Shah, Nina

BackgroundConsolidative autologous hematopoietic stem cell transplantation (AHCT) is commonly used for patients with multiple myeloma (MM). We studied AHCT use and outcomes in patients with MM ≥75 years old.MethodsPatients with MM ≥75 years old receiving AHCT between 2013 and 2017 in the United States were identified using the Center for International Blood and Marrow Transplant Research database. Relapse and/or progression (REL), progression‐free survival (PFS), and overall survival (OS) were modeled using Cox proportional hazards models. Covariates used were age, sex, Karnofsky performance score (KPS), HCT‐comorbidity index (HCT‐CI), International Staging System and/or Durie‐Salmon stage, high‐risk cytogenetics, melphalan dose, and disease status at and 1 year after transplant. AHCT utilization rate using the Surveillance, Epidemiology, and End Results database was used to estimate specific incidence among ≥75 years old by race and gender.ResultsOf 360 patients, 63% were male, 84% were White, 56% had KPS <90, and 57% had HCT‐CI ≥3. The 100‐day transplant‐related mortality was 1% (0%‐2%) with a 2‐year REL rate of 27% (95% confidence interval [CI], 22%‐33%), PFS of 66% (95% CI, 60%‐72%), and OS of 83% (95% CI, 78%‐87%). On multivariate analysis, only high‐risk cytogenetics was associated with REL risk and decreased PFS. In White males, transplant utilization rate was 5.2%‐5.8% compared to 3.5%‐4.0% in African American males (P = .02). There was 3.37‐3.79% transplant utilization in White females compared to 1.88‐2.12% in African American females (P < .01).ConclusionsThe use of AHCT was associated with excellent 2‐year outcomes in this selected MM population ≥75 years old. Transplant utilization for patients ≥75 years old remains low with significant racial and gender disparities.

8022 Background: Maintenance therapy in multiple myeloma (MM) after first autologous hematopoietic cell transplantation (AHCT1) is considered standard of care. Data regarding maintenance therapy after a salvage AHCT (AHCT2) in the setting of relapsed MM are scarce. Therefore, we used data from the Center for International Blood and Marrow Transplant Research (CIBMTR) registry to examine the use of maintenance therapy after AHCT2 in MM patients and its effect on post-transplant patient outcomes. Methods: We included US adult MM patients who underwent AHCT2 after melphalan conditioning regimen from 2010-2018, and excluded patients who underwent tandem transplants. Outcomes of interest included non-relapse mortality (NRM), relapse/progression (REL), progression-free and overall survival (PFS, OS). Cox proportional hazards models were developed to study the main effect (maintenance use) with other covariates of interest including age, sex, race, performance status, HCT-comorbidity index, MM subtype, stage, creatinine, cytogenetic, conditioning melphalan dose, disease status at transplant, and time from AHCT1 to AHCT2. Results: Of 522 patients, 342 received maintenance therapy and 180 did not after AHCT2. Baseline characteristics were similar between the two groups. Median follow up was 58 months in the maintenance group and 61.5 months in the no-maintenance group. Common maintenance regimens included immunomodulatory drugs (IMID)-lenalidomide (N = 145, 42%) or pomalidomide (N = 46, 13%) and proteasome inhibitor, bortezomib (N = 45, 13%). Univariate analysis showed superior outcomes at 5 years in maintenance compared to the no-maintenance group: NRM 2 (0.7-3.9)% vs 9.9 (5.9-14.9)%, p < 0.001, REL 70.2 (64.4-75.8)% vs 80.3 (73.6-86.3)%, p 0.003, PFS 27.8% (22.4-33.5) vs. 9.8% (5.5-15.2), p < 0.001, and OS 54% (47.5-60.5) vs 30.9% (23.2-39.2) p < 0.001, respectively. IMID-containing maintenance regimens were associated with an improved 5-year PFS and OS compared to other maintenance regimens. Use of maintenance therapy retained its association with improved outcomes in multivariate analysis, including NRM: hazard ratio (HR) 0.19 (0.08-0.44), p 0.0001, REL: HR 0.58 (0.47-0.72), p < 0.0001, PFS HR 0.52 (0.43-0.64), p < 0.0001, and OS HR 0.46 (0.36-0.60), p < 0.0001. We conducted additional analyses to investigate a possible selection bias in the maintenance group including landmark analysis at 100-days and 6-months post-AHCT2 as well as a subgroup analysis of patients who received melphalan 200mg/m2 as conditioning for AHCT2 (as a surrogate for fitness)- all these analyses also showed improved outcomes in the maintenance group. Second cancers were reported in 17 (5%) patients in the maintenance group and 6 (3%) patients and no-maintenance group (p 0.39). Conclusions: Maintenance therapy after AHCT2 is associated with superior outcomes in MM patients.

