was evaluated in the MM1S human orthotopic xenograft model, using both early and late treatment approaches. Results. EPC levels were significantly increased in PB of MM patients, including SMM, compared to healthy controls (P<0.05). PB mononuclear cells (PBMCs) from SMM and aMM patients showed an increase ability to form both EC-CFUs (P<0.01) and ECFCs compared to those from healthy controls (P<0.05). EPC levels were significantly increased in PB of transgenic Vk*MYC mice at both early and advanced stage of MM development compared to healthy syngenic mice. In orthotopic MM models we found that levels of circulating EPCs increase early after i.v. injection of either human MM1S-GFP+/luc+ cells (1.5 and 2 times higher after 1 week and 2 weeks, respectively) or murine 5TGM1-turboRFP+ MM cells (2.5 and 3 times higher after 2 and 3 weeks, respectively) compared to naïve mice. By coupling GFP-BM transplantation and subcutaneous femur implantation, we generated a new model that allows the study of BM derived-cell trafficking from one site to another of the BM. The levels of BM-derived GFP+ EPC increased early after i.v. injection of 5TGM1-turboRFP+ cells (2 times increase after 2 weeks, P<0.01); also, the percentage of both total GFP+ cells (7.92% versus 2.635%, P<0.05) and GFP+ EPCs (0.22% versus 0.068%, P<0.05) increased in the BM of implanted femurs of tumor cell injected mice compared to controls. Survival of ID1+/-ID3-/- mice was significantly increased compared to that of wild type littermates after injection of MM Vk*MYC cells (62 versus 27 days median survival time, P=0.0005); this survival advantage was lost after wild type BM was transplanted in ID1+/-ID3-/- mice (34 versus 35 days median survival time). In human MM1S orthotopic xenograft model, treatment with anti-murine VEGFR2 DC101 Ab was able to inhibit MM progression when treatment was started early during smoldering like stages, but not when it was started after significant tumor burden (50.5, 41.5 and 40 days median survival time in DC101 early, late and untargeted IgG treated mice respectively) Conclusion. These results show that EPC mediated vasculogenesis is an important pathogenic process that occurs during the early/smoldering MM stage. Knockout mouse experiments confirm that EPCs are essential for MM tumor progression. These results indicate that anti-angiogenic agents could be effective as an early therapeutic intervention in SMM patients. Disclosures Ghobrial: Millennium/Takeda: Membership on an entity's Board of Directors or advisory committees; Onyx: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees.

Abstract Background: The current standard of care for eligible newly diagnosed multiple myeloma (MM) patients is induction therapy with novel agents followed by high dose chemotherapy and autologous stem cell transplant (ASCT). The International Myeloma Working Group proposed the Revised International Staging System (R-ISS) based on the presence of adverse chromosomal abnormalities (CA) detected by FISH (t(4;14), t(14;16) or del17p), in combination with ISS and LDH at diagnosis. However, there are a limited number of studies that have validated this risk model in the transplant and novel agents setting. Aims: To determine whether R-ISS is an appropriate risk-model for estimating overall survival (OS) and progression free survival (PFS) for transplant-eligible MM patients. Patients and Methods: We retrospectively studied a cohort of 519 MM patients who received novel drugs in the induction and subsequently underwent ASCT at Mayo Clinic Arizona from 2005 to 2014. In all, 95 patients met the inclusion criteria: comprising complete data at diagnosis (ISS, serum LDH level, and CA by FISH). The primary endpoint was OS from SCT and the secondary end point was PFS from ASCT. R-ISS groups were defined as described by Palumbo et al. J Clin Oncol. 