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The treatment of patients with systemic light chain (AL) amyloidosis is a challenge to hematologists. Despite its generally small size, the underlying clone causes a rapidly progressing, often devastating multiorgan dysfunction through the toxic light chains that form amyloid deposits. Clinical manifestations are deceitful and too often recognized at an irreversible stage. However, hematologists are in the unique position to diagnose AL amyloidosis at a presymptomatic stage, checking biomarkers of amyloid organ involvement in patients with monoclonal gammopathies at higher risk to develop the disease. Adequate technology and expertise are needed for a prompt and correct diagnosis, particularly for ruling out non-AL amyloidoses that are now also treatable. Therapy should be carefully tailored based on severity of organ involvement and clonal characteristics, and early and continual monitoring of response is critical. Three recent randomized clinical trials moved AL amyloidosis to evidence-based era. Above all, the daratumumab-bortezomib combination is a new standard-of-care for newly diagnosed patients, inducing rapid and deep responses that translate into high rates of organ response. The availability of new effective drugs allows to better personalize the therapy, reduce toxicity, and improve outcomes. Patients should be treated within clinical trials whenever possible.

High-dose melphalan (HDM) and transplantation are recommended for eligible patients with multiple myeloma. No other conditioning regimen has proven to be more effective and/or safer. We previously reported in a phase 2 study that bortezomib can safely and effectively be combined with HDM (Bor-HDM), with a 32% complete response (CR) rate after transplantation. These data supported a randomized phase 3 trial. Randomization was stratified according to risk and response to induction: 300 patients were enrolled, and 154 were allocated to the experimental arm (ie, arm A) with bortezomib (1 mg/m2 intravenously [IV]) on days −6, –3, +1, and +4 and melphalan (200 mg/m2 IV) on day –2. The control arm (ie, arm B) consisted of HDM alone (200 mg/m2 IV). There were no differences in stringent CR + CR rates at day 60 posttransplant (primary end point): 22.1% in arm A vs 20.5% in arm B (P = .844). There were also no differences in undetectable minimum residual disease rates: 41.3% vs 39.4% (P = .864). Median progression-free survival was 34.0 months for arm A vs 29.6 months for arm B (adjusted HR, 0.82; 95% CI, 0.61-1.13; P = .244). The estimated 3-year overall survival was 89.5% in both arms (hazard ratio, 1.28; 95% CI, 0.62-2.64; P = .374). Sixty-nine serious adverse events occurred in 18.7% of Bor-HDM–treated patients (vs 13.1% in HDM-treated patients). The proportion of grade 3/4 AEs was similar within the 2 groups (72.0% vs 73.1%), mainly (as expected) blood and gastrointestinal disorders; 4% of patients reported grade 3/4 or painful peripheral neuropathy in arm A (vs 1.5% in arm B). In this randomized phase 3 study, a conditioning regimen with Bor-HDM did not improve efficacy end points or outcomes compared with HDM alone. The original trial was registered at www.clinicaltrials.gov as #NCT02197221.

Apoptosis induction by death receptor (DR)-specific agonistic antibodies is a potentially effective antitumor therapy. Nonetheless, to date, all conventional DR-targeting antibodies that induce apoptosis via FcγR-dependent DR clustering failed to show clinical efficacy. HexaBody-DR5/DR5 (GEN1029) has been developed to overcome full FcγR dependence. HexaBody-DR5/DR5 is a mixture of 2 noncompeting DR5-specific immunoglobulin G1 (IgG1) antibodies, each with an E430G mutation in the Fc domain. This mutation enhances Fc-Fc interactions, resulting in antibody hexamerization, followed by FcγR-independent clustering of DR5 molecules. This unique combination of dual epitope targeting and increased IgG hexamerization resulted in potent preclinical antitumor activity in various solid cancers. In this study, we explored the preclinical activity of HexaBody-DR5/DR5 in multiple myeloma (MM), because MM cells are known to express DR5. In bone marrow samples from 48 MM patients, HexaBody-DR5/DR5 induced potent cytotoxicity of primary MM cells. Importantly, HexaBody-DR5/DR5 mediated the highest cytotoxic activity in samples from relapsed/refractory MM patients, including those who are refractory to daratumumab. This improved cytotoxic activity was observed only in patients who received their last anti-MM treatment

Bortezomib, lenalidomide, and dexamethasone plus transplant is a standard of care for eligible patients with multiple myeloma. Because responses can deepen with time, regimens with longer and more potent induction/consolidation phases are needed. In this phase 2 study, patients received eight 28-day cycles of carfilzomib (K) 20/36 mg/m2 (days 1-2, 8-9, 15-16), lenalidomide (R) 25 mg (days 1–21), and dexamethasone (d) 20 mg (days 1-2, 8-9, 15-16, 22-23). All patients proceeded to transplant after 4 cycles and received 1 year of lenalidomide maintenance (10 mg, days 1-21). The primary objective was stringent complete response at the completion of consolidation. Overall, 48 patients were screened and 46 enrolled; 21% had adverse cytogenetics. Among 42 evaluable patients after consolidation, 26 were in stringent complete response (CR; 61.9%), 27 were at least in CR (64.3%): 92.6% had undetectable minimal residual disease according to flow cytometry (≥2.5 × 10−5) and 63.0% according to next-generation sequencing (10−6). Median time to CR was 10.6 months. According to multiparametric flow cytometry and next-generation sequencing, 69.0% and 66.7% of patients, respectively, had undetectable minimal residual disease at some point. With a median follow-up of 60.5 months, 21 patients progressed, and 10 died (7 of multiple myeloma). Median progression-free survival was 56.4 months. There were no KRd-related deaths. Four patients discontinued the program due to toxicities; 56 serious adverse events were reported in 31 patients, including 8 cardiovascular events (2 heart failures, 5 pulmonary embolisms or deep vein thrombosis). Common grade 3/4 adverse events were hematologic (74%) and infectious (22%). In summary, 8 cycles of KRd produce fast and deep responses in transplant-eligible patients with newly diagnosed multiple myeloma. The safety profile is acceptable, but cardiovascular adverse events should be closely monitored. This clinical trial is registered at www.clinicaltrials.gov as #NCT02405364.

