ALBERT

Description: We evaluated the ability of 2 human mAbs directed against TRAILR1 (HGS-ETR1) and TRAILR2 (HGS-ETR2) to kill human myeloma cells. HGS-ETR1 and HGS-ETR2 mAbs killed 15 and 9 human myeloma cell lines (HMCLs; n = 22), respectively. IL-6, the major survival and growth factor for these HMCLs, did not prevent their killing. Killing induced by either HGS-ETR1 or HGS-ETR2 was correlated with the cleavage of Mcl-1L, a major molecule for myeloma survival. Mcl-1L cleavage and anti-TRAILR HMCL killing were dependent on caspase activation. Kinetic studies showed that Mcl-1L cleavage occurred very early (less than 1 hour) and became drastic once caspase 3 was activated. Our data showed that both the extrinsic (caspase 8, Bid) and the intrinsic (caspase 9) pathways are activated by anti–TRAIL mAb. Finally, we showed that the HGS-ETR1 and, to a lesser extent, the HGS-ETR2 mAbs were able to induce the killing of primary myeloma cells. Of note, HGS-ETR1 mAb was able to induce the death of medullary and extramedullary myeloma cells collected from patients at relapse. Taken together, our data clearly encourage clinical trials of anti–TRAILR1 mAb in multiple myeloma, especially for patients whose disease is in relapse, at the time of drug resistance.

Description: Proteasome inhibition has emerged as an important therapeutic strategy in multiple myeloma (MM). Since the publication of the first phase 1 trials of bortezomib 10 years ago, this first-in-class proteasome inhibitor (PI) has contributed substantially to the observed improvement in survival in MM patients over the past decade. Although first approved as a single agent in the relapsed setting, bortezomib is now predominantly used in combination regimens. Furthermore, the standard twice-weekly schedule may be replaced by weekly infusion, especially when bortezomib is used as part of combination regimens in frontline therapy. Indeed, bortezomib is an established component of induction therapy for patients eligible or ineligible for autologous stem cell transplantation. Bortezomib has also been incorporated into conditioning regimens before autologous stem cell transplantation, as well as into post-ASCT consolidation therapy, and in the maintenance setting. In addition, a new route of bortezomib administration, subcutaneous infusion, has recently been approved. Recently, several new agents have been introduced into the clinic, including carfilzomib, marizomib, and MLN9708, and trials investigating these “second-generation” PIs in patients with relapsed/refractory MMs have demonstrated positive results. This review provides an overview of the role of PIs in the treatment of MM, focusing on developments over the past decade.