2015; 33(26):2863-2869. Results: There were 50 (52.6%) men and 45 (47.4%) women who underwent ASCT in this period, with a median age at the time of transplant of 66-years-old (range, 36-78). There were 27 patients (28.4%) with high-risk CA: 12 patients (12.6%) with del17p; 11 patients (11.6%) with t(4;14); and 6 (6%) with t(14;16). In addition, 8 patients (8.5%) had high LDH levels and 9 patients (9.5%) presented with renal impairment at diagnosis. The patients were staged at diagnosis according to the three R-ISS groups: 44 patients (46.3%) had stage I, 26 (27.4%) had stage II, and 25 (26.3%) had stage III. CyBorD was the preferred induction regimen which was received by 42 patients (44%). There were 14 patients (15%) who received at least 2 lines of induction. All patients were in at least partial response (PR) at the moment of transplant: 32 in complete response (CR), 32 in very good partial response (VGPR) and the remaining 31 in PR. The response achieved at day +100 after ASCT improved, with 54 patients (57%) in CR, and only 18 patients (19%) in PR. After a median follow-up of 61 months (range, 14-135), median OS from SCT was 108 months (95% CI: 85 - 132 months) and the median PFS was 45.4 months (95% CI: 31.1 - 53.8 months) in the whole series.MM patients with R-ISS III had a significantly shorter median OS compared to patients with R-ISS II or R-ISS I (32.1 months vs. 94.7 months vs. not reached, respectively, P<0.0001) (Figure). No statistically significant differences in baseline characteristics were identified among these groups to explain the differences in OS observed. PFS among these groups was not statistically significant, only showing a trend towards shorter PFS in R-ISS III compared with either R-ISS I or II: median 22.1 months vs. 35.7 months, respectively, (P=0.2). Renal impairment at diagnosis, IgA subtype, ≥ 2 lines of induction treatment, and less than CR achieved at day +100 after ASCT were also associated with significantly inferior OS. Multivariate analysis selected R-ISS as an independent predictor for OS (HR: 2.3, 95% CI: 1.1-4.8; P=0.03), as well as ≥ 2 lines before ASCT. CR at day +100 after ASCT was the most important independent factor for predicting PFS (HR: 0.4; 95% CI: 0.2-0.6; P<0.001). Conclusion: R-ISS assessed at diagnosis was an independent predictor for OS after ASCT in our series, with median OS for the different R-ISS groups comparable to those reported by Palumbo et al. in their subgroup of younger patients. Thus, this study lends further support for the R-ISS as a reliable prognostic tool for estimating OS in transplant-eligible MM patients. In addition, new treatment approaches are needed for the high-risk patients (R-ISS III) with a median OS of 2.5 years. Figure Figure. Disclosures Reeder: Millennium: Research Funding; BMS: Research Funding; Celgene: Research Funding; Novartis: Research Funding. Mikhael:Abbvie: Research Funding; Onyx: Research Funding; Sanofi: Research Funding; Celgene: Research Funding. Bergsagel:Amgen, BMS, Novartis, Incyte: Consultancy; Novartis: Research Funding. Stewart:celgene: Consultancy. Fonseca:Janssen: Consultancy; Celgene: Consultancy; Sanofi: Consultancy; Novartis: Consultancy; Bayer: Consultancy; AMGEN: Consultancy; AMGEN: Consultancy; AMGEN: Consultancy; Patent: Patents & Royalties: Prognostication of MM based on genetic categorization of FISH of the disease; AMGEN: Consultancy; Millennium, a Takeda Company: Consultancy; Janssen: Consultancy; Sanofi: Consultancy; Patent Pending: Patents & Royalties: The use of calcium isotopes as biomarkers for bone metabolisms; Novartis: Consultancy; Patent: Patents & Royalties: Prognostication of MM based on genetic categorization of FISH of the disease; Millennium, a Takeda Company: Consultancy; Millennium, a Takeda Company: Consultancy; Bayer: Consultancy; Celgene: Consultancy; Patent Pending: Patents & Royalties: The use of calcium isotopes as biomarkers for bone metabolisms; Patent: Patents & Royalties: Prognostication of MM based on genetic categorization of FISH of the disease; Patent Pending: Patents & Royalties: The use of calcium isotopes as biomarkers for bone metabolisms; BMS: Consultancy; Millennium, a Takeda Company: Consultancy; BMS: Consultancy; Patent: Patents & Royalties: Prognostication of MM based on genetic categorization of FISH of the disease; Patent Pending: Patents & Royalties: The use of calcium isotopes as biomarkers for bone metabolisms.

