Citations

Background: The phase 1b/2 CARTITUDE-1 study (NCT03548207) is evaluating ciltacabtagene autoleucel (cilta-cel; JNJ-68284528; LCAR-B38M CAR-T cells), a chimeric antigen receptor T (CAR-T) cell therapy with 2 B-cell maturation antigen-targeting single-domain antibodies, in patients with relapsed/refractory (R/R) multiple myeloma (MM). Cytokine release syndrome (CRS), a known side effect of CAR-T therapy, can be mild to life-threatening and requires careful monitoring and management. Here, we analyzed CRS and cytokine profiles in CARTITUDE-1. Methods: Eligible patients (aged ≥18 years) had a diagnosis of MM per International Myeloma Working Group criteria, measurable disease, Eastern Cooperative Oncology Group performance status ≤1, received ≥3 prior regimens or were double-refractory to a proteasome inhibitor and immunomodulatory drug, and received an anti-CD38 antibody. Bridging therapy was permitted after apheresis. At 5-7 days prior to cilta-cel infusion, lymphodepletion was performed with cyclophosphamide 300 mg/m2 and fludarabine 30 mg/m2 daily for 3 days. Cilta-cel was administered as a single infusion at a target dose of 0.75×106 (range: 0.5-1.0×106) CAR+ viable T cells/kg. CRS was graded using Lee et al (Blood 2014) in the phase 1b portion and American Society for Transplantation and Cellular Therapy (ASTCT) in the phase 2 portion. In this combined analysis, Lee et al criteria were mapped to ASTCT criteria for patients in the phase 1b portion. Serum samples for cytokine profiling were collected prior to lymphodepletion, prior to cilta-cel infusion and 2 hours post-infusion on Day 1, at regular time points until Day 100, and if CRS was suspected or reported. Results: A total of 97 patients with R/R MM were treated with cilta-cel; median follow-up for this analysis was 8.8 months (range: 1.5-20.4). CRS was reported in 92 (94.8%) patients. A total of 48 (49.5%) patients had grade 1 CRS, 38 (39.2%) had grade 2, 4 (4.1%) had grade 3, and 1 had grade 5 (1.0%); maximum toxicity grade according to the ASTCT consensus grading system could not be derived for 1 patient with CRS in the phase 1b portion. Median time to CRS onset from cilta-cel infusion was 7.0 days (range: 1-12). Median duration of CRS was 4.0 days (range: 1-27, excluding n=1 with 97 days). Supportive measures to treat CRS or CRS symptoms were administered to 87 (89.7%) patients, most commonly tocilizumab (69.1%), acetaminophen (68.0%), corticosteroids (20.6%), and anakinra (18.6%). CRS resolved in 91 (98.9%) patients; the patient with grade 5 CRS/hemophagocytic lymphohistiocytosis died on Day 99 subsequent to sequelae of grade 4 CRS. Across all patients, levels of interleukin (IL)-6, IL-10, and interferon-γ peaked at Days 7-14 post-cilta-cel infusion. Conclusions: CRS after cilta-cel treatment was low grade and manageable in most patients with R/R MM. The low rate of grade ≥3 CRS, median time to CRS onset of 7.0 days, and median duration of 4.0 days suggests outpatient dosing of cilta-cel may be feasible; this approach is being explored in the phase 2 CARTITUDE-2 study (NCT04133636). Disclosures Lin: Gamida Cells: Consultancy; Sorrento: Consultancy, Membership on an entity's Board of Directors or advisory committees; Kite, a Gilead Company: Consultancy, Research Funding; Vineti: Consultancy; Takeda: Research Funding; Merck: Research Funding; Legend BioTech: Consultancy; Juno: Consultancy; Bluebird Bio: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Novartis: Consultancy; Janssen: Consultancy, Research Funding. Martin:Janssen: Research Funding; AMGEN: Research Funding; Sanofi: Research Funding; Seattle Genetics: Research Funding; GSK: Consultancy. Cohen:Novartis: Other: Patents/Intellectual property licensed, Research Funding; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees; Takeda,: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees; Kite Pharma: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Genentech/Roche: Membership on an entity's Board of Directors or advisory committees. Jakubowiak:AbbVie, Amgen, BMS/Celgene, GSK, Janssen, Karyopharm: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive, Juno: Consultancy, Honoraria. Usmani:Celgene: Other; Takeda: Consultancy, Honoraria, Other: Speaking Fees, Research Funding; Sanofi: Consultancy, Honoraria, Research Funding; SkylineDX: Consultancy, Research Funding; Seattle Genetics: Consultancy, Research Funding; Pharmacyclics: Research Funding; GSK: Consultancy, Research Funding; Janssen: Consultancy, Honoraria, Other: Speaking Fees, Research Funding; Array Biopharma: Research Funding; Merck: Consultancy, Research Funding; Abbvie: Consultancy; BMS, Celgene: Consultancy, Honoraria, Other: Speaking Fees, Research Funding; Amgen: Consultancy, Honoraria, Other: Speaking Fees, Research Funding; Incyte: Research Funding. Madduri:AbbVie: Consultancy, Honoraria; GSK: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Speaking Engagement, Speakers Bureau; Foundation Medicine: Consultancy, Honoraria; Legend: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Speaking Engagement, Speakers Bureau; Janssen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Kinevant: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Speaking Engagement, Speakers