8016 Background: Patients (pts) with RRMM previously exposed to immunomodulatory agents, proteasome inhibitors (PIs), and CD38 antibodies (mAbs) have poor outcomes with subsequent treatments. Ide-cel, a BCMA-directed CAR T cell therapy, showed frequent, deep, and durable responses in heavily pretreated pts with RRMM in the pivotal KarMMa trial (Munshi NC, et al. J Clin Oncol 2020;38[suppl 15]. Abstract 8503). Here, we present updated data. Methods: Pts with ≥ 3 prior regimens (including immunomodulatory agent, PI, and CD38 mAb) and refractory to their last regimen per IMWG criteria were eligible (NCT03361748). Pts received 150─450 × 106 CAR+ T cells (target dose range) after 3 days of lymphodepletion (cyclophosphamide 300 mg/m2 + fludarabine 30 mg/m2). Endpoints included overall response rate (ORR; primary) and complete response (CR) rate (key secondary). Additional secondary endpoints included progression-free survival (PFS), overall survival (OS), and safety. Results: KarMMa enrolled 140 pts, and 128 received ide-cel. Pts had a median age of 61 years and a median of 6 (range, 3-16) prior regimens; 84% were triple-class refractory, and 26% were penta-class refractory (lenalidomide, pomalidomide, bortezomib, carfilzomib, and daratumumab). Most pts (88%) had bridging therapy. Median follow-up was 15.4 mo (data cutoff, 7 Apr 2020). ORR was 73% and median PFS was 8.8 mo in all treated pts; both increased with higher dose (Table). At the highest target dose (450 × 106 CAR+ T cells), the ORR was 81%, the CR rate was 39%, and the median PFS increased to 12.2 months with longer follow-up. Responses were observed in all subgroups including difficult-to-treat subsets (eg, extramedullary disease [ORR, 70%], high tumor burden [71%], and R-ISS stage III disease [48%]). OS continues to mature and the median has not been reached; the 15-month event-free rate for OS was 71%. Cytopenias (97%) and cytokine release syndrome (CRS; 84%) were the most common any-grade toxicities. CRS was mostly grade 1/2; 5 pts (4%) had grade 3, 1 had grade 4 (at 300 × 106), and 1 had grade 5 (at 300 × 106). Investigator-identified neurotoxicity was reported in 23 pts (18%); 4 pts (3%) had grade 3 and 0 had grade ≥ 4. Tocilizumab was used in 67 and 3 pts with CRS and neurotoxicity, respectively. Conclusions: Updated results from the KarMMa trial continue to demonstrate deep, durable responses with ide-cel in heavily pretreated pts with RRMM. Efficacy and safety reflect prior reports and support a favorable clinical benefit-risk profile for ide-cel across the target dose range. Clinical trial information: NCT03361748. [Table: see text]

8009 Background: Measuring response among patients with multiple myeloma is essential for the care of patients. Deeper responses have been associated with better progression free survival (PFS) and overall survival (OS). Serum (SIFE) and urine immunofixation are the currently used markers for biochemical documentation of CR after which marrow is tested for plasma cell clearance. Next generation flow cytometry and sequencing are used to document the presence of minimal residual disease (MRD). Mass spectrometry of blood by MALDI (Mass-Fix) is a new simple, inexpensive, sensitive, and specific means of detecting monoclonal immunoglobulins. To better test the hypothesis that Mass-Fix is superior to existing methodologies to predict for survival outcomes—especially SIFE-- samples from the STAMINA trial (NCT01109004), a trial comparing 3 transplant approaches among patients who have already received induction, were employed. Methods: Five-hundred and seventy-five patients were included. Samples from enrollment post-induction (post-I) and 1-year post enrollment (1YR) were tested when available. Four response parameters were assessed univariately: Mass-Fix, SIFE, complete response, and MRD by next generation flow cytometry. Mass spectrometry spectra were evaluated in a blinded fashion. Complete response was according to the 2006 International Myeloma Working Group criteria. Multivariate Cox proportional hazard models using stepwise regression were developed to explore the independent effect of the different response parameters on PFS and OS and interactions with other risk factors. Results: Of the 4 response measures, only MRD and Mass-Fix predicted for PFS and OS at multiple testing points on multivariate analyses (Table). Of the 4 post-I measurements, only MRD predicted for PFS; however, Mass-Fix was the only post-I measurement to predict for OS. Of all the 1-year measures, both 1YR Mass-Fix and 1YR MRD positivity predicted for inferior PFS and OS. In models including MRD and Mass-Fix, SIFE and CR were not prognostic for PFS or OS. Conclusions: Mass-Fix is a powerful means to track monoclonal proteins. The full utility of Mass-Fix was not exploited given the absence of a diagnostic sample and the fact that only serum (and not urine) was tested. Despite these limitations, it performed well at pre-induction and at 1 year. Mass-Fix provides a convenient and non-invasive means of predicting for myeloma outcomes. Clinical trial information: NCT01109004. [Table: see text]

