Citations

Abstract Background: Venetoclax (VEN) is a potent, selective, orally available small-molecule BCL-2 inhibitor that induces cell death in multiple myeloma (MM) cell lines and primary samples, particularly those with t(11;14), which mostly have a favorable high BCL-2, low BCL-XL, and low MCL-1 profile. Methods: In this Phase 1, open-label study, patients (pts) with relapsed/refractory (R/R) MM received VEN monotherapy. Objectives of the study were to assess safety, pharmacokinetics, maximum tolerated dose, recommended phase 2 dose, and efficacy (objective response rate [ORR], time to progression [TTP], and duration of response [DoR]) of VEN. After a 2-week lead in period with weekly dose escalation, VEN was given daily at final doses of 300, 600, 900, or 1200mg in dose escalation cohorts and 1200mg in the safety expansion. Pts who progressed during VEN monotherapy could receive VEN plus dexamethasone and continue in the study. Results: As of 01July2016, 66 pts were enrolled in the study (30 in dose escalation cohorts and 36 in safety expansion). Median age was 63 years and 39 (62%) pts were ISS stage II/III. The median number of prior therapies was 5 (range: 1-15), and 62 (94%) pts had received bortezomib (46 [70%] refractory), 62 (94%) received lenalidomide (51 [77%] refractory), and 50 (76%) had prior autologous stem cell transplant. Thirty (46%) pts had t(11;14) MM. Median time on VEN monotherapy for all pts was 2.5 months (.2-23); 17 (26%) elected to receive VEN and dexamethasone combination after disease progression for a median of 1.4 months (.1-11). Fifty-one (77%) pts discontinued the study for the following primary reasons: 39 related to disease progression, 5 due to AEs/toxicity, 2 withdrew consent, 1 was lost to follow up, and 4 for other reasons not specified. Common adverse events (AEs) in ≥20% of pts were nausea (48%), diarrhea (36%), neutropenia (32%), thrombocytopenia (32%), fatigue (27%), anemia (23%), back pain (21%), and vomiting (21%). Grade 3/4 AEs in ≥10% of pts were thrombocytopenia (26%), neutropenia (20%), lymphopenia (15%), anemia (14%), and decreased white blood cells (12%). Serious AEs in ≥2 pts were pneumonia (n=5), sepsis (3), pain, pyrexia, cough, and hypotension (2 each). Two pts experienced dose-limiting toxicities at 600mg of abdominal pain and nausea. Eight deaths were reported: 6 due to disease progression, 1 due to lung disorder, and 1 due to brain hemorrhage following injury; neither were considered by the investigator as related to VEN. Steady state VEN exposures were approximately dose proportional at all doses but 900mg. As of 20July2016, ORR for all pts on VEN monotherapy was 21% (14/66) and 10 (15%) achieved very good partial response (VGPR) or better (2 stringent complete response [sCR], 2 CR, 6 VGPR) (Figure); median DoR and TTP was 9.7 and 2.6 months, respectively. Most objective responses (12/14 [86%]) were reported in the subset of pts with t(11;14) MM. In this group, ORR was 40% (12/30) and 27% (8/30) achieved a response of ≥VGPR; median DoR for pts with t(11;14) was 9.7 months (95% CI: 6.3, -). Pts who achieved at least minimal response in the t(11;14) group (14/30) had a median of 4 prior therapies and were mostly refractory to bortezomib, lenalidomide, or double refractory (71% [10/14] each). For two pts with response in the non-t(11;14)/undetermined group, 1 had a translocation of chromosome 14 with an unidentified partner, and the other had no cytogenetics data available. DoR was 9.5 and 7.2 months in these pts and both are still ongoing. Median TTP for pts with or without/undetermined t(11;14) was 6.6 and 1.9 months, respectively. The median best percent change in primary M protein for pts with t(11;14) (n=23) was -53% vs +11% in the non-t(11;14)/undetermined group (n=23). Additional biomarker subgroup analyses (n=32) showed that efficacy was primarily observed in pts with myeloma cells expressing a favorable BCL-2 family expression profile (high BCL-2, low BCL-XL, low MCL-1) by immunohistochemistry, which was significantly enriched in the t(11;14) population. Indeed, although high BCL-2 expression was observed in a majority of bone marrow core biopsy samples (88%), the t(11;14) subgroup was enriched (81% vs 25%) for tumors expressing high BCL-2, low BCL-XL, and low MCL-1. Conclusions: VEN monotherapy has an acceptable safety profile and clear anti-myeloma activity in pts with R/R MM, primarily with t(11;14) having a high BCL-2, low BCL-XL and low MCL-1 expression levels. Figure Figure. Disclosures Kumar: Janssen: Consultancy, Research Funding; Sanofi: Consultancy, Research Funding; Noxxon Pharma: Consultancy, Research Funding; Skyline: Honoraria, Membership on an entity's Board of Directors or advisory committees; Onyx: Consultancy, Research Funding; Glycomimetics: Consultancy; AbbVie: Research Funding; Array BioPharma: Consultancy, Research Funding; Millennium: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Kesios: Consultancy; BMS: Consultancy. Kaufman:Novartis: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Pharmacyclics: Consultancy; Incyte: Consultancy. Mikhael:Abbvie: Research Funding; Celgene: Research Funding; Onyx: Research Funding; Sanofi: Research Funding. Facon:Amgen: Consultancy, Speakers Bureau; Novartis: Consultancy; Bristol: Consultancy; Millenium/Takeda: Consultancy; Janssen: Consultancy, Speakers Bureau; Celgene: Consultancy, Speakers Bureau; Karyopharm: Consultancy. Benboubker:Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Moreau:Celgene: Honoraria; Janssen: Honoraria; Takeda: Honoraria; Novartis: Honoraria; Amgen: Honoraria. Alzate:AbbVie: Employment. Ross:AbbVie: Employment, Equity Ownership. Dunbar:AbbVie Inc.: Employment, Other: may own stock. Xu:AbbVie: Employment. Agarwal:AbbVie: Employment. Leverson:AbbVie: Employment, Other: Shareholder in AbbVie. Maciag:AbbVie: Employment. Verdugo:AbbVie: Employment, Other: may own stock. Touzeau:AbbVie: Research Funding.