Abstract Backround: Dysregulation of the PI3K/Akt signal transduction pathway has been implicated in the development of a number of malignancies, including multiple myeloma (MM). This cellular signaling mechanism and its downstream targets (eg mTOR) regulate cell growth, proliferation and apoptosis. SF1126 (Semafore) is a water soluble prodrug of the pan-PI3K inhibitor, LY294002, whose anti-proliferative and pro-apoptotic activity has been well described in the literature. Preclinical studies using SF1126 in a variety of malignancies including glioma, prostate, non-small cell lung cancer, and breast cancer appear promising and have demonstrated profound antiangiogenic effects mediated through VEGF inhibition. Aim: To demonstrate in vitro anti-myeloma activity of SF1126, alone and in combination with dexamethasone, bortezomib, and melphalan and evaluate their effects on downstream targets of PI3K/Akt. Methods: MM cell lines (MM.1R, MM.1S, RPMI 8226) were treated with SF1126 (1–100uM), dexamethasone (5uM), bortezomib (5nM), melphalan (10uM) alone, and in combination. Growth inhibition following treatment was measured by MTT assay at 24 and 48 hours. Apoptosis was assessed by annexin-V binding assay using flow cytometry. Immunoblot analysis was performed to measure downstream targets of Akt including: p-PDK1 and mTOR (4E-BP1). Results: A clear dose response was established with an IC50 of 8.75uM in the MM.1R and 7.5uM in the MM.1S cell lines at 48 hours. At 24 and 48 hours, 5uM SF1126 alone resulted in 80% and 64% cell viability by MTT assay, respectively, in the MM.1R cell line. The combination of 5uM SF1126 with conventional agents was then tested in the MM.1R cell line. Combination with 5uM dexamethasone enhanced the efficacy of 5uM SF1126 by 26% at 48 hours. Combination with 10uM melphalan enhanced the efficacy of 5uM SF1126 by 20% at 24 hours. The combination with 5nM bortezomib enhanced the efficacy of 5uM SF1126 by 23% at 48 hours. Given prior experience demonstrating that short exposure to bortezomib activates Akt, we tested sequential administration of bortezomib and SF1126 in the MM.1R cell line. Optimal cell death was induced with bortezomib prior to SF1126, followed by concurrent administration. Immunoblot analysis of p-PDK1, downstream mTOR target (4E-BP1) were performed on the MM.1S cell line treated with 5, 10, 20, and 50uM SF1126 at 12 and 24 hours. At the 12 hour time point, p-PDK-1 appeared to increase, but was significantly reduced by 48 hours. A similar pattern of initial upregulation followed by reduction by 24 hours was seen with the mTOR protein 4E-BP1. Conclusion: SF1126 has dose dependent, in vitro activity in several multiple myeloma cell lines both as a single agent and in combination with dexamethasone, bortezomib, and melphalan. The addition of SF1126 to dexamethasone in a dexamethasone resistant cell line results in increased cell death, possibly by overcoming resistance mechanisms. The addition of SF1126 to bortezomib and melphalan also resulted in increased growth inhibition over either agent alone. These results warrant further study of this promising new pan-PI3K/Akt inhibitor.

