Untreated MM Research Articles

Fixed Duration Daratumumab, Ixazomib, Lenalidomide, and Dexamethasone Quadruplet for Newly Diagnosed Multiple Myeloma - MRD Negativity and Survival Outcomes

Background: The combination of a proteasome inhibitor (PI), an immunomodulatory drug (IMiD), and dexamethasone is the current standard induction therapy for myeloma. Daratumumab (Dara), a monoclonal antibody directed against CD38, is highly effective in treating myeloma and improves response rates and progression free survival (PFS) when added to a PI or IMiD. Recent studies have shown high efficacy rates with quadruplet regimens that contain these three drug classes, potentially allowing for limited duration therapy as well as reduction in the steroid doses. We designed this trial to examine the efficacy of the quadruplet regimen containing daratumumab, ixazomib (an oral proteasome inhibitor), lenalidomide and dexamethasone (Dara-IRd) given for fixed duration, and to evaluate impact of early discontinuation of steroids. Patients and Methods: Patients with previously untreated MM who had measurable disease and adequate organ function were enrolled, irrespective of their autologous stem cell transplant eligibility (NCT03012880). The primary objective was to determine the rate of complete response to Dara-IRD combination. Treatment involved 28-day cycles consisting of ixazomib 4 mg days 1, 8, 15; lenalidomide 25 mg days 1-21, dexamethasone 40 mg, weekly and Dara 16 mg/kg, weekly for two cycles, every other week during cycles 3-6 and then every 4 weeks thereafter during induction (12-cycles) followed by Dara-ixazomib maintenance (maximum 24 cycles). Patients were enrolled into two sequential cohorts: Cohorts A (n=38) and B (N=40), with dexamethasone discontinued after two cycles in Cohort B. Transplant eligible patients were allowed to collect stem cells for future transplant anytime after 4 cycles. Serum immunofixation was assessed with mass spectrometry (MASS-FIX) and marrow MRD negativity by Euro flow (sensitivity of 1 in 105). Results: Seventy-eight patients were enrolled; median age was 63.5 (range 33, 81), 55% were male. A third of the patients were high risk by mSMART criteria and ISS stage 1, 2, and 3 had 41%, 35%, and 24% of patients respectively. All patients have completed the treatment phase and those who have not gone off study continue on observation. Among the 40 patients who have gone off study, the reasons for discontinuation among patients in Cohorts A and B, respectively were: progression, 9 and 12; alternate therapy (most often transplant), 11 and 8. The best overall response on therapy was 96% including 31% CR, 39% VGPR. For the entire cohort, time to response was fast, median time to VGPR, CR or minimal residual disease negative (MRD) negativity was 4 cycles. Responses deepened over the duration of treatment as shown in the figure; 31% of patients achieved a marrow MRD negative status (28% CR and MRDneg). After a median follow up was 37.8 months, median PFS or OS has not been reached. Five patients enrolled on the study have died. A grade 3 or higher adverse event at least possibly attributed to the study drugs was seen in 56% of patients. The most common toxicities included fatigue, neutropenia, lymphopenia, peripheral neuropathy, diarrhea, and nausea. Stem cells were collected in 60 patients; median (range) of CD34 cells/kg 7.8 (2.8, 15.9) x 106, with plerixafor used in 88% of patients as per our standard of care "on-demand” approach based on blood CD34 count. Conclusion: Dara-IRd is an active regimen in newly diagnosed MM, with high overall rates of response and deep and durable responses with nearly a third of the patients being MRDneg (Mass Spec based blood testing and flow based MRD), that improved over time with therapy. The toxicities were manageable, with dose modifications. All patients were able to collect stem cells when required, though the majority needed plerixafor. This study demonstrates excellent outcomes with limited duration quadruplet regimen without planned upfront autologous stem cell transplant and no maintenance till progression. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

P27: HUMORAL RESPONSE RATE POST MRNA COVID19 VACCINATION (BNT162B2) IS HIGLY DEPENDENT TO BONE MARROW PLASMACYTOSIS: LONG FOLLOW-UP OF SYMPTOMATIC MULTIPLE MYELOMA PATIENTS

Background: SARS-COV-2 anti-Spike IgG response following mRNA vaccination (BNT162b2) is suboptimal and highly variable in MM patients. Patients and Methods: We report here a single-institution retrospective analysis of 127 consecutive patients with symptomatic MM (71 males, 56 females), [median age 69.5 years (range 45-85)], 63 patients with untreated MM and 64 patients with MM refractory to one or more previous treatment lines. Myeloma therapies included PI+IMiD combos, IMiD-based regimens, PI-based regimens, anti-CD38 mAb-based therapies, antibody-drug conjugates (Belantamab Mafodotin monotherapy), dexamethasone and high dose melphalan. Anti-spike IgG antibody were detected also in 50 healthy volunteers. Patients with symptomatic MM and healthy controls received two dose of COVID-19 mRNA vaccine (Pfizer BioNTech) on days 1 and 21 between 29 April and 15 May 2021. Patients with prior history of SARS-CoV-2 were excluded from analysis. Quantitative determination of anti-spike S1/S2 IgG antibody was performed at 4 weeks from vaccination completion (LIAISON® SARS-COV-2 S1/S2 IgG, LIAISON®). It was previously established a threshold >15 AU/ml of anti-Spike IgG which was related to neutralizing activity of anti-SARS-COV-2 antibodies. Results: Sixty-five out of 127 patients were evaluable for response. Anti-spike IgG antibody were detected in 50/65 (76.9%) MM patients, defined as responders [177 AU/mL (range 26.4 – 1430)]. 23.1% of MM patients, defined as non-responders, failed to respond at two doses of COVID-19 mRNA vaccine [3.8 AU/mL (range 0.65 – 9.33)]. Seroprotection rate at cutoff of 15 AU/mL was 100% in controls [249 AU/mL (range 104 - 2430)]. No statistically significant differences were found between the two subgroups of patients for myeloma disease phase (relapse/refractory MM vs. untreated symptomatic MM), LDH, residual gammaglobulin levels, WBC, ANC, lymphocytic response, age and sex (Tab. 2). Conversely, plasmacytosis, B2M and haemoglobin concentration were associated with a different response to vaccine. Patients with extreme plasmacytosis (60.0 ± 20.3 vs. 28.2 ± 18.8 mean ± SD; p <0.001) (Tab. 2) had a mean titer less than 15 AU/ml of anti-Spike IgG compared with patients with a low plasmacytosis, who, conversely, showed significantly higher mean titers of anti-Spike IgG. B2M was significantly higher in non-responders compared to responders (4.6 ± 4.1 vs. 3.2 ± 3.6 mean ± SD; p = 0.006) (Tab. 2). Haemoglobin value was significantly lower in non-responders compared to responders (10.8 ± 1.8 vs. 12.1 ± 1.8 mean ± SD; p = 0.008) (Tab. 2). Multivariate analysis confirmed the bone marrow infiltration pattern and haemoglobin value as statistically significant variables. In addition, in the present cohort, the myeloma treatment, including high-dose melphalan and autologous stem cell transplantation, have not been associated with SARS-CoV-2 infection. Conclusions: In our experience, significant fraction of MM patients (23.1%) does not developed any detectable anti-Spike IgG after two dose of COVID-19 mRNA vaccine. Lack of IgG response associated with three statistically significant variables: extreme plasmacytosis, B2M, and haemoglobin concentration. In the subgroup of patients with good response to vaccine, after a median follow-up of 7 months from second dose of COVID-19 mRNA vaccine, no cases of COVID-19 occurred.

