Citations 1268

Novel Three– and Four–Drug Combinations of Bortezomib, Dexamethasone, Cyclophosphamide, and Lenalidomide, for Newly Diagnosed Multiple Myeloma: Encouraging Results From the Multi-Center, Randomized, Phase 2 EVOLUTION Study.

Blood | October 12, 2019 | Volume: 114 | Issue: 22 | Pages: 127-127

10.1182/blood.v114.22.127.127

Abstract Abstract 127 Two- and three-drug regimens incorporating bortezomib (Velcade®, Vc), lenalidomide (Revlimid®, Rev), dexamethasone (Dex), and cyclophosphamide (Cy) (Vc–Dex, Rev–Dex, Vc–Dex–Rev [VDR], and Vc–Dex–Cy [VDC]), have been shown to be effective and well tolerated in previously untreated multiple myeloma (MM). Combining Vc and Dex with Rev and Cy in a novel four-drug regimen (VDCR) may result in even greater activity with improved quality and duration of response. Results from the phase 1 dose-escalation portion of the multi-center EVOLUTION study showed that the VDCR regimen is a highly active and generally well-tolerated induction therapy in previously untreated MM patients (pts). Here we report the efficacy and safety of VDR, VDC, and VDCR from the non-comparative phase 2 portion of the study. Methods: Pts were randomized to receive up to eight 21-d cycles of VDR (Vc 1.3 mg/m2 d 1, 4, 8, 11; Dex 40 mg d 1, 8, 15; Rev 25 mg d 1–14) or VDC (VD as in VDR, plus Cy 500 mg/m2 d 1, 8) or VDCR (VDC plus Rev 15 mg d 1–14) as induction therapy, followed by Vc 1.3 mg/m2 (d 1, 8, 15, 22) for four 42-d maintenance cycles in all treatment arms. Pts received prophylactic antibiotics, acyclovir, transfusion support, and anticoagulants as required. Eligible pts wishing to undergo autologous stem cell transplant (ASCT) could undergo stem cell mobilization any time after cycle 2, and undergo ASCT any time after cycle 4. Response categories were based on the IMWG Criteria with the addition of near complete response (nCR). Adverse events (AEs) were graded using the CTCAE v3.0. Results: In the VDR, VDC, and VDCR arms 42, 32, and 43 pts (including 6 pts treated at the maximum planned dose of Cy (500 mg/m2) from phase 1) have been treated, and 42, 31, and 33 are evaluable for response, respectively, as of data cut-off (31 July 2009). Median ages in the VDR, VDC, and VDCR arms were 60, 62, and 62 years, respectively; 62%, 63%, and 66% had International Staging System stage lI/III disease, and 38%, 25%, and 33% had Karnofsky Performance Status ≤80%, respectively. The median number of VDR, VDC, and VDCR cycles received is 4.5, 6, and 4, respectively (range 1–12). Best unconfirmed response rates are shown in the Table; patients categorized as very good partial response (VGPR) include those who have no measurable M-protein but have not yet had bone marrow assessments to confirm CR/nCR status. The overall rates of treatment-emergent AEs were 95%, 97%, and 88% for the VDR, VDC, and VDCR arms, respectively, with ≥grade 3 reported in 67%, 59%, and 65%. Peripheral neuropathy (PN) was reported as grade 2/3 in 12%/12% in the VDR, 31%/3% in the VDC, and 12%/9% in the VDCR arms; there was no grade 4 PN reported. Grade 3/4 neutropenia was reported in 5%/5%, 28%/13%, and 23%/9% of pts in the VDR, VDC, and VDCR arms, and grade 3/4 thrombocytopenia in 5%/2%, 9%/0%, and 5%/0% of pts, respectively. One case of grade 3 deep-vein thrombosis was reported in the VDCR arm. Overall rates of serious AEs were 24%, 13%, and 37% in the VDR, VDC, and VDCR arms, respectively. Two pts have died in the VDCR arm, both due to renal failure, considered possibly treatment-related. To date, 6 pts have undergone ASCT in the VDR arm, 5 in the VDC arm, and 3 in the VDCR arm. Median CD34+ yield was 4.7, 6.3, and 6.8 × 106/kg in the VDR, VDC, and VDCR arms, respectively. Conclusions: VDR, VDC, and VDCR are highly active and generally well-tolerated regimens in previously untreated MM. Response rates in the VDCR arm appeared somewhat higher than in the VDR and VDC arms at this early time point, although there also appeared to be higher rates of serious AEs, including possible treatment-related mortality in the VDCR arm. Following an interim analysis, dosing in the VDC arm was modified to include Cy on day 15 to examine if this will improve CR rates. Ten pts have been enrolled to date. Disclosures: Kumar: CELGENE: Research Funding; MILLENNIUM: Research Funding; BAYER: Research Funding; GENZYME: Research Funding; NOVARTIS: Research Funding. Flinn:Millennium Pharmaceuticals, Inc.: Membership on an entity's Board of Directors or advisory committees, Research Funding. Hari:Milennium Pharmaceuticals Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Callander:Millenium: Research Funding. Noga:Millennium Pharmaceuticals: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Stewart:Takeda-Millenium, Celgene, Novartis, Amgen: Consultancy; Takeda, Millenium: Research Funding; Genzyme, Celgene, Millenium, Proteolix: Honoraria. Raje:Celgene: Research Funding; Novartis: Research Funding; AstraZeneca: Research Funding. Rifkin:Millennium Pharmaceuticals, Inc: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Speakers Bureau; Cephalon: Speakers Bureau. Shi:Millennium Pharmaceutical Inc.: Employment. Webb:Millennium: Employment, Equity Ownership. Richardson:Keryx: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Johnson and Johnson: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Millennium Pharmaceuticals, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; BMS: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau.
Predicting Poor Peripheral Blood Stem Cell Mobilization in Multiple Myeloma (MM) Using Initial Peripheral CD34 Counts: Developing Target-Based Cut-Points for Early Intervention.