Abstract Abstract 3138 Background: Several recent reports have suggested that doxycycline can inhibit amyloid fibril formation in different in vitro and in vivo model systems. Doxycycline is the antibiotic of choice for infectious disease prophylaxis in patients with penicillin allergy, following autologous peripheral blood stem cell transplantation for various hematological malignancies. We examined the outcome of patients with light chain amyloidosis (AL) undergoing autologous stem cell transplantation to study the impact of doxycycline used as antibacterial prophylaxis. Patients and methods: We studied 455 patients who underwent autologous stem cell transplant (ASCT) for AL between March 1996 and December 2011. We excluded 44 patients who died of transplant related complications or did not survive beyond 100 days after transplant. Patient records were reviewed to ascertain the prophylactic antibiotic used. Survival was estimated using Kaplan Meier method and the survival curves were compared using log-rank test. Cox proportional hazard model was used to estimate the prognostic impact of different variables. Results: The median age of the patients was 58 years (range, 26–74); 290 (67%) were male. The median estimated follow up for the entire cohort was 73 months (95% CI; 66, 79) and 314 (69%) were alive at last follow up. Doxycycline was used a prophylaxis in 106 (23%) of the patients, with most of the remaining receiving penicillin. The usual reason for using doxycycline was a history of penicillin allergy. Hematological response to transplant occurred in 377 (87%) patients, and there was no significant difference between patients receiving doxycycline prophylaxis compared with the rest. The median OS for the entire cohort was 161 months (95% CI; 101, NR). The median OS for those receiving doxycycline prophylaxis was not reached compared with 113 months for the rest (P=0.09). Looking specifically at those patients with a hematological response, the median OS was not reached for the doxycycline group compared with 161 months for the rest (P=0.04, figure). There was no difference in the OS between the groups among those with no hematological response. The impact of the prophylaxis was independent of the number of organs involved as well as organ response to SCT. Conclusions: The results of the current study appear to demonstrate a survival advantage for patients with AL who receives doxycycline prophylaxis, in the setting of hematological response from SCT. The results are consistent with the data regarding the effect of doxycycline on amyloid fibril formation. These initial findings should form the basis of clinical exploration of doxycycline as an adjunctive therapy in patients receiving other standard therapies for AL. Such a study can further clarify if use of doxycycline for longer duration can be of additional benefit. Disclosures: Kumar: Cephalon: Research Funding; Novartis: Research Funding; Millennium: Research Funding; Celgene: Research Funding; Merck: Consultancy, Honoraria; Genzyme: Research Funding.