Abstract Background: Pomalidomide is an immunomodulatory agent (IMiD®) that has been approved for treatment of relapsed and refractory multiple myeloma (MM). Combinations of IMiDs and proteasome inhibitors offer the potential for deeper and more durable responses due to enhanced efficacy. Preliminary results of a phase 1 study of twice weekly bortezomib with pomalidomide have been reported with promising results (Richardson, ASH 2012). This phase I/II trial was designed to evaluate the maximum tolerated doses (MTD) as well as safety and efficacy of the combination of pomalidomide, once weekly bortezomib and dexamethasone (PVD) in patients with relapsed, lenalidomide refractory, MM. Patients and methods: We included patients with relapsed MM who had 1-4 prior lines of therapy and were resistant or refractory to lenalidomide. In the phase I portion of the trial, dose level 1 consisted of pomalidomide 4 mg days 1-21 PO, bortezomib 1.0mg/m2 days 1,8,15, and 22 IV or SQ and dexamethasone 40 mg days 1,8,15, and 22 PO, given every 28 days. Bortezomib was increased to 1.3mg/m2 for dose level 2 and and was adopted for the phase 2 portion. The primary aim of the phase I cohort was to determine the MTD of the combination, and for the phase II cohort was to evaluate the confirmed response rate (PR, VGPR, or CR) in relapsed refractory MM. Response was assessed by the IMWG criteria and toxicity was graded using the CTCAE v4.0. Results: 50 patients were accrued between March 2012 and July 2014 (dose level (DL)1: 3, DL 2: 6, Phase II: 41). We describe results in 47 patients treated at MTD and phase II. Median age was 66, 51% were female and median time from diagnosis to study was 46 months (15-142). Twenty five percent had mSMART defined high-risk status. Median number of prior regimens was 3. All patients had prior lenalidomide, 68% had stem cell transplant, 17% received thalidomide, 56% had alkylators and 57% had bortezomib. With median follow up of 9 months, 72% remain progression free, 96% are alive and 66% remain on treatment. The most common AEs at least possibly attributable to the combination were anemia, fatigue, leukopenia and thrombocytopenia; however, the majority of these were grade 1-2. Grade ≥3 AEs (regardless of attribution) that occurred in at least 3 patients included neutropenia (29), leukopenia (15), lung infection (6), lymphopenia (8) dyspnea (3) and syncope (3). DVT/PE occurred in one patient. Among the 42 patients who were evaluable, confirmed responses (PR, VGPR, or CR) were seen in 34 (81%) including sCR (3), CR (5), VGPR (8), PR (18). Confirmed responses were seen in 9 of 11( 82%) high risk patients. Median progression free survival was 17.7 months (95%CI: 9.5-NA). Conclusions: PVD is a highly effective combination in patients refractory to lenalidomide with confirmed responses in over 80%. Weekly administration of bortezomib enhanced the tolerability and convenience of this regimen. Toxicities are manageable, mostly consisting of mild cytopenias with no significant neuropathy or DVT. PVD is a highly attractive option in patients with relapsed and refractory MM. Disclosures Lacy: Celgene: Research Funding. Lust:Senesco: PI Other. Fonseca:Medtronic, Otsuka, Celgene, Genzyme, BMS, Lilly, Onyx, Binding Site, Millennium, AMGEN: Consultancy, patent for the prognostication of MM based on genetic categorization of the disease. He also has sponsored research from Cylene and Onyx Other, Research Funding. Stewart:Celgene: Consultancy; Novartis: Consultancy; Array BioPharma: Consultancy; BMS: Consultancy; Millenium: Research Funding. Reeder:Millennium, Celgene, Novartis: Research Funding. Mikhael:Onyx: Research Funding; Celgene: Research Funding; Sanofi: Research Funding; Novartis: Research Funding.