Blood | October 12, 2019 | Volume: 114 | Issue: 22 | Pages: 3231-3231

10.1182/blood.v114.22.3231.3231

Abstract Abstract 3231 Poster Board III-168 Background Peripheral blood stem cells (PBSC) are the preferred graft type for autologous stem cell transplantation (ASCT) and mobilization is typically done using growth factor (GF) alone or a combination of chemotherapy (CTX) and GF. The success of mobilization is influenced by several factors such as prior therapy and mobilization strategy. Patients (Pts) failing to mobilize successfully often have GF dose increased and if unsuccessful, mobilization reattempted with chemotherapy + GF or G-CSF (Granulocyte Colony-Stimulating Factor) + GM-CSF (Granulocyte-Macrophage Colony-Stimulating Factor). More recently, plerixafor, a CXCR4 inhibitor, has been found to enhance G-CSF based collection allowing potential early intervention in poor mobilizers. However, this approach requires valid cut-points for peripheral CD34 counts (pCD34) for cost efficient use. Methods We studied 910 first time, G-CSF based PBSC mobilizers with MM (565; 62%), or light chain amyloidosis (345; 38%). Salvage attempts were excluded, as were first attempts using CTX+GCSF, plerixafor or GF combinations. Sensitivity-specificity analysis (ROC) was used to define ideal cut-points for predefined outcomes. We used a CD34 yield of 2 million/kg as the minimum required collection and 4 million/kg as the ideal collection for this analysis. Our current practice is to initiate collection at a pCD34 of 10/uL. Results We first determined the best day 1 pCD34 cutoff for being able to collect at least 2 million/kg PBSC to be 9.2/uL. Among those with ≥9.2/uL, only 1.6% failed to collect at least 2 million compared to 27% among the rest (P < 0.001). These numbers were 1.7% and 25% respectively using the traditional cutoff of 10/uL. We then examined how the pCD34 on day 2 predicted collection, among those failing to reach the current threshold of 10/uL. Among this group, a pCD34 on day 2 of 8/uL was the best cutoff to predict a collection of 2 million/kg. Among those with >8/uL, only 9% failed to collect at least 2 million compared to 48% among the rest (P < 0.001). Among those with day 1 pCD34 < 10, 65% achieved a count of 8/uL on day 2. We then examined what pCD34 on day 1 can best predict a pCD34 ≥ 8 on day 2 and found this to be 5/uL. Among those with day 1 pCD34 ≥ 5/uL, 92% reached day 2 pCD34 ≥ 8 compared to 36% among the rest (P < 0.001).We then determined cutoffs based on ideal targets using only those patients achieving pCD34 count > 10/uL by day 2, since these patients would have started collection without any change in the mobilization technique. We used a maximum of 5 collections to achieve the goal as being ideal, taking into account the most commonly used practice of collecting during weekdays. We examined cutoffs both for a target of 4, 8 and 12 million/kg for one, two or three transplants respectively. Among those with a day 1 or day 2 pCD34 > 10/uL 98% collected 4 million/kg in 5 collections. The best day 1 or day 2 pCD34 predicting a 8 million/kg yield in 5 collections was 21.4/uL and a 12 million/kg yield was 27.9/uL. Among those with day 1or 2 pCD34 ≥ 21.4/uL, 90% collected 8 million compared to 54% among those with pCD34 < 21.4/uL. Similarly, among those with day 1 or 2 pCD34 ≥ 27.9/uL, 79% reached 12 million in ≤ 5 days compared to 17% among those with pCD34 < 27.9/uL (P < 0.001).Finally we examined if poor collection on first day, despite a pCD34 > 10 predicts for poor overall yield. A ratio of day 1 collection (million/kg) to pCD34 day 1 or 2 < 5×104 was highly predictive of failure to get eventual yield of 2 million/kg, with 38% below the cutoff failing to reach the goal compared to 2% for those above the cutoff. Conclusions This study provides an estimate of optimal pCD34 count thresholds for early identification of patients at high risk of collection failure. It is reasonable to use the first or second day pCD34 count, since a substantial proportion of patients will achieve the threshold value by day 2 and have similar outcome as those reaching the threshold by day 1. Based on the results here, interventions such as plerixafor can be considered if pCD34 count is < 5/uL on day 1 or < 9/uL by day 2, to achieve the minimum collection of 2 million/kg. However, in order to achieve the ideal targets, a higher threshold should be considered and the recommendation would be 17/uL, and 28/uL for target of 8 or 12 million respectively. Finally, identification of poor mobilizers after start of collection potentially provides another time point for early intervention, and this needs to be prospectively studied. Disclosures Micallef: Genzyme: Research Funding. Gertz:Genzyme: Research Funding. Kumar:Celgene,Genzyme,Millenium,Novartis,Bayer,: Honoraria, Research Funding.
Increased Circulating Plasma Cells On Multiparametric Flow Cytometry As An Independent Prognostic Biomarker In Newly Diagnosed Multiple Myeloma: Implications For Redefining High-Risk Myeloma