Abstract Abstract 2973 Eukaryotic translation initiation Factor 5A (eIF5A) has been implicated in the regulation of apoptosis and is the only known protein to be modified by hypusination. Hypusinated eIF5A is the predominant form of eIF5A in cancer cells. However, in its unhypusinated form, eIF5A is pro-apoptotic. SNS01-T, designed to treat B-cell cancers, consists of two active components: a plasmid DNA expressing eIF5AK50R (human eIF5A containing a lysine to arginine substitution at position 50) which remains pro-apoptotic because it cannot be hypusinated, and an siRNA against an untranslated region of native eIF5A mRNA. When these two components are combined with linear polyethyleneimine (PEI), the nucleic acids are condensed into nanoparticles for protection from degradation in the blood and enhanced delivery to tissues. The eIF5AK50R transgene is under the control of the B29 promoter and enhancer, which restricts expression to B cells. The mode of action of SNS01-T is to use an eIF5A-specific siRNA to deplete the pool of hypusinated eIF5A in myeloma cells while simultaneously adding pro-apoptotic eIF5AK50R. In vitro cell studies and in vivo xenograft studies have demonstrated the efficacy of this approach. Eligible patients are enrolled sequentially into four cohorts of increasingly higher doses. Each cohort will receive SNS01-T by intravenous infusion twice weekly for 6 consecutive weeks and then be observed every 4 weeks during a 24-week follow-up period. Eligible patients must have been diagnosed with multiple myeloma according to IMWG criteria, have measurable disease, have relapsed disease after two or more prior treatment regimens, have a life expectancy of at least 3 months, and not be eligible to receive any other standard therapy known to extend life expectancy. The primary objective is to evaluate the safety and tolerability of multiple ascending doses of SNS01-T. Secondary objectives include pharmacokinetics, immunogenicity studies, proinflammatory cytokine quantitation, and therapeutic efficacy. The required number of 3 patients completed the dosing schedule in Cohort 1 from a total of 6 patients enrolled. Two of three patients had not progressed on treatment, based on standard response criteria including the monoclonal protein, and were considered stable at week 3 and week 6 the end of the dosing regimen. Three patients were withdrawn from the study by their physicians due to disease progression before completing treatment. One of the responding patients has continued to have stable disease at week 10, a month after the end of treatment with SNS01-T. The first group of patients received 0.0125 mg/kg, approximately 1 mg per patient by intravenous infusion. The planned dose levels for the second, third and fourth groups are 0.05, 0.2 and 0.375 mg/kg, respectively. The results to date of this first in man clinical trial indicate that SNS01-T was safely administered without dose-limiting toxicities in the first group of multiple myeloma patients. The MTD has not yet been reached. (Clinical Trials.gov Identifier: NCT01435720.) Disclosures: Hamadani: Celgene Corp: Speakers Bureau; American Cancer Society 116837-IRG-09–061–01: Research Funding; ASBMT & Millennium New Investigator Award: Research Funding; Conquer Cancer Foundation of ASCO: Research Funding. Barranco:Senesco Technologies: Employment. Thompson:Senesco Technologies Inc.: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Taylor:Senesco Technologies Inc.: stock options Other. Dondero:Senesco Technologies Inc.: Employment.

Abstract We and others previously demonstrated an increased risk of monoclonal gammopathy of undetermined significance (MGUS) in first-degree relatives of multiple myeloma (MM) and MGUS patients, underscoring a familial component to this disease. However, MM is known to be a collection of cytogenetically distinct diseases, with 40-50% of MM cases having a reciprocal translocation involving the IgH locus on chromosome 14q32 and in many of the remaining patients, trisomies. In a small proportion of cases, both IgH abnormalities and trisomies are found in the same clone. These MM cytogenetic subtypes are associated with differential prognosis. Whether there are differences in familial risk by cytogenetic subtypes is not known. Patients with MM were recruited from the Mayo Clinic Hematology practice in Rochester, Minnesota (MN) between 2005 and 2015. Serum samples were collected from first-degree relatives and subjected to electrophoresis and immunofixation for MGUS determination. Age- and sex-specific rates of MGUS from the population-based Olmsted County, MN, prevalence study were used as expected rates for the calculation of risk ratios (RRs) for comparisons of first-degree relatives. Cytogenetic subtypes were classified by FISH testing performed in the clinic and categorized into groups defined by IgH translocation , trisomy, intermediate/ high-risk disease (t(4;14), t(14;16), t(14;20), and del17p). Further, the distribution of cytogenetic subtypes was compared between MM cases with and without evidence of MGUS in first degree relatives using Chi square tests. Analyses were also subset to MM probands diagnosed in MN. There were a total of 442 MM probands, with 1235 first-degree relatives recruited and eligible for the study. MGUS was detected in 78 relatives, for an age- and sex-adjusted prevalence of 6.1% (4.7%-7.5%). Analyses comparing prevalence of MGUS in first degree relatives to population-based rates from Olmsted County showed a 2.5-fold (95% CI=1.9-3.0) increased prevalence. When performing analyses among MN probands only (RR=2.9; 95% CI=2.1-3.8), results were similar. Of the 442 probands, 310 had FISH performed on plasma cells (identified by cIG staining; cIg-FISH) at diagnosis. Of these cases, 49% had a trisomy, 23% had an IgH translocation, and 9% had both. Although the proportion of trisomies and IgH translocations were 4-6% higher among MM probands with a relative with MGUS compared to those without, these differences were not statistically significant (Table 1). MM probands with a first degree relative with MGUS also had a similar proportion of cytogenetic subtypes that are considered of intermediate or high risk compared to those MM without a family history (26.9% vs 25.2%) (p=0.79) (Table 1). When restricted to MM probands from MN, results remained non-statistically significant (Table 1). We showed an increased risk of MGUS in first-degree relatives of MM cases, implying shared environment and/or genetics underlying this malignancy. However, we did not find an association between family history of MGUS in MM probands and the cytogenetic subtypes examined. Larger cohorts are needed to examine if a relationship exists between cytogenetic subtypes of MM and familial risk. Disclosures Kumar: Noxxon Pharma: Consultancy, Research Funding; Array BioPharma: Consultancy, Research Funding; AbbVie: Research Funding; Onyx: Consultancy, Research Funding; Millennium: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Glycomimetics: Consultancy; Kesios: Consultancy; Janssen: Consultancy, Research Funding; Skyline: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Consultancy, Research Funding; BMS: Consultancy.