Abstract Background Conflicting results have emerged, especially with respect to the impact on overall survival (OS), from trials evaluating lenalidomide maintenance (LM) therapy after induction therapy alone or post-autologous stem cell transplant (ASCT) in multiple myeloma (MM). We performed a systematic review and meta-analysis of existing outcome data from LM trials to evaluate role of lenalidomide as maintenance strategy in MM. Patients and methods A comprehensive search of electronic databases and abstracts through June 2013 was performed to identify randomized controlled trials (RCTs) that compared LM vs. placebo/no maintenance. Single arm studies were excluded. Pooled hazard ratio (HR) or odds ratio (OR) estimates with 95% confidence intervals (CIs) were calculated using the random-effects model for clinical endpoints of progression free survival (PFS), OS, response rate (RR) and adverse events (AEs), including second primary malignancies (SPMs). Analyses were performed using Comprehensive Meta-Analysis Software Version 2. We assessed between-study heterogeneity with the Cochran Q test and quantified its extent with the I2 statistic. Results Overall, five RCTs, with data extractable from four phase III trials (3 publications and 1 abstract) were identified (n= 1935). All studies were RCTs with an adequate randomization. MRC MM XI study was excluded from analyses as survival data are not available. Two placebo controlled trials (IFM 05-02, CALGB 100104) addressed the role of LM post-ASCT, one placebo-controlled trial (MM-015) studied LM therapy in the non-transplant setting and the remaining trial (RV-MM-PI209) had a 2 X 2 design comprising of both ASCT and non-transplant randomized arms followed by a second randomization of LM versus no maintenance. There was no heterogeneity for estimate of PFS results (Cochran Q, p=0.68; I2=0%), but considerable heterogeneity for estimate of OS (Cochran Q, p=0.09; I2= 55%), among the studies. There was significant prolongation of both PFS (HR 0.49, 95% CI, 0.41–0.58, p<0.001) and OS (HR 0.77, 95% CI, 0.62–0.95, p=0.013) with LM vs. placebo/no maintenance (Figure 1). Best response during maintenance was reported only in 2 studies and odds of responding (very good partial response or better) were not significantly different with LM (OR 1.28, p=0.3). Grade 3-4 AEs data were available from 3 trials for calculation of pooled OR with LM compared with placebo. We observed a nearly two-fold increase in the risk of SPMs with LM (OR 1.99; 95% CI, 1.31–3.04; p=0.001). Patients on LM were more likely to have grade 3-4 AEs than placebo: neutropenia (OR 4.9, p<0.001), thrombocytopenia (OR 2.7, p<0.001), fatigue (OR 2.3, p=0.01) and venous thromboembolism (OR 3.2, p=0.02). Odds of discontinuing treatment were also significantly higher in patients on lenalidomide (OR 2.9, p<0.001). Conclusions Meta-analysis of RCTs demonstrates significant improvement in PFS and modest improvement in OS with LM. There is an increased risk of grade 3-4 adverse effects, including SPMs with LM. Substantial heterogeneity for estimate of OS among protocols is a limitation of this analysis. Lack of uniform access to lenalidomide upon disease progression in the placebo/no maintenance arms of the constituent studies should be taken into account while interpreting aggregate effect estimates for OS in this meta-analysis. OS: Cochran Q p=0.09, I2=55%, substantial heterogeneity PFS: Cochran Q p=0.68, I2=0%, minimal heterogeneity Disclosures: Off Label Use: Lenalidomide for maintenance therapy in multiple myeloma. Kumar:Merck: Consultancy, Honoraria; Celgene: Consultancy, Research Funding; Millennium: The Takeda Oncology Company: Research Funding; Novartis: Research Funding; Genzyme: Research Funding. Dispenzieri:Celgene, Millenium, Jansenn, Pfizer: Research Funding. Bergsagel:Onyx: Consultancy. Lacy:Celgene Corporation: Research Funding.

Abstract Background: In Phase II trials, carfilzomib (Cfz) was associated with dyspnea (34%), hypertension (14%), renal insufficiency (24%), and peripheral edema (24%) with cardiac events reported in 7% of patients (pts). In order to better understand these toxicities, we prospectively instituted detailed cardiac evaluation in 62 Cfz treated multiple myeloma (MM) pts. Methods: Pts received Cfz between 8/11-5/14. Parameters recorded included Cfz dose, concurrent chemotherapy, hydration, blood pressure, day 1 and 2 creatinine, troponin and NT-proBNP, baseline and cycle 4 echocardiograms with EF, strain and compliance. Notable cardiac events were examined for attribution. Results: Median age was 65 years, with 60% male. 20 pts had no prior therapies, 42 were relapsed; mean 4 prior therapies (range 1-10). 