Blood | October 12, 2019 | Volume: 122 | Issue: 21 | Pages: 1842-1842

10.1182/blood.v122.21.1842.1842

Abstract Background Prior studies have shown that presence of increased circulating plasma cell (PCs) identified using a slide-based immunofluorescence method is an adverse prognostic marker for overall survival in multiple myeloma (MM), and increases the risk of progression in patients with MGUS and smoldering MM. However, utility in clinical settings has been limited by the cumbersome nature of the test and lack of widespread availability. We studied the prognostic value of circulating PCs using sensitive multiparametric flow cytometry that enable us to quantitatively assess circulating PCs in patients with MM. Methods We evaluated all newly diagnosed MM patients seen at the Mayo Clinic, Rochester from 2009 to 2011 who had their peripheral blood samples evaluated by flow cytometry prior to therapy. Patients with plasma cell leukemia were excluded. Each blood sample had its peripheral blood mononuclear cells isolated by ficoll gradient and stained with antibodies to CD45, CD19, CD38, CD138 and cytoplasmic Kappa and Lambda Ig light chains. A six-color multi-parameter flow cytometer (Becton Dickinson FacsCantos II) was used to examine each sample with a target of detecting 150,000 events (cells) that was then analyzed using the Facs Diva Software. PCs were selectively analyzed through combinatorial gating using light scatter properties and CD38, CD138, CD19, and CD45. Normal PC's were then separated from clonal PCs based on the differential expression of CD45, CD19 and polytypic Ig light chains. The clonal PCs detected were reported out as the number of clonal events/150,000 collected total events. For those samples where less than 150,000 events were gated or examined, the number of final clonal events was adjusted to 150,000 events. Survival analysis was performed by the Kaplan-Meier method and differences assessed using the log rank test. Results There were 158 consecutive patients with newly diagnosed MM who had their peripheral blood evaluated via flow cytometry as part of their routine clinical evaluation. The median age of this group was 66 years (39-95) and 59% were male. At the time of this analysis, 25 patients had died and the 2-year OS rate for the cohort was 83%. The 2-year OS for the 89 (55%) patients with any circulating PCs was 76% compared with 91% for those with none (P=0.02). The median number of circulating clonal PCs was 33 (range, 0-46,413)/ 150,000 gated events. Using a ROC analysis the best cutoff predicting 1 and 2-year mortality were 435 and 376 events, respectively. Based on this, we defined >=400 events as a cutoff for defining patients with high-risk disease. The median time-to-next-treatment (TTNT) for patients with circulating clonal PCs >=400 (n=37, 23%) was 14 months compared with 26 months for those with <400 events (n=121, 77%) (p<0.001; Fig 1a). The median OS for those with >=400 clonal PC events was 32 months compared with not reached for those with <400 events (p<0.001; Fig 1b). Patients with >= 400 circulating PCs had higher ISS stage, creatinine, LDH, PC labeling index and bone marrow PC% compared with the rest. In a univariate analysis examining the presence of circulating PC >=400, LDH, labeling index, marrow PC% and FISH risk status, only circulating PCs were prognostic for overall survival (P = 0.0011). Among the 89 patients with any circulating PCs, 26 (30%) had CD45+ clonal PCs. The TTNT in patients with a clonal CD45+ population was inferior to those with no CD45+ clonal PCs in circulation (median 11 vs. 19 months, P = 0.034) as was the OS (P = 0.039). Conclusion Quantitative estimation of circulating clonal PCs in patients with newly diagnosed MM is a powerful predictor of early relapse from therapy and mortality. A cutoff of >=400 clonal events/150,000 gated mononuclear events predicts for a median TTNT of 14 months and OS of 32 months. This parameter is more powerful than the current high-risk parameters such as FISH risk status as well as traditional high-risk markers such as ISS stage and LDH levels, and is able to identify a group of patients with particularly poor outcome. Disclosures: Kumar: Celgene: Consultancy, Research Funding; Millennium: Consultancy, Research Funding; Onyx: Consultancy, Research Funding.
Increased Incidence of Extramedullary Plasmacytomas In Patients with Multiple Myeloma In the Era of Novel Therapy and Effect of Pomalidomide on Extramedullary Disease