Bureau. Stewart:Janssen, BMS, Sanofi-Aventis, GSK: Honoraria; Tempus, Inc., Genomics England LLC: Membership on an entity's Board of Directors or advisory committees. Singh:Janssen: Current Employment. Zudaire:Janssen: Current Employment. Yeh:Janssen: Current Employment. Allred:Janssen: Current Employment. Olyslager:Janssen: Current Employment. Banerjee:Janssen: Current Employment. Goldberg:Johnson & Johnson: Current Employment, Current equity holder in publicly-traded company. Schecter:Janssen: Current Employment. Jackson:Memorial Sloan Kettering Cancer Center: Consultancy; Janssen: Current Employment. Deraedt:Janssen: Current Employment, Current equity holder in publicly-traded company. Geng:Legend Biotech USA Inc.: Current Employment. Wu:Legend Biotech USA Inc.: Current Employment. Carrasco:Legend Biotech USA Inc.: Current Employment. Akram:Legend Biotech USA Inc.: Current Employment. Hossain:Legend Biotech USA Inc.: Current Employment. Wang:Legend Biotech USA Inc.: Current Employment. Berdeja:CRISPR Therapeutics: Consultancy, Research Funding; EMD Sorono: Research Funding; Teva: Research Funding; Servier: Consultancy; Vivolux: Research Funding; Abbvie: Research Funding; Novartis: Research Funding; Janssen: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Karyopharm: Consultancy; Kesios: Research Funding; Kite Pharma: Consultancy; Legend: Consultancy; Genentech, Inc.: Research Funding; BMS: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Cellularity: Research Funding; Constellation: Research Funding; Glenmark: Research Funding; CURIS: Research Funding; Bioclinica: Consultancy; Amgen: Consultancy, Research Funding; Bluebird: Research Funding; Poseida: Research Funding; Acetylon: Research Funding; Prothena: Consultancy; Lilly: Research Funding. Jagannath:BMS, Janssen, Karyopharm, Legend Biotech, Sanofi, Takeda: Consultancy.

Background: Multiple myeloma (MM) negatively affects health-related quality of life (HRQoL), and with each relapse, patients with MM experience further declines in HRQoL. Patient-reported HRQoL is therefore an important treatment outcome, in addition to clinical response to therapy. CARTITUDE-1 (NCT03548207) is a phase 1b/2 study evaluating the safety and efficacy of ciltacabtagene autoleucel (cilta-cel; JNJ-68284528; LCAR-B38M CAR-T cells), a chimeric antigen receptor T (CAR-T) cell therapy with 2 B-cell maturation antigen-targeting single-domain antibodies, in patients with relapsed/refractory (R/R) MM. We evaluated symptoms, functioning, and overall HRQoL through patient-reported outcome measures, which is a secondary objective of CARTITUDE-1. Methods: Patients were ≥18 years of age with a diagnosis of MM per International Myeloma Working Group criteria, measurable disease, and Eastern Cooperative Oncology Group performance status ≤1. Patients had received ≥3 prior regimens for MM or were double-refractory to a proteasome inhibitor and immunomodulatory drug, and had received an anti-CD38 antibody. Cilta-cel was given as a single infusion on Day 1 (target dose: 0.75×106 [range: 0.5-1.0×106] CAR+ viable T cells/kg) 5-7 days after start of lymphodepletion (cyclophosphamide 300 mg/m2 + fludarabine 30 mg/m2 daily for 3 days). In the phase 2 portion of CARTITUDE-1, HRQoL was assessed at baseline, on Days 7, 28, 56, 78, and 100, and every 28 days thereafter using 3 patient-reported instruments: the European Organization for Research and Treatment of Cancer QoL Questionnaire Core 30 (EORTC QLQ-C30), 4 items from the EORTC QLQ-Multiple Myeloma (MY20) module, and the 5-level EuroQol Five Dimension (EQ-5D-5L) measure. Raw EORTC QLQ-C30 and EORTC QLQ-MY20 scores were linearly transformed to a scale ranging from 0 to 100; the EQ-5D-5L visual analog scale (VAS) score ranges from 0 to 100. Clinically meaningful changes in EORTC QLQ-C30 symptoms, physical functioning, and overall HRQoL were based on anchor-based methods using a patient global impression of change item. Repeated-measures mixed-effects models were used to analyze mean changes in HRQoL from baseline to subsequent assessment time points in patients in the modified intent-to-treat population with ≥1 post-baseline assessment. Median time to event of HRQoL scores was calculated descriptively, using a change in score ≥0.5×standard deviation of values prior to cilta-cel infusion as improvement/worsening with death due to progression defined as worsening. Results: For the 68 patients in the phase 2 portion of CARTITUDE-1 (63.2% male; median age: 62.0 years [range: 43-78]), questionnaire completion rates at baseline and Day 100, respectively, were 92.6% and 69.2% for both the EORTC QLQ-C30 and EORTC QLQ-MY20 items and 92.6% and 70.8% for the EQ-5D-5L. For EORTC QLQ-C30 subscales, clinically meaningful improvements at Day 100 were seen for 71.1% of patients for pain, 62.2% for fatigue, 72.1% for physical functioning, and 51.1% for global health status. Mean changes in pain and fatigue showed a reduction in these symptoms over time (following an initial worsening of fatigue at Day 7; Figure). This trend of improvements over time was also observed for overall HRQoL and EORTC QLQ-MY20 single items. Clinically meaningful improvements at Day 100, defined by a literature-based minimal important difference of 10 points