Comparable Outcomes With Bortezomib-Cyclophosphamide-Dexamethasone (VCD) and Bortezomib-Lenalidomide-Dexamethasone (VRD) For Initial Treatment Of Newly Diagnosed Multiple Myeloma (MM)

Comparable Outcomes With Bortezomib-Cyclophosphamide-Dexamethasone (VCD) and Bortezomib-Lenalidomide-Dexamethasone (VRD) For Initial Treatment Of Newly Diagnosed Multiple Myeloma (MM)

Interim Safety Analysis of a Phase 2 Randomized Study of Daratumumab (Dara), Lenalidomide (R), Bortezomib (V), and Dexamethasone (d; Dara-Rvd) Vs. Rvd in Patients (Pts) with Newly Diagnosed Multiple Myeloma (MM) Eligible for High‐Dose Therapy (HDT) and Autologous Stem Cell Transplantation (ASCT)

Background: Addition of Dara to Vd and Rd improved complete (CR) and overall response rates (ORR) and progression‐free survival (PFS) in relapsed MM. RVd followed by HDT, ASCT, and consolidation RVd achieves high response rates in previously untreated MM. The primary objective of this study is to determine if the addition of Dara to RVd will increase the stringent CR (sCR) rate by the end of post‐ASCT consolidation therapy.Methods: This is an ongoing multicenter, randomized, open‐label, active‐controlled study conducted in the US. Key eligibility criteria include age 18‐70 years; eligibility for HDT and ASCT; documented MM per IMWG 2015 criteria; ECOG performance score of 0‐2; and no prior systemic therapy for MM. An initial safety run-in phase was performed in 16 pts treated with Dara-RVd in order to assess potential dose limiting toxicities (DLTs) during Cycle 1. Following successful completion of the safety run-in phase, approximately 200 pts will be randomized 1:1 to Dara‐RVd or RVd. Pts receive 4 induction cycles (every 21 days) of RVd +/‐ Dara; followed by stem cell mobilization, HDT, ASCT; 2 consolidation cycles (every 21 days) of RVd +/‐ Dara; and maintenance therapy with R +/‐ Dara for 24 months. During induction and consolidation (cycles 1‐6), all pts receive R 25 mg orally on Days 1‐14; V 1.3 mg/m2 subcutaneously on Days 1, 4, 8, and 11; and d 40 mg weekly. In the Dara‐RVd group, Dara 16 mg/kg IV is given on Days 1, 8, and 15 of cycles 1‐4 and on Day 1 of cycles 5‐6. During maintenance (cycles 7-32), all pts receive R 10 mg daily (15 mg beginning at Cycle 10 if no tolerability issues) on Days 1‐21 every 28 days; Dara 16 mg/kg IV is given every 56 days (every other cycle) in the Dara‐RVd arm only. Here, we present the results of the pre-planned safety analysis after the first 4 cycles of therapy in the safety run-in phase of the study.Results: Sixteen pts were enrolled in the safety run-in, and all pts had completed at least 4 cycles of Dara-RVd as of 05 July 2017. Median age was 62.5 (range 46 to 65) years, and 50% were male. Thirteen percent of pts were ISS stage II and stage III, each. Most pts (63%) were ECOG 1. During Cycle 1, 3 pts experienced AEs that met Sponsor pre-defined DLT criteria: grade 3 fatigue on Day 15, gastroenteritis on Day 21, pneumonitis (due to infection) and hypotension on Day 5. None of these events were determined by the investigator to require treatment discontinuation, and all 3 pts remained on therapy. All 16 pts experienced at least 1 treatment emergent adverse event (TEAE) during cycles 1-4; 3 (19%) pts had at least 1 serious AE (SAE), with 2 (13%) related to Dara (gastroenteritis and pneumonitis). Eight (50%) pts had grade 3-4 TEAEs, with 6 (38%) related to Dara. The most commonly reported grade 3-4 TEAEs were neutropenia and thrombocytopenia (19% each), lymphopenia and leukopenia (13% each). Six (38%) pts experienced infections, including 1 Grade 3 SAE of gastroenteritis. There were no events of febrile neutropenia. There was no fatal outcome and no pt discontinued treatment due to TEAEs. Dara infusion related reactions (all Grade ≤2) were reported in 31% of pts during Cycles 1-4. To date, 11 pts had undergone mobilization with a median stem cell yield of 6.0 x 106 (range 3.5-10.6) CD34+ cells/kg. All 16 pts in the safety run-in phase continue study treatment. Updated data and follow-up on these 16 pts will be presented at ASH.Conclusion: No new safety signals were identified with the addition of Dara to RVd during the first 4 cycles of Dara-RVd in 16 pts with newly diagnosed MM. The overall safety profile was consistent with those previously reported for Dara and RVd. The first 4 cycles of safety run-in phase are completed, and all 16 pts continue therapy. Enrollment to the main phase of the randomized study is ongoing. DisclosuresVoorhees:Novartis: Consultancy; Oncopeptides: Consultancy; Janssen: Consultancy, Speakers Bureau; Bristol-Myers Squibb: Consultancy; Takeda: Consultancy; Amgen: Speakers Bureau; Celgene: Consultancy, Speakers Bureau. Rodriguez:Celgene: Other: advisory board, Speakers Bureau; Takeda: Speakers Bureau. Lutska:Janssen: Employment. Hydutsky:Janssen: Employment. Pei:Janssen: Employment. Ukropec:Janssen: Employment. Qi:Johnson & Johnson, LLC: Equity Ownership; Janssen: Employment. Lin:Janssen: Employment. Richardson:Jazz Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Oncopeptides AB: Membership on an entity's Board of Directors or advisory committees.

Lenalidomide and dexamethasone with or without clarithromycin in patients with multiple myeloma ineligible for autologous transplant: a randomized trial

Although case-control analyses have suggested an additive value with the association of clarithromycin to continuous lenalidomide and dexamethasone (Rd), there are not phase III trials confirming these results. In this phase III trial, 286 patients with MM ineligible for ASCT received Rd with or without clarithromycin until disease progression or unacceptable toxicity. The primary endpoint was progression-free survival (PFS). With a median follow-up of 19 months (range, 0–54), no significant differences in the median PFS were observed between the two arms (C-Rd 23 months, Rd 29 months; HR 0.783, p = 0.14), despite a higher rate of complete response (CR) or better in the C-Rd group (22.6% vs 14.4%, p = 0.048). The most common G3–4 adverse events were neutropenia [12% vs 19%] and infections [30% vs 25%], similar between the two arms; however, the percentage of toxic deaths was higher in the C-Rd group (36/50 [72%] vs 22/40 [55%], p = 0.09). The addition of clarithromycin to Rd in untreated transplant ineligible MM patients does not improve PFS despite increasing the ≥CR rate due to the higher number of toxic deaths in the C-Rd arm. Side effects related to overexposure to steroids due to its delayed clearance induced by clarithromycin in this elderly population could explain these results. The trial was registered in clinicaltrials.gov with the name GEM-CLARIDEX: Ld vs BiRd and with the following identifier NCT02575144. The full trial protocol can be accessed from ClinicalTrials.gov. This study received financial support from BMS/Celgene.

