Kinney, Gene G.

Abstract Amyloid light-chain (AL) amyloidosis is a rare, typically fatal disease characterized by the accumulation of misfolded immunoglobulin light chains (LCs). Birtamimab is an investigational humanized monoclonal antibody designed to neutralize toxic LC aggregates and deplete insoluble organ-deposited amyloid via macrophage-induced phagocytosis. VITAL was a phase 3 randomized, double-blind, placebo-controlled clinical trial assessing the efficacy and safety of birtamimab + standard of care (SOC) in 260 newly diagnosed, treatment-naive patients with AL amyloidosis. Patients received 24 mg/kg IV birtamimab + SOC or placebo + SOC every 28 days. The primary composite end point was the time to all-cause mortality (ACM) or centrally adjudicated cardiac hospitalization ≥91 days after the first study drug infusion. The trial was terminated early after an interim futility analysis; there was no significant difference in the primary composite end point (hazard ratio [HR], 0.826; 95% confidence interval [CI], 0.574-1.189; log-rank P = .303). A post hoc analysis of patients with Mayo stage IV AL amyloidosis, those at the highest risk of early mortality, showed significant improvement in the time to ACM with birtamimab at month 9 (HR, 0.413; 95% CI, 0.191-0.895; log-rank P = .021). At month 9, 74% of patients with Mayo stage IV AL amyloidosis treated with birtamimab and 49% of those given placebo survived. Overall, the rates of treatment-emergent adverse events (TEAEs) and serious TEAEs were generally similar between treatment arms. A confirmatory phase 3 randomized, double-blind, placebo-controlled clinical trial of birtamimab in patients with Mayo stage IV AL amyloidosis (AFFIRM-AL; NCT04973137) is currently enrolling. The VITAL trial was registered at www.clinicaltrials.gov as #NCT02312206.

Abstract Background: Light chain (AL) amyloidosis is a rare, progressive, and typically fatal hematologic disorder caused by plasma cells that produce misfolded AL protein, resulting in deposits of amyloid in tissues and organs that cause organ dysfunction and failure. Birtamimab is an investigational monoclonal antibody designed to neutralize circulating soluble amyloid and deposited insoluble amyloid, thus promoting the phagocytic clearance of amyloid deposits. In 2018, the global phase 3 VITAL study in newly diagnosed, treatment-naïve patients was terminated based on a futility analysis of the composite primary endpoint (time to all-cause mortality [ACM] or time to cardiac hospitalization >90 days after first study drug infusion); the final hazard ratio (HR) numerically favored birtamimab + standard of care (SOC) over placebo + SOC (0.835, 95% CI 0.5799, 1.2011; p=0.330). Post hoc analysis of ACM over 9 months revealed a pronounced survival benefit (HR=0.413, 95% CI 0.191, 0.895; p=0.025; Figure) in a subgroup of patients at high risk for early mortality (Mayo stage IV). At 9 months, the proportions of surviving patients were 74% and 49% in the birtamimab + SOC and placebo + SOC groups, respectively. Post hoc analyses of secondary endpoints in this subgroup also supported clinical and functional benefits of birtamimab + SOC, with clinically meaningful improvements observed in health-related quality of life (assessed with 36-Item Short Form Health Survey version 2; SF-36v2) and 6-minute walk test (6MWT) distance (both nominal p<0.05) at 9 months. Across all birtamimab clinical trials, no drug-related deaths, dose-limiting toxicities, or major risks were identified. Aims: To evaluate the efficacy and safety of birtamimab + SOC versus placebo + SOC in Mayo stage IV patients with AL amyloidosis by assessing time to ACM over 9 months. Methods: The phase 3, double-blind, placebo-controlled AFFIRM-AL study will enroll up to 150 Mayo stage IV patients with newly diagnosed, untreated AL amyloidosis. Patients will receive either 24 mg/kg intravenous birtamimab or placebo every 28 days (both arms will also receive SOC, defined as concomitant chemotherapy with a first-line bortezomib-containing regimen). Patients will be randomly assigned 2:1 to birtamimab or placebo and will be stratified at randomization based on their 6MWT distance (<300 meters vs ≥300 meters). The primary efficacy endpoint of AFFIRM-AL is time to ACM using a log-rank test. Secondary endpoints are change from baseline to month 9 in SF-36v2 and 6MWT distance. Safety endpoints include adverse events, clinical laboratory observations, and immunogenicity analyses. An interim