in mean score, were observed for the EORTC QLQ-MY20 single items: thinking about illness and worries about dying or future health. Approximately 50% of the population reported an event of improvement or worsening in EORTC QLQ-C30 and EQ-5D-5L scales, with the rest censored in this early data cut; among these patients, median time to improvement was approximately 1-2 months (with median time to worsening occurring less than 1 month after cilta-cel treatment). There was a trend for an improvement in mean EORTC QLQ-C30 global health status, physical functioning, pain, and fatigue, and EQ-5D-5L VAS at Day 100 with increased depth of response. Conclusions: Some patients with heavily pretreated MM showed rapid and clinically meaningful improvements in pain, fatigue, physical functioning, overall HRQoL, and future perspectives, consistent with their clinical outcomes. With additional follow-up, it is possible that these early improvements in symptoms will translate into greater improvement in overall HRQoL in the long term. Disclosures Martin: Janssen: Research Funding; Sanofi: Research Funding; AMGEN: Research Funding; Seattle Genetics: Research Funding; GSK: Consultancy. Lin:Vineti: Consultancy; Janssen: Consultancy, Research Funding; Kite, a Gilead Company: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Novartis: Consultancy; Legend BioTech: Consultancy; Bluebird Bio: Consultancy, Research Funding; Juno: Consultancy; Merck: Research Funding; Takeda: Research Funding; Gamida Cells: Consultancy; Sorrento: Consultancy, Membership on an entity's Board of Directors or advisory committees. Cohen:Kite Pharma: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees; Takeda,: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees; Novartis: Other: Patents/Intellectual property licensed, Research Funding; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Genentech/Roche: Membership on an entity's Board of Directors or advisory committees. Htut:City of Hope Medical Center: Current Employment. Stewart:Janssen, BMS, Sanofi-Aventis, GSK: Honoraria; Tempus, Inc., Genomics England LLC: Membership on an entity's Board of Directors or advisory committees. Hari:GSK: Consultancy; BMS: Consultancy; Takeda: Consultancy; Amgen: Consultancy; Incyte Corporation: Consultancy; Janssen: Consultancy. Berdeja:Teva: Research Funding; Cellularity: Research Funding; Kesios: Research Funding; BMS: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; CURIS: Research Funding; EMD Sorono: Research Funding; Genentech, Inc.: Research Funding; Karyopharm: Consultancy; Poseida: Research Funding; Novartis: Research Funding; Lilly: Research Funding; Amgen: Consultancy, Research Funding; Acetylon: Research Funding; Glenmark: Research Funding; Janssen: Consultancy, Research Funding; Vivolux: Research Funding; Takeda: Consultancy, Research Funding; Servier: Consultancy; CRISPR Therapeutics: Consultancy, Research Funding; Constellation: Research Funding; Bluebird: Research Funding; Abbvie: Research Funding; Prothena: Consultancy; Bioclinica: Consultancy; Kite Pharma: Consultancy; Legend: Consultancy. Madduri:Foundation Medicine: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; GSK: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Speaking Engagement, Speakers Bureau; AbbVie: Consultancy, Honoraria; Legend: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Speaking Engagement, Speakers Bureau; Kinevant: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Speaking Engagement, Speakers Bureau; Celgene: Consultancy, Honoraria. Usmani:Takeda: Consultancy, Honoraria, Other: Speaking Fees, Research Funding; SkylineDX: Consultancy, Research Funding; Seattle Genetics: Consultancy, Research Funding; Merck: Consultancy, Research Funding; Incyte: Research Funding; Pharmacyclics: Research Funding; Janssen: Consultancy, Honoraria, Other: Speaking Fees, Research Funding; GSK: Consultancy, Research Funding; Abbvie: Consultancy; Array Biopharma: Research Funding; Celgene: Other; Amgen: Consultancy, Honoraria, Other: Speaking Fees, Research Funding; Sanofi: Consultancy, Honoraria, Research Funding; BMS, Celgene: Consultancy, Honoraria, Other: Speaking Fees, Research Funding. Yeh:Janssen: Current Employment. Allred:Janssen: Current Employment. Olyslager:Janssen: Current Employment. Banerjee:Janssen: Current Employment. Goldberg:Johnson & Johnson: Current Employment, Current equity holder in publicly-traded company. Schecter:Janssen: Current Employment. Jackson:Janssen: Current Employment; Memorial Sloan Kettering Cancer Center: Consultancy. Deraedt:Janssen: Current Employment, Current equity holder in publicly-traded company. Gries:Janssen: Current Employment, Current equity holder in publicly-traded company. Fastenau:Janssen: Current Employment, Current equity holder in publicly-traded company. Wu:Legend Biotech USA Inc.: Current Employment. Carrasco:Legend Biotech USA Inc.: Current Employment. Akram:Legend Biotech USA Inc.: Current Employment. Hossain:Legend Biotech USA Inc.: Current Employment. Jakubowiak:AbbVie, Amgen, BMS/Celgene, GSK, Janssen, Karyopharm: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive, Juno: Consultancy, Honoraria. Jagannath:BMS, Janssen, Karyopharm, Legend Biotech, Sanofi, Takeda: Consultancy.