Daratumumab, Ixazomib, Lenalidomide, and Dexamethasone for Newly Diagnosed Multiple Myeloma

Daratumumab, Ixazomib, Lenalidomide, and Dexamethasone for Newly Diagnosed Multiple Myeloma

Abstract A144: The transcriptomic profile of peripheral T-cells that maintain dormant state of melanoma cells in patients treated with allogenic melanoma vaccine

Abstract Melanoma (MM) cells leave primary tumors early and evolve at different sites in parallel. However, timing in human MM is unknown. Lymphatic dissemination is fast shortly after the dermal invasion, but metastases may occur late. Such delay in metastases formation suggests possible host defense mechanism, or particular nature of non-actively proliferative (dormant) MM stem cell (MSC) population. T lymphocytes may also induce tumor dormancy. The proposed mechanism involves a cytostatic mode of tumor silencing resulting from the suppression of both neoplastic cell proliferation and cell cycle progression. Significant progress in the development of novel advanced MM therapies was made. However, not all patients benefit from the therapy, developing late metastases decades after treatment ends. Moreover, using the immunotherapy-based model of MM dormancy in mouse, vaccination against MM prevented tumor growth but failed to prevent tumor cell dissemination or elimination of all MM cells. We have developed therapeutic gene modified allogenic MM vaccine (AGI-101H) that has been tested since 1997 and resulted in long-term survival of a substantial fraction of patients. Genetic modification of vaccine cells to express designer cytokine cDNA encoding Hyper-IL-6 protein (comprising of IL-6 linked with a soluble IL-6 receptor) has altered AGI-101H cells phenotype towards MSC-like with high activity of aldehyde dehydrogenase isoenzyme (ALDH1A1). We have found significant induction of anti-MSCs response in immunized patients by a generation of functionally active cytotoxic CD8+T-cells and antibodies specific for ALDH1A1 in circulation. However, the AGI-101H mode of action is complex: besides inducing a direct anticancer response to MSC population, long-term vaccination may induce MM dormancy through T-cell mediated immunity. The above hypothesis is based on clinical observations of AHI-101H treated patient who was progression-free for many years, but injury induced metastases formation in the bruise. This patient developed skin MM in 1999. In 2002 in transit metastases appeared (resected). The patient was enrolled into AGI-101H program. In 2003 metastases in liver (resected), 2004 metastasis in ovary (resected). 11 years (2004-2015) no progression. In Nov. 2015 she had bicycle accident, trauma, and MM metastasis presenting with a bruise (resected). The treatment continues with no progression. The aim was to determine the molecular mechanisms of peripheral T-cell-mediated induction of MM dormancy induced by vaccination. Therefore, T-cell mRNA expression profiling of long-term surviving patients was carried out. PBMCs were isolated from treated patients (18), untreated MM patients (13) and healthy controls (8). Untouched T-cells were separated by magnetic beads and total RNA isolated. The transcriptome profiling was performed with Affymetrix HG U219 microarray (19,285 markers). Differential gene expression (DGE) analysis between all groups was conducted and validated with RT-qPCR and FACS. The transcriptomic results were further analyzed with Gene Set Enrichment Analysis (GSEA) tool. DGE analyses comparing AGI-101H vaccinated (AV) and nonimmunized (C) patients revealed 538 differentially expressed genes (DEGs), with 373 downregulated and 165 upregulated in AV (adj p &amp;lt; 0.05). Among these 538 markers, the expression of 14 (with |log2FC| &amp;gt; 1) is now being validated with RT-qPCR and FACS. Also, GSEA analysis revealed significant enrichment of “TNFa_signaling_via_NFkB”, “TGFb_signaling” and “G2/M_checkpoint” hallmark processes (MSigDB Hallmark gene sets) in AGI-101H vaccinated patients, that indicates considerable activation of antitumor response and prevention of conversion of MM dormanT-cells into proliferative metastases. Transcriptome profiling of peripheral T-cells in long-surviving MM patients immunized with AGI-101H suggests activation of the molecular mechanism that sustains MM cells in the non-actively proliferative dormant state. Citation Format: Andrzej A. Mackiewicz, Partycja Czerwinska, Marcin Rucinski, Katarzyna Gryska, Iga Grzadzielewska, Anna Jaworska, Jacek Mackiewicz. The transcriptomic profile of peripheral T-cells that maintain dormant state of melanoma cells in patients treated with allogenic melanoma vaccine [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A144.

Phase 2 Trial of Ixazomib, Lenalidomide, Dexamethasone and Daratumumab in Patients with Newly Diagnosed Multiple Myeloma

Background: The combination of a proteasome inhibitor (PI), an immunomodulatory drug (IMiD), and dexamethasone is the current standard induction therapy for myeloma. Daratumumab, a monoclonal antibody directed against CD38, is highly effective in treating myeloma and improves response rates and progression free survival (PFS) when added to PI or IMiD. Ixazomib, lenalidomide and dexamethasone (IRd) is an effective, all oral, induction regimen that has been studied in phase 2 and 3 trials. We designed this trial to examine the feasibility and efficacy of adding daratumumab to the IRd regimen.Patients and Methods: Patients with previously untreated MM, with measurable disease and adequate organ function were enrolled irrespective of their transplant eligibility. The primary objective was to determine the rate of complete response to the IRD-Dara combination in patients with NDMM. Treatment consisted of Ixazomib 4mg days 1, 8, 15; lenalidomide 25 mg days 1-21, dexamethasone 40 mg, weekly and daratumumab 16 mg/kg, weekly for two cycles, every other week during cycles 3-6 and then every 4 weeks after that. Overall, 40 patients were accrued; data on 38 patients were available for analysis as of July 02, 2018 (Table 1).Results: The median age was 62 (41-81); 52.6% female. All patients were alive and progression free at last assessment with a median follow up of 5.2 (2.0-12.9) months (median 5 cycles, range 2-13). One patient had gone off for alternate therapy. Responses were rapid with 90% partial response or better (32% VGPR) after 2 cycles, and 100% PR or better (50% VGPR) for 32 patients who have completed 4 cycles. The overall best confirmed response rate among the 38 patients was 95% including 11% CR and 47% VGPR. Overall, 231 cycles have been administered across the study, with dose modifications/ hold required for ixazomib, lenalidomide, daratumumab and dexamethasone in 3 (8%), 11 (29%), 2 (5%), and 8 (21%) patients respectively, the most common reasons being hematologic and skin rash. A grade 3 or higher adverse event at least possibly attributed to the study drugs was seen in 42% of patients, hematologic in 37% and non-hematologic in 11% (Figure). 11 patients have so far proceeded to stem cell collection, all have collected adequate numbers of stem cells for one or two intended transplants(median CD34+ collected 8.4 million/kg; range 3.8-12.3). Updated results with additional 6 months of follow up and MRD testing will be presented at the meeting.Conclusion: This represents the first reported results of this combination for treatment of newly diagnosed myeloma. The early results from the use of IRd-Dara in newly diagnosed myeloma suggests excellent efficacy with rapid responses that deepen quickly over the initial cycles of therapy. The regimen was well tolerated with limited dose modifications and no discontinuation for toxicity and no influence on the ability to collect stem cells. [Display omitted] DisclosuresKumar:Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; KITE: Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding. Kapoor:Takeda: Research Funding; Celgene: Research Funding. Dingli:Alexion Pharmaceuticals, Inc.: Other: Participates in the International PNH Registry (for Mayo Clinic, Rochester) for Alexion Pharmaceuticals, Inc.; Alexion Pharmaceuticals, Inc.: Other: Participates in the International PNH Registry (for Mayo Clinic, Rochester) for Alexion Pharmaceuticals, Inc.; Millennium Takeda: Research Funding; Millennium Takeda: Research Funding. Lacy:Celgene: Research Funding. Dispenzieri:Celgene, Takeda, Prothena, Jannsen, Pfizer, Alnylam, GSK: Research Funding. Gertz:Prothena: Honoraria; Amgen: Consultancy; Abbvie: Consultancy; Teva: Consultancy; annexon: Consultancy; janssen: Consultancy; celgene: Consultancy; Alnylam: Honoraria; Medscape: Consultancy; Apellis: Consultancy; spectrum: Consultancy, Honoraria; Physicians Education Resource: Consultancy; Ionis: Honoraria; Research to Practice: Consultancy.