Abstract Background: Patients with monoclonal gammopathies typically have a single clone making a unique type of monoclonal protein, one heavy chain and one light chain. In a small proportion of patients, more than one (typically two) types of monoclonal protein can be seen and differ with respect to the heavy chain or light chain or both. There is limited information on the clinical course of patients with more than one monoclonal protein identified in their serum or urine. Objectives: We report outcomes of patients with more than one monoclonal protein at our institution over the past thirty years. Patients and Methods: We queried the existing clinical database to identify all patients with at least two different monoclonal protein types identified on serum or urine studies during the course of their disease. Retrospective chart review was performed on 551 patients, who had more than one type of monoclonal protein on electrophoresis and/or immunofixation. Results: Among the entire study cohort (N=551), 461 pts (84%) had a biclonal pattern, 7 (1%) had a triclonal pattern and the remaining 83 (15%) had a monoclonal pattern at the time of initial positive study. The median age at the time of initial diagnosis was 69.7 years (range; 32-93); 359 (65%) were male. Among these, 390 were diagnosed as MGUS/BGUS, 18 with SMM, 36 with MM, 20 with WM, and rest with another lymphoproliferative disorders. The median duration between the initial detection of monoclonal protein and the emergence of the biclonal protein was 40 months for the 83 patients, who were monoclonal initially. The distributions of the dominant monoclonal proteins were GK (30%), GL (21%), MK (22%), ML (9%), AK (9%), and AL (8%). The distributions of the second monoclonal proteins were GK (27%), GL (24%), MK (16%), ML (15%), AK (10%), and AL (7%). Overall, 20 patients with a MGUS/BGUS progressed to smoldering or symptomatic myeloma, while 12 patients with an initial diagnosis of SMM progressed to MM. The median estimated follow up for the MGUS/BGUS group and those with SMM were 6.5 years (95% CI; 5, 7) and 9.8 (95% CI; 4, 13), respectively. This translates to 20 progressions over 3822 person years of follow up for the MGUS/BGUS patient group and 12 progressions over 131 person years of follow up for the SMM group. The rate of progression was ~1% per year for patients with MGUS/BGUS and the median estimated time to progression was 2.6 years for the SMM group. (Figure). In majority of patients, the dominant M spike increased with the disease progression. Conclusion: Patients with biclonal gammopathies appear to have a similar rate of progression compared to what has been historically described for MGUS/ SMM population. For the patients who progressed and received treatment, both M proteins typically responded to therapy, and during relapse, the original dominant M protein typically reemerged as the dominant M protein. Figure 1 Figure 1. Disclosures Kumar: Janssen: Consultancy, Research Funding; Array BioPharma: Consultancy, Research Funding; Sanofi-Aventis: Consultancy, Research Funding; Onyx Pharmaceuticals: Consultancy, Research Funding; Millennium: The Takeda Oncology Co.: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Skyline Diagnostics: Membership on an entity's Board of Directors or advisory committees.

