Dong Geng

Chimeric antigen receptor (CAR) T-cell therapies are highly effective for multiple myeloma (MM) but their impressive efficacy is associated with treatment-related neurotoxicities in some patients. In CARTITUDE-1, 5% of patients with MM reported movement and neurocognitive treatment-emergent adverse events (MNTs) with ciltacabtagene autoleucel (cilta-cel), a B-cell maturation antigen-targeted CAR T-cell therapy. We assessed the associated factors for MNTs in CARTITUDE-1. Based on common features, patients who experienced MNTs were characterized by the presence of a combination of at least two variables: high tumor burden, grade ≥2 cytokine release syndrome (CRS) or any grade immune effector cell-associated neurotoxicity syndrome (ICANS) after cilta-cel infusion, and high CAR T-cell expansion/persistence. Strategies were implemented across the cilta-cel development program to monitor and manage patients with MNTs, including enhanced bridging therapy to reduce baseline tumor burden, early aggressive treatment of CRS and ICANS, handwriting assessments for early symptom detection, and extended monitoring/reporting time for neurotoxicity beyond 100 days post-infusion. After successful implementation of these strategies, the incidence of MNTs was reduced from 5% to <1% across the cilta-cel program, supporting its favorable benefit-risk profile for treatment of MM.

Introduction:Rareevents of T-cell lymphoma (TCL) derived from CAR-T cells (2 cases) have been reported in patients receiving nonviral piggyBac transposon-based CAR-T therapy (Micklethwaite et al, Blood, 2021). Ciltacabtagene autoleucel (cilta-cel) is an anti-BCMA CAR-T therapy produced via conventional lentiviral transduction. In the randomized, phase 3 CARTITUDE-4 study (NCT04181827), cilta-cel significantly improved PFS (HR=0.26) vs standard of care in lenalidomide-refractory patients with multiple myeloma and 1-3 prior lines of therapy. We present the clinicogenomic characterization of a CARTITUDE-4 patient who developed a CAR+ TCL post cilta-cel. Methods: Diagnostic and staging workup included biopsy analyses and FDG-PET scan. Presence of CAR+ cells in lymph node biopsy (LNB) was assessed by quantitative polymerase chain reaction (qPCR), in situ hybridization (ISH), and immunohistochemistry (IHC). Whole genome sequencing (WGS), transcriptome sequencing, whole exome sequencing (WES), T-cell receptor (TCR) sequencing, and genome-wide CAR integration analyses were conducted. Results:A 51 y/o male patient received cilta-cel; CAR+ T cells in blood peaked 14 d post-infusion (77 cells/μL) and decreased to 3 cells/μL at d 92 post-infusion, when he achieved stringent complete response (sCR) and MRD negativity at 10 -5. At 5 mo post-infusion, a relatively rapidly growing erythematous nasofacial plaque developed. TCL was diagnosed based on facial lesion biopsy showing an infiltrate of atypical T cells positive for CD2 and CD3 but negative for CD4, CD8, CD7, CD56, ALK, EBER-ISH, TdT, CD30, and cytotoxic T cell markers. FDG-PET showed bilateral FDG-avid cervical lymphadenopathy, with similar T cell infiltrate in submandibular LNB. qPCR and ISH/IHC revealed 90-100% of LNB cells to be CAR+. At d 162 post-infusion (after TCL diagnosis but before TCL-directed chemotherapy) CAR+ T cells in blood had re-expanded, independent of BCMA antigen, to 378 cells/μL. CAR integration analysis of LNB revealed a dominant insertion into the 3′UTR of PBX2 (91.1% of total reads from all integration sites), suggesting tumor monoclonality. TCR sequencing (1.8×10 -6 sensitivity) of LNB showed a monoclonal sequence in 91% of all T cells. Analysis of the drug product revealed the same unique TCR sequence from the monoclone at low frequency (~2×10 -6), suggesting the presence of this clone in apheresis material. WGS showed low overall mutational burden in the LNB (1.26 mutations/megabase) with 37 coding and 3286 non-coding variants, including 2 predicted loss-of-function TET2 mutations; a PTPRB truncation; and a focal duplication involving the 5′UTR to intron 16 of NFKB2. No dominant mutational signatures or gross copy number changes were observed. WES of the LNB indicated that a TET2 mutation (p.H1416R), which was not due to CAR insertion, was heterozygous and likely clonal. Targeted sequencing (0.5% sensitivity) of stored CD34+ cells and bone marrow aspirate collected from the patient 2 y earlier showed no abnormalities. Germline samples revealed the presence of a heterozygous JAK3 variant (p.V722I) that has been described as an activating variant, implicated in TCL, and detected in germline samples from patients with antigen-induced TCL (Blombery et al, Haematologica, 2016). The patient received CHOEP-21 (cyclophosphamide-doxorubicin-vincristine-prednisone-etoposide) and achieved metabolic CR but relapsed soon after treatment was stopped. Subsequent treatment with gemcitabine-dexamethasone-cisplatin-alemtuzumab was followed by consolidation with fludarabine plus melphalan and matched allogeneic stem cell transplant. He relapsed with cutaneous disease within 3 mo. Conclusions: To our knowledge, this is the first case of CAR+ TCL occurring after infusion of a CAR-T therapy produced via lentiviral transduction (cilta-cel). This rare malignancy was potentially driven by genetic mutations (e.g., TET2, NFKB2, PTPRB and/or JAK3), some of which may have existed in the form of a clone with malignant potential before cilta-cel manufacturing (e.g., TET2 p.H1416R and JAK3 p.V722I variants). A potential contributory role of the CAR insertion in the 3′ untranslated region of PBX2 to TCL development remains unclear and cannot be excluded at this time. Further investigation is needed to elucidate the differential contributions of these genomic factors to the etiology of this TCL case.