Blood | October 12, 2019 | Volume: 116 | Issue: 21 | Pages: 3047-3047

10.1182/blood.v116.21.3047.3047

Abstract Abstract 3047 Background: There is concern about the increased incidence of extramedullary plasmacytomas among patients with multiple myeloma (MM) in recent years (Varettoni et al Annals of Oncology 21: 325–330, 2010). There is controversy about whether novel agents increase the risk of extramedullary disease (EMD). EMD may be associated with decreased overall survival in MM. The purpose of this study was to determine the incidence of true, treatment-emergent EMD in MM among a cohort of patients who have been previously exposed to novel agent (thalidomide, lenalidomide, or bortezomib) therapy, and to evaluate the activity of pomalidomide in patients with EMD. Methods: We examined 174 consecutive patients with relapsed refractory multiple myeloma that were enrolled on a phase II clinical trial of pomalidomide plus low-dose dexamethasone. The study cohort was chosen since all patients had previously been exposed to novel agents, and were followed systematically. We adopted a strict definition of EMD which required that in order to be considered extramedullary, plasmacytomas must not have risen from any bone. Thus, masses arising from the bone with a soft tissue component were not considered extramedullary. Results: Of 174 patients studied, 16 patients (9.2%) had EMD prior to enrollment. In 3 of the 16 patients, EMD was present at time of diagnosis and was therefore not considered as treatment-emergent disease for this analysis. In 13 of 174 patients (7.5%) EMD developed during the course of MM, after starting therapy. All 13 patients by inclusion criteria were exposed to novel agents prior to the onset of EMD, including 100% to immunomodulatory agents (thalidomide or lenalidomide); and 78% (10 patients) were exposed to bortezomib prior to developing EMD. The median number of lines of prior therapy in these patients was 6, range 1–12). EMD occurred a median of 48 months following diagnosis (range, 16–183 months); the rate of EMD in the first 3 years following diagnosis of MM was 3%. Since all patients had prior exposure to immunomodulatory agents in this cohort, we were able to calculate the median length of time from initiation of immunomodulatory agents to onset of EMD as 24 months (range 7–119 months). The EMD sites involved included the temporal area soft tissue (3), muscle (3 [1 pt with 10 different areas of involvement, 1 pt with 5 muscles involved]), chest wall not attached to bone (3), abdominal/pelvic masses (3), kidney (2), scrotum (2), sinus (1), paraspinal (1), hilar/pleural based (1), paraesophageal (1), subcutaneous tissue (1), pancreas (1), spleen (1), mediastinum (1), pleural fluid (1), liver (1). Per protocol, all patients received pomalidomide (2-4 mg per day) and low dose dexamethasone (40 mg once a week). Of the 13 patients, there were 2 CR (with complete disappearance of EMD), 2 PR, 2 stable disease, 3 with progressive disease, and 4 patients who did not have their EMD re-evaluated. Thirty percent (n=4) of patients had a 50% or greater reduction in size of the EMD including one patient who received concomitant radiation. Overall survival from measured from trial entry was significantly shorter for patients who presented with EMD compared to those who did not have EMD, median 16 months versus not reached, p=0.002 (log-rank). Conclusion: We found that 7.5% of patients with relapsed refractory myeloma in the era of novel agents develop EMD during the course of their myeloma, including 3% within 3 years of diagnosis. The underlying reasons for the possible increased incidence of EMD may include better radiographic detection (the role of PET/CT scans and MRI), improved overall survival of patients in recent years, and the possibility that novel agents may increase the risk for strictly defined, true EMD among patients who did not have EMD at time of initial MM diagnosis. These need further study. Disclosures: Dispenzieri: Celgene: Honoraria, Research Funding; Binding Site: Honoraria. Gertz:Celgene: Honoraria; Millennium: Honoraria, Membership on an entity's Board of Directors or advisory committees. Kumar:Celgene: Consultancy, Research Funding; Millennium: Research Funding; Merck: Consultancy, Research Funding; Novartis: Research Funding; Genzyme: Consultancy, Research Funding; Cephalon: Research Funding.
A Novel Prognostic Staging System for Light Chain Amyloidosis (AL) Incorporating Markers of Plasma Cell Burden and Organ Involvement.