20 received induction chemotherapy (Cfz, dex, thalidomide, cyclophosphamide). At relapse, Cfz was given alone in 21 pts, with added cyclophosphamide in 10, and with an IMiD in 10. Cfz dose was 20mg/m2 days 1,2 and ranged from 27-45mg/m2in subsequent treatment days. Dex was given at 20-40mg weekly in 77% pts. Hydration (250-500ml) was delivered in 89% of patients pre and 63% post treatment. Baseline hypertension (>140mmHg) was present in 20% of pts and rose ≥10mmHg in 26% on day 2, but dropped ≥10mmHg in 36%. On day 8, more pts (32%) had hypertension pre-treatment. Baseline creatinine was elevated in 25% pts. 7 of 55 (13%) pts had a creatinine rise (≥0.3 mg/dL) on day 2, 5 of whom had elevation at baseline. Thus, with normal baseline creatinine and pre-treatment hydration 2/45 (4%) pts had a creatinine rise. Troponin levels on day 1 were normal in all 16 tested patients. 2/25 pts had an elevated troponin on day 2, one with associated MI on day 4. In these 2 pts, symptomatic pre-existing ischemic heart disease and severe cardiac amyloid were confounding factors. Mean baseline NT-proBNP (n=22) was elevated at 565 pg/mL (range <50-3666; normal <77) with normal baseline values in only 41%. On day 2 (n=25), the mean was significantly higher at 1580 pg/mL. Between day 1 and 2, 72% of pts had a rise ≥50 pg/mL; mean change 1387 (range 0 to +6187). On day 2, 52% had a NT-proBNP ≥500 pg/mL, while 36% were ≥1000 pg/mL. 30 pts had baseline and post-C4 treatment echocardiograms, all with normal pre-treatment EFs. Three pts (10%) developed impaired systolic function (EF<50%), however, 2 had plausible concurrent alternative etiologies (VTE/PE, hospitalized multilobar pneumonia) while one patient (during C2) had an asymptomatic unexplained decline in EF (56 to 42%) detected pre-op while hospitalized for hip fracture. Thus, 1/30 (3%) had an EF change in absence of concurrent acute illness. A fourth patient had normal echo at C4 but was hospitalized at C10 with severe sepsis and a diminished EF was documented. All 4 pts with low EF were pre-treated (≥2 therapies plus SCT). Changes in cardiac strain often precede an EF fall. Only 14/25 pts had normal baseline cardiac strain (≥ -18%). Post treatment strain measurement significantly improved in 4 pts and worsened in 4 pts, the latter accompanied by EF decline within the normal range in 2 pts (68/60%, 65/58%). 28 pts had E/e’ ratio (LVEDP) reviewed as a marker of ventricular compliance. 46% had abnormal ratios (≥ 15), prior to Cfz treatment. 20% of patients experienced worsening parameters post treatment, however, an equal number of pts demonstrated improvement. There was no consistent correlation with change in EF. Conclusions: MM pts frequently have baseline elevated cardiac peptides (59%) and abnormal cardiac strain (15% of newly diagnosed and 36% at relapse). A frequent, and sometimes dramatic, rise in the NT-proBNP occurs immediately following Cfz based chemotherapy. Acute structural cardiac events were however uncommon (3%) in the absence of confounding illness. Overall 5/62 (8%) patients had serious cardiac events during treatment with Cfz (4 EF decline, 1 MI). These toxicities were considered probably attributable to Cfz in 3/62 (5%) patients. Prospective controlled studies with longer term follow up and bortezomib treated controls are necessary to accurately document the cardiovascular impact of Cfz and the role of proteasome inhibition. Disclosures Off Label Use: bortezomib was used in combination therapy to treat relapsed low grade lymphomas and Waldenstrom's macroglobulinemia. Fonseca:Medtronic, Otsuka, Celgene, Genzyme, BMS, Lilly, Onyx, Binding Site, Millennium, AMGEN: Consultancy, patent for the prognostication of MM based on genetic categorization of the disease. He also has sponsored research from Cylene and Onyx Other, Research Funding. Bergsagel:Novartis: Research Funding; Constellation Pharmaceutical: Research Funding; OncoEthix: Research Funding; MundiPharma: Research Funding. Reeder:Millennium, Celgene, Novartis: Research Funding. Mikhael:Onyx: Research Funding; Celgene: Research Funding; Sanofi: Research Funding; Novartis: Research Funding. Stewart:Celgene Novartis Array BioPharma BMS, research funding Millenium: Consultancy, Research Funding.