Description: Abstract 432 Elotuzumab is a humanized monoclonal IgG1 antibody directed against CS1, a cell surface glycoprotein, which is highly and uniformly expressed in multiple myeloma (MM). Elotuzumab induces significant antibody-dependant cytotoxicity (ADCC) against primary myeloma cells in the presence of either autologous or allogeneic peripheral lymphocytes (PBMC), which is significantly enhanced when PBMC effector cells were pretreated with lenalidomide (Tai et al., Blood 112:1329, 2008). The primary objective of the phase 1 portion of the study is to evaluate the maximum tolerated dose (MTD) of elotuzumab in combination with lenalidomide and low dose dexamethasone in patients with relapsed MM. The study is also evaluating safety, pharmacokinetics (PK) and clinical response. Lenalidomide (25 mg PO) is given on Days 1-21 of a 28-day cycle. Elotuzumab in three escalating dose cohorts (5, 10 and 20 mg/kg) is administered by IV infusion on Days 1, 8, 15 and 22 of the 28-day cycle in the first two cycles and then on Days 1 and 15 of each subsequent cycle. Dexamethasone is given weekly at 40 mg PO. Initially, patients received 6 cycles of treatment unless withdrawn earlier due to disease progression or unacceptable. toxicity. The protocol was amended to allow for patients in the 10 and 20 mg/kg cohorts to receive treatment for up to 12 months following enrollment of the last patient. Key entry criteria: age ≥ 18 years; MM with at least one relapse; measurable disease M-protein component in serum and/or in urine; and prior lenalidomide treatment, if any, more than 6 weeks of first dose. To date, 24 patients with a median age of 60 years have been enrolled in the study and 23 patients have received study drug. The median time from initial diagnosis of MM was 5 years and patients had received a median of 3 prior MM treatments. Patients had been previously treated with thalidomide (58%), bortezomib (67%) or lenalidomide (21%) and 42% were refractory to their most recent MM therapy. Patients have been treated in the 3 cohorts; 3 patients each in the first two cohorts (5 and 10 mg/kg elotuzumab) and 17 patients (7 in dose-escalation phase and 10 in the expansion phase) in the third cohort (20 mg/kg). No dose limiting toxicities were identified during the dose-escalation phase of the study and no MTD was established. One patient discontinued in the first cycle due to grade 4 allergic reaction resulting from elotuzumab infusion in the expansion phase of the study. Additional SAEs (1 of each) included grade 2 atrial fibrillation (related to lenalidomide/dexamethasone) and unrelated grade 4 ruptured diverticulum, grade 3 neutropenic fever and grade 3 diarrhea.. Other common grade 3 or 4 AEs included neutropenia (25%) and thrombocytopenia (25%), which were managed by dose withholding or dose reduction of lenalidomide. Approximately 25% of patients experienced grade 1 or 2 chills and/or pyrexia associated with elotuzumab infusion. The best clinical response (IMWG criteria) in the 13 patients who have received at least two cycles of treatment is shown in the table below. Preliminary PK analysis of elotuzumab suggests a serum half-life of 10-11 days at 10 and 20 mg/kg. Elotuzumab at all three doses resulted in near complete saturation of CS1 sites on plasma cells and NK cells in bone marrow and NK cells in the peripheral compartment. In conclusion, the combination of elotuzumab with lenalidomide and low-dose dexamethasone has a manageable adverse event profile and compared to historical data for lenalidomide and high-dose dexamethasone, the preliminary efficacy data (≥ PR of 92%) are very encouraging. Additional safety, efficacy and PK/PD data will be presented at the meeting. Disclosures: Lonial: Celgene: Consultancy; Millennium: Consultancy, Research Funding; BMS: Consultancy; Novartis: Consultancy; Gloucester: Research Funding. Off Label Use: Lenalidomide/dexamethasone in combination with elotuzumab in patients with relapsed/refractory multiple myeloma. Vij:Celgene: Research Funding, Speakers Bureau. Harousseau:Celgene France: Advisory Board; Janssen Cilag France: Advisory Board; Celgene: Honoraria; Janssen Cilag: Honoraria; Novartis: Honoraria; Amgen: Honoraria. Facon:Celgene: Membership on an entity's Board of Directors or advisory committees; Janssen Cilag: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees. Kaufman:Celgene: Consultancy, Research Funding; Millennium: Consultancy; Genzyme: Consultancy; Merck: Research Funding. Mazumder:Celgene: Speakers Bureau; Millennium: Speakers Bureau. Leleu:Celgene: Research Funding, Speakers Bureau. Fry:Facet Biotech: Employment. Singhal:Facet Biotech: Employment. Jagannath:Millennium: Advisory Board; Merck: Advisory Board.

Description: Abstract 1817 Poster Board I-843 Deletion of the short arm of chromosome 17 [del(17p)] is known to confer a poor prognosis in multiple myeloma (MM). However, no large study has been specifically dedicated to this purpose, especially in the novel drug era. We analyzed a series of 1324 patients with MM at diagnosis, treated within or according to IFM trials, and analyzed for del(17p). Most of the patients were under 65 years of age (1122 of the 1324 patients), and were treates either with a VAD-based induction or a Velcade®/Dexamethasone-based induction, followed by one or two courses of high-dose melphalan. Del(17p) was correlated to the major other prognostic parameters, both for event free survival and overall survival. Del(13) was observed in 71% of the patients with del(17p). A significant association was observed with anemia 〈 10g/dl (p=.05), with thrombocytopenia 〈 130 G/l (p3.5 mg/l (p=.006). No specific association was observed with t(4;14) (17% of the del(17p)-positive patients displayed t(4;14)). Del(17p) was observed in 10% of the patients. Del(17p) was associated with a very poor outcome, both in young and elderly patients. Actually, the prognostic value was observed only in patients displaying del(17p) in at least 70% of their plasma cells. The median EFS and OS were 18 and 28 months respectively, versus 30 and 69 months for patients lacking the del(17p). A particularly poor outcome was observed in patients presenting both del17p and t(4;14), with a median EFS of 4.5 months and a median OS of 12 months. Of particular importance, none of the treatment modality (high-dose melphalan, thalidomide, bortezomib) overcame the poor prognosis associated with del(17p), although patients lacking del(17p) displayed a better outcome when treated with Vel/Dex or MP-Thalidomide. In conclusion, del(17p) is associated with an especially poor outcome, independently of the type of treatment, including novel drugs. Disclosures No relevant conflicts of interest to declare.