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 &amp;gt;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 &amp; 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 &amp; 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 &amp; 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 Biot

8505 Background: JNJ-68284528 (JNJ-4528) is a chimeric antigen receptor T (CAR-T) cell therapy containing 2 BCMA-targeting single-domain antibodies. Here we present updated CARTITUDE-1 (NCT03548207) phase 1b results with longer follow-up. Methods: Pts had MM per IMWG criteria, measurable disease, received ≥3 prior regimens or were double refractory to a PI and IMiD, and received anti-CD38 antibody. Cyclophosphamide 300 mg/m 2 + fludarabine 30 mg/m 2 over 3 days were used for lymphodepletion. JNJ-4528 (median, 0.73x10 6 CAR+ viable T cells/kg) was given as a single infusion. Cytokine release syndrome (CRS) was graded by Lee et al2014 and neurotoxicity by CTCAE, v5.0 and ASTCT grading. Response was assessed per IMWG criteria. Results: As of 17 Jan 2020, median follow-up is 9 mo (3–17). Phase 1b enrollment is complete (N = 29 treated; median 5 (3–18) prior lines, 76% penta-exposed, 86% triple-refractory, 31% penta-refractory, 97% refractory to last line of therapy). Most frequent adverse events (AEs) were neutropenia (100%), CRS (93%), and thrombocytopenia (93%). Grade (Gr) ≥3 hematologic AEs were neutropenia (100%), thrombocytopenia (69%), and leukopenia (59%). 27 (93%) pts had CRS; 25 Gr 1–2, 1 Gr 3, and 1 Gr 5 (day 99 subsequent to dose-limiting toxicity of prolonged Gr 4 CRS). Median time to onset of CRS was 7 days (2–12). 4 pts had treatment-related neurotoxicity: 3 Gr 1–2 and 1 Gr 3. ORR was 100%, with 22 (76%) stringent complete responses (sCRs), 6 (21%) very good partial responses (VGPRs), and 1 (3%) PR. Median time to ≥CR was 2 mo (1–9). 26/29 pts are progression-free, with 6-mo progression-free survival rate of 93% and longest response ongoing at 15 mo. 1 death due to CRS and 1 to acute myeloid leukemia (not treatment-related) occurred during the study. All 16 pts (14 sCR, 2 VGPR) evaluable at 6 mo were minimal residual disease negative at 10 −5 or 10 −6 . JNJ-4528 CAR+ T cell expansion peaked between day 10–14. At 6-mo individual follow-up, 22/28 pts had JNJ-4528 CAR+ T cells below the level of quantification (2 cells/µL) in peripheral blood, suggesting CAR-T persistence in peripheral blood did not seem to correlate with deepening of response. At peak expansion, preferential expansion of CD8+ CAR-T cells with a central memory phenotype was observed in peripheral blood. Conclusions: JNJ-4528 treatment led to responses in all pts. These responses were early, deep, and durable at a low dose of CAR-T cells with 26/29 (90%) pts progression free at median 9-mo follow-up. CRS was manageable in most pts, supporting outpatient dosing. Clinical trial information: NCT03548207 .