Biological correlative analyses and updated clinical data of ciltacabtagene autoleucel (cilta-cel), a BCMA-directed CAR-T cell therapy, in lenalidomide (len)-refractory patients (pts) with progressive multiple myeloma (MM) after 1–3 prior lines of therapy (LOT): CARTITUDE-2, cohort A

8020

Background: Cohort A of the multicohort phase 2 CARTITUDE-2 (NCT04133636) study is evaluating cilta-cel safety and efficacy in pts with MM who received 1–3 prior LOT and were len-refractory – a difficult-to-treat population with poor prognosis. We present updated results. Methods: Pts had progressive MM after 1–3 prior LOT, including a PI and IMiD, were len-refractory, and had no prior exposure to BCMA-targeting agents. A single cilta-cel infusion (target dose 0.75×106 CAR+ viable T cells/kg) was given post lymphodepletion. Safety and efficacy were assessed, and the primary endpoint was MRD negativity at 10-5. Management strategies were implemented to minimize risk of movement/neurocognitive AEs (MNTs). Pharmacokinetic (PK) analyses (Cmax and Tmax of CAR+ T-cell transgene levels in blood) are being conducted, as well as analyses of levels of CRS-related cytokines (eg, IL-6) over time, peak levels of cytokines by response and CRS, association of cytokine levels with ICANS, and CAR+ T cell CD4/CD8 ratio by response, CRS, and ICANS. Results: As of January 2022 (median follow-up [MFU] 17.1 mo [range 3.3–23.1]), 20 pts (65% male; median age 60 y [range 38–75]) received cilta-cel. Pts received a median of 2 (range 1–3) prior LOT, and a median of 3.5 y (range 0.7–8.0) since MM diagnosis. 95% were refractory to last LOT, and 40% were triple-class refractory. ORR was 95%, 90% achieved CR or better, and 95% had ≥VGPR. Median times to first and best response were 1.0 mo (range 0.7–3.3) and 2.6 mo (range 0.9–13.6), respectively. 16 pts were MRD-evaluable, all of whom achieved MRD negativity at 10-5. Median DOR was not reached and 12-mo event-free rate was 79%. The 12-mo PFS rate was 75%. Median time to onset of CRS was 7 d (range 5–9) and occurred in 95% of pts (gr 3/4: 10%), with median duration of 3 d (range 2–12). Neurotoxicity occurred in 30% of pts (5 gr 1/2; 1 gr 3/4). 3 pts (15%) had ICANS (all gr 1/2); 1 pt had gr 2 facial paralysis. No MNTs were seen. 1 death occurred due to COVID-19 (assessed as tx-related by the investigator), 2 due to progressive disease, and 1 due to sepsis (not related to tx). Preliminary PK analyses indicate that peak expansion of CAR-T cells occurred at d 10.5 (range 8.7–42.9) and median persistence was 153.5 d (range 57.1–336.8). Conclusions: At a longer MFU of 17.1 mo, a single cilta-cel infusion led to deepening and durable responses in pts with MM who had 1–3 prior LOT and were len-refractory. Follow-up is ongoing. Updated and in-depth PK, cytokine, and CAR-T subset analyses and clinical correlation will be presented and provide novel insights into biological correlates of efficacy and safety in this pt population. This pt population is being further evaluated in the CARTITUDE-4 study (NCT04181827), which has concluded enrollment. Clinical trial information: NCT04133636.

Health-related quality of life (HRQoL) in patients with relapsed/refractory multiple myeloma (RRMM) receiving real-life current standard of care (SOC) in the LocoMMotion study