A phase 1/2 study of durvalumab (DURVA) in combination with lenalidomide (LEN) with or without dexamethasone (DEX) in patients (pts) with newly diagnosed multiple myeloma (NDMM).

TPS8055 Background: LEN + DEX (Rd) is approved for pts with newly diagnosed MM, including those who are transplant non-eligible (TNE). DURVA is a monoclonal antibody to programmed death ligand 1 (PD-L1) that blocks PD-L1 binding to programmed death-1 (PD-1). Preclinical studies showed anti-MM immune responses with PD-1/PD-L1 blockade that were enhanced with LEN (Görgün et al, 2015). Here, we present a phase 1/2, multicenter, open-label trial in progress (MEDI4736-MM-002) designed to evaluate DURVA in combination with LEN ± DEX in a target population of pts who are TNE and/or with high-risk NDMM. Methods: Enrollment of up to 138 pts from the US, Canada, and Europe is planned to determine the recommended dose of DURVA (primary endpoint) with LEN ± DEX for the treatment (Tx) of NDMM. Key secondary endpoints include safety, response outcomes, pharmacokinetics, progression-free survival, and overall survival. Pts with previously untreated MM with ≥ 1 of the following will be included: 1 of the CRAB criteria or clonal bone marrow plasma cells ≥ 60% and an Eastern Cooperative Oncology Group performance status of ≤ 2. Pts with a history of primary immunodeficiency will be excluded. Each independent cohort (A, B, C) will enroll 6 pts in parallel in the dose-finding phase (Table). Dose-limiting toxicities will be evaluated during the first cycle of Tx. The optimal regimen will be determined from the dose-finding phase and a parallel dose-expansion phase of up to 40 pts per cohort. Tx will continue until progressive disease or unacceptable toxicity. To date, 15 pts have enrolled. Clinical trial information: NCT02685826. [Table: see text]

Phase 1 Study of the Investigational Proteasome Inhibitor Ixazomib Alone or in Combination with Lenalidomide–Dexamethasone (Rd) in Japanese Patients (Pts) with Relapsed and/or Refractory Multiple Myeloma (RRMM)

Background Ixazomib is the first oral proteasome inhibitor to be investigated clinically for the treatment of MM. Phase 1 studies have shown single-agent activity and manageable toxicities in RRMM (Kumar et al. Blood 2014) and phase 1/2 studies have suggested the feasibility and activity of weekly oral ixazomib plus Rd in previously untreated MM (Kumar et al. ASH 2012; Richardson et al. ASH 2013). These findings have led to ongoing phase 3 trials of weekly ixazomib 4 mg + Rd in RRMM and previously untreated MM. However, the early-phase studies were conducted in Western pts. This phase 1, open-label multicenter study aimed to determine the safety, tolerability, and pharmacokinetics (PK) of weekly ixazomib alone or with Rd in Japanese pts with RRMM (Japic Clinical Trials Information no. 121822). Methods Primary objectives were to evaluate the safety and tolerability, including dose-limiting toxicities (DLTs) and adverse events (AEs), and the PK of ixazomib alone or with Rd. A secondary objective was evaluation of antitumor activity. Japanese pts aged ≥20 years with RRMM who had received at least 2 prior regimens, which must have included bortezomib, thalidomide or lenalidomide, and corticosteroids, were eligible. All had measurable disease and ECOG performance status of 0–2. Pts with grade ≥2 peripheral neuropathy or grade ≥2 diarrhea at study entry were excluded. Pts received ixazomib 4 mg on days 1, 8, and 15 of 28-day cycles, alone or with Rd (lenalidomide 25 mg on days 1–21, dexamethasone 40 mg on days 1, 8, 15, and 22), per the regimen used in the ongoing phase 3 trials. AEs were graded per NCI-CTCAE v4.03. Blood samples for PK analysis were taken at multiple time points prior to and after dosing on days 1 and 15 of cycle 1. Responses were assessed per IMWG uniform response criteria. Results Fourteen pts were enrolled; 8 (57%) were male, median age was 62.5 yrs (range 53–71), 4 pts were aged ≥65 yrs, median number of prior therapies was 7. Seven pts received single-agent ixazomib and 7 received ixazomib + Rd. One pt in each cohort was excluded from the DLT-evaluable population. Two patients experienced DLTs in cycle 1: 1 pt receiving single-agent ixazomib had grade 4 thrombocytopenia and grade 3 diarrhea, hypertension, hypokalemia, hyponatremia, and nausea; 1 pt in the ixazomib + Rd cohort had grade 4 thrombocytopenia and neutropenia. All events were considered treatment-related. At data cut-off (Jan 6 2014), 6 pts remained on treatment and 8 had discontinued due to: progressive disease (PD; n=3), AEs (n=3), symptomatic deterioration, and protocol violation (each n=1). At data cut-off, pts (n=14) had received a median of 6 cycles of ixazomib (range 1–21); the 7 pts in the ixazomib + Rd cohort had received a median of 4 cycles (range 1–12) of ixazomib + Rd. Thirteen (93%) pts experienced treatment-related AEs; the most common were neutropenia (71%), thrombocytopenia (71%), leukopenia (64%), lymphopenia (57%), and diarrhea (50%). There were no cases of peripheral neuropathy. Nine (64%) pts had grade ≥3 AEs; the most common were lymphopenia (50%), neutropenia (43%), and thrombocytopenia (36%). Two (14%) pts (single-agent cohort) had serious AEs (grade 2 bronchitis in 1 pt, and grade 4 thrombocytopenia and grade 3 hypokalemia in 1 pt). Three pts discontinued due to AEs; 1 due to diarrhea in the single-agent cohort, and 1 due to neutropenia and 1 due to thrombocytopenia in the ixazomib + Rd cohort. There were no deaths. PK data showed ixazomib was rapidly absorbed with a Tmax at 1.08–1.83 hrs. Terminal half-life (geometric mean) was 5.7 days for single-agent ixazomib and 5.2 days for ixazomib + Rd. There were no substantial differences in the ixazomib PK profile between the two cohorts. Thirteen pts were response-evaluable. One pt (ixazomib + Rd cohort) had a partial response; at data cut-off, this pt remained in response with a 100% M-protein reduction (unconfirmed VGPR) and duration of response of ~10.8 months. Seven pts had stable disease (including 3 with M-protein reductions of 25–50%), 2 had PD, and 3 were not assessable. Conclusions These data suggest that ixazomib 4 mg alone or with Rd is feasible and tolerable in Japanese pts with RRMM. The AEs were manageable, reflecting the AE profile seen in Western populations, supporting the use of this dose and schedule in Japanese pts. Disclosures Handa: Celgene: Research Funding; Yakult: Research Funding; Kirin: Research Funding; Chugai: Research Funding. Off Label Use: Investigational agent ixazomib for the treatment of Japanese patients with relapsed and/or refractory multiple myeloma.. Matsushima:Takeda Pharmaceutical Company Limited : Employment.