Background: Multiple myeloma (MM) remains an incurable plasma cell (PC) malignancy. Despite improvements in clinical outcomes, variability in treatment response exists. Some patients experience innate resistance, while others develop resistance over the course of treatment. Identifying signatures of treatment response and resistance is essential to predicting effective treatment strategies. Given the phenotypic clonal heterogeneity observed in MM, we hypothesize that resistant and sensitive subpopulations have unique phenotypic signatures. We used mass cytometry (CyTOF) to characterize primary MM samples and correlated their phenotypic signatures with treatment response. Methods: We characterized 102 primary MM samples by CyTOF using 37 antibodies (see figure). Frozen whole BM specimens were thawed, stained with antibodies, barcoded, and analyzed on a Helios mass cytometer. Data was processed using Cytobank or Pathsetter and analyzed using t-distributed stochastic neighbor embedding (t-SNE) algorithm. T-SNE plots for CD45+ cells were created using lineage defining markers. T-SNE plots of neoplastic PCs (CD138+,CD3-,CD16-,CD19-,cytoplasmic kappa or lambda+) were created using all remaining markers. A differential analysis of each sample's clusters was performed against all other events. Z-score values, representing marker changes from the differential analysis, for each cluster were used to group similar clusters across all samples, allowing us to compare sub populations of PCs between patients (see figure). From these groups of clusters with similar changes in markers, we calculated the proportion of cells with increases or decreases in markers for each sample. Results were compared to IMWG 90-day response criteria using a random forest model. Results: We performed mass cytometry on 102 samples from 68 unique MM patients. Median age was 66 years (range 34-95) with a 1.5:1 male:female ratio. 37 (36%) had NDMM, 55 (54%) had RRMM, 2 (2%) had SMM and 8 cases (8%) had unknown status. FISH studies revealed 47 (46%) had hyperdiploidy without a recurrent primary IgH rearrangement, 31 (30%) had t(11;14), 13 (13%) had t(4;14), 5 (5%) had 14;16 or 14;20, 3 (3%) had hyperhaploidy and 3 (3%) had an undefined primary. 54 (53%) had 1q gain/amp, 22 (22%) had TP53 deletion, 22 (22%) had a MYC rearrangement and 71% had high mSMART risk. Nearly all patients received an immunomodulatory compound, a proteasome inhibitor and dexamethasone. 2 (2%) had complete response (CR), 10 (9.8%) very good partial response (VGPR), 36 (35%) had partial response (PR), 14 (14%) had minimal response (MR), 13 (13%) had stable disease (SD) and 17 (17%) had progressive disease (PD). Characterization of CD45+ cells identified a relatively conserved and reproducible map from each patient. Notable differences included an ~2-fold reduction in the percentage of total B cells (CD45+,CD3-,CD19+)/total CD45+ cells in cases with high risk mSMART, RRMM and TP53 deletion compared to cases with standard risk, NDMM or normal TP53 status. Similar B-cell reductions were found in RRMM vs. NDMM samples from matched-patients. In contrast to the conserved t-SNE structure of the CD45+ population, the neoplastic PC population displayed dramatically reduced t-SNE structural consistency. Heterogeneity between patient samples and between the same patient samples over time was observed. We focused our analysis on 22 patients with serial samples. The proportion of each t-SNE group present in each patient sample was calculated and then correlated to the 90-day response metric. We identified a phenotypic group whose proportion increased in relation to disease progression (R2=0.85). This group had elevated BCL-2, pSTAT3, CD56 levels and reduced CD45 and CD81 levels. Evaluating individual markers, we found an increase in the proportion of cells with elevated BCL-2, pS6, Ki67, and IKZF1 levels in relation to disease progression. We also observed an increase in the proportion of cells with reduced pCREB levels and a reduction in the proportion of cells with reduced CD147 levels in relation to disease progression. Conclusions: We have utilized CyTOF to characterize phenotypic and functional markers in MM cells on a single cell level and can identify unique subgroups that change in relation to disease progression. Future analysis will correlate phenotypic signatures with ISS stage, mSMART risk, cytogenetic abnormality and type of treatment. Figure 1 Disclosures Kumar: Kite Pharma: Consultancy, Research Funding; Oncopeptides: Consultancy, Other: Independent Review Committee; IRC member; Celgene/BMS: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Takeda: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Sanofi: Research Funding; MedImmune: Research Funding; Karyopharm: Consultancy; Merck: Consultancy, Research Funding; Carsgen: Other, Research Funding; Cellectar: Other; Novartis: Research Funding; Adaptive Biotechnologies: Consultancy; AbbVie: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Genecentrix: Consultancy; Genentech/Roche: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Janssen Oncology: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Amgen: Consultancy, Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments, Research Funding; Tenebio: Other, Research Funding; BMS: Consultancy, Research Funding; Dr. Reddy's Laboratories: Honoraria.