8036 Background: Ide-cel, a BCMA-directed CAR T cell therapy, showed promising efficacy in patients (pts) with RRMM in the KarMMa study with an ORR of 73% and a CRR of 33% across target doses of 150–450 × 106 CAR+ T cells (Munshi NC, et al. J Clin Oncol 2020;38[suppl 15]. Abstract 8503). Associations of neurotoxicity (NT) with pt and disease characteristics, pt management, and impact on outcomes in the KarMMa study are reported here. Methods: Enrolled pts were triple-class exposed and refractory to their last regimen, with ide-cel given at target doses of 150, 300, or 450 × 106 CAR+ T cells after lymphodepletion (NCT03361748). Investigator-identified NT events were captured under the single preferred term of neurotoxicity and graded according to NCI CTCAE v4.03. Events were managed with corticosteroids (CS), anakinra (ANR), and tocilizumab (Toci) as needed. Results: Of 128 pts treated with ide-cel, NT was reported in 23 (18%); 12 pts (9%) had maximum grade (gr) 1 NT, 7 (5%) had gr 2, and 4 (3%) had gr 3. No gr 4 or 5 NT occurred. Most baseline characteristics were similar in pts with and without NT, including stage III disease (22% and 15%), high-risk cytogenetics (39% and 34%), and extramedullary disease (35% and 40%); exceptions were high tumor burden (65% and 48%) and sex (48% and 62% men). NT (any gr/gr 3) occurred in 0%/0%, 17%/1%, and 20%/6% of pts at doses of 150, 300, and 450 × 106 CAR+ T cells. Median time to onset was similar regardless of gr, and there were no late-onset events (Table). NT was managed with CS in 10 pts (43%), Toci in 3 (13%), and ANR in 1 (4%). Median (range) time to first use of CS was 2 d (1–6). ORR and DOR were similar in pts with and without NT (Table). All NT occurred in the proximity of cytokine release syndrome (CRS) events with the start date of NT events either overlapping with or occurring within 1 wk of the start of a CRS event. Conclusions: NT occurred early in the KarMMa study, was generally of short duration, and was mostly gr 1/2 with no gr ≥4 events. All NT was proximal to CRS. Pts with NT had a favorable ORR after ide-cel treatment. These results continue to demonstrate the durable efficacy and tolerability of ide-cel in pts with RRMM. Clinical trial information: NCT03361748. [Table: see text]

Introduction: VRD (bortezomib, lenalidomide, dexamethasone) and VCD (bortezomib, cyclophosphamide, dexamethasone) are the two most commonly used triplet induction regimens in transplant eligible patients with multiple myeloma (MM). VCD is commonly used in patients with renal dysfunction at diagnosis. Given the variable results seen in head to head comparison of these (or similar) regimens to date, no definitive conclusion can be made on whether they are equivalent. This large CIBMTR registry study compares the outcomes with VRD vs. VCD induction therapy in patients undergoing upfront autologous stem cell transplant (ASCT). Methods: Patients were included if they underwent upfront ASCT for MM from January 2013 to December 2018 within 6 months of diagnosis, received VRD or VCD induction therapy and achieved at least a partial response pre-transplant. Of 1,135 patients, 914 patients received VRD and 221 received VCD therapy. Cox proportional hazards models were created for progression-free survival (PFS) and overall survival (OS). The following covariates were adjusted in the models: induction regimen (main effect), age, sex, race, performance score, hematopoietic cell transplant-comorbidity index (HCT-CI), estimated glomerular filtration rate (eGFR) at diagnosis, immunoglobulin subtype, cytogenetics, ISS stage, response status at transplant, melphalan dose, and maintenance therapy. Results: As shown in Table 1, patients in the VRD and VCD cohorts had similar age at transplant, adjusted HCT-CI scores, and distribution of high-risk cytogenetics. Patients in the VCD group were more likely to have renal impairment and ISS stage III disease. An eGFR (mL/min/1.73m2) at diagnosis &lt; 60 was seen in 26% of VRD patients vs. 48% of VCD patients. ISS stage III was seen in 17% vs. 34% of patients, respectively. Treatment and Response: Pre-transplant response in the VRD cohort was: complete response (CR)- 17%, very good partial response (VGPR)- 48% and partial response (PR)- 35%. Response in the VCD cohort was: CR- 17%, VGPR- 42% and PR- 41%. Conditioning dose was melphalan 200 mg/m2 in 80% of patients receiving VRD vs. 69% in the VCD group. Post-transplant response was at least VGPR in 74% vs. 75% of patients, respectively. Maintenance in the VRD group was: lenalidomide based (+/- bortezomib)- 80%, bortezomib based- 5%, other-3% and none- 12% of patients. In the VCD group, maintenance was: lenalidomide based- 63%, bortezomib based- 11%, other- 1% and none- 24%. Survival: Patients receiving VRD induction had superior outcomes compared to VCD induction with median PFS from transplant of 44.6 (38.0-55.8) months vs 34.1 (25.8-44.7) months, p 0.004 respectively. Median OS was not reached for either group, with 5-year OS 79 (74-83)% for VRD and 60 (50-69)% for VCD, p &lt;0.001. Univariate PFS and OS outcomes by induction regimen and eGFR at diagnosis are shown in Table 2 and Figure 1. Multivariate analysis is shown in Table 3. After adjusting for prognostic factors, there was no statistically significant difference between the two induction regimens, with hazard ratio (HR) for PFS in the VCD vs VRD group being 1.22 (95% CI: 0.96-1.55, p=0.10). ISS stage, cytogenetics, disease status prior to transplant, and maintenance were independent prognostic factors for PFS. Similarly, on multivariate analysis