Blood | October 12, 2019 | Volume: 114 | Issue: 22 | Pages: 2797-2797

10.1182/blood.v114.22.2797.2797

Abstract Abstract 2797 Poster Board II-773 Background: Primary systemic amyloidosis (AL) is characterized by deposition of light chain derived amyloid fibrils in multiple organs leading to varying degree of dysfunction. Cardiac involvement is a common feature of AL, and when significant is highly predictive of poor outcome. The currently used prognostic classification is based on cardiac biomarkers troponin-T (cTnT) and N-terminal pro B-type Natriuretic peptide (NT-ProBNP) and is effective at predicting outcome in patients with AL. However, this is driven primarily by the degree of cardiac involvement and does not take into account the degree of plasma cell burden and its impact on the disease course. It is possible that some of the heterogeneity in outcome can be explained by the plasma cell characteristics rather than the degree of the end organ damage. Methods: We examined the baseline clinical and laboratory data from 2119 patients with AL who were seen at our institution with in 90 days of their diagnosis. The data were collected from a prospectively maintained data base, and additional testing was done for free light chain levels (FLC) on stored sera from patients seen before the routine introduction of FLC testing. Cox proportional hazards analysis was performed to estimate the prognostic values of different variables. Results: We first examined the impact of plasma cell clone related characteristics namely, difference between involved and uninvolved FLC (FLC-Diff), bone marrow plasma cell (BMPC) %, plasma cell labeling index (PCLI), beta 2 microglobulin (B2M), and presence of circulating plasma cells, on overall survival (OS) from diagnosis. All variables were dichotomized into high and low based on their median value (FLC-diff: 20 mg/dL, BMPC: 10%, PCLI as a continuous variable, B2M: 3 mg/dL and circulating cells: absent or present). While all were found to be prognostic for OS in univariate analysis; in a multivariate analysis incorporating a stepwise selection only B2M and FLC-diff were significant. We then used these two variables along with the cTnT and NT-ProBNP that are used in the current model to develop a staging system. The median values for all four variables were used for developing the scores. Patients were assigned a score of 1 for presence of each characteristic (FLC difference > 20 mg/dL, troponin-T > 0.02, NT-ProBNP > 1000, and B2M > 3) or 0 if the value was at or below the cutoff. The scores were added to obtain a composite prognostic score that grouped the 370 patients (who had all the variables available for analysis) into 5 groups with very different OS (4.4, 9.3, 24.4, 43, and not reached for stages 4, 3, 2, 1, and 0 respectively; Figure A). However, since the NT-ProBNP did not have independent impact on survival in a multivariable model incorporating all the four variables, we also examined a system that only included FLC-diff, cTnT and B2M. This system again allowed grouping of patients (n=450 with all three variables available) into four distinct groups with divergent outcome with OS of 4.6, 10.5, 36.8, and not reached for stages 3, 2, 1, and 0 respectively; (Figure B). Conclusion: Incorporation of plasma cell related measurements into the existing staging system using cardiac biomarkers allows better risk stratification of patients with AL amyloidosis. The system using FLC, B2M and troponin has the advantage of easily available laboratory values and can be widely adopted. Addition of NT-ProBNP into the system allows better refinement of the intermediate risk groups. This system will allow upfront risk stratification and development of risk-adapted therapies for patients with AL. Disclosures: Gertz: Genzyme: Research Funding.
Investigational Agent MLN2238/MLN9708, a Specific, Orally Available, Small Molecule Proteasome Inhibitor, Shows Promising In Vitro Activity Against Multiple Myeloma Cell Lines

Blood | October 12, 2019 | Volume: 116 | Issue: 21 | Pages: 3014-3014

10.1182/blood.v116.21.3014.3014

Abstract Abstract 3014 Background: Proteasome inhibitors have proven particularly effective in treatment of multiple myeloma, the second most frequent hematologic malignancy in the western world. Bortezomib, the first in class proteasome inhibitor in clinical use, was first approved in 2003 via fast FDA track, given the remarkable activity shown during phase II clinical trials. Nevertheless, more than 50% of multiple myeloma patients did not respond to single agent bortezomib when administered as second line agent. Moreover, bortezomib is only available for intravenous administration, representing a cumbersome therapy for patients, and its use is limited by significant toxicities (especially peripheral neuropathy). MLN9708 (Millennium Pharmaceuticals, Inc.), an investigational orally available, small molecule, is a potent, specific and reversible inhibitor of the 20S proteasome. It is currently under clinical investigation for the treatment of hematologic and non-hematologic malignancies. Upon exposure to aqueous solutions or plasma, MLN9708 rapidly hydrolyzes to MLN2238, the biologically active form, and MLN2238 was used for all of the preclinical studies reported here. In vitro biochemistry studies have shown that MLN2238 has a faster dissociation rate from the proteasome compared to bortezomib, and in vivo studies of MLN2238 have shown antitumor activity in a broader range of tumor xenografts when compared to bortezomib. Given these encouraging preclinical results, we set to investigate the anti-myeloma activity of MLN2238 in vitro. Results: MLN2238 proved to have anti-proliferative and pro-apoptotic activity against a broad range of MM cell lines with EC50 at 24 hours ranging between 10 and 50 nM, even in relatively resistant MM cell lines (OPM2, DOX6, RPMI, etc.). In MM.1S cells, induction of apoptosis was time and dose dependent and related to activation of both caspase 8 and 9. When compared to MM.1S treated for 24 hours with EC50 dose of bortezomib, treatment with EC50 dose of MLN2238 resulted in the same extent of caspases cleavage occurring at an earlier time point (8-12 hours), possibly suggesting more rapid onset and/or irreversibility of apoptosis in cells treated with MLN2238. Treatment with MLN2238 was associated with early, but persistent induction of endoplasmic reticulum (ER) stress with BiP being induced 2–4 hours after treatment with EC50 dose and gradually increasing over time. While bortezomib has been associated with early induction and late decrease in proteins involved in ER stress, MLN2238 appears to induce a persistent rise in these factors, suggesting either more sustained proteasome blockade with stabilization of proteasome substrates or de-novo induction of unfolded protein response (UPR) genes. MLN2238 also proved effective in reducing phosphorylation of ERK1-2 with no overall alteration in the total ERK level, thus accounting for the observed reduction in proliferation upon treatment. Preliminary data indicate potential for additive and synergistic combination with widely used drugs, including doxorubicin and dexamethasone. Conclusion: While further clinical data are needed to establish the effectiveness of MLN2238 in the treatment of multiple myeloma, these preliminary nonclinical data, together with the favorable biochemical and pharmacokinetic properties, including oral bioavailability, make the investigational agent MLN9708 an appealing candidate for treatment of multiple myeloma. Further in vitro data could help establish whether a difference in the apoptotic mechanisms exist between MLN2238 and other proteasome inhibitors, primarily bortezomib, and could also help inform combination treatment approaches aimed at increasing effectiveness, overcoming bortezomib resistance and decreasing toxicity. Disclosures: Kumar: Celgene: Consultancy, Research Funding; Millennium: Research Funding; Merck: Consultancy, Research Funding; Novartis: Research Funding; Genzyme: Consultancy, Research Funding; Cephalon: Research Funding.
Recent Improvements In Survival In Light Chain Amyloidosis and the Importance of An Early Mortality Risk Score