Background: Ciltacabtagene autoleucel (cilta-cel; JNJ-68284528; LCAR-B38M CAR-T cells) is a chimeric antigen receptor T (CAR-T) cell therapy with 2 B-cell maturation antigen-targeting single-domain antibodies designed to confer avidity. In the phase 1 LEGEND-2 study in China, LCAR-B38M yielded deep, durable responses with a manageable safety profile in patients (pts) with relapsed/refractory multiple myeloma (R/R MM). The phase 1b/2 CARTITUDE-1 study (NCT03548207) is further evaluating cilta-cel in this pt population in the US. We present updated data from the phase 1b portion along with initial phase 2 data. Methods: Eligible pts (aged ≥18 y) were diagnosed with MM per International Myeloma Working Group (IMWG) criteria and had measurable disease, Eastern Cooperative Oncology Group performance status ≤1, received ≥3 prior regimens or were double-refractory to a proteasome inhibitor and immunomodulatory drug, and received an anti-CD38 antibody. After apheresis, bridging therapy was permitted. Cyclophosphamide 300 mg/m2 and fludarabine 30 mg/m2 daily for 3 d were used for lymphodepletion. A single infusion of cilta-cel at a target dose of 0.75×106 (range 0.5-1.0×106) CAR+ viable T cells/kg was administered 5-7 d after start of lymphodepletion. The primary objective of the phase 1b portion was to characterize cilta-cel safety and establish the recommended phase 2 dose; the primary objective of the phase 2 portion was to evaluate cilta-cel efficacy. Response was assessed per IMWG criteria and minimal residual disease (MRD) by next-generation sequencing. Adverse events (AEs) were graded using CTCAE v5.0. In the phase 1b portion, cytokine release syndrome (CRS) was graded by Lee et al (Blood 2014) and neurotoxicity by CTCAE v5.0; in the phase 2 portion, CRS and neurotoxicity were graded by American Society for Transplantation and Cellular Therapy (ASTCT) criteria. In this combined analysis, Lee et al and CTCAE v5.0 were mapped to ASTCT criteria for CRS and immune effector cell-associated neurotoxicity syndrome (ICANS), respectively. Results: As of the May 20, 2020 clinical cutoff, 97 pts (58.8% male; median age 61.0 y [range 43-78]) with R/R MM received cilta-cel (29 in phase 1b; 68 in phase 2). Median follow-up duration was 8.8 mo (range 1.5-20.4). Pts had received a median of 6 prior lines of therapy (range 3-18); 83.5% were penta-exposed, 87.6% were triple-refractory, 41.2% were penta-refractory, and 97.9% were refractory to last line of therapy. Overall response rate per independent review committee (primary endpoint) was 94.8% (95% CI 88.4-98.3), with a stringent complete response rate of 55.7% (95% CI 45.2-65.8), very good partial response rate of 32.0% (95% CI 22.9-42.2), and partial response rate of 7.2% (95% CI 3.0-14.3). All pts achieved a reduction in M-protein. Median time to first response was 1.0 mo (range 0.9-5.8; 80.4% ≤1.0 mo), and median time to complete response or better was 1.8 mo (range 0.9-12.5; 74.1% ≤3.0 mo); responses deepened over time (Figure). Median duration of response was not reached (NR). Of 52 MRD-evaluable pts, 94.2% were MRD-negative at 10-5. The 6-mo progression-free survival (PFS) and overall survival (OS) rates (95% CI) were 87.4% (78.9-92.7) and 93.8% (86.7-97.2), respectively; median PFS and OS were NR. Ten deaths occurred during the study; 8 were due to AEs (both related and unrelated; CRS/hemophagocytic lymphohistiocytosis, neurotoxicity, respiratory failure, sepsis, septic shock, pneumonia, lung abscess, and acute myelogenous leukemia [n=1 each]), and 2 due to progressive disease. AEs reported in >70% of pts were CRS (94.8%; grade [gr] 3/4 4.1%), neutropenia (90.7%; gr 3/4 90.7%), anemia (81.4%; gr 3/4 68.0%), and thrombocytopenia (79.4%; gr 3/4 59.8%). Median time to CRS onset was 7.0 d (range 1-12) and median duration 4.0 d (range 1-27, excluding n=1 with 97 d). CAR-T cell-related neurotoxicity was reported in 20.6% of pts (gr 3/4 10.3%). Cilta-cel CAR+ T cells showed maximum peripheral expansion at 14 d (range 9-43). Among pts with 6 mo' individual follow-up, 67% had cilta-cel CAR+ T cells below the level of quantification (2 cells/µL) in peripheral blood. Conclusions: Preliminary phase 1b/2 data from CARTITUDE-1 indicate a single low-dose infusion of cilta-cel leads to early, deep, and durable responses in heavily pretreated pts with MM with a safety profile consistent with LEGEND-2. Further investigation of cilta-cel in other MM populations is underway. Disclosures Madduri: Celgene: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria; Foundation Medicine: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Legend: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Speaking