Concurrent De Novo Myeloid Neoplasm and Plasma Cell Dyscrasia: A Clinicopathologic Study of 27 Cases

Background: Myeloid and plasma cell neoplasms represent clonal disorders of different lineages. Patients with plasma cell dyscrasia (PCD) may develop secondary myelodysplastic syndrome/acute myeloid leukemia (MDS/AML) following cytotoxic chemotherapy for PCD. Therapy-related MDS/AML has a poor prognosis and is clonally distinct from the PCD. Coexistence of de novo MDS/AML and PCD without prior chemotherapy has only occasionally been reported in the literature. Whether these two distinct neoplasms are derived from the same ancestral pre-malignant stem cell is uncertain. In this study, we report 27 cases of concurrent MDS/AML and PCD, and summarize the clinicopathologic features.Methods and Materials: Twenty-seven cases of untreated smoldering MM (SMM) or monoclonal gammopathy of undetermined significance (MGUS) with concurrent de novo MDS, AML or myelodysplastic/myeloproliferative neoplasm (MDS/MPN) were identified from the pathology database at the Department of Hematopathology, Moffitt Cancer Center between 2005 and 2014. Bone marrow biopsies, laboratory data, flow cytometric and cytogenetic studies of each case were reviewed. Clinical features were obtained by chart review.Results: There were 20 (74%) males and 7 females (26%) with a median age of 71 (range, 57 -87) years. Twenty-two (81%) patients had a diagnosis of MDS/AML made at the same time as the diagnosis of PCD. Four (15%) patients had a history of MGUS ranging from 6 months to 20 years and received no treatment. One (4%) patient had a history of low grade MDS/refractory cytopenia with multilineage dysplasia (RCMD) for 7 years before the development of PCD. None of the patients received prior cytotoxic chemotherapy, radiotherapy or immunomodulatory therapy before the concurrent neoplasms were diagnosed. Thirteen (48%) patients were diagnosed with MGUS, and 14 (52%) patients were diagnosed with SMM. Four patients with MGUS evolved to SMM and none of the patients with MGUS or SMM showed progression to symptomatic MM. The myeloid neoplasms included MDS (n=17, 63%), AML (n=6, 22%), chronic myelomonocytic leukemia, type 1 (CMML-1: n=3, 11%), and refractory anemia with ring sideroblasts associated and thrombocytosis (RARS-T: n=1, 4%). The MDS cases were 1 case of MDS with isolated del(5q) (4%), 2 cases of RARS (7%), 10 cases of RCMD, (37%), 1 case of refractory anemia with excess blasts, type 1 (RAEB-1, 4%), and 3 cases of RAEB-2 (11%). Twenty-five patients (93%) received therapy for the myeloid neoplasms, including DNA hypomethylating agent(s) (HMA) and/or combination chemotherapy. Of them only 2 patients were treated for PCD. Excluding 6 patients with AML, 10 of 19 patients with MDS or MDS/MPN have full or partial response to HMA therapy. However, the remaining 9 patients showed disease progression. Two patients with low grade MDS had progression to RAEB-1, while 6 patients (3 RAEB I or II and 3 RCMD) had progression to AML. The patient with RARS-T showed sequential progression of disease to CMML and AML. Two of the three patients with CMML-1 showed progression of disease to CMML-2, but without further progression to AML. The median duration of follow up was 20 (range, 2 – 143) months, and 9 patients (33%) died of the disease, and one patient died from concurrent lung cancer. Of the 17 patients with MDS, 76% were categorized as low/intermediate-1 risk and 24% were intermediate-2 or high risk according to the International Prognostic Scoring System (IPSS). Based on the IPSS risk score, the median overall survival (OS) was 23, 24, 20, and 13 months for low, intermediate-1, intermediate-2, and high-risk categories, respectively. There were no differences in the OS rates. The 5-year OS rate of the 13 patients with low/intermediate-1 risk MDS was 62%.Conclusion: Based on the review of over 1000 myeloid neoplasms registered at our institutional pathology database during the time period, the concurrent de novo MDS/AML and PCD is considered an uncommon occurrence but represents an important clinical entity. A subpopulation of patients with low grade MDS tended to have a rapid disease progression, while the SMM cases remained indolent without progression to symptomatic MM. Excluding an underlying myeloid disorder has therapeutic implication in a patient with otherwise MGUS /SMM and cytopenias without bone or renal disease. DisclosuresNo relevant conflicts of interest to declare.

Phase III Trial Of Bortezomib, Melphalan, and Prednisone (VMP) Versus Bortezomib, Thalidomide, and Prednisone (VTP) In Elderly Multiple Myeloma (MM) Patients: Update Follow-Up, Patterns Management Of First Relapse/Progression

BackgroundInitial results of the Spanish GEM2005mas65 phase III trial comparing VMP versus VTP as induction therapy in elderly patients with newly diagnosed MM did not show any difference in terms of OS or PFS. The purpose of this study was to update clinical results with a longer follow-up. Secondary objectives were to know the patterns of symptomatic relapse and response to therapy in patients previously exposed to novel agents. MethodsGEM2005mas65 trial lasted from March, 2006, and October, 2008. Overall, 260 patients with untreated MM, 65 years and older, from 63 Spanish centres, were randomly assigned to receive six cycles of VMP (n=130) or VTP (n=130) as induction therapy followed by maintenance therapy with bortezomib plus prednisone (n=87) or bortezomib plus thalidomide (n=91). ResultsWith a median follow-up of 53.2 months, median OS of the entire cohort of patients was 42.45 months. Median OS was 62 months in patients receiving VMP versus 42.6 months in patients receiving induction with VTP (P = 0.045) (Figure 1). No differences were observed in PFS, being 31 and 24.4 months in the VMP and VTP groups, respectively.At the time of the study, 167 patients had relapsed or progressed and 92 of them received some kind of post relapse treatment. Front-line therapy and clinical and biological characteristics at the time of relapse in this subgroup of patients are summarized in Table 1.Initial induction treatment consisted of VMP in 40 (43.4%) patients and VTP in 52 (56.5%) patients. Overall, after induction and maintenance therapy 66 (71.7%) patients had been exposed to bortezomib and thalidomide and 26 (28.2%) patients received bortezomib-based therapy without immunomodulatory agents before relapse.At symptomatic relapse, median age was 74 years (range 65-87) and 43 (46.7%) were male. Serum creatine level > 2 mg/dL was present in 11.9% of the patients and 4.3 % had hypercalcemia. Extramedullary disease and plasma cell leukemia was present in 17% and 4.4% of patients, respectively. Finally, severe bone disease was observed in 39 the patients.Management of relapse was very heterogeneous. Subsequent drugs used in first clinical relapse included lenalidamide combinations in 40 (43.4%) patients, bortezomib-based therapy in 19 (20.5%) patients, different chemotherapy combinations in 25 (27.1%) patients and bendamustine-prednisone in 2 (2.1%) patients. Six (6.5%) patients received only supportive at time of first relapse. Overall, 45 (52%) patients achieved partial response or better after rescue therapy. Response rates were higher after lenalidomide-based therapy (62.5%) when compared with bortezomib (42.1%) and conventional chemotherapy-based regimens (40.7%),although this difference did not translate into significant PFS advantage.After a median follow-up of 16.4 months (range 0-50.2) from clinical relapse,58 (63%) patients had died. Median PFS and OS were 10 (CI95%; 10.7-50.2) and 15.6 months (CI95%; 8.5-16.5%), respectively. In patients initially treated with VMP (n = 40) and VTP (n =52) median survival from start of subsequent therapy was 15.6 and 15.4 months, respectively. Among characteristics at relapse, only ISS stage had an impact on survival (P= 0.03).There was no difference in OS or PFS from front-line induction and/or maintenance therapies or salvage therapy. ConclusionsThis updated analysis of the GEM2005mas65trial shows a survival advantage of the VMP arm when compared with patients receiving VTP. Patterns of relapse were similar regardless previous induction and maintenance therapy. Finally, and when analyzing the subgroup of patients receiving active therapy at relapse, only ISS stage seemed to have a prognostic impact on OS. [Display omitted] Group A: VMP, group B : VTD Disclosures:Mateos:Janssen, Celgene, Onyx, Millennium, Mundipharma: Honoraria. Oriol:Celgene: Consultancy. Off Label Use: Bendamustine, bortezomib and prednisone is a combination not approved for newly diagnosed myeloma patients.