Bortezomib (BTZ) was recently evaluated in a randomized phase 3 clinical trial by the Children’s Oncology Group (COG) that compared standard chemotherapy (cytarabine, daunorubicin, and etoposide [ADE]) vs standard therapy with BTZ (ADEB) for de novo pediatric acute myeloid leukemia (AML). Although the study concluded that BTZ did not improve outcome overall, we examined patient subgroups benefiting from BTZ-containing chemotherapy using proteomic analyses. The proteasome inhibitor BTZ disrupts protein homeostasis and activates cytoprotective heat shock responses. Total heat shock factor 1 (HSF1) and phosphorylated HSF1 (HSF1-pSer326) were measured in leukemic cells from 483 pediatric patients using reverse phase protein arrays. HSF1-pSer326 phosphorylation was significantly lower in pediatric AML compared with CD34+ nonmalignant cells. We identified a strong correlation between HSF1-pSer326 expression and BTZ sensitivity. BTZ significantly improved outcome of patients with low-HSF1-pSer326 with a 5-year event-free survival of 44% (ADE) vs 67% for low-HSF1-pSer326 treated with ADEB (P = .019). To determine the effect of HSF1 expression on BTZ potency in vitro, cell viability with HSF1 gene variants that mimicked phosphorylated (S326A) and nonphosphorylated (S326E) HSF1-pSer326 were examined. Those with increased HSF1 phosphorylation showed clear resistance to BTZ vs those with wild-type or reduced HSF1-phosphorylation. We hypothesize that HSF1-pSer326 expression could identify patients who benefit from BTZ-containing chemotherapy.

Background: Systemic AL amyloidosis is a rare disease characterized by amyloid fibril deposits, most commonly in the heart and kidneys; there are currently no health authority-approved treatments. Therapies for the treatment of multiple myeloma (MM), including bortezomib, cyclophosphamide, and dexamethasone (VCd), have been shown to improve outcomes in AL amyloidosis, but more effective therapies are needed to achieve deep and rapid hematologic responses, reverse amyloid-mediated organ dysfunction, and improve overall survival. Daratumumab is an anti-CD38 monoclonal antibody approved as monotherapy or in combination with other agents for the treatment of MM. ANDROMEDA (NCT03201965) is a randomized, open-label, active-controlled phase 3 trial of VCd ± daratumumab subcutaneous (DARA SC) in patients with newly-diagnosed AL amyloidosis. After a median follow-up of 11.4 months, the complete hematologic response rate was 53% for DARA SC + VCd (DARA-VCd) and 18% for VCd (odds ratio, 5.1; 95% CI, 3.2-8.2; P Methods: Patients with newly-diagnosed AL amyloidosis with measurable hematologic disease, ≥1 involved organ, cardiac stage (Mayo 2004) I-IIIA, eGFR ≥20 mL/min, and absence of symptomatic MM were randomized 1:1 to DARA-VCd or VCd and treated for six 28-day cycles; thereafter, patients in the DARA-VCd group received DARA SC alone every 4 weeks for up to 24 cycles. PROs were assessed on Day 1 of Cycles 1-6 for both treatment groups and every 8 weeks thereafter in the DARA-VCd group. PRO assessments included the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30-item (EORTC QLQ-C30), the EuroQol 5-dimensional descriptive system (EQ-5D-5L), and Short Form-36 (SF-36). Improvements in EORTC QLQ-C30 global health status (GHS) and fatigue scale scores and SF-36 mental component summary (MCS) score were secondary endpoints. Assessment of physical functioning, symptom improvement, functional improvement, and health utility as measured by the SF-36, EORTC QLQ-C30 with supplemental symptom items, and the EQ-5D-5L were exploratory outcomes. Patients completed PRO questionnaires prior to study assessments or study drug administration. Analyses of PROs were performed on the intent-to-treat analysis set; patients without a baseline or post-baseline assessment were censored at date of randomization. Compliance with PRO assessments was calculated as the number of assessments received divided by the number of assessments expected at each time point. Descriptive statistics are provided for all PRO endpoints at each time point by treatment group. A distribution-based method was used to define worsening/improvement in scores. Time to worsening/improvement, hazard ratios, and associated 95% confidence intervals were estimated using Kaplan Meier methods and Cox proportional hazards regression. Change from baseline at each time point up to Cycle 6 (Week 24) was calculated using a mixed effects model with repeated measures with patients as a random effect and baseline value, treatment group, time (weeks), treatment-by-time interaction, and stratification factors as fixed effects. Results: A total of 388 patients were randomized (DARA-VCd, n=195; VCd, n=193). Compliance rates for all PRO questionnaires were >90% at baseline and >83% through Cycle 6. Median time to improvement was shorter and median time to worsening was longer in the DARA-VCd group than in the VCd group for EORTC QLQ-C30 GHS and fatigue scales and EQ-5D-5L visual analog scale (VAS) (Table 1). Least squares mean scores for EORTC QLQ-C30 GHS and fatigue, EQ-5D-5L VAS, and SF-36 MCS remained stable in the DARA-VCd group but worsened compared with baseline in the VCd group; between-group differences are shown in Table 2. The greatest between-group differences in PRO score changes from baseline were observed at Week 16 (Cycle 4). After Cycle 6, patients in the DARA-VCd group reported improvements in mean GHS and fatigue scores that continued while on treatment (Figure). Conclusions: Patients with AL amyloidosis treated with DARA-VCd experienced clinical improvements without any decrement in health-related quality of life over 6 cycles. Following Cycle 6, improvements in GHS and fatigue were reported in patients in the DARA-VCd group. These findings further support the value of DARA-VCd in patients with AL amyloidosis. Disclosures Sanchorawala: UpToDate: Patents & Royalties; Abbvie: Other: advisory board; Proclara: Other: advisory board; Caleum: Other: advisory board; Regeneron: Other: advisory board; Oncopeptide: Research Funding; Caelum: Research Funding; Prothena: Research Funding; Celgene: Research Funding; Janssen: Research Funding; Takeda: Research Funding. Palladini:Celgene: Other: Travel support; Jannsen Cilag: Honoraria, Other. Minnema:Servier: Consultancy; Amgen: Consultancy; Kite, a Gilead Company: Speakers Bureau; Celgene: Other: travel support, Research Funding. Jaccard:Janssen: Consultancy, Honoraria, Other: A.J. has served in a consulting or advisory role for Janssen and has received honoraria from, received research funding from, and had travel, accommodations, or other expenses paid for or reimbursed by Janssen., Research Funding; Celgene: Honoraria, Other: A.J. has served in a consulting or advisory role for Janssen and has received honoraria from, received research funding from, and had travel, accommodations, or other expenses paid for or reimbursed by Celgene., Research Funding. Lee:Janssen: Consultancy, Research Funding; Genentech: Consultancy; GlaxoSmithKline: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Amgen: Consultancy, Research Funding; Genentech: Consultancy; Regeneron: Research Funding; Sanofi: Consultancy; Daiichi Sankyo: Research Funding. Gibbs:Janssen, BMS/Celgene, Amgen, Takeda, Pfizer, Caelum, Abbvie and Eidos: Membership on an entity's Board of Directors or advisory committees. Mollee:Pfizer: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS/Celgene: Membership on an entity's Board of Directors or advisory committees; Caelum: Membership on an entity's Board of Directors or advisory committees. Venner:Janssen, BMS/Celgene, Sanofi, Takeda, Amgen: Honoraria; Celgene, Amgen: Research Funding. Schönland:Janssen: Honoraria, Other: travel support to meetings, Research Funding; Prothena: Honoraria, Other: travel support to meetings, Research Funding; Takeda: Honoraria, Other: travel support to meetings, Research Funding. Suzuki:Bristol-Myers Squibb, Celgene and Amgen: Research Funding; Takeda, Amgen, Janssen and Celgene: Consultancy; Takeda, Celgene, ONO, Amgen, Novartis, Sanofi, Bristol-Myers Squibb, AbbVie and Janssen: Honoraria. Kim:BMS, Takeda, Amgen, Celgene, Janssen: Consultancy, Honoraria, Research Funding. Cibeira:Janssen, Akcea Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen, Celgene, Amgen: Honoraria, Other: Educational lectures. Beksac:Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sanofi: Consultancy, 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; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Valent:Celgene: Other: Teaching, Speakers Bureau; Takeda Pharmaceuticals: Other: Teaching, Speakers Bureau; Amgen Inc.: Other: Teaching, Speakers Bureau. Wong:GSK: Research Funding; Roche: Research Funding; Janssen: Research Funding; Bristol Myers Squibb: Research Funding; Fortis: Research Funding; Amgen: Consultancy; Sanofi: Membership on an entity's Board of Directors or advisory committees. Rosenzweig:Janssen: Speakers Bureau. Bumma:Amgen: Speakers Bureau; Sanofi: Speakers Bureau. Gries:Janssen: Current Employment, Current equity holder in publicly-traded company. Fastenau:Janssen: Current Employment, Current equity holder in publicly-traded company. Tran:Janssen: Current Employment, Current equity holder in publicly-traded company. Qin:Janssen: Current Employment. Vasey:Janssen Research & Development: Current Employment, Current equity holder in publicly-traded company. Tromp:Janssen: Current Employment, Current equity holder in publicly-traded company. Weiss:Janssen: Current Employment, Current equity holder in publicly-traded company. Vermeulen:Janssen: Current Employment, Current equity holder in publicly-traded company. Comenzo:Caleum: Consultancy; Amgen: Consultancy; Janssen: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Sanofi: Consultancy; Unum: Consultancy; Karyopharm: Consultancy, Research Funding; Prothena: Consultancy, Research Funding. Kastritis:Amgen: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Genesis Pharma: Consultancy, Honoraria. Wechalekar:Takeda: Honoraria, Other: Travel; Celgene: Honoraria; Janssen: Honoraria, Other: Advisory; Caelum: Other: Advisory.