Blood | October 12, 2019 | Volume: 116 | Issue: 21 | Pages: 1892-1892

10.1182/blood.v116.21.1892.1892

Abstract Abstract 1892 Background: Primary or light chain amyloidosis (AL) is a clonal plasma cell disorder characterized by a relatively low plasma cell burden and multi-organ deposition of immunoglobulin light chain derived amyloid fibrils. The survival of patients with amyloidosis is quite variable with median survival of 12–18 months in different series, and largely dependent on the number and severity of organs involved. In addition to new drugs, the combination of melphalan and dexamethasone is an effective regimen for AL and risk adapted approaches to SCT has decreased treatment related mortality. It is not clear if the recent progress in risk stratification and treatment approaches have translated into improved survival for these patients. Methods: We studied two separate cohorts of patients; the first cohort consisting of 2118 patients with AL seen at Mayo Clinic over a 40-year period between November 1967 and August 2006 was used to examine the trends in overall survival from diagnosis during this time period. The second cohort of 443 patients seen between September 2006 and August 2009 were examined only for the changes in early mortality and for validation of a model for predicting early mortality developed using the first cohort of patients. Results: The estimated median follow up for the entire group was 7.8 years (95% CI; 7.1, 8.5). The patients were divided into 4 cohorts based on date of diagnosis; 1966–1976 (n=121), 1977–1986 (n=343), 1987–1996 (n=636) and 1997–2006 (n=1017). The median OS from diagnosis for the four cohorts were 0.9, 1.2, 1.2 and 1.5 years respectively, P < 0.001 (Figure 1). More importantly there was steady improvement in the long-term survival among these patients with 4-year survival estimates of 16%, 21%, 24% and 33% respectively. Next, we specifically looked at the survival trends within the last cohort (1996-2006), dividing the patients into three time periods; 1996–1999 (n=263), 2000–2003 (n=291) and 2003–2006 (n=463). While the OS from diagnosis was relatively unchanged between the first and second time periods (28 vs. 30% 4 year survival), there was significant improvement in the last three year period (42% survival at 4 years); P =0.02. Given the high early mortality in this disease, we specifically examined the one-year mortality among the entire patient cohort and found no clear improvement in terms of one-year mortality. Using logistic regression analysis, we identified cTnT > 0.01, NT-ProBNP > 4200 and Uric Acid > 8.0 mg/dL to be the best predictors of death within one year of diagnosis. The probability of death within one year for those with none, 1, 2, and 3 risk factors was 19, 38, 61, and 78% respectively, P < 0.01 (Figure 2). This model was further validated among patients seen during the most recent three years, September 2006 and August 2009. Conclusion: Survival in AL amyloidosis has improved over time, particularly in the recent years and likely reflects the recent improvements in therapy. However, early mortality remains a problem and baseline factors can be used to identify patients at risk for early mortality, who then can be targeted for risk adapted therapy approaches in clinical trials. Disclosures: Kumar: Celgene: Consultancy, Research Funding; Millennium: Research Funding; Merck: Consultancy, Research Funding; Novartis: Research Funding; Genzyme: Consultancy, Research Funding; Cephalon: Research Funding. Off Label Use: Lenalidomide for treatment of newly diagnosed myeloma. Dispenzieri:Celgene: Honoraria, Research Funding; Binding Site: Honoraria.
Efficacy of Retreatment with Immunomodulatory Compounds In Patients Receiving Initial Therapy for Newly Diagnosed Multiple Myeloma