efficacy analysis is planned when ~50% of the events have occurred. Results: Given the >50% relative risk reduction for ACM observed in the post hoc analysis of VITAL for the AL amyloidosis subpopulation of patients with Mayo stage IV disease, the phase 3 AFFIRM-AL study is designed to confirm this effect of birtamimab under a Special Protocol Assessment agreement with the US FDA. Conclusion/Summary: Effective treatments to improve survival in AL amyloidosis are needed, particularly for patients with advanced cardiac involvement, as median overall survival for those with Mayo stage IV disease is approximately 6-9 months. Birtamimab is the only investigational therapeutic in which a survival benefit has been observed, in a post hoc subgroup analysis of VITAL in patients with AL amyloidosis with advanced cardiac involvement. AFFIRM-AL is expected to initiate in mid-2021. (NCT04973137) Figure 1 Figure 1. Disclosures Gertz: Alnylam, Amgen, Annexon, Appellis, Celgene, Ionis/Akcea, Janssen, Medscape, Physicians Education Resource, Prothena, Research to Practice: Other: personal fees; Spectrum: Other: personal fees, Research Funding; AbbVie: Other: personal fees for Data Safety Monitoring board; Teva, Johnson and Johnson, Medscape, DAVA oncology: Other: speaker fees; Pharmacyclics, Proclara: Other: Advisory Board; i3Health: Other: development of educational materials; Springer Publishing: Patents & Royalties. Tripuraneni: Prothena Biosciences Inc.: Current Employment, Current holder of stock options in a privately-held company, Patents & Royalties: related to birtamimab (NEOD001). Kinney: Prothena Biosciences Inc.: Current Employment, Current holder of stock options in a privately-held company, Patents & Royalties: related to birtamimab (NEOD001).

Abstract Background: Amyloid light chain (AL) amyloidosis is caused by the deposition of misfolded light chain (LC) proteins, which may cause organ failure and death. Current treatments, which target the plasma cells that produce LC, induce organ responses in only 30% to 40% of patients. There is a substantial need for a safe and effective amyloid-directed therapy to improve recovery of organ function. NEOD001, a monoclonal antibody that targets misfolded LC, is hypothesized to neutralize circulating LC aggregates and to clear insoluble organ deposits. In an ongoing phase 1/2 study (NCT02613182; Gertz M et al. J Clin Oncol. 2016;34(10):1097-1103) in 27 patients with AL amyloidosis and persistent organ dysfunction, monthly NEOD001 infusions were well tolerated and produced no infusion-related hypersensitivity reactions. In a best response analysis of subjects who fulfilled eligibility criteria at baseline, 57% met cardiac and 60% met renal response criteria. Supported by these positive results, the current study (VITAL; NCT02312206) is a randomized, double-blind, placebo-controlled, phase 3 trial of NEOD001 in patients with cardiac AL amyloidosis. Here we present the study design for this trial in progress. Patients and Methods: Eligible patients (estimated enrollment, 236) with a diagnosis of AL amyloidosis (newly diagnosed, treatment naive) and cardiac dysfunction (N-terminal probrain natriuretic peptide [NT-proBNP] ≥650 and <8500 pg/mL, clinical signs of heart failure, left ventricular wall thickness >12 mm, or cardiac biopsy-detected amyloidosis) and with estimated glomerular filtration rate ≥30 mL/min/1.73 m2 will be randomly assigned (1:1) to receive NEOD001 (24 mg/kg q28d) plus standard of care (SOC) chemotherapy or placebo plus SOC therapy. Subjects will be stratified according to Mayo Clinic stage, renal stage, and 6-minute walk test (6MWT) distance. The primary end point is a composite, evidence-based measure consisting of all-cause mortality or cardiac hospitalization. Key secondary end points include cardiac response measured by NT-proBNP (as defined by Comenzo RL et al. Leukemia. 2012;26(11):2317-2325) and change in 6MWT distance, Short Form-36 Health Survey response, Neuropathy Impairment Score-Lower Limb and renal response (as defined by Palladini G et al. Blood. 