Although no therapies are approved for light chain (AL) amyloidosis, cyclophosphamide, bortezomib, and dexamethasone (CyBorD) is considered standard of care. Based on outcomes of daratumumab in multiple myeloma (MM), the phase 3 ANDROMEDA study (NCT03201965) is evaluating daratumumab-CyBorD vs CyBorD in newly diagnosed AL amyloidosis. We report results of the 28-patient safety run-in. Patients received subcutaneous daratumumab (DARA SC) weekly in cycles 1 to 2, every 2 weeks in cycles 3 to 6, and every 4 weeks thereafter for up to 2 years. CyBorD was given weekly for 6 cycles. Patients had a median of 2 involved organs (kidney, 68%; cardiac, 61%). Patients received a median of 16 (range, 1-23) treatment cycles. Treatment-emergent adverse events were consistent with DARA SC in MM and CyBorD. Infusion-related reactions occurred in 1 patient (grade 1). No grade 5 treatment-emergent adverse events occurred; 5 patients died, including 3 after transplant. Overall hematologic response rate was 96%, with a complete hematologic response in 15 (54%) patients; at least partial response occurred in 20, 22, and 17 patients at 1, 3, and 6 months, respectively. Renal response occurred in 6 of 16, 7 of 15, and 10 of 15 patients, and cardiac response occurred in 6 of 16, 6 of 13, and 8 of 13 patients at 3, 6, and 12 months, respectively. Hepatic response occurred in 2 of 3 patients at 12 months. Daratumumab-CyBorD was well tolerated, with no new safety concerns versus the intravenous formulation, and demonstrated robust hematologic and organ responses. This trial was registered at www.clinicaltrials.gov as #NCT03201965.

Triplet regimens, such as lenalidomide, bortezomib, and dexamethasone (RVd) or thalidomide, bortezomib, and dexamethasone (VTd), are standard induction therapies for transplant-eligible patients with newly diagnosed multiple myeloma (NDMM). The addition of daratumumab to RVd and VTd has been investigated in the GRIFFIN and CASSIOPEIA trials, respectively, resulting in improvement in the rate of minimal residual disease (MRD) negativity. In this study, we conducted a cost-effectiveness analysis with a 10-year time horizon to compare first-line and second-line use of daratumumab for transplant-eligible patients with NDMM. Because long-term follow-up data for these clinical trials are not yet available, we developed a Markov model that uses MRD status to predict progression-free survival. Daratumumab was used either in the first-line setting in combination with RVd or VTd or in the second-line setting with carfilzomib plus dexamethasone (Kd). Quality-adjusted life-years (QALYs) and incremental cost-effectiveness ratios were calculated from a Japanese and US payer perspective. In the Japanese analysis, D-RVd showed higher QALYs (5.43 vs 5.18) and lower costs (¥64 479,793 vs ¥71 287 569) compared with RVd, and D-VTd showed higher QALYs (5.67 vs 5.42) and lower costs (¥43 600 310 vs ¥49 471,941) compared with VTd. Similarly, the US analysis demonstrated dominance of a strategy incorporating daratumumab in first-line treatment regimens. Given that overall costs are reduced and outcomes are improved when daratumumab is used as part of a first-line regimen, the economic analysis indicates that addition of daratumumab to first-line RVd and VTd regimens is a dominant strategy compared with reserving its use for the second-line setting.