Blood | October 12, 2019 | Volume: 116 | Issue: 21 | Pages: 1964-1964

10.1182/blood.v116.21.1964.1964

Abstract Abstract 1964 Background: Thalidomide (thal), lenalidomide (len) and pomalidomide (pom) have been shown to have considerable efficacy in patients with newly diagnosed as well as relapsed multiple myeloma (MM). They are often used as initial therapy in patients proceeding to stem cell transplant (SCT), and based on the initial response, are usually considered for salvage therapy during their disease course. However, the retreatment efficacy of these compounds is unknown. We conducted this study to ascertain the degree of response that can be obtained by retreatment with immunomodulatory compounds. Patients and Method: 410 patients with newly diagnosed MM who received either thalidomide-dexamethasone or lenalidomide-dexamethasone were studied. Of these, 183 patients received thalidomide, lenalidomide or pomalidomide (with or without dexamethasone) as one of the salvage regimens following relapse, and form the study group. We included all patients who received the repeat immunomodulatory therapy as salvage treatment at any time during the MM disease course. Results: The median (range) age of the MM patient group was 60 (29-80) years; 117 (64%) were male. Thalidomide and lenalidomide were used as initial therapy in 106 (58%) and 77 (42%) patients, respectively. Patients received a median of 2 treatments (range, 1–6) prior to salvage therapy; bortezomib was used as one of the salvage treatment (prior to the repeat immunomodulatory therapy) in 41 (22%) patients. An autologous stem cell transplant was performed in 118 (64%) patients after the initial immunomodulatory therapy. Almost one half (89; 49%) of the patients went off the first line therapy to undergo a SCT; whereas drug toxicity (26; 14%) and disease progression (21; 11%) were other causes requiring a treatment change. The compound used for salvage therapy was thalidomide, lenalidomide or pomalidomide in 40 (22%), 129 (70%) and 14 (8%) patients, respectively. The responses to salvage therapy based on the initial therapy and the salvage regimen are as shown in Table 1. Overall, 67 (37%) patients achieved a partial response or better and 73 (40%) patients achieved less than a partial response (stable and progressive disease) to repeat immunomodulatory therapy, while the remaining 43 (23%) had non evaluable disease response. Conclusions: Retreatment with an immunomodulatory therapy, especially a different compound, was associated with excellent response rates. Lowest response rates were seen in patients retreated with thalidomide after having received lenalidomide as their initial therapy after the diagnosis of MM. This information is valuable in deciding on the choice of repeat therapy with immunomodulatory compounds in patients with relapsed disease. Disclosures: Dispenzieri: Celgene: Honoraria, Research Funding; Binding Site: Honoraria. Kumar:Celgene: Consultancy, Research Funding; Millennium: Research Funding; Merck: Consultancy, Research Funding; Novartis: Research Funding; Genzyme: Consultancy, Research Funding; Cephalon: Research Funding.
A Risk Adapted Approach Utilizing Plerixafor in Autologous Peripheral Blood Stem Cell Mobilization.

Blood | October 12, 2019 | Volume: 114 | Issue: 22 | Pages: 3211-3211

10.1182/blood.v114.22.3211.3211

Abstract Abstract 3211 Poster Board III-148 Although autologous stem cell transplantation (ASCT) has become standard of care for many patients with hematologic malignancies, many patients fail to collect a minimum number of CD34 + stem cells to support high dose chemotherapy and ASCT. Recently, plerixafor, a CXCR4 antagonist, was FDA approved for use in combination with G-CSF for autologous peripheral blood stem cell mobilization in patients with NHL or Multiple Myeloma. In February 2009, we commenced a risk adapted approach to the utilization of plerixafor. The study was restricted to patients mobilized with GCSF alone and patients undergoing chemotherapy primed PBSC mobilization were excluded. Peripheral blood stem cell mobilization was commenced with G-CSF at 10 mcg/kg/day. On day 4, a peripheral blood (PB) CD34 count was measured. For patients whose PB CD34 was ≥10/μL, apheresis was commenced the following morning. For patients whose PB CD34 was <10/μL, it was measured again on day 5; if ≥10/μL then apheresis was commenced the following morning. If PB CD34 was <10/μL on day 5, plerixafor (0.24 mg/kg sc) was administered on the evening of day 5 and apheresis was commenced the following day (Group A). In addition, during apheresis, for patients whose collection yield was < 0.5 × 106 CD34/kg, in the absence of instrument failure or problems with the collection procedure, plerixafor was added (Group B). Morning administration of G-CSF and evening dosing of plerixafor continued daily until apheresis was complete. From February to July 2009, 174 mobilization attempts occurred; 27 with chemotherapy and 147 with cytokines alone. The 147 pts who underwent mobilization with cytokines alone are presented here. The underlying diagnosis was as follows: Myeloma 61 pts, NHL 54 pts, Amyloid 17 pts, Hodgkin 10 pts, POEMS 4 pts and 1 pt with a solid tumor. For the entire group the median number of CD34 cells collected was 5.5 × 106 CD34/kg (range 0.1-17). The median number of apheresis was 3 (range 1-12). 67 patients (46%) received plerixafor; 37 patients started plerixafor during mobilization (Group A) and 30 patients during collections due to a poor yield (Group B). 12 pts of the 37 received plerixafor on day 4 because of prior mobilization failure or high risk of mobilization failure and are included in Group A. Table 1 outlines the details of mobilization and collection by groups. By disease category, of the 61 patients with MM, 28 (46%) received plerixafor (8 Group A and 20 Group B). Median apheresis in all the MM pts was 2 (range 1-12) with a total of 6.8 × 106 CD34/kg (2.2-16.7). In the 54 NHL pts, 32 (59%) received plerixafor (24 Group A and 8 Group B). Median apheresis for all pts with NHL was 3 (range 1-7) with a total of 4.6 × 106 CD34/kg (range 0-11.4). Overall, only 7 of 147 (5%) mobilization attempts failed to achieve a minimum of 2 × 106 CD34/kg. This compares to a 22% failure rate prior to institution of this risk adapted approach. In conclusion, implementing this risk adapted approach allows poor mobilizers to be identified promptly and for plerixafor to be initiated during mobilization and collection, thereby reducing the number of mobilization failures. In patients who predictably would not have successful collection based on a PB CD34 <10/μL, addition of plerixafor results in a majority of patients achieving an adequate collection. This risk adapted approach may be more cost effective than reattempting mobilization after a prior failure or utilizing combination G-CSF and plerixafor for upfront mobilization. Table 1. Mobilization and Collection data. All patients N=147 Group A1 N=37 Group B2 N=30 No Plerixafor N=80 PB CD34 day 4 Median 11 0 7 19 Range 0-331 0-7 0-32 0-331 PB CD34 day 5 Median 10 4.5 12 15 Range 0-51 2-9 11-23 9-51 Apheresis Yield Median 5.5 4.4 6.0 6.2 Range 0.1-17 3.1-12.7 3.0-12.2 2-17 Number of Apheresis Median 3 3 5 2 Range 1-12 1-7 4-12 1-8 Days of Plerixafor Median n/a 3 2 n/a Rang 1-7 1-8 1 Group A – Plerixafor initiated prior to apheresis 2 Group B – Plerixafor initiated during apheresis Disclosures No relevant conflicts of interest to declare.
Implications of Body Weight Calculations for Autologous Peripheral Blood Stem Cell Transplantation.