Abstract Objective: To fully contextualize the benefit of novel agents such as daratumumab (DARA) monotherapy for the treatment of patients with heavily pre-treated and highly refractory multiple myeloma (MM), it is critical to understand the real-world outcomes of this patient population on current standard of care (SOC) therapies. The objective of this study was to perform adjusted comparisons to determine the comparative effectiveness of DARA monotherapy versus real-world SOC therapies. Methods: Data for patients treated with DARA 16 mg/kg monotherapy were available from clinical trials MMY2002 (n=106) and GEN501 (n=42), while patients treated with SOC therapies were derived from the International Myeloma Foundation (IMF) chart review of patients with MM who had ≥3 prior lines of therapy and were double refractory to a proteasome inhibitor (PI) and an immunomodulatory drug (IMiD) (n=543) (Kumar et al., ASH 2016; submitted). The pooled DARA studies demonstrated a median overall survival (OS) of 20.1 months versus 13.0 months for SOC based on the IMF cohort (Usmani et al., Blood 2016; Kumar et al., ASH 2016; submitted). The relative treatment effect of DARA versus SOC was estimated using two adjusted comparison methodologies, propensity score matching (PSM) and multivariate Cox regression analyses. Both methodologies utilized individual patient data to compare OS. Modeled covariates for the PSM were age, gender, prior lines of therapy, albumin, and refractory status to bortezomib (BOR), carfilzomib (CAR), lenalidomide (LEN), and pomalidomide (POM). PSM was performed using caliper matching with a caliper width 25% of the standard deviation of the logit-transformed propensity score, using sampling without replacement. For the regression analysis, the covariates included in the multivariate proportional hazards regression model were age, gender, prior lines of therapy, albumin, beta-2 microglobulin, prior exposure to POM and CAR, and PI/IMiD refractory status. Clustering of observations at the treatment-line level within patients was controlled for using the robust sandwich estimate for the covariance matrix, making confidence intervals (CIs) more conservative. For both PSM and regression, statistical significance testing was performed using a two-tailed p-value of <0.05, and all comparisons between treatment groups were reported with hazard ratios (HRs) and 95% CIs. Results: Prior to PSM, imbalances between the DARA and SOC groups were significant for prior lines of therapy and proportions of patients refractory to POM, CAR, BOR, and LEN. After PSM, the DARA and SOC groups were well balanced for all covariates included in propensity score calculations. After PSM, comparisons found significant improvement in favor of DARA relative to SOC for OS (HR=0.44 [95% CI 0.31-0.63]) (Figure 1). Regression analyses revealed consistent results. After adjustment for differences in all covariates included in regression between the DARA and SOC groups, results showed significant improvement in favor of DARA compared with SOC for OS (HR=0.43 [95% CI 0.32-0.59]) (Figure 2). Conclusions: Findings from both PSM and regression analyses were consistent and suggest that DARA is associated with significant gains in OS compared with SOC therapies for patients with heavily pre-treated and highly refractory MM. References: 1. Usmani SZ, Weiss BM, Plesner T, Bahlis NJ, Belch A et al. (2016) Clinical efficacy of daratumumab monotherapy in patients with heavily pretreated relapsed or refractory multiple myeloma. Blood 128 (1): 37-44. 2. Kumar SK, et al. (2016) Natural history of relapsed myeloma, refractory to immunomodulatory drugs and proteasome inhibitors: a multicenter IMWG study. The 58th Annual Meeting of the American Society of Hematology: submitted. Disclosures Kumar: Celgene: Consultancy, Research Funding; Noxxon: Consultancy, Honoraria; Janssen: Research Funding; AbbVie: Research Funding; BMS: Consultancy; Amgen: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Sanofi: Consultancy, Research Funding; Skyline: Consultancy, Honoraria. Durie:Amgen: Consultancy; Takeda: Consultancy; Janssen: Consultancy. Su:Janssen: Research Funding. Diels:Johnson & Johnson: Employment, Equity Ownership. Hutton:Essai Canada: Consultancy; Cornerstone Research Group: Consultancy; Janssen: Research Funding. Lam:Janssen: Employment. Tetsuro:Johnson & Johnson: Equity Ownership; Janssen: Employment.

Abstract Background: Among patients with immunoglobulin light chain (AL) amyloidosis, there is little consensus on when reinstitution of chemotherapy should occur (Milani and Dispenzieri, International Society of Amyloidosis 2016). AL amyloidosis patients who are treated with high dose chemotherapy followed by autologous stem cell transplant (ASCT) are a relatively low-risk and homogenous population, making them an ideal group to study practice patterns. Methods: We conducted a retrospective study to evaluate the patterns of relapse or progression and the timing of re-initiation of therapy among 146 patients who were initially treated with ASCT at Mayo Clinic between 1996 and 2009 and who received second-line therapy between 7/9/1997 and 4/12/2012. Results: The median time from ASCT to second-line therapy was 23.6 months and the median follow up post ASCT was 57.5 months. The indications for second-line treatment were: 1) both hematologic and organ progression 24.7% (36 patients); 2) organ progression only 41.1% (60); 3) hematologic relapse only 34.2% (50). The median dFLC at the time of starting second-line therapy was 10.5 mg/dL (1.6 - 59.5 mg/dL), which was 44.9% (13.8-167.2%) of dFLC level at diagnosis. Increase in proteinuria by > 50% from nadir (that was also at least 1g/24 hours, i.e. renal progression) was present in 35.8%. Increase in NT proBNP by >30% from nadir and minimum of 300 pg/mL was present in 48.9% of patients. The respective 4 years overall survival rates from the time of ASCT were 87.8%, 63.9%, and 56.7% (p=0.0016) for patients who had hematologic relapse, organ progression only and both organ and hematologic progression. Comparisons of laboratory markers at diagnosis, nadir of post ASCT and initiation of second-line therapy are listed in the table. Conclusions: Our study investigated the patterns of relapse / progression following upfront ASCT. This provides some insights on practice patterns of when physicians re-initiate therapy. Table Table. Disclosures Gertz: NCI Frederick: Honoraria; Celgene: Honoraria; Med Learning Group: Honoraria, Speakers Bureau; Research to Practice: Honoraria, Speakers Bureau; Novartis: Research Funding; Prothena Therapeutics: Research Funding; GSK: Honoraria; Sandoz Inc: Honoraria; Ionis: Research Funding; Alnylam Pharmaceuticals: Research Funding; Annexon Biosciences: Research Funding. Kumar:Millennium: Consultancy, Research Funding; Array BioPharma: Consultancy, Research Funding; Sanofi: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Noxxon Pharma: Consultancy, Research Funding; AbbVie: Research Funding; Glycomimetics: Consultancy; Janssen: Consultancy, Research Funding; BMS: Consultancy; Skyline: Honoraria, Membership on an entity's Board of Directors or advisory committees; Onyx: Consultancy, Research Funding; Kesios: Consultancy. Kapoor:Celgene: Research Funding; Amgen: Research Funding; Takeda: Research Funding. Dispenzieri:Prothena: Membership on an entity's Board of Directors or advisory committees; Alnylam: Research Funding; Celgene: Research Funding; Jannsen: Research Funding; pfizer: Research Funding; GSK: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding.