Background: Systemic AL amyloidosis is characterized by the deposition of insoluble amyloid fibrils produced by light chains synthesized by clonal CD38+ plasma cells. Combining daratumumab (DARA) with bortezomib, cyclophosphamide, and dexamethasone (VCd) has demonstrated significantly improved outcomes in patients with AL amyloidosis. The classification of hematologic complete response (CR) in this disease is evolving, and the absolute reduction of the involved free light chain (iFLC) and the difference between iFLC and uninvolved free light chain (dFLC) are being recognized as very meaningful endpoints. Here, we present results from the ANDROMEDA study (NCT03201965) to demonstrate the impact of achieving deep reductions of iFLC and dFLC on major organ deterioration progression-free survival (MOD-PFS), a novel, key secondary endpoint in this study. Methods: Key eligibility criteria included newly diagnosed AL amyloidosis with measurable hematologic disease (serum monoclonal protein ≥0.5 g/dL by protein electrophoresis or serum free light chain ≥5.0 mg/dL with an abnormal kappa:lambda ratio or dFLC ≥50 mg/L), ≥1 involved organ, cardiac stage I-IIIA, eGFR ≥20 mL/min, and absence of symptomatic multiple myeloma. Patients were randomized (1:1) to receive DARA-VCd or VCd alone. All patients received bortezomib (1.3 mg/m2 subcutaneous [SC] weekly), cyclophosphamide (300 mg/m2 oral [PO] or intravenous [IV] weekly), and dexamethasone (20-40 mg PO or IV weekly) for six 28-day cycles. DARA SC (1800 mg, co-formulated with recombinant human hyaluronidase PH20 in 15 mL) was administered by injection weekly in Cycles 1-2, every other week in Cycles 3-6, and every 4 weeks thereafter for up to 24 cycles. Disease evaluations occurred every 4 weeks (Cycles 1-6) and every 8 weeks (after Cycle 7) until major organ deterioration, death, end of study, or withdrawal. The primary endpoint was overall (ie, at any time) hematologic CR rate, defined here as normalization of FLC levels and ratio (FLCr) and negative serum and urine immunofixation, confirmed at a subsequent visit; normalization of uninvolved FLC level and FLCr were not required if iFLC Results: A total of 388 patients were randomized to receive DARA-VCd (n=195) or VCd alone (n=193). Baseline characteristics were well balanced between treatment groups. The median age was 64 years and 65% of patients had ≥2 organs involved. The proportions of patients with heart and kidney involvement were 71% and 59%, respectively, and the proportions of patients with cardiac stage I, II, and IIIA were 23%, 40%, and 37%, respectively. The median duration of treatment was 9.6 months for DARA-VCd and 5.3 months for VCd. Median follow-up was 11.4 months (range, 0.03-21.3+). The rates of deep hematological responses by all criteria strongly favored the DARA-VCd treatment arm (Table). MOD-PFS was longer in patients achieving deep hematological responses by all criteria (Figure). In addition, the corresponding MOD-PFS was similar regardless of the hematological response criteria used. Conclusions: Regardless of the criteria used, the addition of DARA to VCd increased the rates of deep hematologic responses in patients with newly diagnosed AL amyloidosis, which, in turn, was associated with prolonged MOD-PFS. These results support the benefit of DARA in this patient population. References 1. Comenzo RL, et al. Leukemia. 2012;26(11):2317-25 2. Sidana S, et al. Leukemia. 2019;34(5):1472-75 3. Muchtar E, et al. Leukemia. 2019;33(3):790-94 4. Manwani R, et al. Blood. 2019;134(25):2271-2280 Disclosures Comenzo: Amgen: Consultancy; Sanofi: Consultancy; Prothena: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Unum: Consultancy; Karyopharm: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Caleum: Consultancy. Kastritis:Pfizer: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Research Funding; Genesis Pharma: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria. Palladini:Celgene: Other: Travel support; Jannsen Cilag: Honoraria, Other. Minnema:Celgene: Other: travel support, Research Funding; Kite, a Gilead Company: Speakers Bureau; Amgen: Consultancy; Servier: Consultancy. Wechalekar:Caelum: Other: Advisory; Janssen: Honoraria, Other: Advisory; Takeda: Honoraria, Other: Travel; Celgene: Honoraria. Jaccard:Celgene: Honoraria, Other: A.J. has served in a consulting or advisory role for Janssen and has received honoraria from, received research funding from, and had travel, accommodations, or other expenses paid for or reimbursed by Celgene., Research Funding; Janssen: Consultancy, Honoraria, Other: A.J. has served in a consulting or advisory role for Janssen and has received honoraria from, received research funding from, and had travel, accommodations, or other expenses paid for or reimbursed by Janssen., Research Funding. Sanchorawala:Proclara: Other: advisory board; Abbvie: Other: advisory board; UpToDate: Patents & Royalties; Regeneron: Other: advisory board; Caleum: Other: advisory board; Janssen: Research Funding; Takeda: Research Funding; Celgene: Research Funding; Prothena: Research Funding; Caelum: Research Funding; Oncopeptide: Research Funding. Lee:Janssen: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Genentech: Consultancy; GlaxoSmithKline: Consultancy, Research Funding; Sanofi: Consultancy; Daiichi Sankyo: Research Funding; Regeneron: Research Funding; Genentech: Consultancy; Celgene: Consultancy, Research Funding; Amgen: Consultancy, Research Funding. Gibbs:Janssen, BMS/Celgene, Amgen, Takeda, Pfizer, Caelum, Abbvie and Eidos: Membership on an entity's Board of Directors or advisory committees. Mollee:Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS/Celgene: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Caelum: Membership on an entity's Board of Directors or advisory committees. Venner:Celgene, Amgen: Research Funding; Janssen, BMS/Celgene, Sanofi, Takeda, Amgen: Honoraria. Schönland:Janssen, Prothena, Takeda: Honoraria, Other: travel support to meetings, Research Funding. Suzuki:Takeda, Amgen, Janssen and Celgene: Consultancy; Bristol-Myers Squibb, Celgene and Amgen: Research Funding; Takeda, Celgene, ONO, Amgen, Novartis, Sanofi, Bristol-Myers Squibb, AbbVie and Janssen: Honoraria. Kim:Amgen, BMS, Janssen, Sanofi, Takeda: Consultancy, Honoraria, Research Funding. Cibeira:Janssen, Akcea Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen, Celgene, Amgen: Honoraria, Other: Educational lectures. Beksac:Deva: 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; Takeda: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sanofi: Speakers Bureau; Amgen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen&janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Valent:Amgen Inc.: Other: Teaching, Speakers Bureau; Takeda Pharmaceuticals: Other: Teaching, Speakers Bureau; Celgene: Other: Teaching, Speakers Bureau. Wong:Fortis: Research Funding; GSK: Research Funding; Amgen: Consultancy; Janssen: Research Funding; Roche: Research Funding; Bristol Myers Squibb: Research Funding; Sanofi: Membership on an entity's Board of Directors or advisory committees. Rosenzweig:Janssen: Speakers Bureau. Bumma:Sanofi: Speakers Bureau; Amgen: Speakers Bureau. Dimopoulos:BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Speakers Bureau; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau. Tran:Janssen: Current Employment, Current equity holder in publicly-traded company. Qin:Janssen: Current Employment. Vasey:Janssen Research & Development: Current Employment, Current equity holder in publicly-traded company. Tromp:Janssen: Current Employment, Current equity holder in publicly-traded company. Weiss:Janssen: Current Employment, Current equity holder in publicly-traded company. Vermeulen:Janssen: Current Employment, Current equity holder in publicly-traded company.