Engagement, Speakers Bureau; Kinevant: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Speaking Engagement, Speakers Bureau; GSK: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Speaking Engagement, Speakers Bureau. Berdeja:Teva: Research Funding; Bluebird: Research Funding; Bioclinica: Consultancy; Celgene: Consultancy, Research Funding; EMD Sorono: Research Funding; Kite Pharma: Consultancy; Prothena: Consultancy; Cellularity: Research Funding; Karyopharm: Consultancy; Servier: Consultancy; Legend: Consultancy; Poseida: Research Funding; Lilly: Research Funding; Acetylon: Research Funding; CURIS: Research Funding; Janssen: Consultancy, Research Funding; Genentech, Inc.: Research Funding; Glenmark: Research Funding; Takeda: Consultancy, Research Funding; BMS: Consultancy, Research Funding; Constellation: Research Funding; CRISPR Therapeutics: Consultancy, Research Funding; Vivolux: Research Funding; Abbvie: Research Funding; Amgen: Consultancy, Research Funding; Kesios: Research Funding; Novartis: Research Funding. Usmani:Celgene: Other; BMS, Celgene: Consultancy, Honoraria, Other: Speaking Fees, Research Funding; GSK: Consultancy, Research Funding; Pharmacyclics: Research Funding; Merck: Consultancy, Research Funding; Abbvie: Consultancy; Sanofi: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Other: Speaking Fees, Research Funding; Janssen: Consultancy, Honoraria, Other: Speaking Fees, Research Funding; SkylineDX: Consultancy, Research Funding; Seattle Genetics: Consultancy, Research Funding; Incyte: Research Funding; Array Biopharma: Research Funding; Amgen: Consultancy, Honoraria, Other: Speaking Fees, Research Funding. Jakubowiak:Adaptive, Juno: Consultancy, Honoraria; AbbVie, Amgen, BMS/Celgene, GSK, Janssen, Karyopharm: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Cohen:Celgene: Membership on an entity's Board of Directors or advisory committees; Takeda,: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees; Kite Pharma: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Genentech/Roche: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Other: Patents/Intellectual property licensed, Research Funding. Stewart:Janssen, BMS, Sanofi-Aventis, GSK: Honoraria; Tempus, Inc., Genomics England LLC: Membership on an entity's Board of Directors or advisory committees. Hari:Amgen: Consultancy; BMS: Consultancy; GSK: Consultancy; Janssen: Consultancy; Takeda: Consultancy; Incyte Corporation: Consultancy. Htut:City of Hope Medical Center: Current Employment. Munshi:OncoPep: Consultancy, Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties; BMS: Consultancy; Janssen: Consultancy; Adaptive: Consultancy; Legend: Consultancy; Amgen: Consultancy; Karyopharm: Consultancy; Takeda: Consultancy; AbbVie: Consultancy; C4: Current equity holder in private company. Deol:Novartis: Consultancy; Kite, a Gilead Company: Consultancy. Lesokhin:BMS: Consultancy, Honoraria, Research Funding; Genentech: Research Funding; Janssen: Research Funding; Juno: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Serametrix Inc.: Patents & Royalties; GenMab: Consultancy, Honoraria. Singh:Janssen: Current Employment. Zudaire:Janssen: Current Employment. Yeh:Janssen: Current Employment. Allred:Janssen: Current Employment. Olyslager:Janssen: Current Employment. Banerjee:Janssen: Current Employment. Goldberg:Johnson & Johnson: Current Employment, Current equity holder in publicly-traded company. Schecter:Janssen: Current Employment. Jackson:Janssen: Current Employment; Memorial Sloan Kettering Cancer Center: Consultancy. Deraedt:Janssen: Current Employment, Current equity holder in publicly-traded company. Zhuang:Janssen: Current Employment. Infante:Janssen: Current Employment. Geng:Legend Biotech USA Inc.: Current Employment. Wu:Legend Biotech USA Inc.: Current Employment. Carrasco:Legend Biotech USA Inc.: Current Employment. Akram:Legend Biotech USA Inc.: Current Employment. Hossain:Legend Biotech USA Inc.: Current Employment. Rizvi:Legend Biotech USA Inc.: Current Employment. Fan:Legend Biotech USA Inc.: Current Employment. Jagannath:BMS, Janssen, Karyopharm, Legend Biotech, Sanofi, Takeda: Consultancy. Lin:Kite, a Gilead Company: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Merck: Research Funding; Legend BioTech: Consultancy; Juno: Consultancy; Bluebird Bio: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Novartis: Consultancy; Vineti: Consultancy; Takeda: Research Funding; Gamida Cells: Consultancy; Sorrento: Consultancy, Membership on an entity's Board of Directors or advisory committees. Martin:AMGEN: Research Funding; Seattle Genetics: Research Funding; Janssen: Research Funding; GSK: Consultancy; Sanofi: Research Funding.