for OS, there was no statistically significant difference in the two groups, with HR for OS in VCD vs VRD group being 1.33 (95% CI: 0.93-1.92, p=0.12). ISS stage, cytogenetics, disease status prior to transplant, and maintenance were independent prognostic factors for OS. Conclusions: In patients with MM undergoing upfront transplant after VRD or VCD induction, no difference in outcomes was seen based on the induction therapy received after adjusting for other prognostic factors. As several MM patients with renal dysfunction are started on VCD, it is reassuring to see that VCD was not associated with inferior PFS, likely due to the eventual transition to maintenance therapy in the majority due to subsequent improvement of renal function. The use of maintenance treatment was uniformly associated with superior outcomes. Disclosures Sidana: Janssen: Consultancy. Kumar:Oncopeptides: Consultancy, Other: Independent Review Committee; IRC member; Kite Pharma: Consultancy, Research Funding; Genentech/Roche: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Celgene/BMS: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Dr. Reddy's Laboratories: Honoraria; Amgen: Consultancy, Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments, Research Funding; Janssen Oncology: 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; AbbVie: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Novartis: Research Funding; Sanofi: Research Funding; MedImmune: Research Funding; Karyopharm: Consultancy; BMS: Consultancy, Research Funding; Tenebio: Other, Research Funding; Genecentrix: Consultancy; Carsgen: Other, Research Funding; Cellectar: Other; Merck: Consultancy, Research Funding; Adaptive Biotechnologies: Consultancy. Giralt:Johnson & Johnson: 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, Research Funding; Actinuum: Other: Advisory board, Research Funding; Amgen: Other: Advisory Board, Research Funding; KITE: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; OMEROS: Research Funding; SPECTRUM Pharma: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Membership on an entity's Board of Directors or advisory committees, Research Funding; GSK: Membership on an entity's Board of Directors or advisory committees, Research Funding; PFIZER: Membership on an entity's Board of Directors or advisory committees, Research Funding; Jensenn: 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; MILTENYI: Research Funding; JAZZ Pharmaceutical: Membership on an entity's Board of Directors or advisory committees. Qazilbash:Janssen: Research Funding; Bioclinica: Consultancy; Amgen: Research Funding; Angiocrine: Research Funding; Bioline: Research Funding. Shah:GSK, Amgen, Indapta Therapeutics, Sanofi, BMS, CareDx, Kite, Karyopharm: Consultancy; BMS, Janssen, Bluebird Bio, Sutro Biopharma, Teneobio, Poseida, Nektar: Research Funding. D'Souza:Janssen: Consultancy; Akcea: Consultancy; Imbrium: Consultancy; Merck: Research Funding; Pfizer: Consultancy; Teneobio: Research Funding; Amgen: Research Funding.

Background: BCMA targeted immunotherapy has yielded promising results for relapsed/refractory multiple myeloma (RRMM). TNB-383B is a BCMA x CD3 bispecific T-cell redirecting antibody incorporating a unique anti-CD3 moiety that preferentially activates effector over regulatory T-cells and uncouples cytokine release from anti-tumor activity, as well as 2 heavy-chain-only anti-BCMA moieties for a 2:1 tumor associated antigen to CD3 stoichiometry. Results from the ongoing phase 1 dose escalation and expansion First-in-Human (FIH) study of TNB-383B are presented (NCT03933735). Methods: Eligible patients have RRMM and have been exposed to at least 3 prior lines of therapy including a proteasome inhibitor, an immunomodulatory drug, and an anti-CD38 monoclonal antibody. Patients have been treated with escalating doses of TNB-383B infused IV over 1-2 hours Q3W (without step-up dosing). The primary objectives are to determine the safety/tolerability and clinical pharmacology of TNB-383B and to identify the MTD/RP2D. The study used a 3+3 design for dose escalation, with additional patients enrolled on cleared dose levels. Patients on earlier dose cohorts were allowed to increase to the highest cleared dose with investigator consensus. Responses were assessed by IMWG criteria and Adverse Events (AEs) were graded according to CTCAE v5.0. Minimal residual disease (MRD) assessment was performed via NGS on bone marrow samples in patients achieving a complete response (CR). Results: As of 13 July 2020, 38 subjects have been dosed with TNB-383B (0.025 - 40 mg). Demographics and disease characteristics at study entry are summarized in Table 1. The most common Gr 3/4 AEs were anemia (6/38; 16%) and thrombocytopenia (5/38; 13%). The most common drug-related AEs were CRS (8/38; 21%) and headache (5/38; 13%). One case of Gr 2 CRS was observed at 0.075 mg; all other CRS events were seen at 5.4 mg and above. Cases of CRS were grade 1 (5/8) or 2 (3/8) and occurred only after the first dose of TNB-383B. All but 3 subjects were managed with fluids and acetaminophen (the other 3 received 1 dose each of tocilizumab). One DLT, Gr3 confusion that resolved within 6 hours without sequelae was seen at the 20 mg dose in an additional patient enrolled on this cohort. No IRRs were observed. Dose modification was necessary in 1 subject for Gr 3 neutropenia associated with CRS; the subject escalated to their full dose after tolerating subsequent doses without incident. 