Introduction Selinexor is a first-in-class, oral, potent selective inhibitor of nuclear export (SINE) which blocks XPO1, forcing the nuclear retention and activation of tumor suppressor proteins, leading to cancer cell apoptosis. Selinexor has demonstrated antimyeloma activity in triple class refractory multiple myeloma (MM) [Chari et al. NEJM 2019]. Selinexor synergizes with proteasome inhibitors (PIs) in PI-sensitive and -resistant cell lines and produces high response rates in patients with PI refractory and non-refractory MM (Bahlis et al. Blood 2018). In the phase 3 BOSTON study, the combination of once weekly (QW) selinexor, QW bortezomib, and dexamethasone (SVd) in patients who had received 1-3 prior therapies led to a significantly longer (47%) median progression-free survival (PFS) of 13.93 vs 9.46 months, with a hazard ratio of 0.70 (P=0.0075) compared to standard twice weekly bortezomib and dexamethasone (Vd). In addition, SVd regimen produced higher response rates and deeper responses (ORR: 76.4% vs 62.3% and ≥CR 16.9% vs 10.2%) compared with Vd. The benefit with SVd was observed across all efficacy endpoints and was associated with lower incidence and severity of bortezomib-induced peripheral neuropathy. Here we analyzed the effect of prior PI therapy (bortezomib, carfilzomib, ixazomib) on the efficacy and safety of SVd compared with Vd. Methods BOSTON is an open-label, randomized phase 3 study in patients with MM comparing SVd (QW oral selinexor 100 mg, QW subcutaneous bortezomib 1.3 mg/m2, and BIW oral dexamethasone 20 mg), versus Vd (BIW bortezomib 1.3 mg/m2 and QIW dexamethasone 20 mg). Patients previously treated with a PI must have had at least a partial response (PR) to the PI and 6 months since the last PI regimen. The study primary end point was PFS. Here we report subgroup analysis of treatment outcomes based on prior PI treatment. Results Subgroups consisted of PI naïve patients (n=95; 24%) and patients with prior PI treatment (n=307; 76%). Both the subgroups and study arms were comparable for baseline patient demographic and disease characteristics. However, those with prior PI treatment more frequently had a previous stem cell transplant (38% vs 24%) or 3 lines of prior anti MM therapy (21% vs 13%). Median PFS was improved with SVd compared with Vd in both the PI naïve group (PFS not reached (NR) vs 9.7 months; HR 0.2585 [95% CI, 0.1116-0.5988]; P=0.0003) and in the PI treated group (11.7 vs 9.4 months; HR 0.7839 [95% CI, 0.5791-1.0612]; P=0.06). Other efficacy endpoints are shown in the table. Peripheral neuropathy ≥grade 2 (a secondary study endpoint) was less frequent in the SVd compared with the Vd arm (PI naïve: 25.5%, Vd 43.8%, P=0.0302; PI treated: SVd 19.6%, Vd 31.4%, P=0.0092). Adverse events of ≥grade 3 occurred in 71% of patients in the PI naïve group (SVd 77%, Vd 65%) and 74% of patients in the PI treated group (SVd 88%, Vd 60%). Thrombocytopenia was more frequent in patients in the SVd arms (PI naïve: SVd 32%, Vd 13%; PI treated: SVd 42%, Vd 19%) as was anemia (PI naïve: SVd 15%, Vd 6%; PI treated: SVd 16%, Vd 12%), and fatigue (PI naïve: SVd 15%, Vd 2%; PI treated: SVd 13%, Vd 1%). Conclusions The once-weekly SVd combination was associated with significant clinical benefit and reduced peripheral neuropathy as compared with standard twice-weekly Vd in patients with MM and 1-3 prior therapies, regardless of prior therapy with a PI. However, the benefits of SVd over Vd were more pronounced in patients who had never been treated with a PI (PFS HR 0.26), suggesting that selinexor could be an optimal partner for combining with weekly bortezomib as the first PI-containing MM regimen. Figure 1 Disclosures Mateos: Roche: Honoraria; Seattle Genetics: Honoraria; EDO Mundipharma: Honoraria; Adaptive Biotechnologies: Honoraria; GlaxoSmithKline: Honoraria; Abbvie: Honoraria; Takeda: Honoraria; Amgen: Honoraria; Bristol-Myers Squibb: Honoraria; Janssen: Honoraria. Gavriatopoulou:Amgen: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria; Genesis Pharma: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria. Facon:Celgene, Janssen, Takeda, Amgen, Roche, Karyopharm, Oncopeptides, BMS, Sanofi: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Auner:Karyopharm: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Research Funding. Leleu:AbbVie: Honoraria; GSK: Honoraria; Amgen: Honoraria; Novartis: Honoraria; Carsgen: Honoraria; Incyte: Honoraria; Merck: Honoraria; BMS-celgene: Honoraria; Janssen: Honoraria; Oncopeptide: Honoraria; Sanofi: Honoraria; Karyopharm: Honoraria. Hajek:Novartis: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria, Research Funding; Oncopeptides: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharma MAR: Consultancy, Honoraria; BMS: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Dimopoulos:Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau; BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Speakers Bureau; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau. Delimpasi:GENESIS: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria. Spicka:Celgene, Amgen, Janssen-Cilag, Takeda, Bristol-Myers Squibb, Novartis, Sanofi: Consultancy, Honoraria, Speakers Bureau. Kryachok:Janssen, Bayer, Karyopharm, MSD, Acerta, AvbbVie, Debiopharm: Research Funding; Takeda, Janssen: Consultancy; Takeda, MSD, AbbVie, Ro: Other: Travel, accommodations, expenses; Takeda, Janssen, Novartis, Roche, MSD, Bayer: Consultancy, Research Funding. Sinha:Dr Reddys Lab, Intas Pharmaceuticals, Karyopharm Therapeutics: Honoraria. Venner:Celgene, Amgen: Research Funding; Janssen, BMS/Celgene, Sanofi, Takeda, Amgen: Honoraria. Garg:Janssen, Takeda, Celgene, Novartis, Sanofi: Honoraria. Stevens:Amgen, MorphoSys: Consultancy. Quach:GlaxoSmithKline: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Research Funding; Glaxo Kline Smith: Consultancy, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Janssen Cilag: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria, Research Funding. Jagannath:BMS, Janssen, Karyopharm, Legend Biotech, Sanofi, Takeda: Consultancy. Moreau:Amgen: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; Takeda: Honoraria; Janssen: Consultancy, Honoraria; Celgene/Bristol-Myers Squibb: Consultancy, Honoraria; Novartis: Honoraria. Levy:Karyopharm,Takeda, BMS: Consultancy, Honoraria, Speakers Bureau. Badros:Amgen: Consultancy; University of Maryland: Current Employment. Anderson:Karyopharm: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; GSK: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding. Bahlis:Sanofi: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; BMS/Celgene and Janssen: Consultancy, Honoraria, Other: Travel, Accomodations, Research Funding; AbbVie: Consultancy, Honoraria; Genentech: Consultancy, Honoraria; Karyopharm Therapeutics: Consultancy, Honoraria; GSK: Consultancy, Honoraria. Cavo:Jannsen, BMS, Celgene, Sanofi, GlaxoSmithKline, Takeda, Amgen, Oncopeptides, AbbVie, Karyopharm, Adaptive: Consultancy, Honoraria. Chai:Karyopharm Therapeutics Inc: Current Employment. Arazy:Karyopharm Therapeutics Inc.: Current Employment. Shah:Karyopharm Therapeutics Inc: Current Employment, Current equity holder in publicly-traded company. Shacham:Karyopharm: Current Employment, Current equity holder in publicly-traded company, Patents & Royalties: (8999996, 9079865, 9714226, PCT/US12/048319, and I574957) on hydrazide containing nuclear transport modulators and uses, and pending patents PCT/US12/048319, 499/2012, PI20102724, and 2012000928) . Kauffman:Karyopharm Therapeutics Inc: Current Employment, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees. Richardson:Celgene/BMS, Oncopeptides, Takeda, Karyopharm: Research Funding.