8030

Background: Evaluation of patient (pt)-reported outcomes provides insight into how real-life SOC treatments (tx) affect HRQoL for pts with RRMM. LocoMMotion (NCT04035226) is the first prospective, multinational study of real-life SOC in triple-class exposed pts with RRMM. Here, we present measures of symptoms, functioning, and overall HRQoL. Methods: LocoMMotion is a prospective, noninterventional study across 76 sites (63 European; 13 US). Pts had received ≥3 prior lines of therapy (LOT) or were refractory to PI and IMiD; received PI, IMiD, and anti-CD38 mAb; and had disease progression during/after last LOT. Real-life SOC tx were defined as those used in local clinical practice. The questionnaires were EORTC QLQ-C30, 4 single items from EORTC QLQ-MY20, and EQ 5D-5L. HRQoL was assessed at baseline (BL), day 1 of each tx cycle, end of tx visit, and during the follow-up period (every 4 weeks). Improvement compared to BL health status was evaluated using established thresholds. Within-group change was assessed using mixed models for repeated measures. Results: Questionnaire completion for pts in the LocoMMotion study (N=248; 54.4% male; median age 68 yrs; median 4.0 [range, 1–20] cycles of SOC) was 75.6% during SOC tx. Most pts did not achieve meaningful improvement in PRO scores, defined by a literature-based minimally important difference of 10 points in mean score. This was most pronounced in pain symptoms (62% of pts had no meaningful improvement during the first 3 months of tx; 55% had no improvement during full tx duration). For the overall population, the least square (LS) mean changes from BL during SOC tx and subsequent LOT are described (Table). Pts who achieved very good partial response and better during SOC tx had greater improvement in PRO scores, including in LS mean change for pain score (-14.9 [95% confidence interval (CI): -22.9, -7.0]). Conclusions: In this first prospective study of real-life current SOC in triple-class exposed pts, limited gains in HRQoL were reported, most notably in pain symptoms. There is an urgent need for effective therapies that can help pts achieve deep responses and delay disease progression, as these are associated with improved HRQoL. Clinical trial information: NCT04035226. [Table: see text]

Subgroup analyses in patients with relapsed/refractory multiple myeloma (RRMM) receiving real-life current standard of care (SOC) in the LocoMMotion study

8031

Background: Patients (pts) with RRMM who are triple-class exposed (proteasome inhibitor [PI], immunomodulatory drug [IMiD], and anti-CD38 monoclonal antibody [mAb]) have an urgent and currently unmet clinical need. LocoMMotion (NCT04035226) is the first prospective multinational study of real-life SOC in triple-class exposed pts with RRMM. Here we present efficacy in subgroups of pts treated with SOC therapies in the LocoMMotion study. Methods: LocoMMotion is a noninterventional study across 76 sites (63 European; 13 US). Eligible pts had received ≥3 prior lines of therapy (LOT) or were double refractory to a PI and an IMiD; received a PI, an IMiD, and anti-CD38 mAb; and had disease progression during/after their last LOT. Real-life SOC treatments were defined as those used in local clinical practice. Responses and disease progression were assessed by response review committee, per IMWG criteria. Subgroups were defined by baseline (BL) characteristics: age, Eastern Cooperative Oncology Group performance status (ECOG PS), renal function, ISS stage, presence of extramedullary plasmacytoma, LDH level, % of bone marrow plasma cells, number of prior LOT, triple-class or penta-drug exposure, and refractoriness. Results: As of May 21, 2021 (median follow-up 11.0 mo), 248 pts were enrolled and treated with median 4.0 (range, 1–20) cycles of SOC therapy. Evaluation of efficacy outcomes in subgroups demonstrated that refractoriness to 3 classes of antimyeloma therapy, presence of extramedullary plasmacytomas, high LDH, and ECOG PS ≥1 were associated with generally worse outcomes, compared with pts who did not have these characteristics (Table). Overall response rate (ORR) ranged from 20.0–43.1% across all subgroups. Age and number of prior LOT did not have an impact on efficacy outcomes. Conclusions: Subgroup analyses of this first prospective study of real-life SOC tx in triple-class exposed pts with RRMM indicate that specific pt and disease characteristics were associated with poor outcomes. Triple-class refractory and non-triple-class refractory pts had poor outcomes, although the latter had longer median progression-free survival (PFS). These findings should be considered when planning bridging strategy for CAR-T therapy. Clinical trial information: NCT04035226. [Table: see text]

Biological correlative analyses and updated clinical data of ciltacabtagene autoleucel (cilta-cel), a BCMA-directed CAR-T cell therapy, in patients with multiple myeloma (MM) and early relapse after initial therapy: CARTITUDE-2, cohort B