Description: Vascular endothelial growth factor (VEGF) induces proliferation of MM cells and induces interleukin-6 (IL-6) secretion in a paracrine loop involving MM cells and bone marrow stromal cells. In turn, IL-6 triggers multiple myeloma (MM) cell proliferation and also protects against apoptosis by upregulating Myeloid-cell-leukemia 1 (Mcl-1), a critical survival protein in MM cells. The goal of our study was to investigate the role of Mcl-1 in VEGF induced-proliferation and protection against apoptosis. Using two murine embryonic fibroblast cell lines as a model (a Mcl-1 deleted cell line and its wild type: Mcl-1Δ/null and Mcl-1wt/wt MEFs, respectively), we here demonstrate that deletion of Mcl-1 reduces fetal bovine serum (FBS), VEGF, and IL-6 induced-proliferation. In addition, we demonstrate that the percentage of cells in S phase is lower in Mcl-1Δ/null compared to Mcl-1wt/wt MEFs (21% (+/−1) versus 30% (+/− 3), respectively). Taken together, these results demonstrate that Mcl-1 is required to mediate VEGF, Il-6 and FBS-induced-proliferation and cell cycle progression. To highlight the key anti-apoptotic role of Mcl-1 in MM cells, humans MM1s cells were transfected with Mcl-1 siRNA. Specific inhibition of Mcl-1 was associated with decreased proliferation (42% and 61% decreases at 24 and 48 h, respectively) and induction of apoptosis (subG1 peak: 22% and 41% in Mcl-1 siRNA transfected cells versus 15% and 15 % in non-transfected cells at 24 and 48 h, respectively), confirming that Mcl-1 is critical for both proliferation and protection against apoptosis in MM cells. In 3 human MM cell lines (MM1s, U266 and MM1R) and MM patient cells we next showed that Mcl-1 protein expression, but not other bcl-2 family members, is upregulated by VEGF in a time and dose manner; and conversely that the pan-VEGF inhibitor GW654652, blocks VEGF induced-upregulation of Mcl-1. Furthermore using flow cytometry with a double staining (CD38-FITC and Apo 2.7-PE), we demonstrate that VEGF protects MM patient cells from FBS-starvation-induced-apoptosis: the percentage of apoptotic MM patient cells (CD38++ and Apo 2.7+) in non starved medium (RPMI 1640 supplemented with 10% FBS) was 15% versus 93% in starved medium (RPMI 1640 supplemented with FBS 2%), and 48% in starved medium supplemented with 25ng/ml VEGF. In conclusion, our study demonstrates that VEGF protects MM cells against apoptosis, and that VEGF-induced MM cell proliferation and survival is mediated via Mcl-1. these studies provide the preclinical framework for novel therapeutics targeting both Mcl-1 and/or VEGF to improve patient outcome in MM.

Description: Introduction Invasive fungal infections (IFI) due to Candida and Aspergillus species remain a major complication of allo-SCT. In the myeloablative setting, previous studies have demonstrated that fluconazole, administered for 75 days after transplant (400 mg/d), in a prophylaxis setting, can allow for a decreased risk of gut GVHD and disseminated candida infections or candidiasis-related death, resulting in an overall survival benefit (Marr et al., Blood 2000). However, to our knowledge, there is currently no study, addressing the potential benefit of fluconazole prophylaxis in the setting of reduced-intensity conditioning (RIC) allo-SCT. Methods This retrospective study included 105 patients with acute leukemia (AML, n=55, ALL, n=11) or myelodysplastic/myeloproliferative disorders (MDS, n=24; myeloproliferative disorder n=15) who received an allo-SCT between January 2000 and December 2011. In this series, patients received one (n=105) or two (n=4) RIC allo-SCT and PBSC as stem cell source for all. Among these 109 procedures, we compared those cases receiving (n=53) or not (n=56) fluconazole prophylaxis after transplant. The post-transplant fluconazole prescription or not was at the discretion of the attending physician and was homogeneous for each physician. There were not significant differences between both groups in terms of gender, median age (fluco: 55 vs 57 years), median follow-up (fluco: 42 months (range: 19-76) vs 37 months (range: 11-124)), median year of transplant (fluco: 2008 (range: 2003-2011) vs 2009 (range: 2000-2011)), type of disease and disease status at time of transplant or type of donor. Results The median time of fluconazole administration (400mg/day) after transplant was 88 days (range: 7-324). Fluconazole was stopped only in 2 patients because of (reversible) liver cytolysis. Before day +100, only 2 Aspergillus infections were documented in the fluconazole group vs 4 in the non-fluconazole group (P=NS). No Candida infections (septicemia or cutaneous candidiasis) developed in the fluconazole group compared to 2 in the non-fluconazole group (P=NS). After day +100, Aspergillus infections were documented in 5 patients in the fluconazole group versus 3 in the non-fluconazole group (P=NS). The number of patients receiving pre-emptive or curative antifungal treatment (voriconazole, caspofungin or ambisome) after transplant was higher in the non-fluconazole group (52% of cases vs 34%, P=0.09). 3-year OS, DFS and NRM were similar between both groups (fluco: 42% vs 51%, P=0.42, fluco: 38% vs 46%, P=0.62, and fluco: 28% vs 23%, p=0.67). Also, there were no significant differences in term of cumulative incidences of acute grade II-IV GVHD (fluco: 27% vs 36%, P=0.29), acute grade III-IV GVHD (fluco: 21% vs 18%, P=0.42) or chronic GVHD (fluco: 47% vs 33%, P=0.67). Conclusion This is the first series reporting the comparison of the use or not of fluconazole as prophylaxis after RIC allo-SCT. Our results showed that the use of fluconazole has no impact in term of fungal infections or overall outcomes after RIC allo-SCT, suggesting that fluconazole is not required after RIC allo-SCT. Large prospective studies are warranted to further confirm this important therapeutic issue. Disclosures: Moreau: CELGENE: Honoraria, Speakers Bureau; JANSSEN: Honoraria, Speakers Bureau. Mohty:Novartis: Honoraria, Research Support Other.