Introduction Monoclonal immunoglobulin (Ig) is a valuable diagnostic marker in patients with multiple myeloma (MM). An inevitable consequence of extensive Ig synthesis is overload of misfolded proteins that saturate proteasome capacity making the myeloma cells highly sensitive to proteasome inhibitors (PI). Even though PI are regularly used in the clinic, resistance often emerges leaving clinicians with limited treatment options. Therefore, there is a need for a robust marker selecting MM patients for precise PI-based combination therapy. Methods We performed a multiple database search for genes associated with Ig production and MM patients' survival. Additionally, we compared gene expression profiles (RNAseq) of primary MM cells with low and high Ig levels. Next, we validated the identified hits by shRNA knockdown and overexpression studies using myeloma cell lines, primary MM samples, and mouse models. We also applied mass spectrometry-based proteomic analysis, advanced biochemical approaches, and genetic models to reveal the Ig production pathway components and function. Finally, we performed a limited rational drug screening to select suitable compounds for combination treatment. Results RNAseq and database mining revealed a strong association between the expression of plasma cell-specific deubiquitinase OTUD1, Ig production, and MM patient survival. Suppression of OTUD1 with shRNAs in RPMI8226 and MM1.S cell lines reduced Ig levels, increased proliferation, and induced bortezomib resistance. Conversely, inducible OTUD1 overexpression enhanced Ig production, slowed down proliferation, and increased bortezomib sensitivity. In the xenografts mouse models cells with high OTUD1 levels synthesized more Ig and developed smaller tumors. Intriguingly, the transcription of Ig genes was not influenced by OTUD1 expression suggesting that OTUD1 functions as a posttranslational regulator of Ig assembly. To gain mechanistic insight into the Ig pathway regulation by OTUD1, we utilized the biotin proximity labeling method (Turbo-ID) combined with mass spectrometry analysis. We found several novel OTUD1 interaction partners including the E3 ubiquitin ligase KEAP1 and endoplasmic reticulum (ER) redox protein PRDX4. We demonstrated that KEAP1 acts upstream of OTUD1 by regulating OTUD1 ubiquitination and stability. Consistently, survival analysis revealed that MM patients with high KEAP1 expression (low OTUD1) had a worse prognosis than patients with low levels of KEAP1 (high OTUD1). PRDX4 regulates disulfite bonds formation during protein folding and is uniquely expressed in fully differentiated plasma cells. Here, we revealed that OTUD1 specifically deubiquitinates and thus stabilizes PRDX4 inside the ER. Additionally, we performed rescue genetic experiments and found a direct link between the OTUD1-PRDX4 axis and Ig production. The increase in OTUD1 expression (high Ig) led to a dramatic increase in the total pool of ubiquitinated proteins formed mainly by misfolded Ig, while OTUD1 knockdown (low Ig) had an opposite effect. We showed that changes in the level of ubiquitinated proteins correlated with PI sensitivity. Of note, OTUD1 did not affect the expression of proteasome subunits, either their enzymatic activity. Our mechanistic findings prompted us to propose a novel therapeutic opportunity in PI resistant MM patients. We hypothesize that the resensitization of Ig low MM cells to PI could be achieved by enhancing ER stress leading to an increase in misfolded proteins that would ultimately saturate proteasomes. Indeed, from clinically relevant drugs tested so far, the HSP-90 inhibitor (17-AAG) reverted the PI resistance in OTUD1 low (Ig low) myeloma cells. An in vivo validation of the combination treatment and testing of Ig involvement in PI sensitivity and proliferation of MM cells is ongoing. Conclusion Here we present the discovery of a novel regulatory mechanism for Ig production in plasma cells. Based on our results and previously published studies, we conclude that Ig synthesis is a clinically significant factor related to PI response and MM patient survival. Our findings suggest that the intracellular Ig level is an important biomarker to identify patients benefiting the most from PI-based therapies. Finally, we provide a rational solution for selective, combination therapy to overcome PI resistance in MM patients with a decreased capacity to synthesize Ig. Figure Disclosures Hajek: Janssen: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Research Funding; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Consultancy, Honoraria; PharmaMar: Consultancy, Honoraria; Oncopeptides: Consultancy.