Circulating Mir-16 and Mir-25 As New Prognosticators For Multiple Myeloma

PurposeWhile international stage (ISS) and the presence of absence of cytogenetic abnormalities on FISH somewhat define the clinical risk of MM patients, additional biomarkers are necessary for more precise risk-based classification. Emerging studies have shown that circulating microRNAs (miRNAs) can be detected in patients with a variety of malignancies, including MM, and they could be non-invasive biomarkers. We measured serum miRNA levels of a large cohort of well-characterized previously untreated MM patients and correlated results with clinical outcome to test their prognostic impact.Methods and PatientsTo profile the expression of circulating microRNAs in the serum of MM patients, we performed NanoString-nCounter microRNA assays on samples obtained from a discovery cohort of 54 newly diagnosed MM patients enrolled on a randomized GIMEMA phase 3 study comparing Velcade-Melphalan-Prednisone-Thalidomide versus Velcade-Melphalan-Prednisone followed by maintenance with Velcade-Thalidomide. To further analyze the expression of the differentially expressed microRNAs, stem-loop-RT-PCR was performed on a validation cohort of 234 MM patients enrolled in the same trial. The prognostic significance of differentially expressed microRNAs were evaluated in relation to progression-free (PFS) and overall survival (OS) using univariate and multivariate Cox proportional hazards models. The utility of incorporating microRNA expression into a risk score with known risk factors – specifically ISS stage and the presence of del17, t(4;14) or t(14;16) by FISH – was also explored. ResultsOut of the 800 miRNAs evaluated, only 25 were detectable (≥100 counts) in at least 20% of the patients. The expression of these miRNAs were then measured in a validation set, but only 10 (miRs-92a, 21, 30a, 720, 451, 223, 126, 19b, 25 and miR-16) were validated to be differentially expressed. We found that levels of miR-16 and miR-25, used as continuous variables, had significant impact on OS duration: miR-16 (HR 0.87; p=0.019) and miR-25 (HR 0.81; p=0.0012) where low expression corresponded with worse survival. Based on these observations we generated a microRNA-based risk score which was significantly associated with OS duration (p=0.008). We then integrated this score with ISS stage and presence of high risk features by FISH, generating an integrated-microRNA risk score that was significantly associated with OS (p<0.0001), and was better than a risk score that combined ISS and FISH (p=0.014), see figure. [Display omitted] ConclusionsCirculating miR-16 and miR-25 can risk stratify elderly, previously untreated, MM patients beyond ISS-stage and high risk genetic features. The opportunity to isolate circulating miRNAs allows us to sequentially sample cancer patients in a relatively non-invasive manner, opening new avenues of investigation for disease stratification and response to therapy. Disclosures:Bringhen:Onyx: Consultancy.

Comparing Gene Expression Profiling (GEP) Features Of Bone Marrow Biopsies (BMBx) Of Patients With Multiple Myeloma (MM) and Normal Donors (NL): 24 Microenvironment Specific Gene Probes Distinguish MM From NL

It is becoming more evident that the bone marrow micro-environment (ME) plays an important role in MM development, progression and treatment response. Studies of the bone ME have largely been limited to in-vitro differentiated cellular subsets. Removing the cells from the from their physiologic cellular environment and manipulating them over an extended period inducing artificial changes results in a significant bias and thus severely limits the applicability of conclusion drawn from those systems to the primary unaltered bone marrow.In order to identify differences between the bone marrow ME of healthy donors and patients with MM we subjected whole BMBx from 378 untreated MM patients and 48 NL subjects, which had been snap frozen immediately after they were taken from the patients, to GEP analysis. Since whole bone marrow biopsies also include plasma cells (PC) we selected probe sets that are unique to the non-PC bone marrow ME. 783 probe sets were selected for having a log2 transformed mean expression > 8 in RNBX (in any of the 7 molecular subgroups CD1, CD2, MF, MS, HY, PR and LB) and < 8 in RNAS (in all molecular subgroups).The training set comprised 242 MM and 40 NL and the test set 136 MM and 8 NL individuals. Approximately 80% of 783 probe sets were differentially expressed between MM and NL samples. We then identified 24 differentially expressed genes to create a gene score, which differentiates between NL and MM samples. ROC plots for the training and test set are depicted in Figure 1a and 1b respectively. Boxplots of 24-gene scores showed minimal overlap between MM and NL in training and test sets (Figure 1c and 1d). 98% of patients were correctly classified as MM or NL by the 24-gene score in the test set (Table 1).Table 1True and predicted Normal and MM samples by 24-probes score in the test set. 133/136 (98%) of MM patients and 8/8 (100%) of Normal patients were classified correctly.Predicted NormalPredicted MMTrue Normal80True MM3133 [Display omitted] We hypothesized that, upon achieving CR, the ME signature normalizes gradually reflecting the diminishing submicroscopic tumor burden and MM-inflicted ME alteration. Therefore, we applied the GEP24 model to 428 CR samples treated with Total Therapy 2 and 3 (TT2, TT3). The time course of sampling from onset of CR with annotations of normalized CR (NL-CR) and non-normalized CR (non-NL-CR) is depicted in Figure 4. Within the 1st year of CR, 14% of patients qualified for NL-CR; the corresponding values for years 2, 3 and 4 were 18%, 19%, and 20%, respectively. Normalization of the bone marrow ME was independent of GEP70 defined risk. Investigation of random biopsies from patients with asymptomatic MM (AMM) and monoclonal gammopathy of undetermined significance (MGUS) revealed a distinct stepwise shift of 24-gene score distributions with the transition from NL to MGUS to AMM and ultimately MM (Figure 5). Patients in CR had similar distributions of the 24-gene score as patients with AMM.We conclude that ME GEP provides important clues to MM biology and therapeutic response that has now been quantitated for the first time. Normalization of the bone marrow ME could predict for recovery of normal hematopoiesis. Results will be presented as to whether NL-CR status can serve as a surrogate marker for long-term disease control and cure that can aid in guiding the length of post-CR maintenance therapy. Investigations are also in progress to determine whether ME GEP can capture MDS-associated alterations and thus help in quantitating the risk of such treatment sequelae. [Display omitted] Disclosures:No relevant conflicts of interest to declare.