Abstract A genetic rearrangement of the MYC locus, resulting in dysregulated expression of MYC, is the most common mutation in human multiple myeloma (MM). The genetically engineered Vk*MYC mouse model is based on dysregulation of MYC, and has been extensively validated as a clinically and biologically faithful model of untreated MM. We previously reported 9 drugs or classes of drugs (DNA alkylators, glucocorticoids, proteasome inhibitors, IMiDs, nab-paclitaxel, histone deacetylase inhibitors, TACI-Ig, perifosine and SNS-032, a CDK2,7,9 inhibitor) with more than 20% partial response (PR) rate in Vk*MYC MM. Among those, the first 5 also have more than 20% PR in patients with MM for a positive predictive value of 56%. Although the HDACi did not show single agent activity in relapsed/refractory MM patients, the PANORAMA phase 3 study of panobinostat in combination with bor+dex has shown superior PFS compared to bor+dex, suggesting the possibility that HDACi may have shown single agent activity if tested in a less advanced clinical setting. In contrast, 11/12 drugs that have less than 20% PR in Vk*MYC MM also have less than 20% PR in patients with MM for a NPV of 92%. Confident that drugs with activity in Vk*MYC mice will likely be effective in the treatment of MM, we have used this model to study novel drugs for prioritization in clinical trials. Pim kinases are constitutively active serine/threonine kinases identified using retroviral mutagenesis as potent suppressors of MYC induced apoptosis and can be inhibited by the pan-PIM kinase inhibitor LGH447. KPT-276 is a selective inhibitor of nuclear export CRM1/XPO1 inhibitor. Both drugs are active in Vk*MYC MM and are showing early evidence of promising clinical activity, increasing the PPV of the Vk*MYC model of MM to 64% (or 73% if HDACi are considered clinically active). Also active in the Vk*MYC model were the bromodomain inhibitors GSK I-BET151, CPI-203, CPI-456, OTX-015, which, like JQ1, compete with acetylated histones for the binding to BRD4, inhibiting super-enhancer activity and MYC transcription. The histone methyltransferase enhancer of Zeste homolog 2 (EZH2) induces transcriptional repression through histone H3 lysine 27 trimethylation (H3K27me3) at the promoter of silenced genes. Activating mutations in the SET domain of EZH2 are prevalent in germinal center DLBCL and follicular lymphoma but have not been identified in MM, where the frequent dysregulation of MMSET by t(4;14) translocation or biallelic deletion of UTX are thought to play a tumorigenic role equivalent to EZH2 activation. EZH2 inhibitors have demonstrated activity against lymphoma with EZH2 activating mutations. Interestingly, we found the EZH2 inhibitor CPI-169 active against Vk*MYC MM, identifying EZH2 as a promising new epigenetic target in MM. EDO-S101 is a novel drug resulting from the fusion of a molecule of bendamustine with a molecule of vorinostat, with the aim of increasing the efficacy of the alkylator through the HDACi-mediated chromatin relaxation that would make DNA more accessible to the damaging effect of bendamustine. It induced a high rate of response in Vk*MYC MM that was sustained for more than 3 months in mice receiving only 2 doses, one week apart. Remarkably EDO-S101 is the only drug we have identified with single agent activity in the very aggressive, multi-drug resistant Vk12653 transplant model of relapsed/refractory MM. Finally, 2 agents (anti-murine PD-L1 and LCL161) that primarily modulate the immune microenvironment, with little to no direct anti-MM activity, also induced responses. Anti-PD-L1 blocks immunosuppressive signaling from MM cells to PD1 on T cells. LCL161 is an IAP antagonist that leads to constitutive activation of the alternative NFkB pathway with direct stimulation of the innate and adaptive immune systems. Although antibodies to CD38 are among the most exciting new agents for the treatment of MM, they cannot be evaluated in Vk*MYC MM since murine normal or malignant plasma cells do not express CD38. In contrast while SLAMF7 is expressed in Vk*MYC MM, there is no murine equivalent of elotuzumab. In summary, we report 7 new drugs with single agent activity in Vk*MYC MM, nearly doubling the number of drugs or classes of drugs with promising anti-MM activity. Two (LGH447 and KPT-330) are already beginning to demonstrate clinical efficacy in MM. All of these agents should be prioritized for rapid evaluation in clinical trials of patients with MM. Disclosures Bergsagel: Novartis: Research Funding; Constellation Pharmaceutical: Research Funding; OncoEthix: Research Funding; MundiPharma: Research Funding.