Introduction Selinexor is a first-in-class, oral, potent selective inhibitor of nuclear export (SINE) which blocks XPO1, forcing the nuclear retention and activation of tumor suppressor proteins, leading to cancer cell apoptosis. Selinexor has demonstrated antimyeloma activity in triple class refractory multiple myeloma (MM) [Chari et al. NEJM 2019]. Selinexor synergizes with proteasome inhibitors (PIs) in PI-sensitive and -resistant cell lines and produces high response rates in patients with PI refractory and non-refractory MM. (Bahlis et al. Blood 2018). In the phase 3 BOSTON study, the combination of once weekly (QW) selinexor, QW bortezomib and dexamethasone (SVd) in patients who had received 1-3 prior therapies led to a significantly (47%) longer median progression-free survival (PFS) of 13.93 versus 9.46 months (HR 0.70; P=0.0075) compared to standard twice weekly bortezomib and dexamethasone (Vd). In addition, SVd regimen produced higher response rates and deeper responses (ORR: 76.4% vs 62.3% and ≥CR 16.9% vs 10.2%) compared with Vd. The benefit with SVd was observed across all efficacy endpoints and was associated with lower incidence and severity of bortezomib-induced peripheral neuropathy. Here we present subgroup analyses according to number of prior lines of therapy and prior treatment with lenalidomide (LEN). Methods BOSTON is an open-label, randomized phase 3 study in patients with MM comparing SVd (QW selinexor 100 mg, QW subcutaneous bortezomib 1.3 mg/m2, and 20 mg twice weekly [BIW] dexamethasone), versus Vd (1.3 mg/m2 bortezomib BIW and dexamethasone 20 mg 4 x weekly [QIW]). Patients previously treated with a PI must have had at least a partial response (PR) to the PI and 6 months since the last PI regimen. The study primary end point was PFS. Results Of the 402 patients in the BOSTON study, 198 (49%) had 1 prior line versus 204 (51%) with 2-3 prior lines. In addition, 154 (38%) comprised the LEN treated subgroup, versus 248 (62%) in the LEN naïve subgroup. Of note, 41% patients received prior thalidomide, which is consistent with most of the BOSTON study patients being treated in the EU. Baseline demographic and disease characteristics were well balanced between treatment arms across subgroups. A very good partial response (VGPR) or better to most recent prior line anti-MM therapy was more frequent in patients with 1 prior line of therapy (63% vs 41%) versus those with 2-3 prior lines of therapy. Patients with prior LEN therapy were more likely to have had 2-3 prior therapies (72.1%) compared with LEN naive patients (37.5%). As shown in the table, SVd was associated with longer PFS compared with Vd in all subgroups. Overall response rates (ORR) and times-to-next-treatment (TTNT) were statistically greater with SVd compared with Vd in all subgroups. Rates of very good partial response or better (VGPR) were statistically greater for SVd vs Vd in the LEN-naïve group and 1 prior treatment group. Grade ≥2 peripheral neuropathy (a key secondary endpoint prespecified in the study) occurred less frequently across all SVd subgroups compared with Vd: LEN treated (21% SVd, 37% Vd, P=0.0166); LEN-naïve (21% SVd, 33% Vd, P=0.0252), 1 prior line (21% SVd, 33% Vd, P=0.0501); 2-3 prior lines (21% SVd, 36% Vd, P=0.0107). Adverse events of ≥grade 3 were more commonly reported in the SVd treatment arm than in the Vd arm, LEN treated (83% SVd, 57% Vd), LEN-naïve (76% SVd, 55% Vd), 1 prior line (77% SVd, 56% Vd), 2-3 prior lines (81% SVd, 56% Vd), and were mostly managed with dose modification and/or supportive treatment. Pneumonia occurred at comparable rates between treatment arms. There were no differences between subgroups in grade 3 adverse events. Conclusions In the BOSTON study, once-weekly SVd significantly improved PFS, ORR, TTNT and reduced rates of ≥grade 2 peripheral neuropathy compared with Vd regardless of number of prior treatments or whether patients were previously treated with LEN. Adverse events were managed with dose modification and treatment-related discontinuation rates did not differ between the 2 regimens for any subgroup. The PFS of 16.6 months with SVd after 1 prior therapy, and the HR of 0.63 in patients with prior LEN treatment support the use of once-weekly SVd for the second line treatment of MM following a LEN-containing regimen. Table Disclosures Mateos: Takeda: Honoraria; Abbvie: Honoraria; GlaxoSmithKline: Honoraria; EDO Mundipharma: Honoraria; Seattle Genetics: Honoraria; Roche: Honoraria; Bristol-Myers Squibb: Honoraria; Janssen: Honoraria; Amgen: Honoraria; Adaptive Biotechnologies: Honoraria. Jagannath:Takeda: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria; Legend Biotech: Consultancy, Honoraria. Delimpasi:GENESIS: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria. Spicka:Celgene, Amgen, Janssen-Cilag, Takeda, Bristol-Myers Squibb, Novartis, Sanofi: Consultancy, Honoraria, Speakers Bureau. Kryachok:Takeda, Janssen, Novartis, Roche, MSD, Bayer: Consultancy, Research Funding; Janssen, Bayer, Karyopharm, MSD, Acerta, AvbbVie, Debiopharm: Research Funding; Takeda, MSD, AbbVie, Ro: Other: Travel, accommodations, expenses; Takeda, Janssen: Consultancy. Gavriatopoulou:Amgen: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria; Genesis Pharma: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria. Dimopoulos:Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Speakers Bureau; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau; BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees. Auner:Amgen: Consultancy, Honoraria, Research Funding; Karyopharm: Consultancy, Honoraria; Takeda: Consultancy, Honoraria. Leleu:BMS-celgene: Honoraria; Carsgen: Honoraria; Incyte: Honoraria; Merck: Honoraria; AbbVie: Honoraria; Oncopeptide: Honoraria; Janssen: Honoraria; Novartis: Honoraria; Amgen: Honoraria; GSK: Honoraria; Sanofi: Honoraria; Karyopharm: Honoraria. Sinha:Dr Reddys Lab, Intas Pharmaceuticals, Karyopharm Therapeutics: Honoraria. Venner:Celgene, Amgen: Research Funding; Janssen, BMS/Celgene, Sanofi, Takeda, Amgen: Honoraria. Garg:Janssen, Takeda, Celgene, Novartis, Sanofi: Honoraria. Stevens:Amgen, MorphoSys: Consultancy. Quach:Amgen, Celgene, karyopharm, GSK, Janssen Cilag, Sanofi.: Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline, Karyopharm, Amgen, Celgene, Janssen Cilag: Honoraria; GlaxoSmithKline, Karyopharm, Amgen, Celgene, Janssen Cilag: Consultancy; Amgen, sanofi, celgene, Karyopharm, GSK: Research Funding. Moreau:Novartis: Honoraria; Amgen: Consultancy, Honoraria; Celgene/Bristol-Myers Squibb: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Honoraria; Sanofi: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria. Levy:Sanofi: Consultancy, Honoraria, Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; Karyopharm: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Bristol Meyers Squibb: Consultancy, Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Research Funding; BeiGene: Consultancy, Research Funding, Speakers Bureau; Baylor University Med Center: Current Employment; Takeda: Consultancy, Honoraria, Research Funding. Badros:Amgen: Consultancy; University of Maryland: Current Employment. Anderson:Janssen: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; GSK: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Honoraria, Research Funding; Karyopharm: Consultancy, Honoraria, Research Funding. Bahlis:Genentech: Consultancy, Honoraria; Karyopharm Therapeutics: Consultancy, Honoraria; GSK: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria; BMS/Celgene and Janssen: Consultancy, Honoraria, Other: Travel, Accomodations, Research Funding; Sanofi: Consultancy, Honoraria. Facon:Celgene, Janssen, Takeda, Amgen, Roche, Karyopharm, Oncopeptides, BMS, Sanofi: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Cavo:Jannsen, BMS, Celgene, Sanofi, GlaxoSmithKline, Takeda, Amgen, Oncopeptides, AbbVie, Karyopharm, Adaptive: Consultancy, Honoraria. Chai:Karyopharm Therapeutics Inc: Current Employment. Arazy:Karyopharm Therapeutics Inc.: Current Employment. Shah:Karyopharm Therapeutics Inc: Current Employment, Current equity holder in publicly-traded company. Shacham:Karyopharm: Current Employment, Current equity holder in publicly-traded company, Patents & Royalties: (8999996, 9079865, 9714226, PCT/US12/048319, and I574957) on hydrazide containing nuclear transport modulators and uses, and pending patents PCT/US12/048319, 499/2012, PI20102724, and 2012000928) . Kauffman:Karyopharm Therapeutics Inc: Current Employment, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees. Richardson:Celgene/BMS, Oncopeptides, Takeda, Karyopharm: Research Funding.