2014;124(15):2325-2332). Disclosures Liedtke: Gilead: Research Funding; Pfizer: Consultancy, Research Funding; Novartis: Research Funding; Amgen: Consultancy, Research Funding; Prothena: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Celgene: Research Funding. Merlini:Takeda and Janssen-Cilag: Honoraria. Landau:Janssen: Consultancy; Spectrum Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; Onyx/Amgen: Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Prothena: Honoraria, Membership on an entity's Board of Directors or advisory committees. Comenzo:Takeda: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Prothena: Consultancy, Research Funding; Karyopharm: Research Funding. Sanchorawala:Prothena: Research Funding; Takeda: Research Funding; Celgene: Research Funding. Weiss:Janssen: Consultancy, Other: Travel, accommodations, Research Funding; Millennium: Consultancy, Other: Travel, accommodations; GlaxoSmithKline: Consultancy; Prothena: Other: Travel, accommodations, Research Funding; Novartis: Consultancy. Zonder:Array Biopharma: Consultancy; Prothena: Consultancy; Celgene: Consultancy, Research Funding; BMS: Consultancy; Takeda: Consultancy; Janssen: Consultancy; Seattle Genetics: Consultancy. Walling:Stealth: Consultancy; KaloBios: Consultancy; Exelixis: Consultancy; Newgen: Consultancy; Mateon (was Oxigene): Consultancy; Apex: Consultancy; Corcept: Consultancy; Aduro: Consultancy; Prothena: Consultancy; BioMarin: Equity Ownership; Amgen: Equity Ownership, Patents & Royalties; NuMedii: Consultancy; Pharm-Olam: Consultancy; Crown Bioscience: Consultancy; Codexis: Consultancy; Upsher Smith: Consultancy, Patents & Royalties. Kinney:Prothena: Employment, Equity Ownership, Other: Leadership. Koller:Prothena: Employment, Equity Ownership, Other: Travel, accommodations. Gertz:Ionis: Research Funding; Prothena Therapeutics: Research Funding; Novartis: Research Funding; Alnylam Pharmaceuticals: Research Funding; Annexon Biosciences: Research Funding; Research to Practice: Honoraria, Speakers Bureau; Med Learning Group: Honoraria, Speakers Bureau; Celgene: Honoraria; NCI Frederick: Honoraria; Sandoz Inc: Honoraria; GSK: Honoraria.

BACKGROUND: AL amyloidosis is a rare, progressive, and typically fatal disease caused by both soluble and insoluble (amyloid) forms of misfolded immunoglobulin light chain (LC) proteins, with no approved treatments. Production and tissue deposition of LC aggregates result in various organ system dysfunction (most commonly cardiac and renal), causing significant morbidity and mortality. NEOD001 is an investigational humanized IGg1 designed to directly neutralize soluble toxic aggregates of misfolded LCs and promote phagocytic clearance of amyloid deposits. AIM: To evaluate efficacy and safety of NEOD001 + standard of care (SOC) vs placebo + SOC in patients with AL amyloidosis by assessing time to all-cause mortality (ACM) or cardiac hospitalization (CH). METHODS: This Phase 3, double-blind, placebo-controlled study randomized 260 newly diagnosed, untreated AL amyloidosis patients (stratified by Mayo stage (Kumar et al., 2012), renal stage, & 6MWD) with cardiac involvement. Patients were randomized 1:1 to 24 mg/kg IV NEOD001 + SOC or placebo + SOC every 28 days. SOC was concomitant chemotherapy with a first line bortezomib-containing regimen. Primary endpoint (PE) was time to ACM or time to centrally adjudicated CH (CH: >90 days after first study drug infusion). Futility analysis based on 103 adjudicated events favored NEOD001 but was not statistically significant (HR 0.84, 95% CI 0.57-1.204, p=0.386). The study was terminated early and post hoc analyses were performed. To our knowledge, this study was the first randomized, placebo-controlled, Phase 3 study evaluating an amyloid-targeting agent in AL amyloidosis. RESULTS: Study arms were balanced with regard to demographics and baseline clinical characteristics. The final PE results (intent-to-treat, ITT) were consistent with the futility analysis: HR 0.835, 95% CI 0.5799-1.2011, p=0.330. Favorability of HR for NEOD001 was largely attributable to time to all-cause mortality rather than cardiac hospitalization. Study termination was the primary reason for discontinuation (majority occurring after 12 months). The 12-month study period was defined as modified ITT (mITT). Further mITT analyses by prognostic Mayo staging categories suggest benefit favoring NEOD001 for both PE (HR=0.635) and ACM (HR=0.498) in stage IV patients (n=77), who have highest risk of early mortality. Median overall survival in stage IV (mITT) was 8.3 months for placebo + SOC and was not reached (>12 months) for NEOD001 + SOC. One or more treatment-emergent adverse events (TEAEs) were experienced by 257 patients. Of the 88 NEOD001-treated patients with a serious adverse event (SAE), the majority of SAEs (95.5%) were considered not related to study drug. The most common TEAEs (fatigue, nausea, peripheral