Introduction: Response assessment at day 100 post Autologous Stem Cell Transplant (ASCT) is associated with long-term relapsed free survival (RFS) and overall survival (OS) in multiple myeloma (MM). The International Myeloma Working Group (IMWG) are the preferred criteria to define best response to treatment and define relapse. In the last years, response assessment has incorporated minimal residual disease (MRD) status -associated with improved RFS and OS (Munshi et al); and PET/CT combined with clinical characteristics -also associated with favorable outcomes (Zamagni et al. NCT01910987; MMY3033). The 2016 IMWG MRD criteria, combined imaging (PET/CT) plus next-generation sequencing (NGS) MRD-negative to define complete response (CR). To our knowledge, there is limited data examining the correlation and prognostic value of MRD and FDG-PET/CT at day 100 post ASCT in MM. IN this study, we aimed to determine the prognostic valued of MRD by NGS combined with PET/CT in RFS and OS status after high dose chemotherapy and ASCT in MM. Methods: Patients who underwent ASCT for MM at Mayo Clinic Arizona and had MRD and PET/CT data were included in the study. Clinical data was obtained via retrospective chart review. Cytogenetic risk (CyR) was classified using the mSMART criteria . Disease and ASCT related characteristics were compared by MRD status. MRD was measured by NGS on bone marrow aspirates using the previosly validated clonoSEQ ® Assay (Adaptive Biotechnologies Corporation, Seattle, USA) tracking the IgH, IgK and IgL rearrangements at a minimum sensitivity level of 10-5. MRD was defined by residual clonal cells per million nucleated cells as: negative= 0, borderline= 1-5, positive >5. PET/CT scans were performed locally at baseline and at day 100. Comparisons were performed using the chi-square test for categorical variables, Wilcoxon rank-sum test for continuos variables, McNemar's test and Cohens's Kappa for agreement measures. Results: A total of 103 patients had matched MRD and PET/CT assessment around day 100 (+/-9 days) and were included in the analysis. Median age at diagnosis was 62 years (range, 54-66 years), 71 patients (68.9%) were men. CyR was standard risk in 49 (47.6%), high-risk in 39 (37.9%) and unknown in 15 (14.6%) patients. Most 75 (72.8%) patients were MRD positive, 16 (15.5%) were MRD negative, and 12 (11.7%) borderline. The median main MRD clone detected was 64 (range 0-91,874). 70 patients (68%) and 33 (32%) had a negative and positive PET/CT respectively. The median follow-up time was 18 months (range, 13-31 months). At the time of data analysis, 10 patients (9.7%) had relapsed and only 4 (3.9%) had died. There was a high-correlation between MRD status and PET/CT, 31 patients (93.9%) with positive PET/CT were also MRD positive (p=0.0027). There were no statistical differences between PET/CT and CyR (p=0.95). We analyzed the correlation using the FREQ procedure (McNemars's test); there was a strong association between positive PET/CT and positive MRD in 31/33 patients (93.9%, high sensitivity), and low association for negative PET/CT the negative/borderline MRD in 26/70 (37.1%, low specificity; p<0.001). The agreement measure between the PET/CT and MRD using negative/borderline combined had a kappa of 0.23 (95% CI 0.11, 0.35) indicating a fair agreement beyond chance (Figure 1). PET/CT-CT was a statistically significant predictor of worse RFS (HR 3.53, 95%CI: 1.02-12.24, p<0.0337) and OS (HR 11.38, 95%CI: 1.18-109.56, p<0.0078) (Figure 2-3, respectively). MRD was not predictive of neither RFS (HR 1.72, 95%CI: 0.36-8.14, p<0.49) or OS (p<0.16). Conclusions: In conclusion, we demonstrate that the combination of MRD by NGS (clonoSEQ ®) and PET/CT at day 100 are complementary and have a high sensitivity (true positive rate) and fair correlation of agreement but low specificity (true negative rate). PET/CT was the best most sensitive technique to prognosticate RFS and OS. We did not find prognostic correlation of MRD with RFS and OS. However, our findings might be confounded by the low risk of relapse and death, a longer follow-up may demonstrate clinically important differences. Our results add evidence that MRD plus PET/CT improve the definition of CR in MM patients post ASCT. Prospective studies are needed to elucidate the optimal timing and role of combined MRD, PET/CT with other prognostic markers of clinical outcomes. Disclosures Larsen: Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen Oncology: Honoraria, Membership on an entity's Board of Directors or advisory committees. Fonseca:Juno: Consultancy; Kite: Consultancy; Aduro: Consultancy; OncoTracker: Consultancy, Membership on an entity's Board of Directors or advisory committees; Merck: Consultancy; Bayer: Consultancy; Janssen: Consultancy; Takeda: Consultancy; Novartis: Consultancy; Pharmacyclics: Consultancy; Sanofi: Consultancy; Oncopeptides: Consultancy; GSK: Consultancy; AbbVie: Consultancy; Adaptive Biotechnologies: Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy; BMS: Consultancy; Celgene: Consultancy.