Bortezomib is a standard therapy in light-chain amyloidosis (AL), but little is known about response duration. A difference in involved amyloidogenic and uninvolved serum-free light chains (dFLC)10 mg/L (low dFLC response) predicts survival in AL patients with low presenting dFLC (20-50 mg/L). We report outcomes in the largest AL cohort treated with upfront bortezomib and explore the impact of posttreatment dFLC10 mg/L ("stringent dFLC response"). A total of 915 newly diagnosed AL patients treated with bortezomib and assessed at our center were included. Hematologic responses, 6-month dFLC, organ responses, overall survival (OS), and time-to-next-treatment (TNT) (excluded patients who died without starting second-line treatment) were evaluated. Overall response rate (intent-to-treat) was 65%, with 49% complete response (CR)/very good partial response/low dFLC response and with a stringent dFLC response, dFLC 10-40 mg/L, and dFLC40 mg/L was 30%, 22%, and 48%, respectively. Median OS was 72 months. A total of 289 patients died without progressing to second-line treatment. Median TNT was not reached, and 55% had not progressed to further treatment at 7 years. Patients with stringent dFLC responses had significantly better OS and TNT than did those with lesser responses. A total of 72% of CR patients did not progress to further treatment at 3 years compared with 84% with stringent dFLC responses. Cardiac responses were better in those with stringent dFLC responses (61%) compared with lesser responses (45%; P = .005). Upfront bortezomib confers durable hematologic responses. A stringent dFLC response predicts prolonged TNT and impressive organ responses.

Insights into immune-mediated thrombotic thrombocytopenic purpura (iTTP) pathophysiology have led to novel targeted therapies. Immunomodulatory strategies target anti-ADAMTS13 antibodies: rituximab is effective in inducing responses in refractory/relapsed TTP and increasing relapse-free survival; caplacizumab targets the von Willebrand factor–platelet interaction to hasten platelet count recovery and reduce mortality and TTP-related ischemic events. Bortezomib and recombinant ADAMTS13 are under investigation. This review examines how targeted therapies are disrupting current treatment paradigms to improve outcomes of iTTP.

The phase 3 CLARION study compared carfilzomib-melphalan-prednisone (KMP) with bortezomib-melphalan-prednisone (VMP) in transplant-ineligible newly diagnosed multiple myeloma (NDMM) patients. Patients were randomized 1:1 to KMP or VMP for nine 42-day cycles (C). Patients received carfilzomib on days (D) 1, 2, 8, 9, 22, 23, 29, 30 (20 mg/m2: C1D1, C1D2; 36 mg/m2 thereafter) or bortezomib on D1, 4, 8, 11, 22, 25, 29, 32 (1.3 mg/m2; D4, 11, 25, 32 omitted for C5-9). Melphalan (9 mg/m2) and prednisone (60 mg/m2) were administered on D1-4. The primary endpoint was progression-free survival (PFS). Nine hundred fifty-five patients were randomized (intention-to-treat population: KMP, n = 478; VMP, n = 477). Median PFS was 22.3 months with KMP vs 22.1 months with VMP (hazard ratio [HR], 0.906; 95% confidence interval [CI], 0.746-1.101; P = .159). Median overall survival was similar and not reached in either group (HR, 1.08; 95% CI, 0.82-1.43). Overall response rate was 84.3% for KMP and 78.8% for VMP. Complete response rate was 25.9% for KMP and 23.1% for VMP. Minimal residual disease–negative rates were 15.7% (KMP) and 15.5% (VMP). Adverse events (AEs) of interest (any grade) occurring with a ≥5% higher patient incidence in the KMP arm were acute renal failure (13.9% [KMP] vs 6.2% [VMP]) and cardiac failure (10.8% vs 4.3%). Grade ≥3 AE rates were 74.7% (KMP) and 76.2% (VMP). Grade ≥2 peripheral neuropathy was lower for KMP vs VMP (2.5% vs 35.1%). Treatment with KMP in CLARION did not yield a statistically significant difference in PFS vs VMP. This trial was registered at www.clinicaltrials.gov as #NCT01818752.

Carfilzomib (Cfz), an irreversible proteasome inhibitor licensed for relapsed/refractory myeloma, is associated with cardiotoxicity in humans. We sought to establish the optimal protocol of Cfz-induced cardiac dysfunction, to investigate the underlying molecular-signaling and, based on the findings, to evaluate the cardioprotective potency of metformin (Met). Mice were randomized into protocols 1 and 2 (control and Cfz for 1 and 2 consecutive days, respectively); protocols 3 and 4 (control and alternate doses of Cfz for 6 and 14 days, respectively); protocols 5A and 5B (control and Cfz, intermittent doses on days 0, 1 [5A] and 0, 1, 7, and 8 [5B] for 13 days); protocols 6A and 6B (pharmacological intervention; control, Cfz, Cfz+Met and Met for 2 and 6 days, respectively); and protocol 7 (bortezomib). Cfz was administered at 8 mg/kg (IP) and Met at 140 mg/kg (per os). Cfz resulted in significant reduction of proteasomal activity in heart and peripheral blood mononuclear cells in all protocols except protocols 5A and 5B. Echocardiography demonstrated that Cfz led to a significant fractional shortening (FS) depression in protocols 2 and 3, a borderline dysfunction in protocols 1 and 4, and had no detrimental effect on protocols 5A and 5B. Molecular analysis revealed that Cfz inhibited AMPKα/mTORC1 pathways derived from increased PP2A activity in protocol 2, whereas it additionally inhibited phosphatidylinositol 3-kinase/Akt/endothelial nitric oxide synthase pathway in protocol 3. Coadministration of Met prevented Cfz-induced FS reduction and restored AMPKα phosphorylation and autophagic signaling. Conclusively, Cfz decreased left ventricular function through increased PP2A activity and inhibition of AMPKα and its downstream autophagic targets, whereas Met represents a novel promising intervention against Cfz-induced cardiotoxicity.

In ENDEAVOR, carfilzomib (56 mg/m2) and dexamethasone (Kd56) demonstrated longer progression-free survival (PFS) over bortezomib and dexamethasone (Vd) in patients with relapsed/refractory multiple myeloma (RRMM). Here we evaluated Kd56 vs Vd by baseline renal function in a post hoc exploratory subgroup analysis. The intent-to-treat population included 929 patients (creatinine clearance [CrCL] ≥15 to