Blood | October 12, 2019 | Volume: 108 | Issue: 11 | Pages: 5445-5445

10.1182/blood.v108.11.5445.5445

Abstract Background: Obesity is a prevalent health problem and significant heterogeneity is seen in the body weight and BMI among adult patients undergoing autologous stem cell transplantation (SCT). At least two critical steps of the SCT are influenced by the body weight. Stem cell collection targets are usually determined based on the actual body weight and conditioning chemotherapy doses are usually determined based on corrected ideal body weight. One could hypothesize that since the stem cells home to bone marrow, the ideal body weight (IBW) being based on the height may be a better indicator of the stem cell numbers required rather than the actual body weight (ABW). Since chemotherapy doses are calculated based on corrected ideal body weight, and the volume of distribution is higher in obese patients, these patients may have decreased drug exposure and hence a higher risk of progression. Methods: We retrospectively evaluated the engraftment kinetics and response outcome of 306 SCTs done at our institution between March 1998 and October 2001. These included patients who had undergone SCT for multiple myeloma (46%), NHL (34%), HD (6%) and AL amyloidosis (14%). Body weight, height, stem cell dose and engraftment data was obtained from medical records. The stem cell dose received was calculated based on their ABW as well as IBW and correlated with the time to white cell and platelet engraftment. We also evaluated the effect of BMI on the progression free survival after the stem cell transplant using various cut offs. Results: The mean (range) for the ABW, IBW and BMI were 46.6 kg to 189 Kg; 45.5 kg to 94 kg; and 17.5 to 55.8 respectively. Using logistic regression, we estimated the ability of CD34 cell dose by actual and ideal body weight to predict the likelihood of platelet engraftment (50,000) by day 21 post transplant. The coefficients using both the doses were very similar (.391 for ideal and 0.361 for actual). Using Receiver operating characteristic analysis (ROC analysis); we determined the stem cell dose cutoff that best predicted for failure to engraft neutrophils by 21 days post transplantation, median CD34 dose by ABW of 3.6 million/Kg and by IBW of 4.2 million/Kg. Similarly, for failure to engraft platelets by day 30 the cutoffs were 2.89 million/Kg by actual weight and 3.77 million/kg by ideal weight. Among the individuals with actual body weight more than 25% of ideal body weight (n=122, 40%), we calculated the optimal total CD34 dose required and compared to the actual dose infused using both the cutoff sets (286 million vs. 446 million, P < 0.001 using ANC cutoff and 251 million vs. 446 million using the platelet cutoff, P < 0.001). We then examined the effect of BMI on progression free and overall survival from transplant. The progression free and overall survival post transplant was similar for patients with BMI over 30 kg/m2 compared to those below this cutoff. There was no difference when patients with myeloma or lymphoma were studied separately. Conclusion: This study, as in previous studies, confirms that stem cell dose determined on the basis of ideal body weight is comparable to that by actual body weight in terms of engraftment kinetics. In patients significantly above the ideal body weight, it is reasonable to use a target based on ideal body weight which will allow for collection of less numbers of CD34 cells, thus conserving resources. Among patient undergoing stem cell transplant, the practice of using corrected ideal body weight does not appear to compromise the outcome of stem cell transplant.