5 subjects died from their underlying disease during follow-up. 15 subjects discontinued treatment, all of them for progressive disease. Preliminary PK data support Q3W dosing of TNB-383B. Activity was observed in one patient each at 0.2 mg and 1.8 mg; at doses of 5.4 - 40 mg an ORR of 52% (12/23) was observed. Depth and duration of response are summarized in Table 2. Conclusions: TNB-383B is well tolerated at doses up to 40 mg, without the need for step/split dosing. A preliminary ORR of 52% (12/23) was observed at doses ≥ 5.4 mg, including deep (6 PR / 3 VGPR / 3 CR) and durable (up to 24 weeks) responses despite dosing only every 3 weeks. Enrollment into the dose escalation arm is ongoing; updated data will be presented at the meeting. Disclosures Rodriguez: BMS, Takeda, Amgen: Consultancy, Speakers Bureau. D'Souza:Amgen: Research Funding; Akcea: Consultancy; Pfizer: Consultancy; Teneobio: Research Funding; Imbrium: Consultancy; Merck: Research Funding; Janssen: Consultancy. Shah:GSK, Amgen, Indapta Therapeutics, Sanofi, BMS, CareDx, Kite, Karyopharm: Consultancy; BMS, Janssen, Bluebird Bio, Sutro Biopharma, Teneobio, Poseida, Nektar: Research Funding. Voorhees:Bristol-Myers Squibb: Other: Personal fees; Adaptive Biotechnologies: Other: Personal fees; Novartis: Other: Personal fees; Celgene: Other: Personal fees; Janssen: Other: Personal fees; Oncopeptides: Other: Personal fees; TeneoBio: Other: Personal fees; Levine Cancer Institute, Atrium Health: Current Employment. Buelow:Teneobio, Inc.: Current Employment, Current equity holder in private company. Kumar:Karyopharm: Consultancy; Tenebio: Other, Research Funding; Sanofi: Research Funding; Oncopeptides: Consultancy, Other: Independent Review Committee; IRC member; AbbVie: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Genecentrix: Consultancy; Dr. Reddy's Laboratories: Honoraria; Adaptive Biotechnologies: Consultancy; Merck: Consultancy, Research Funding; Takeda: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; BMS: Consultancy, Research Funding; Cellectar: Other; Janssen Oncology: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Carsgen: Other, Research Funding; Amgen: Consultancy, Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments, Research Funding; Celgene/BMS: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Novartis: Research Funding; MedImmune: Research Funding; Genentech/Roche: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Kite Pharma: Consultancy, Research Funding.

Introduction: Cytokine release syndrome (CRS) is an expected and potentially life-threatening toxicity associated with CAR T cell therapy. Idecabtagene vicleucel (ide-cel, bb2121), a BCMA-directed CAR T cell therapy, demonstrated promising efficacy in triple-class exposed and highly refractory patients with multiple myeloma in the pivotal phase 2 KarMMa study, with an overall response rate (ORR), complete response (CR) rate, median duration of response, and median progression-free survival of 73%, 33%, 10.7 months, and 8.8 months, respectively, across the target dose levels of 150−450 × 106 CAR+ T cells, and 82%, 39%, 11.3 months, and 12.1 months at the highest target dose of 450 × 106 CAR+ T cells (Munshi et al. J Clin Oncol. 2020;38[suppl, abstr]:8503). Identifying the patterns of CRS evolution, associations with baseline patient and disease characteristics, and the impact of interventions are key to understanding this adverse event in the context of ide-cel. In addition, a better understanding of lower-grade CRS, including maximum grade 1 events, is important as these are easier to manage and represent a lower burden on the healthcare system. We report results of an examination of CRS events in the KarMMa study. Methods: Patients in the KarMMa trial (NCT03361748) were required to have ≥3 prior regimens (including an immunomodulatory agent, a proteasome inhibitor, and an anti-CD38 antibody) and were refractory to their last regimen per International Myeloma Working Group criteria. Patients received ide-cel target doses of 150, 300, or 450 × 106 CAR+ T cells 2 days after lymphodepletion with cyclophosphamide 300 mg/m2 plus fludarabine 30 mg/m2 daily for 3 days. The primary endpoint was ORR. The key secondary endpoint was CR rate; other secondary endpoints included safety. CRS was graded according to criteria in Lee et al. (Blood. 2014;124:188). Patient characteristics and CRS management were examined by CRS grade to identify variables associated with higher-grade CRS. Management of CRS included tocilizumab 8 mg/kg with the addition of corticosteroids and other agents as needed. Results: Of 128 patients treated with ide-cel, 107 (84%) experienced CRS; 61 patients (48%) had maximum grade 1 and 46 (36%) had maximum grade ≥2 CRS (grade 2, n=39; grade 3, n=5; grade 4, n=1; and grade 5, n=1). Baseline characteristics were generally balanced among patients with maximum grade 1 and grade ≥2 (Table). Thirty patients (65%) with maximum grade ≥2 CRS progressed from initial grade 1 events, whereas 16 (35%) had initial grade ≥2. Median time to onset of CRS was the same (1 day) regardless of initial or maximum grade (Table). Median duration was 5.0 days in patients with maximum grade 1, 5.5 days in patients with maximum grade 