Hypoxia Reduces CD138 Expression and Induces Immature Phenotype in Myeloma Cells

Abstract 3956 Introduction:Although CD138 expression is a hallmark of plasma cells and myeloma cells, decreased expression of CD138 is occasionally found. We previously reported in the last ASH meeting that 1) CD138 expression decreases in patients with relapsed/progressive disease compared with untreated MM patients and that 2) Patients with low levels of CD138 expression had a worse overall survival compared with patients with high levels of CD138 expression. However, the mechanisms of CD138 down-regulation in myeloma cells are still unclear. It is known that myeloma patient’s bone marrow environment is hypoxic (Colla et al. Leukemia. 2010; 24: 1967–1970). It is also reported that tumor progression delivers hypoxic environment to MM cells in vivo (Azab et al. Blood. 2012; 119: 5782–5794). Based upon our and other reports, we hypothesized that CD138 expression may be down regulated by hypoxia. In the present study, we examined changes of CD138 and transcription factor expression in myeloma cells under hypoxic condition. Materials and methods:Two myeloma cell lines (RPMI 8226 and KMS-12-BM) were cultured under normoxic (20% O2) and hypoxic (1% O2) conditions for 24 hrs to 72 hrs. CD138 expression of these cell lines under normoxic and hypoxic conditions were analyzed by flow cytometry. Only viable cells were analyzed by excluding 7-AAD positive dead cells. Real time RT-PCR analysis was utilized to analyze gene expression between normoxic and hypoxic cells. Amounts of IRF4 at protein level were determined with western blotting and flow cytometry. Results:CD138 expression was found to decrease under hypoxic condition compared to normoxic condition in 24 hrs in culture of RPMI 8226 and in 48 hrs in KMS-12-BM when examined with flow cytometry. Real time RT-PCR analysis revealed that CD138 expression was down-regulated under hypoxic condition, indicating that CD138 was down-regulated at transcriptional level. Gene expressions of IRF4, PRDM1 and XBP1, known as plasma cell specific transcription factors, were down-regulated under hypoxic condition compared to those under normoxic condition. Western blot and flow cytometry analysis showed IRF4 was also down-regulated under hypoxic condition. Interestingly, the decreased CD138 expression rendered under hypoxic condition recovered when they were placed under normoxic condition along with an increase of IRF4 expression. Conclusions:We conclude that hypoxia induces down regulation of CD138 in myeloma cells, accompanying with decreased expressions of IRF4, PRDM1 and XBP1. The present data together with our previous finding that reduced CD138 expression is frequently seen in patients with relapsed/progressive diseases suggest that the microenvironment of myeloma cells in patients with relapsed/progressive diseases may be more hypoxic comparing to that at diagnosis. Since IRF4 is a master transcription factor required for the maturation of plasma cells, the hypoxia-induced down-regulation of IRF4 suggests phenotypic shift from mature to immature state, which resembles to the report demonstrating a shift of disease status by hypoxia to more aggressive and immature phenotypes in solid tumors (Axelson et al. Semin Cell Dev Biol. 2005; 16: 554–563). Since IRF4 is also important as a target of IMiDs, further analysis of CD138-negative myeloma cells might contribute not only to better understanding of disease progression but also to drug resistance mechanisms. Disclosures:No relevant conflicts of interest to declare.

Multiple myeloma cells expressing low levels of CD138 have an immature phenotype and reduced sensitivity to lenalidomide

CD138 expression is a hallmark of plasma cells and multiple myeloma cells. However, decreased expression of CD138 is frequently observed in plasma cells of myeloma patients, although the clinical significance of this is unclear. To evaluate the significance of low expression of CD138 in MM, we examined the phenotypes of MM cells expressing low levels of CD138. Flow cytometric analysis of primary MM cells revealed a significant decrease in CD138 expression in patients with relapsed/progressive disease compared with untreated MM patients. Patients with low levels of CD138 had a worse overall survival compared with patients with high levels of CD138, in newly diagnosed patients and patients receiving high-dose chemotherapy followed by autologous stem-cell transplantation. Two MM cell lines, KYMM-1 (CD138− low) and KYMM-2 (CD138− high), were established from a single MM patient with decreased CD138 expression. High expression of BCL6 and PAX5, and downregulation of IRF4, PRDM1 and XBP1 was observed in KYMM-1 compared with KYMM-2 cells, indicative of the immature phenotype of KYMM-1. KYMM-1 was less sensitive to lenalidomide than KYMM-2, while no difference in sensitivity to bortezomib was observed. KYMM-2 cells were further divided in CD138+ and CD138− fractions using anti-CD138-coated magnetic beads. CD138− cells sorted from the KYMM-2 cell line also showed high BCL6, low IRF4 expression and decreased sensitivity to lenalidomide compared with CD138+ cells. Our observations suggest that low CD138 expression relates to i) poor prognosis, ii) immature phenotype and iii) low sensitivity to lenalidomide. The observed distinct characteristics of CD138 low MM cells, suggest this should be recognized as a new clinical entity. Establishment of a treatment strategy for MM cells expressing low levels of CD138 is needed to improve their poor outcome.

ELOQUENT-1: A phase III, randomized, open-label trial of lenalidomide/dexamethasone with or without elotuzumab in subjects with previously untreated multiple myeloma (CA204-006).

TPS8113 Background: Elotuzumab (Elo) is a humanized monoclonal IgG1 antibody targeting the cell surface glycoprotein CS1, which is highly expressed on &gt;95% of MM cells. In a MM xenograft mouse model, the combination of Elo + lenalidomide (Len) significantly reduced tumor volume in a synergistic manner compared with either agent alone. In a phase 2 study (N=73) of Elo (10 or 20 mg/kg) in combination with Len and low-dose-dexamethasone (Dex) in pts with RR MM, the 10 mg/kg dose group (n=36) demonstrated objective response rates (ORR) of 92% in all pts, and 100% in pts who had received only 1 prior therapy (n=16). The higher response rate in pts with fewer prior lines of therapy provides a rationale for investigating this combination earlier in the disease course. This randomized, open-label, phase 3 trial will determine if the addition of Elo to Len/Dex improves progression-free survival (PFS) in pts with newly diagnosed, untreated MM. Methods: Pts (N=750) with newly diagnosed symptomatic MM ineligible for stem cell transplant will be randomized in a 1:1 ratio to receive 28-day cycles of Len 25 mg PO (days1-21) and Dex 40 mg PO (days 1, 8, 15 and 22) with or without Elo. Elo dose and schedule is 10 mg/kg IV on days 1, 8, 15, 22 in the first 2 cycles and on days 1 and 15 of cycles 3-18 followed by 20 mg/kg on day 1 of cycle 19 onward. Dex 8 mg IV + 28 mg PO is used during the weeks with Elo. Treatment will continue until disease progression, death, or withdrawal of consent. Pts will be followed up for response every 4 weeks until progressive disease and for survival every 16 weeks. The primary endpoint is PFS (90% power for a hazard ratio [experimental to control arm] of 0.74) and the secondary endpoints are ORR and overall survival. Exploratory endpoints are safety, time to response, duration of response, time to subsequent therapy, health-related quality of life, and pharmacokinetics and immunogenicity of Elo. Potential biomarkers will also be assessed. As of January 1, 2012, 13 pts were enrolled and 9 pts were treated. NCT01335399.