Description: Abstract 3472 Allo-SCT procedures are currently undergoing a profound evolution. The spectra of patients and diseases for which this approach is now considered have increased considerably over the past years. This is mainly due to the introduction in routine practice of the so-called nonmyeloablative or RIC regimens. While it is well established that fludarabine is the backbone drug to secure engraftment, there is a wide variability in the degree of myeloablation between the different RIC protocols, and the toxicity profile might vary significantly from one protocol to another. The combination of fludarabine and Busulfan (usually 8 mg/Kg total dose) with or without ATG, is among the most widely used RIC protocols worldwide. In an attempt to further decrease the toxicity of the transplant procedure, we hypothesized that further reduction (50%) of the Busulfan dose can allow improving transplant outcome for lymphoid neoplasms. With this background, this retrospective analysis was performed to assess whether a RIC regimen including fludarabine (120 mg/m2), low dose busulfan (4 mg/Kg total dose administered orally over a single day) and ATG (Thymoglobuline®, 2.5 mg/Kg/d for 2 days; FB1A protocol, n=44), is a valid alternative to the classical RIC regimen including fludarabine (90 mg/m2) and TBI (2 Gy.) (FTBI, n=27) prior to allo-SCT. The cohort included 37 males (52%) and 34 females (48%) treated consecutively in a single centre, with a median age at time of allo-SCT of 53 (range, 15–66) y. Diagnoses included 39 NHL (55%), 17 Hodgkin lymphomas (24%), 12 CLL (17%) and 3 myeloma (4%). PBSCs were used as stem cell source in 42 patients (91%), while 4 patients (9%) received classical bone marrow. A matched-related donor was used in 18 cases (39%) and an unrelated donor in 28 cases (61%). With a median follow-up of 43 (range, 3.7–85) months after allo-SCT, all patients, but one (from the FTBI group) engrafted. In the FB1A group, the acute grade 3–4 GVHD rate was 20.5% (n=9), the chronic GVHD rate was 32% (n=14), the relapse rate was 23% (n=10) and the TRM rate was 25% (n=11). In the FTBI group, the rate of grade 3–4 acute GVHD rate was 44% (n=12; P=0.03 in comparison to the FB1A group), the chronic GVHD rate was 52% (n=14; P=0.09), the relapse rate was 15% (n=4; P=NS) and the TRM rate was 37.0% (n=10; P=NS). At 2 years, overall survival was 66% (95%CI, 51–78%) in the FB1A group versus 55% (95%CI, 36–73%) in the FTBI group (P=NS). Disease-free survival (DFS) was also comparable between both groups (at 2 years, 59% in the FB1A group, vs. 48% in the FTBI group, P=NS). In a Cox multivariate analysis for OS or DFS, the type of RIC regimen was not significantly associated with outcome. In all, these results suggest that in patients with lymphoid malignancies, a RIC regimen including Fludarabine, ATG and low dose busulfan (4 mg/Kg total dose) is a valid alternative to the classical Fludarabine and low dose TBI-based RIC regimen with a favorable toxicity profile and efficient disease control. Disclosures: No relevant conflicts of interest to declare.