Abstract Abstract 2948 Background: Deletions and mutations in the tumor suppressor protein p53 are an uncommon observation in new multiple myeloma (MM) patients and are observed more commonly in patients with advanced disease. p53 deletion has been observed to correlate with poor overall and progression free survival in MM patients. Wild type p53 modulates the expression levels of a broad array of proteins involved in cell cycle progression, apoptosis ultimately leading to cell cycle arrest and apoptosis. p53 is negatively regulated by MDM2. MDM2 binds to and ubiquitinates p53 marking it for proteasomal degradation. In addition, MDM2 is a direct downstream regulator of p53. Targeting the p53-MDM2 interaction by developing agents that bind to the p53 binding motif of MDM2 and reactivating p53 has therefore been an active area of research. Here, we present results from our pre-clinical studies using AT219, a small molecule inhibitor that binds to MDM2 preventing its interaction with p53. Methods: AT219 was obtained from Ascenta Therapeutics. Stock solutions were made using DMSO and working stock solutions were made using RPMI 1640 media containing 10% fetal bovine serum (20% serum for primary patient cells) supplemented with L-Glutamine, penicillin, and streptomycin. Akt1/2 kinase inhibitor (Akti) was purchased from Sigma. MTT assay was performed to study drug induced cytotoxicity and thymidine uptake was used as a measure to study differences in proliferation. Flow cytometry using Annexin V-FITC and propidium iodide (PI) was used to measure drug induced apoptosis in cell lines and patient cells. In addition, apo-2.7 was also used to measure apoptosis in patient cells. Mitocapture and cytochrome-c assays were also performed to confirm the induction of apoptosis in MM cell lines. In order to study the mechanism of action of the drug, immunoblotting studies were performed on lysates made from cell lines incubated with the drug for various time points. Results: AT219 induced potent cytotoxicity in MM cell lines MM1S, MM1R and H929, all three expressing wild type p53 with IC50 values of 2.5–5μM. Similar effects were observed when the above mentioned cell lines were treated with AT219 and the inhibitory effect of proliferation of these cells were examined. When MM1S or H929 cells were cultured with bone marrow stromal cells (BMSCs) derived from MM patients or with one of the three tumor promoting cytokines implicated in MM (IL6, IGF or VEGF) and treated with AT219, the drug was able to inhibit the proliferation of both cell lines to similar extents as observed when cultured independently without BMSCs or the cytokines. The increase in cytotoxicity was found to be due to cells undergoing apoptosis as observed when MM1S or H929 cells were cultured with AT219 and % apoptotic cells were measured as measured by annexin/PI, mitocapture and cytochrome c assays. AT219 was also observed to induce more potent apoptosis in primary cells obtained from new MM patients with wild type p53 than in cells obtained from relapsed MM patients with wild type p53. AT219 clearly upregulated p53 as observed by performing immunoblots after treatment with the drug in MM1S and H929 cells. In addition, MDM2 and p21 were also found to be significantly upregulated and Bax was slightly upregulated post drug treatment. Bcl2, Mcl1 and Xiap levels were down regulated. In MM1S cells AT219 treatment resulted in a slight down regulation of pAkt (Ser 473). However, in H929 cells we observed a transient upregulation of pAkt following AT219 treatment. This prompted us to test AT219 in combination with Akti on MM cell lines. Our results on both MM1S and H929 cells using AT219 in combination with Akti demonstrated synergy. We are currently testing this combination in primary cells drawn from MM patients with both wild type p53 and those with p53 deletions and mutations. Conclusions: Our studies validate the anti-MM activity of AT219 in MM patients with wild type p53. In addition to using AT219 in combination with Akti, we are testing AT219 in combination with existing anti- MM chemotherapeutic agents. Interesting results from our studies will form the basis for clinical evaluation of AT219 as a single agent or in combination with an Akt inhibitor or other agents in MM patients. Disclosures: Kumar: Celgene: Consultancy, Research Funding; Merck: Consultancy, Honoraria; Millennium Pharmaceuticals, Inc.: Research Funding; Novartis: Research Funding; Genzyme: Research Funding; Cephalon: Research Funding.