2, and 11.0 days in patients with maximum grade ≥3 CRS. Median duration was shorter in patients with maximum grade 1 CRS than in those with initial grade 1 events that progressed to grade ≥2 (5.0 days vs 7.0 days). Most patients (83%) with maximum grade ≥2 CRS received at least 1 dose of tocilizumab and approximately one-third (35%) received corticosteroids, compared with 48% and 5%, respectively, of patients with maximum grade 1 CRS. A higher percentage of patients with initial grade ≥2 vs initial grade 1 CRS received multiple doses of tocilizumab (50% vs 37%) or at least 1 dose of corticosteroids (50% vs 27%). Conclusions: Almost half of the patients treated with ide-cel experienced maximum grade 1 CRS. Baseline disease and patient characteristics were similar among patients experiencing grade 1 and higher-grade CRS events. CRS was effectively managed with tocilizumab and corticosteroids, and more frequent use of these interventions in patients with grade ≥2 CRS was not associated with prolonged CRS events. The time to onset of CRS was predictable and equivalent in patients with maximum grade 1 and higher-grade CRS events. Duration of CRS was similar in patients with maximum grade 1 and 2 but was longer in patients with maximum grade ≥3 CRS. These data demonstrate the feasible management of CRS and thus confirm the tolerability of ide-cel in patients with relapsed and refractory multiple myeloma. Table 1 Disclosures Kansagra: Karyopharm: Honoraria; Pharmacyclics: Honoraria; Alnylam: Honoraria; BMS: Honoraria; GSK: Honoraria; Janssen: Honoraria; Takeda: Honoraria; Sanofi: Honoraria. Lin:Novartis: Consultancy; Sorrento: Consultancy, Membership on an entity's Board of Directors or advisory committees; Gamida Cells: Consultancy; Janssen: Consultancy, Research Funding; Kite, a Gilead Company: Consultancy, Research Funding; Vineti: Consultancy; Takeda: Research Funding; Celgene: Consultancy, Research Funding; Bluebird Bio: Consultancy, Research Funding; Juno: Consultancy; Legend BioTech: Consultancy; Merck: Research Funding. Berdeja:BMS: Consultancy, Research Funding; Cellularity: Research Funding; Lilly: Research Funding; Amgen: Consultancy, Research Funding; Abbvie: Research Funding; Poseida: Research Funding; Celgene: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Bioclinica: Consultancy; Bluebird: Research Funding; Prothena: Consultancy; Legend: Consultancy; Kesios: Research Funding; Kite Pharma: Consultancy; Karyopharm: Consultancy; Constellation: Research Funding; Novartis: Research Funding; Teva: Research Funding; Servier: Consultancy; Takeda: Consultancy, Research Funding; CRISPR Therapeutics: Consultancy, Research Funding; Glenmark: Research Funding; EMD Sorono: Research Funding; Vivolux: Research Funding; Genentech, Inc.: Research Funding; CURIS: Research Funding; Acetylon: Research Funding. Shah:GSK, Amgen, Indapta Therapeutics, Sanofi, BMS, CareDx, Kite, Karyopharm: Consultancy; BMS, Janssen, Bluebird Bio, Sutro Biopharma, Teneobio, Poseida, Nektar: Research Funding. Oriol:Celgene: Consultancy, Speakers Bureau; Amgen: Consultancy, Speakers Bureau; Janssen: Consultancy. Yakoub-Agha:Celgene: Honoraria; Jazz Pharmaceuticals: Honoraria; Novartis: Honoraria; Gilead/Kite: Honoraria, Other: travel support; Janssen: Honoraria. Einsele:Amgen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding, Speakers Bureau; Novartis: Honoraria, Speakers Bureau; Takeda: Consultancy, Honoraria, Speakers Bureau; Sanofi: Consultancy, Honoraria, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau; GlaxoSmithKline: Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau. Rambaldi:BMS/Celgene: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); University of Milan: Current Employment; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support of parent study and funding of editorial support. Received travel support., Research Funding; Omeros: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company). Advisory board and speaker fees from Pfizer.; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company). Research grant from Amgen Inc.; Sanofi: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Astellas: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support from Gilead.. Truppel-Hartmann:bluebird bio, Inc: Current Employment, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); F. Hoffmann La Roche: Current equity holder in publicly-traded company, Ended employment in the past 24 months. Rowe:Bristol-Myers Squibb: Current Employment. Wang:Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Agarwal:Bristol-Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Campbell:BMS: Current Employment, Current equity holder in publicly-traded company. Lonial:Takeda: Consultancy, Other: Personal fees, Research Funding; Amgen: Consultancy, Honoraria, Other: Personal fees; Novartis: Consultancy, Honoraria, Other: Personal fees; Millennium: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Other: Personal fees, Research Funding; BMS: Consultancy, Honoraria, Other: Personal fees, Research Funding; Onyx: Honoraria; Genentech: Consultancy; Karyopharm: Consultancy; Sanofi: Consultancy; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees; Merck: Consultancy, Honoraria, Other: Personal fees; JUNO Therapeutics: Consultancy; GSK: Consultancy, Honoraria, Other: Personal fees; Abbvie: Consultancy.