Description: Recently, a significant improvement in time to progression (TTP) was reported for pegylated liposomal doxorubicin (PLD) + bortezomib combination therapy vs. bortezomib monotherapy in a phase III randomized trial in relapsed or refractory multiple myeloma (RRMM) (Orlowski, JCO 2007). This pre-specified analysis assessed the efficacy of PLD+bortezomib in RRMM based on the number of prior lines of therapy and previous anthracycline exposure status. Patients with ≥1 prior therapy were randomized to receive PLD at 30 mg/m2 on day 4 and bortezomib at 1.3 mg/m2 on days 1, 4, 8, and 11, or bortezomib alone for up to eight 21-day cycles, or at least 2 cycles beyond CR, or optimal response unless disease progression, or unacceptable toxicities occurred. The baseline beta-2 microglobulin levels were comparable between the subgroup with ≥2 prior treatments and that with 1 treatment (median 3.98 vs. 4.01 mg/L), as well as between anthracycline-exposed and -naïve patients (median 3.91 vs. 4.55 mg/L). The improved TTP reported previously with PLD+bortezomib over bortezomib in the total study population was similarly observed in all four subgroups of patients (patients with ≥2 lines of prior therapy or 1 prior therapy, anthracycline-exposed (median 144 mg/m2 in both treatment arms) or -naïve groups (Table)), indicating a consistent therapeutic benefit favoring the PLD+bortezomib combination. Furthermore, TTP was comparable for the PLD+bortezomib combination between groups with ≥2 lines of prior therapy vs. 1 prior therapy (heterogeneity test, p=0.523), as well as patients who were anthracycline-exposed or -naïve (heterogeneity test, p=0.716). Incidence of treatment-related SAEs, grade 3/4 neuropathy, and symptomatic cardiac events was comparable between treatment arms in each subgroup (Table). PLD-related hand-foot syndrome was also

Description: We analyzed the presenting features and survival in 1689 patients with multiple myeloma aged younger than 50 years compared with 8860 patients 50 years of age and older. Of the total 10 549 patients, 7765 received conventional therapy and 2784 received high-dose therapy. Young patients were more frequently male, had more favorable features such as low International Staging System (ISS) and Durie-Salmon stage as well as less frequently adverse prognostic factors including high C-reactive protein (CRP), low hemoglobin, increased serum creatinine, and poor performance status. Survival was significantly longer in young patients (median, 5.2 years vs 3.7 years; P 〈 .001) both after conventional (median, 4.5 years vs 3.3 years; P 〈 .001) or high-dose therapy (median, 7.5 years vs 5.7 years; P = .04). The 10-year survival rate was 19% after conventional therapy and 43% after high-dose therapy in young patients, and 8% and 29%, respectively, in older patients. Multivariate analysis revealed age as an independent risk factor during conventional therapy, but not after autologous transplantation. A total of 5 of the 10 independent risk factors identified for conventional therapy were also relevant for autologous transplantation. After adjusting for normal mortality, lower ISS stage and other favorable prognostic features seem to account for the significantly longer survival of young patients with multiple myeloma with age remaining a risk factor during conventional therapy.

Description: Multiple myeloma is a very devastating cancer with a high capacity to destroy bone matrix. Matrix metalloproteinases (MMPs) play a critical role in bone remodeling and tumor invasion. In this study, we have investigated the involvement of interstitial collagenase (MMP-1) and gelatinases (MMP-2 and MMP-9) in the biology of multiple myeloma. We show (1) that myeloma cells express MMP-9 and (2) that this expression is not subjected to regulation either by interleukin-6 (IL-6), the major myeloma cell growth factor, or by other cytokines involved in the multiple myeloma cytokine network. In the tumoral environment, we show that bone marrow stromal cells express MMP-1 and MMP-2. Whereas MMP-1 is positively regulated by IL-1β, tumor necrosis factor-α, and Oncostatin M, MMP-2 is not modulated by any of these cytokines. To evaluate whether myeloma cells can modify the bone marrow stromal environment, we have examined these MMP activities in coculture. Interestingly, we have observed an upregulation of MMP-1 and a partial conversion of the proMMP-2 into its activated form. We conclude that the increase of MMP activity produced or induced by myeloma cells in these cocultures could favor bone resorption and tumor invasion. Inhibition of such activities could represent a new therapeutical approach in multiple myeloma.