8029

Background: In cohort B of the multicohort phase 2 CARTITUDE-2 (NCT04133636) study, the efficacy and safety of cilta-cel are being evaluated in patients (pts) with MM who had early relapse after initial therapy. These pts have functionally high-risk disease, with early relapse post autologous stem cell transplantation (ASCT) being a poor prognostic factor and representing an unmet medical need. We present updated results. Methods: Eligible pts had MM, received 1 prior LOT (PI and IMiD required), had disease progression per IMWG (either ≤12 mo after ASCT or ≤12 mo after start of anti-myeloma therapy for pts who did not undergo ASCT), and were tx-naive to CAR-T/anti-BCMA therapies. A single cilta-cel infusion (target dose 0.75×106 CAR+ viable T cells/kg) was given post lymphodepletion. Safety and efficacy were assessed, and the primary endpoint was MRD negativity at 10-5. Management strategies were implemented to minimize risk of movement/neurocognitive AEs (MNTs). Pharmacokinetic (PK) analyses (Cmax and Tmax of CAR+ T-cell transgene levels in blood) are being conducted, as well as analyses of levels of CRS-related cytokines (eg, IL-6) over time, peak levels of cytokines by response and CRS, association of cytokine levels with ICANS, and CAR+ T cell CD4/CD8 ratio by response, CRS, and ICANS. Results: As of January 2022, 19 pts (median age 58.0 y [range 44–67]; 74% male; median follow-up 13.4 mo [range 5.2–21.7]) received cilta-cel. 79% of pts received prior ASCT. ORR was 100.0%, 90% achieved CR or better, and 95% achieved ≥VGPR. Median time to first response and best response were 0.95 mo (range 0.9–9.7) and 5.1 mo (range 0.9–11.8), respectively. Of pts who were MRD-evaluable (n = 15), 14 (93%) achieved MRD 10-5 negativity during this study. Median DOR was not reached and 12-mo event-free rate was 88.9%. The 12-mo PFS rate was 90%. Median time to onset of CRS was 8 d (range 5–11) and occurred in 16 (84.2%) pts (1 gr 4). CRS resolved in all pts. ICANS (gr 1) occurred in 1 pt; MNT (gr 3) occurred in 1 pt, previously reported. 1 pt died post cilta-cel due to PD at d 158. Preliminary PK analyses indicate that peak expansion of CAR-T cells occurred on d 13.1 (range 8.96–209.9) and median persistence was 76.9 d (range 40.99–221.8). Conclusions: A single cilta-cel infusion led to deep and durable responses in a functionally high-risk pt population who experienced early clinical relapse/tx failure to initial therapy, with a manageable safety profile. In this pt population with ineffective or insufficient response to ASCT, cilta-cel led to responses. Responses continue to deepen, and follow-up is ongoing. Updated and in-depth PK, cytokine, and CAR-T subset analyses and clinical correlation will be presented and provide novel insights into biological correlates of efficacy and safety in this pt population. Clinical trial information: NCT04133636.

Cilta-cel versus conventional treatment in patients with relapse/refractory multiple myeloma

8030

Background: CARTITUDE-1 is a single arm study of Ciltacabtagene autoleucel (cilta-cel; JNJ-68284528) anti-BCMA CAR-T cell therapy in US patients (pts) with relapsed multiple myeloma (RRMM) refractory to both IMiD and proteasome inhibitor (PI) or with at least 3 prior lines of therapy and previously exposed to anti-CD38 monoclonal antibody (MoAb). While recently reported efficacy results of cilta-cel were encouraging, it is unknown how they compare with similar pts receiving conventional (non CAR-T) treatment. Methods: We utilized a contemporary US-based dataset of pts with MM refractory to anti-CD38 MoAb (MAMMOTH) to identify pts who would meet eligibility for CARTITUDE-1 and who received conventional therapy. We analyzed the intent-to-treat population (ITT) in CARTITUDE-1, defined as pts who underwent apheresis (N=113) and a modified ITT population (mITT) defined as subset of pts who received cilta-cel at the RP2D (N=97). From the MAMMOTH dataset, we identified a population corresponding to CARTITUDE-1 ITT (N=190) and a mITT population, pts without death or progression within 47 days (median time between apheresis and cilta-cel infusion) from onset of therapy (N=122). We calculated propensity scores (PS) with demographics, N of prior therapies, cytogenetics and refractoriness to MM agents as covariates. An analyst blinded to outcomes performed nearest neighbor 1:1 PS matching. We analyzed overall response rate (ORR), progression-free (PFS) and overall survival (OS) for ITT and mITT in CARTITUDE-1 vs matching MAMMOTH cohorts. Results: Ninety-five ITT (75 received bridging therapy, 82 received cilta-cel) and 69 mITT (54 received bridging) CARTITUDE-1 pts matched MAMMOTH pts (Table). Among the pts in the MAMMOTH ITT cohort 34% received pomalidomide, 24% anti-CD38 MoAb, 19% carfilzomib and 35% cytotoxic chemotherapy in next therapy. ORR in the ITT cohorts was higher in CARTITUDE-1 (84% vs. 28%). Compared to their MAMMOTH counterparts, pts in CARTITUDE-1 ITT cohort had improved PFS (12 mo. 73% vs. 12%) and OS (12 mo. 83% vs 39%). Between the mITT cohorts, CARTITUDE-1 pts had superior ORR (96% vs. 30%), PFS (12 mo 79% vs. 15%) and OS (12 mo. 88% vs. 41%). Conclusions: In pts with RRMM beyond therapy with IMID, PI, and anti-CD38 MoAb, treatment with cilta-cel is associated with higher response rate and superior PFS and OS when compared to conventional treatment.[Table: see text]