Abstract The oncogenic transcription factor c-Maf has been proposed as an ideal therapeutic target for multiple myeloma (MM), but how to achieve it is still elusive. In the present study, we found the Otub1/c-Maf axis could be a potential target. Otub1, an OTU family deubiquitinase, was found to interact with c-Maf by mass spectrometry. Otub1 abrogates c-Maf K48-linked polyubiquitination, thus preventing its degradation and enhancing its transcriptional activity. Specifically, this deubiquitinating activity depends on its Lys71 and the N terminus but is independent of UBE2O, a known E2 of c-Maf. Otub1 promotes MM cell survival and MM tumor growth. In contrast, silence of Otub1 leads to c-Maf degradation and c-Maf-expressing MM cell apoptosis. Therefore, the Otub1/c-Maf axis could be a therapeutic target of MM. In order to explore this concept, we performed a c-Maf recognition element–driven luciferase-based screen against US Food and Drug Administration–approved drugs and natural products, from which the generic cardiac glycoside lanatoside C (LanC) is found to prevent c-Maf deubiquitination and induces its degradation by disrupting the interaction of Otub1 and c-Maf. Consequently, LanC inhibits c-Maf transcriptional activity, induces c-Maf-expressing MM cell apoptosis, and suppresses MM growth and prolongs overall survival of model mice, but without apparent toxicity. Therefore, the present study identifies Otub1 as a novel deubiquitinase of c-Maf and establishes that the Otub1/c-Maf axis is a potential therapeutic target for MM.

8537 Background: Carfilzomib (CFZ) is a proteasome inhibitor, active against hematologic malignancies. Preclinically, CFZ overcomes bortezomib (BTZ) resistance in multiple tumors, including myeloma (MM). PX-171–004 is an ongoing Phase II study evaluating safety and efficacy of CFZ in MM patients with relapsed disease after 1–3 prior therapies. Overall Response Rate (ORR) of 35.5% for all subjects was previously reported (ASH 2008); updated data are now available. Methods: Patients were divided into two cohorts: BTZ-naïve and BTZ-exposed. CFZ 20 mg/m2 was administered Days 1, 2, 8, 9, 15 and 16 in a 28-day cycle, for up to 12 cycles. Dexamethasone 4 mg po was administered prior to each dose in Cycle 1. The primary endpoint was ORR, defined as Partial Response (PR) or better. Secondary endpoints included Duration Of Response (DOR) and Time To Progression (TTP). Results: 31 patients were enrolled; 14 (45%) BTZ-naïve and 17 (55%) BTZ-exposed. Of the BTZ-exposed cohort, 2 subjects received BTZ exclusively as a single agent, 6 had BTZ in a chemotherapy combination, and 9 received BTZ in a transplant regime. Overall, 23 (74%) subjects had > 1 prior therapy and 27 (87%) received transplant. In BTZ-naïve patients, CFZ achieved an ORR of 57%; median DOR of 8.6 mos (range >1.9 to >9.7 mos). To date, 7 patients (50%) remain progression free and 3 patients have completed 12 cycles. The median follow-up was 10 mos and the median TTP has not been reached. For the BTZ- exposed group, CFZ achieved an ORR of 18%; median DOR not yet reached (>8.5 mos) (range >1 d to >8.5 mos). 7 patients (41%) are progression free and 3 patients have completed 12 cycles. Median follow-up and TTP were 9.2 and 8.9 mos, respectively. Conclusions: These preliminary results demonstrate that single-agent CFZ is tolerable for at least 1 yr and achieves sustained responses in relapsed MM. Prior BTZ mono/combination therapy does not preclude durable response with CFZ. These data support continuing evaluation of CFZ in the treatment of relapsed MM. [Table: see text] [Table: see text]