edema, constipation, and diarrhea) were similar in both arms. Overall safety results were similar within and across Mayo stages. CONCLUSION: After study termination, further calculations supported that the VITAL study as designed would not have achieved statistical significance. No statistically significant differences between NEOD001 + SOC vs. placebo + SOC were observed for the PE. Overall, the incidence, severity, and seriousness of AEs were similar in each arm, suggesting that NEOD001 was generally safe and well tolerated. Post hoc analyses suggest a potential survival benefit of NEOD001 for AL amyloidosis patients with the highest risk of early mortality (Mayo stage IV). This population has historically been the most in need of therapy to improve outcomes, therefore additional clinical studies for NEOD001 are warranted. Disclosures Gertz: Ionis/Akcea: Consultancy; Alnylam: Consultancy; Annexon: Consultancy; Physicians Education Resource: Consultancy; Celgene: Consultancy; Janssen: Consultancy; Medscape: Consultancy, Speakers Bureau; Appellis: Consultancy; Prothena Biosciences Inc: Consultancy; Spectrum: Consultancy, Research Funding; Amgen: Consultancy; Abbvie: Other: personal fees for Data Safety Monitoring board; Research to Practice: Consultancy; DAVA oncology: Speakers Bureau; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees; Proclara: Membership on an entity's Board of Directors or advisory committees; i3Health: Other: Development of educational programs and materials; Springer Publishing: Patents & Royalties; Amyloidosis Foundation: Research Funding; International Waldenstrom Foundation: Research Funding; Johnson and Johnson: Speakers Bureau; Teva: Speakers Bureau. Cohen:Poseida Therapeutics, Inc.: Research Funding. Comenzo:Caelum: Consultancy, Membership on an entity's Board of Directors or advisory committees; Takeda: Research Funding; Unum: Membership on an entity's Board of Directors or advisory committees, Research Funding; Myself: Patents & Royalties: Patent 9593332, Pending 20170008966; Sanofi-Aventis: Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Karyopharm: Research Funding; Prothena Biosciences: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Du Mond:Inclin, Inc.: Employment; Prothena: Consultancy. Kastritis:Genesis: Honoraria; Prothena: Honoraria; Pfizer: Honoraria; Amgen: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Takeda: Honoraria. Landau:Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Karyopharm: Consultancy, Honoraria; Pfizer: Membership on an entity's Board of Directors or advisory committees; Amgen: Research Funding; Caelum: Membership on an entity's Board of Directors or advisory committees; Prothena: Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding. Libby:Alnylam: Consultancy; Abbvie: Consultancy; Pharmacyclics and Janssen: Consultancy; Akcea: Consultancy. Liedtke:Adaptive: Membership on an entity's Board of Directors or advisory committees; Agios: Research Funding; Amgen/Onyx: Consultancy, Honoraria, Research Funding; BlueBirdBio: Research Funding; Caelum: Membership on an entity's Board of Directors or advisory committees; Celator: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech/Roche: Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding; IQVIA/Jazz: 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; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Prothena: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding. Merlini:University of Pavia: Employment. Sanchorawala:Proclara: Consultancy, Honoraria; Caelum: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Research Funding; Takeda: Research Funding; Prothena: Research Funding; Celgene: Research Funding. Schönland:Prothena: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Medac: Other: Travel Grant; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding. Wechalekar:Janssen-Cilag: Honoraria; GSK: Honoraria; Amgen: Research Funding; Celgene: Honoraria; Takeda: Honoraria. Zonder:Celgene Corporation: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Intellia: Consultancy, Membership on an entity's Board of Directors or advisory committees; Caelum: Consultancy, Membership on an entity's Board of Directors or advisory committees; Alnylam: Consultancy, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees. Kinney:Prothena Biosciences Inc: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties: named inventor on multiple patents and patent applications related to NEOD001.