Abstract Introduction High dose chemotherapy and autologous stem cell transplantation (ASCT) is an effective therapy for eligible patients with newly diagnosed systemic AL amyloidosis. Dose attenuated melphalan is used in patients with older age, renal dysfunction, and multi-organ involvement in an effort to limit treatment related mortality. Reducing the dose of melphalan compromises response rates and survival outcomes, but this is often contributed to frailty of these patients. The revised Mayo staging (MS) system improves risk stratification and helps develop risk-adapted therapies. We analyzed the outcomes of ASCT following standard [(200 mg/m2); SD group] versus risk adapted [(140-160 mg/m2); RD group] melphalan conditioning, in the context of the factors typically leading to dose modification. Methods Three hundred and twenty nine patients with newly diagnosed systemic AL amyloidosis who underwent conditioning with melphalan followed by ASCT at Mayo Clinic between 2006 and 2015 were identified using existing databases. The clinical and laboratory data, treatment and follow - up details were collected by chart review and analyzed retrospectively. Overall survival(OS) was defined as the time from start of initial therapy until death from any cause or last follow up. Progression free survival(PFS) was defined as the time to relapse or progression requiring change or reinstitution of treatment or death from any cause. The OS and PFS curves were estimated using Kaplan-Meier method while log rank test was used to estimate their difference. Multivariate survival analysis was performed using the Cox proportional hazards model. Results Among the 329 patients, 240 patients were in SD group and 89 patients were in RD group (1 patient received 120 mg/ m2, 2 received 160 mg/m2 and the rest received 140 mg / m2). In the SD group, median age was 58.5 years (25.6 - 72.3); 59.6% were males; 38.7% / 61.7 %/ 7.5% had cardiac / renal /hepatic involvement; and 47.1% / 35.7% / 8.8% / 8.4% had MS I/II/III/IV. In the RD group, median age was 60.8 years (40 - 73.7); 62.9% were males; 66.3% / 71.9 %/ 11.2% had cardiac / renal /hepatic involvement; and 26.2% / 32.5% / 21.2% / 20% had MS I/II/III/IV. The response rates for patients in the SD group [complete response (CR) - 53.7%, very good partial response (VGPR) - 19.6%, partial response (PR) - 12.5%, no response (NR) - 1.2%, progressive disease (PD) - 1.6%] were significantly higher than patients in the RD group (CR - 34.8%, VGPR - 20.2%, PR - 15.7%, NR - 10.1%, PD - 1.1%) (85.8 vs 70.7%; p < 0.002). The PFS and OS for both the groups according to Mayo stage are presented in Figure 1. Multivariate survival analysis for PFS and OS was performed using age (≤ vs > 70 years), serum creatinine (≤ vs > 2 mg/dL), number of major organs involved (heart, kidney, liver, gastrointestinal tract and autonomic neuropathy), MS (1 vs 2 vs 3 and 4) and dose of melphalan (SD vs RD). The dose of melphalan (p=0.0002), MS (p=0.03) and the number of organs involved (p=0.04) were significant for PFS while the dose of melphalan (p=0.0001) and the MS (p = 0.004) were significant for OS. Conclusion Reducing the dose of melphalan during conditioning for frontline ASCT in systemic AL amyloidosis renders more patients eligible for transplant but compromises on the response rates. There is no impact on PFS and OS in Mayo stage I patients. However the OS as well as PFS in Mayo stage II, III and IV were significantly lower in RD group as compared to SD group. These results suggest a suboptimal outcome with use of reduced dose melphalan, even after accounting for the pother prognostic factors, suggesting that high dose therapy should potentially be limited to those eligible to receive the full dose conditioning. Disclosures Dispenzieri: Jannsen: Research Funding; pfizer: Research Funding; GSK: Membership on an entity's Board of Directors or advisory committees; Alnylam: Research Funding; Prothena: Membership on an entity's Board of Directors or advisory committees; Celgene: Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding. Kapoor:Takeda: Research Funding; Amgen: Research Funding; Celgene: Research Funding. Kumar:Skyline: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Research Funding; BMS: Consultancy; AbbVie: Research Funding; Array BioPharma: Consultancy, Research Funding; Sanofi: Consultancy, Research Funding; Onyx: Consultancy, Research Funding; Glycomimetics: Consultancy; Kesios: Consultancy; Noxxon Pharma: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Millennium: Consultancy, Research Funding.