Decreased CD138 Expression in Myeloma Cells: A Potential Indicator of Poor Prognosis and Aberrant Differentiation,

Abstract 3939▪▪This icon denotes a clinically relevant abstract Introduction:CD138 expression is a hallmark of plasma cells. However, decreased expression of CD138 is frequently found although its clinical significance is unknown. To evaluate the significance of decreased CD138 expression, we examined clinical phenotypes of cases with decreased CD138 expression (CD138-dim cases). Furthermore, we attempted to elucidate the mechanism(s) regulating CD138 expression by utilizing two MM cell lines, KYMM-1 and KYMM-2, established from a CD138-dim case. Materials and methods:CD138 expression levels were determined in 107 primary MM cases using flowcytomerty with the CD38 gating method. Cases with more than 20% of MM cells with CD138 negative population were categorized as CD138-dim cases. Real time RT-PCR was utilized to analyze gene expression. Two MM cell lines, KYMM-1 and KYMM-2, were established from pleural effusion of a CD138-dim case. Both KYMM-1 and KYMM-2 had high CD38 expression with cytoplasmic kappa light chains, while lacking CD19 and CD20 expression. EB virus infection was undetectable with PCR in both cell lines. Identical DNA fingerprinting profile (Cell ID™ System, Promega KK, JAPAN) was observed in patient’s primary pleural effusion cells, KYMM-1 and KYMM-2. We also analyzed methylation status of the promoter region of CD138, IRF4 and Blimp-1 by treating KYMM-1 genomic DNA with sodium bisulfite. Results:Flowcytometry analysis of primary MM cells revealed a significant decrease of CD138 expression in those with relapse or progressive diseases compared to untreated MM patients (p<0.05, Fisher’s exact test). Mean survival duration of CD138-dim cases (1,039 days) was significantly shorter than that of untreated patients with high CD138 expression (2,321 days) (Figure 1, p<0.05, Log-rank test). Percent CD138 surface expression in KYMM-1 was 8.56, while that in KYMM-2 was 41.3, indicating expression of CD138 was differentially regulated in these two cell lines despite these came from the same patient (Figure 2). CD138 mRNA expression was significantly less in KYMM-1 compared to U266 and KYMM-2, suggesting that CD138 was down-regulated at the transcriptional level. The expression of Blimp1 and IRF4, genes associated with plasma cell differentiation and highly expressed in plasma cells and MM cells, was low in KYMM-1 than in KYMM-2, suggesting an aberrant differentiation state in a CD138-dim MM cell line. No aberrant methylation was observed in the promoter lesion of CD138, IRF4 and Blimp-1. High expression of BCL6 in KYMM-1, which is a repressor of IRF4 and Blimp-1, was found (Figure 3). [Display omitted] [Display omitted] [Display omitted] Conclusions:Our observations suggest that low CD138 expression in MM cells could serve as an indicator for poor prognosis. Since reduced CD138 expression is preferentially seen in previously treated cases, the regulation of CD138 gene could be associated with disease progression or drug resistance. Previous reports have showed the significance of BCL6 in MM (Hideshima et al. Blood.2010; 115 (18): 3772–3775. Fuhler GM et al. Exp Cell Res. 2010; 316(11):1816–28). High expression of BCL6 in KYMM-1 suggests immature phenotype resulted from down-regulation of IRF4 and Blimp-1 by BCL6. The observed distinctly different expression profile of transcription factors regulating the differentiation of plasma cells in the two cell lines suggest that a transition of differentiation state may have occurred during disease progression. Disclosures:No relevant conflicts of interest to declare.

The Vk*MYC Mouse Model of Myeloma Identifies Successful Combination Therapies for the Treatment of Bortezomib Refractory Myeloma Patients

AbstractAbstract 3015Several preclinical models are available to assess the efficacy of novel anti-myeloma therapies, each of them with specific utilities. The most commonly utilized are: 1) Human myeloma cell lines (HMCLs) offer the advantage of being easily manipulated and well genetically characterized and therefore are best used to provide in-vitro target validation and to demonstrate specific target inhibition by a drug. On the other hand, they are highly proliferative and do not recapitulate the complexity of the human disease in an endogenous micro-environment. 2) Xenograft studies, in which HMCLs are injected into immunodeficient mice, serve the purpose of demonstrating that in-vivo target inhibition can be achieved under physiological conditions, but again fail to represent the indolence of human MM and its complex interaction with the BM stromal cells. Drug screenings performed on both these models tend inevitably to overestimate the antimyeloma activity of compounds that simply inhibit proliferation, but are ineffective in targeting the bulk of MM tumor. 3) Direct cytotoxic studies on primary patients cells, alone or in co-culture with stroma cell lines, are useful in assessing a pro-apoptotic activity in a way that is completely independent on proliferation. However, once again this in-vitro model does not capture the complete biology of human MM.The immuno-competent Vk*MYC mouse model of myeloma has already demonstrated high biological fidelity to the human disease, making it an ideal model to study the behavior of myeloma cells in the context of a native microenvironment and immune system. Furthermore, this model offers the advantage of studying both indolent, BM localized, untreated MM (primary MM), and, with the use of transplants into syngeneic hosts, advanced, more proliferative and refractory disease (secondary MM). Using the primary MM model, we have assessed the anti-myeloma activity of 30 known and novel compounds, many of which currently in clinical trials, and found that agents effective in the treatment of patients are active in this model, whereas agents ineffective in the treatment of patients are not. From this study, the most promising class of novel agents in clinical trials are the HDAC inhibitors vorinostat and panobinostat. Based on this promising single agent activity, we sought to model the effects of combination therapy in the secondary myeloma models that we specifically generated to be bortezomib refractory or multidrug resistance. Although transplanted mice treated with full dose single agent bortezomib, vorinostat or panobinostat showed no response and died within three weeks post transplant, recipient mice treated with bortezomib in combination with either vorinostat or panobinostat achieved complete response and are still alive 10 weeks post-transplant.We conclude that the bortezomib + HDAC inhibitors is an active combination that overcomes in vivo bortezomib resistance. Furthermore, the Vk*MYC model provides an excellent platform for the development of novel combinations aimed to the treatment of refractory MM disease. Disclosures:Bergsagel:Amgen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Genentech: Membership on an entity's Board of Directors or advisory committees; Millennium: Speakers Bureau; Novartis: Speakers Bureau.

Phase II multisite study to evaluate efficacy and safety of single weekly administration of bortezomib (BZ) and dexmethasone (dex) in newly diagnosed multiple myeloma (NDMM) patients (pts).

TPS307 Background: BZ is proteasome inhibitor with demonstrated efficacy in NDMM when given on twice a week (wk) schedule. However, neuropathy is one of the side effects that limit its use in a proportion of pts. Therefore, there is a need to investigate efficacy and safety of a weekly regimen of BZ. Methods: We are conducting a one-stage phase II multicenter, open-label single-arm noninferiority study of once a wk BZ in combination with dex, for the treatment of NDMM in Veterans Hospitals nationwide. The purpose is to show that the study regimen is not inferior to the standard BZ therapy with respect to objective response (OR) rate in pts with NDMM not undergoing transplant. Previously untreated MM pts who are not considered for autologous stem cell transplant (ASCT) due to age > 65 and/or comorbidities, or who are age ≥60 and have declined ASCT are eligible.Pts receive 1.6 mg/m2 IV BZ weekly, for 4 weeks followed by 1 week off. They also receive 40 mg dex PO the day of and day after each dose of BZ. Pat...