Abstract Introduction: Systemic amyloidoses are a group of rare disorders characterized by the accumulation of misfolded proteins in tissue, resulting in the dysfunction of vital organs (eg, heart and kidneys). In amyloid light chain (AL) amyloidosis, the most common form of systemic amyloidosis, the amyloidogenic protein is a misfolded light chain (LC) or a fragment of an LC produced by clonal plasma cells. Current therapies used to treat AL amyloidosis limit LC production but do not directly target deposits underlying multiorgan failure. NEOD001, a monoclonal antibody, targets misfolded LC and is thought to neutralize circulating LC aggregates and to clear insoluble deposits. In an interim analysis of a phase 1/2 dose-escalation study in 27 patients with AL amyloidosis and persistent organ dysfunction (NCT01707264; EudraCT2012-002683-27), monthly infusions of NEOD001 were safe, well tolerated, and associated with renal and cardiac responses.1 Here we report updated results from the escalation phase and new results from the expansion phase of this study. Patients and Methods: Inclusion criteria for this trial were that patients complete ≥1 PCD treatment before enrollment, attain partial hematologic response (HR) or better to any previous therapy, and have persistent organ dysfunction. NEOD001 was administered intravenously every 28 days. During the dose-escalation phase, 27 patients received NEOD001 at 0.5, 1, 2, 4, 8, 16, or 24 mg/kg in a 3+3 study design. An additional 42 patients with renal, cardiac, or peripheral nerve involvement were enrolled and treated (24 mg/kg) in the expansion phase. We assessed safety/tolerability, pharmacokinetics, immunogenicity, cardiac and renal responses based on consensus criteria, and neuropathy responses using the Neuropathy Impairment Score-Lower Limb (NIS-LL). Results: The 42 additional patients enrolled in the expansion study included cohorts with renal (16 patients), cardiac (15 patients), and peripheral nerve (11 patients) involvement. In the overall population (n = 69), the median age was 60 years, and 61% of patients were men. Median (range) time since diagnosis was 2.8 (0.4-12.8) years, and 45% of patients underwent ≥3 previous plasma cell-directed regimens. The total number of infusions administered was 913 over a mean of 13.2 (range, 3-35) months. NEOD001 treatment was not associated with dose-limiting toxicities or discontinuations; patients did not develop antidrug antibodies or treatment-related serious adverse events. The most frequent treatment-emergent adverse events, regardless of relationship to study drug, were fatigue, upper respiratory tract infection, nausea, and diarrhea. In a best response analysis, 53% of cardiac-evaluable patients (N = 36) and 63% of renal-evaluable patients (N = 35) met respective criteria for organ response; no patients experienced disease progression. The median time to initial response was 2 months (cardiac) and 4 months (renal). After 9 months of treatment, 82% of patients with measurable peripheral neuropathy at baseline (N = 11) achieved a peripheral neuropathy response based on the NIS-LL score. Conclusions: Our interim results demonstrated that monthly NEOD001 infusions were safe and well tolerated and that organ response rates compared favorably with traditional chemotherapy. These updated results from the escalation phase and these new results from the expansion phase, including results from patients with peripheral nerve involvement, support the design of ongoing late-stage clinical studies. Antibody therapy may allow for effective treatment of patients with AL amyloidosis. Reference: 1. Gertz MA, Landau H, Comenzo RL, et al. First-in-human phase 1/2 study of NEOD001 in patients with light chain amyloidosis and persistent organ dysfunction. J Clin Oncol. 