Abstract Background . Cell-free DNA (cfDNA) sequencing enables serial temporal sampling, which offers the possibility of following the dynamics of biomarkers and clonal evolution in Multiple Myeloma (MM) over time. The use of cfDNA in clinical practice as a molecular biomarker and for monitoring response/resistance is dependent on a comprehensive profile of matched cfDNA and tumor DNA (tDNA) samples. Here we performed Ultra-Low Pass Whole Genome Sequencing (ULP-WGS) followed by whole-exome sequencing (WES) and targeted deep sequencing of matched cfDNA/tDNA samples from MM patients. Methods. We performed next generation sequencing of matched cfDNA/tDNA samples for 63 patients with newly diagnosed or relapsed MM, SMM, or MGUS. Libraries were constructed using the Kappa Hyper kit and sequenced by ultra-low-pass whole-genome sequencing (ULP-WGS, 0.1x coverage) to quantify tumor fraction within cfDNA. WES was performed on 30 matched samples cfDNA/tDNA/germline DNA from 10 patients with more than 5% of tumor fraction. Libraries were hybridized to the Nextera Rapid Capture Exome kit (Illumina) and then sequenced on HiSeq 4000 (Illumina). Targeted deep sequencing was performed on 32 matched cfDNA/tDNA samples from 16 patients using the HaloPlex HS technology (Agilent), allowing for molecular barcoding. Libraries were constructed according to the manufacturer's instructions and sequenced on HiSeq 2500 (Illumina). Sequencing data were analyzed using the Firehose pipelines, including MuTect, ABSOLUTE, ReCapSeg, GISTIC and MutSig. Results. We first used a cost-effective approach to establish the tumor content of cfDNA in a large-scale manner by ULP-WGS. Among 63 tested samples (53 MM, 6 SMM and 4 MGUS patient samples), the tumor fraction within cfDNA ranged from 0 to 81% with a mean of 10%. About 43% of these samples had tumor fraction greater than 5% within cfDNA. To assess whether cfDNA can capture the genetic diversity of MM and inform clinical management, we performed WES of matched cfDNA/tDNA/germline DNA samples for 10 patients (mean target coverage 194x). Copy number alterations (CNAs) assessed by WES (ReCapSeg) were consistent between cfDNA and tumor DNA. Similarly, focal CNAs assessed by GISTIC were consistent between tDNA and cfDNA. We then examined the overlap of somatic single nucleotide variants (SSNVs) between WES of cfDNA and matched tDNA. We found, on average, 100% of the clonal and 96% of the subclonal (range 54-100%) SSNVs that were detected in the tumor were confirmed to be present in cfDNA. Similarly, for mutations detected in the cfDNA, we found, on average, 100% of the clonal and 99% of the subclonal (range 98-100%) SSNVs were confirmed in the tumor. To assess whether targeted deep sequencing of cfDNA could be a good proxy for tumor biopsy we used a targeted deep sequencing approach of known MM driver genes. Libraries were prepared using unique molecular barcodes to avoid duplication rates, for 32 matched cfDNA/tDNA samples from 16 patients with MM. The mean target coverage was 596x. We found similar frequencies of altered MM driver genes in both cfDNA and tDNA, including KRAS, NRAS, and TP53, indicating that cfDNA can be used for precision medicine. Conclusions. Our study demonstrates that both WES and targeted deep sequencing of cfDNA are consistently representative of tumor DNA alterations in terms of CNAs, focal CNAs and SSNVs. This approach could therefore be used to longitudinally follow clonal evolution across the course of the disease and precision medicine in patients with MM. Disclosures Palumbo: Takeda: Employment, Honoraria; Janssen Cilag: Honoraria. Kumar:Noxxon Pharma: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Millennium: Consultancy, Research Funding; Skyline: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Research Funding; Kesios: Consultancy; Glycomimetics: Consultancy; BMS: Consultancy; Array BioPharma: Consultancy, Research Funding; Sanofi: Consultancy, Research Funding; AbbVie: Research Funding; Onyx: Consultancy, Research Funding. Roccaro:Takeda Pharmaceutical Company Limited: Honoraria. Facon:Amgen: Consultancy, Speakers Bureau; Novartis: Consultancy; Janssen: Consultancy, Speakers Bureau; Bristol: Consultancy; Millenium/Takeda: Consultancy; Celgene: Consultancy, Speakers Bureau; Karyopharm: Consultancy. Ghobrial:Celgene: Honoraria, Research Funding; BMS: Honoraria, Research Funding; Noxxon: Honoraria; Novartis: Honoraria; Takeda: Honoraria; Amgen: Honoraria.