Introduction: Chimeric antigen receptor (CAR) T cell therapy directed against B-cell maturation antigen (BCMA) has shown promising results for the treatment of relapsed refractory multiple myeloma (RRMM). bb21217 is an anti-BCMA CAR T cell therapy that uses the same CAR molecule as idecabtagene vicleucel (bb2121), but adds the PI3K inhibitor bb007 during ex vivo culture to enrich the drug product (DP) for memory-like T cells, thereby reducing the proportion of highly differentiated or senescent T cells. To investigate whether DP properties correlate with clinical outcomes including duration of response (DOR), we conducted extensive molecular characterization of patient DPs. Methods: CRB-402 (NCT03274219) is an ongoing, multi-center phase 1 dose escalation trial of bb21217 in RRMM patients who received ≥3 prior regimens, including proteasome inhibitor and immunomodulatory agent, or are double-refractory to both classes. In the expansion cohort, patients additionally required prior exposure to an anti-CD38 antibody and were required to be refractory to last line. Planned enrollment is 74 patients, including 50 in the expansion cohort. Patients undergo lymphodepletion with fludarabine (30 mg/m2) and cyclophosphamide (300 mg/m2) daily for 3 days, then receive a single infusion of bb21217 at 150, 300 or 450 x 106 CAR+ T cells. The primary outcome measure is incidence of adverse events (AEs), including dose-limiting toxicities (DLTs). Additional outcome measures include overall response rate and DOR by IMWG Uniform Response Criteria. We profiled DP and apheresis starting material (PBMC) by RNAseq and cyTOF and correlated expression of memory/senescence markers from apheresis to DP with clinical outcomes, including DOR. Results: Asof March 1, 2020, 46 patients (median age 62 [33-74]) received bb21217, 24 in escalation (12 at 150, 6 at 300 and 6 at 450) and 22 in expansion (8 at 300 and 14 at 450); median follow up for all patients is 8.5 (&lt;1-29) months. Patients had a median of 6 (3-17) prior lines of therapy with 26/46 (57%) triple refractory. Cytokine release syndrome (CRS) developed in 31/46 (67%) patients and included one death (14 G1, 15 G2, 1 G3 and 1 G5). Median time to first onset was 3 days (1-20); tocilizumab (18 pts) +/- corticosteroids (6 pts) was used to manage CRS. Ten (22%) patients developed neurotoxicity [5 G1, 2 G2, 2 G3, 1 G4] with median time to first onset of 7 (3-24) days. Response was assessed per investigator for 44 patients with ≥ 2 months of follow up or PD/death within 2 months. Twenty-four (55%) patients had confirmed response per IMWG criteria including 8 (18%) with ≥CR and 13 (30%) with VGPR. Median time to CR was 2.5 (1-24) months. The median DOR was 11.9 (95% CI: 8.1-17.0) months across target dose levels of 150-450 x106 CAR+ T cells. The 450 target dose was selected as the RP2D and dose expansion is ongoing. bb21217 DPs from 44 patients were characterized. Paired analysis of T cells from PBMC and DP showed bb21217 DP is significantly enriched for memory-like T cells (LEF1+, CD27+, CCR7+) and depleted of highly differentiated or senescent CD57+ T cells. Patients with DPs most enriched for early memory markers (LEF1+, CCR7+ and CD27+) and with low expression of effector/exhaustion markers (EOMES+, GZMA+, CD57+) were more likely to have higher peak CAR+ T cell expansion. To evaluate the association of these DP markers with DOR, we split the 24 responders (≥PR) on median marker expression (high vs low) and analyzed DOR in these exploratory subgroups. High CD127 expression, associated with long-lasting memory T cell formation, was positively correlated with DOR, while multiple markers associated with differentiated T cells (e.g. EOMES+, TBET+) were negatively correlated with DOR. Conclusions: The adverse events observed are consistent with known toxicities of CAR T cell therapies. Initial efficacy results with bb21217 are encouraging, with 48% of patients treated across target dose levels of 150-450 obtaining ≥VGPR. The presence of T cell markers associated with memory and the absence of T cells markers associated with differentiation/senescence in DP correlated positively with peak expansion and DOR. These preliminary correlative data support the mechanistic hypothesis that enrichment for memory like T cells in bb21217 DP may result in improved clinical outcomes. Data for approximately 14 additional patients at the 450 target dose will be presented. Disclosures Alsina: Janssen: Honoraria, Speakers Bureau; Celgene: Consultancy, Honoraria; Amgen: Honoraria, Speakers Bureau; BMS: Consultancy, Research Funding. Shah:GSK, Amgen, Indapta Therapeutics, Sanofi, BMS, CareDx, Kite, Karyopharm: Consultancy; BMS, Janssen, Bluebird Bio, Sutro Biopharma, Teneobio, Poseida, Nektar: Research Funding. Raje:Janssen: Consultancy; Celgene: Consultancy; Immuneel: Membership on an entity's Board of Directors or advisory committees; Caribou: Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy; Astrazeneca: Consultancy; Bluebird, Bio: Consultancy, Research Funding; Karyopharm: Consultancy; BMS: Consultancy; Amgen: Consultancy. Jagannath:Karyopharm: Consultancy, Honoraria; Legend Biotech: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; BMS: Consultancy, Honoraria. Madduri:Janssen: Consultancy; BMS: Consultancy; Takeda: Consultancy; Legend: Consultancy; Sanofi: Consultancy; GSK: Consultancy; Kinevant: Consultancy; Foundation Medicine: Consultancy. Kaufman:Janssen: Consultancy, Honoraria; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees; Tecnopharma: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; AbbVie: Consultancy; TG Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sanofi/Genyzme: Consultancy, Honoraria. Siegel:Amgen: Consultancy, Honoraria, Speakers Bureau; Merck: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; BMS: Consultancy, Honoraria, Speakers Bureau; Takeda: Consultancy, Honoraria, Speakers Bureau; Karyopharma: Consultancy, Honoraria; Celulatiry: Consultancy. Munshi:BMS: Consultancy; OncoPep: Consultancy, Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties; C4: Current equity holder in private company; Janssen: Consultancy; Adaptive: Consultancy; Legend: Consultancy; Amgen: Consultancy; AbbVie: Consultancy; Karyopharm: Consultancy; Takeda: Consultancy. Lin:Novartis: Consultancy; Celgene: Consultancy, Research Funding; Bluebird Bio: Consultancy, Research Funding; Juno: Consultancy; Legend BioTech: Consultancy; Merck: Research Funding; Takeda: Research Funding; Gamida Cells: Consultancy; Sorrento: Consultancy, Membership on an entity's Board of Directors or advisory committees; Vineti: Consultancy; Janssen: Consultancy, Research Funding; Kite, a Gilead Company: Consultancy, Research Funding. 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. Timm:bluebird bio: Current Employment, Current equity holder in publicly-traded company. Turka:bluebird bio: Current Employment. Mao:bluebird bio: Current Employment, Current equity holder in publicly-traded company. Martin:BMS: Current Employment, Current equity holder in publicly-traded company. Campbell:BMS: Current Employment, Current equity holder in publicly-traded company. Hege:Arcus Biosciences: Divested equity in a private or publicly-traded company in the past 24 months; Mersana Therapeutics: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; BMS: Current Employment, Current equity holder in publicly-traded company, Other: Travel, accommodations, expenses, Patents & Royalties: Numerous, Research Funding. Bitter:Novartis AG, Predicant Biosciences, Biospect, F Hofmann-La Roche: Ended employment in the past 24 months; bluebird bio: Current Employment, Current equity holder in publicly-traded company; Novartis: Ended employment in the past 24 months, Patents & Royalties. Petrocca:bluebird, bio: Current Employment, Current equity holder in publicly-traded company. Berdeja:Celgene: Consultancy, Research Funding; Cellularity: Research Funding; Constellation: Research Funding; CRISPR Therapeutics: Consultancy, Research Funding; CURIS: Research Funding; EMD Sorono: Research Funding; Takeda: Consultancy, Research Funding; Servier: Consultancy; Teva: Research Funding; Prothena: Consultancy; Poseida: Research Funding; Novartis: Research Funding; Lilly: Research Funding; Legend: Consultancy; Kite Pharma: Consultancy; Kesios: Research Funding; Karyopharm: Consultancy; Janssen: Consultancy, Research Funding; Glenmark: Research Funding; Genentech, Inc.: Research Funding; BMS: Consultancy, Research Funding; Bioclinica: Consultancy; Bluebird: Research Funding; Acetylon: Research Funding; Amgen: Consultancy, Research Funding; Abbvie: Research Funding; Vivolux: Research Funding.

AbstractWe studied 2,528 patients with upfront autologous haematopoietic cell transplantation (AHCT) for multiple myeloma (MM) from 2008–2017 to develop a prognostic model to predict outcomes. High‐risk cytogenetics included t(4;14), t(14;16), t(14;20), del13q on karyotype, del17p, +1q or 1pdel. A Cox model identified factors prognostic of progression/relapse in a training subset (n = 1,246). A weighted score using these factors was assigned to a validation cohort (n = 774). Presence of high‐risk cytogenetics [hazard ratio, (HR) 1·68 (1·3–2·17)] and pre‐AHCT bone marrow plasma cells (BMPCs) ≥10% [1·68 (1·33–2·12)] were assigned 4 points each; albumin at diagnosis <3·5 g/dl [1·31 (1·07–1·61)] 2; standard risk cytogenetics 1, and no cytogenetics abnormality, BMPCs <10% at AHCT and albumin ≥3·5 g/dl at diagnosis 0 points each. A three‐category system with low risk (0–3), intermediate risk (4–8) and high risk (9–10) showed 3‐year progression‐free survival in the low vs. intermediate vs. high risk of 58% (95% CI: 52–63) vs. 49% (95% CI: 43–56) vs. 31% (95% CI: 12–51), P < 0.001 respectively, and 3‐year OS in low vs. intermediate vs. high risk of 88% (95% CI: 84–91) vs. 81% (95% CI: 76–86) vs. 64% (95% CI: 39–80); P < 0·001. Our prognostic scoring system can identify MM patients at risk for early relapse after AHCT.