2016;34(10):1097-1103. Disclosures Gertz: Prothena Therapeutics: Research Funding; Novartis: Research Funding; Alnylam Pharmaceuticals: Research Funding; Research to Practice: Honoraria, Speakers Bureau; Med Learning Group: Honoraria, Speakers Bureau; Celgene: Honoraria; NCI Frederick: Honoraria; Sandoz Inc: Honoraria; GSK: Honoraria; Ionis: Research Funding; Annexon Biosciences: Research Funding. Comenzo:Karyopharm: Research Funding; Janssen: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Prothena: Consultancy, Research Funding. Landau:Janssen: Consultancy; Spectrum Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Prothena: Honoraria, Membership on an entity's Board of Directors or advisory committees; Onyx/Amgen: Research Funding. Sanchorawala:Celgene: Research Funding; Takeda: Research Funding; Prothena: Research Funding. Weiss:Prothena: Other: Travel, accommodations, Research Funding; GlaxoSmithKline: Consultancy; Millennium: Consultancy, Other: Travel, accommodations; Janssen: Consultancy, Other: Travel, accommodations, Research Funding; Novartis: Consultancy. Zonder:BMS: Consultancy; Celgene: Consultancy, Research Funding; Prothena: Consultancy; Array Biopharma: Consultancy; Takeda: Consultancy; Janssen: Consultancy; Seattle Genetics: Consultancy. Walling:Stealth: Consultancy; BioMarin: Equity Ownership; Apex: Consultancy; Pharm-Olam: Consultancy; NuMedii: Consultancy; Amgen: Equity Ownership, Patents & Royalties; Crown Bioscience: Consultancy; KaloBios: Consultancy; Exelixis: Consultancy; Newgen: Consultancy; Mateon (was Oxigene): Consultancy; Corcept: Consultancy; Prothena: Consultancy; Aduro: Consultancy; Codexis: Consultancy; Upsher Smith: Consultancy, Patents & Royalties. Kinney:Prothena: Employment, Equity Ownership, Other: Leadership. Koller:Prothena: Employment, Equity Ownership, Other: Travel, accommodations. Schenk:Prothena: Employment, Equity Ownership, Other: Leadership. Guthrie:Prothena: Employment, Equity Ownership, Other: Leadership. Liu:Prothena: Employment, Equity Ownership; Weston Brain Institute: Honoraria. Liedtke:Prothena: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Amgen: Consultancy, Research Funding; Celgene: Research Funding; Gilead: Research Funding; Pfizer: Consultancy, Research Funding; Novartis: Research Funding.

Abstract Introduction:In amyloid light chain (AL) amyloidosis, the most common form of systemic amyloidosis, misfolded light chain (LC) or a fragment of an LC produced by clonal plasma cells accumulates in tissue, resulting in the dysfunction of vital organs and systems (eg, heart, kidneys, nervous system). Current therapies used to treat AL amyloidosis limit LC production but do not directly target deposits underlying multiorgan failure. Approximately 75% of patients do not achieve organ responses and have persistent organ dysfunction. Amyloid-directed therapies may stabilize and potentially reverse organ damage by specifically targeting existing LC aggregates. NEOD001, a monoclonal antibody, targets misfolded LC and is thought to neutralize circulating LC aggregates and to clear insoluble deposits. We have previously reported that monthly infusions of NEOD001 were safe and well tolerated. In addition, NEOD001 was associated with renal and cardiac responses. Here we analyzed the association between organ response and depth and time since last plasma cell-directed (PCD) treatment in the entire cohort of 69 patients enrolled in both the dose-escalation and the expansion phases of the phase 1/2 study. Methods: Inclusion criteria for this trial were that patients complete ≥1 PCD treatment before enrollment, attain partial hematologic response (HR) or better to any previous therapy, and have persistent organ dysfunction. NEOD001 was administered intravenously every 28 days. During the dose-escalation phase, 27 patients received NEOD001 at 0.5, 1, 2, 4, 8, 16, or 24 mg/kg in a 3+3 study design. An additional 42 patients with renal, cardiac, or nerve involvement were enrolled and treated (24 mg/kg) in the expansion phase. We assessed cardiac and renal responses based on consensus criteria and neuropathy responses using the Neuropathy Impairment Score-Lower Limb (NIS-LL). For this analysis, we focused on the relationship between organ response after treatment with NEOD001 to the time since last or best HR and the depth of best and last HR. Results: A total of 69 patients were enrolled, 27 in the dose-escalation and 42 in the expansion cohorts. The entire population included 36 cardiac-evaluable patients, 35 renal-evaluable patients, and 11 patients evaluated for peripheral neuropathy; 39% were women, and the median age was 60 years. Time since diagnosis was 2.8 (0.4-12.8; median, range) years, and 45% of patients had undergone ≥3 previous PCD regimens. Of the patients evaluable for organ response, best response rates indicating organ response were observed in 53% of cardiac-evaluable patients (n = 19/36) and 63% of renal-evaluable patients (n = 22/35). NIS-LL scores indicated that 82% (n = 9/11) of patients met criteria for a peripheral neuropathy response to NEOD001. Cardiac and renal response rates for NEOD001-treated patients could not be attributed to previous PCD treatment regimens. For example, 37% of the NEOD001 cardiac responders and 35% of nonresponders received cyclophosphamide-bortezomib-dexamethasone. Similarly, for NEOD001 renal responders vs nonresponders, 27% vs 25% were treated with autologous stem cell transplantation and 27% vs 31% were treated with bortezomib-dexamethasone. There was no relationship between NEOD001 cardiac, renal, or peripheral nerve organ response and time since last chemotherapy, time since last or best HR, or depth of last or best HR. Finally, an equivalent percentage of evaluable patients experienced renal or cardiac response regardless of whether they had received their most recent PCD treatment ≤6 months or >6 months before NEOD001 initiation. The median time since last PCD treatment to the start of NEOD001 intervention for all patients was 6.5 (range, 0.6-85.8) months and the median time to first cardiac response after NEOD001 treatment for all cardiac responders was 2 months. NEOD001 treatment was safe and well tolerated. Conclusions: Patients treated with monthly NEOD001 infusions had high organ response rates that were independent of time since previous chemotherapy, depth of hematologic response, or predominant type of PCD treatment. Ongoing studies of NEOD001 include VITAL (phase 3 in patients with newly diagnosed AL amyloidosis) and PRONTO (phase 2b in previously treated AL amyloidosis patients with persistent cardiac dysfunction). Disclosures Liedtke: Gilead: Research Funding; Prothena: Consultancy, Research Funding; Amgen: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Novartis: Research Funding; Takeda: Consultancy, Research Funding; Celgene: Research Funding. Comenzo:Takeda: Consultancy, Research Funding; Karyopharm: Research Funding; Janssen: Consultancy, Research Funding; Prothena: Consultancy, Research Funding. Landau:Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Prothena: Honoraria, Membership on an entity's Board of Directors or advisory committees; Onyx/Amgen: Research Funding; Spectrum Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy. Sanchorawala:Prothena: Research Funding; Takeda: Research Funding; Celgene: Research Funding. Weiss:Prothena: Other: Travel, accommodations, Research Funding; GlaxoSmithKline: Consultancy; Millennium: Consultancy, Other: Travel, accommodations; Janssen: Consultancy, Other: Travel, accommodations, Research Funding; Novartis: Consultancy. Zonder:Prothena: Consultancy; Celgene: Consultancy, Research Funding; BMS: Consultancy; Takeda: Consultancy; Janssen: Consultancy; Seattle Genetics: Consultancy; Array Biopharma: Consultancy. Walling:Corcept: Consultancy; Stealth: Consultancy; Codexis: Consultancy; Exelixis: Consultancy; Newgen: Consultancy; Mateon (was Oxigene): Consultancy; Apex: Consultancy; Aduro: Consultancy; Prothena: Consultancy; Upsher Smith: Consultancy, Patents & Royalties; KaloBios: Consultancy; NuMedii: Consultancy; Pharm-Olam: Consultancy; Crown Bioscience: Consultancy; BioMarin: Equity Ownership; Amgen: Equity Ownership, Patents & Royalties. Kinney:Prothena: Employment, Equity Ownership, Other: Leadership. Koller:Prothena: Employment, Equity Ownership, Other: Travel, accommodations. Schenk:Prothena: Employment, Equity Ownership, Other: Leadership. Guthrie:Prothena: Employment, Equity Ownership, Other: Leadership. Liu:Prothena: Employment, Equity Ownership; Weston Brain Institute: Honoraria. Gertz:Annexon Biosciences: Research Funding; Ionis: Research Funding; Prothena Therapeutics: Research Funding; Novartis: Research Funding; Alnylam Pharmaceuticals: Research Funding; Research to Practice: Honoraria, Speakers Bureau; Med Learning Group: Honoraria, Speakers Bureau; Celgene: Honoraria; NCI Frederick: Honoraria; Sandoz Inc: Honoraria; GSK: Honoraria.