Comparison of outcomes with ciltacabtagene autoleucel (cilta-cel) in CARTITUDE-1 versus real-world standard of care (RW SOC) for patients (pts) with triple-class exposed relapsed/refractory multiple myeloma (RRMM)

8045

Background: Pts with RRMM who are triple-class exposed (to immunomodulatory drugs [IMiDs], proteasome inhibitors [PIs] and an anti-CD38 antibody) cycle through multiple salvage regimens with progressively worse outcomes. CARTITUDE-1 (NCT03548207) is a single-arm phase 1b/2 study evaluating cilta-cel, a chimeric antigen receptor T-cell therapy with 2 B-cell maturation antigen–targeting single-domain antibodies, in pts with RRMM who received ≥3 prior lines of therapy (LOT) or were double refractory to an IMiD and PI, were triple-class exposed, had ECOG score of 0 or 1, and had disease progression ≤12 mo after the last LOT. Here, we compare efficacy outcomes for pts who received cilta-cel in CARTITUDE-1 (N = 97) with pts treated with SOC in a synthetic cohort from RW clinical practice. Methods: The Flatiron database, a primarily US community-based MM registry (Sep 2020 data cutoff), was used to identify a RW pt cohort who met CARTITUDE-1 (Sep 2020 data cutoff) eligibility criteria, including organ function. Progression-free/overall survival (PFS/OS) were compared between the cilta-cel–treated US pts and RW SOC cohort, using inverse probability of treatment (tx) weighting (IPTW) propensity scores adjusting for unbalanced baseline covariates of prognostic significance. Sensitivity analyses were conducted using multivariate Cox regression models and propensity score matching. Results: Baseline characteristics were similar between the 2 cohorts after propensity score weighting (Table). SOC tx regimens in the RW cohort primarily included pomalidomide (33%), carfilzomib (32%), daratumumab (13%), elotuzumab (16%), and ixazomib (8%). Pts had improved PFS and OS with cilta-cel (N = 97; median follow-up 12.4 mo) vs RW SOC (N = 196; median follow-up 9.2 mo) with a reduction in risk of progression/death and death by 84% and 78%, respectively (Table). Cilta-cel treatment benefit was robust across sensitivity analyses. Conclusions: Cilta-cel shows significantly better efficacy outcomes over RW SOC for PFS and OS, highlighting its potential as an effective tx option in pts with triple-class exposed RRMM. Clinical trial information: NCT03548207. [Table: see text]

LocoMMotion: A prospective, non-interventional, multinational study of real-life current standards of care in patients with relapsed/refractory multiple myeloma (RRMM) receiving ≥3 prior lines of therapy

8041

Background: Multiple myeloma (MM) remains incurable despite advances in medical treatment that have improved survival. Even with these improvements, most patients with MM eventually progress through standard drug classes of proteasome inhibitors (PIs), immunomodulatory drugs (IMiDs), anti-CD38 monoclonal antibodies (mAbs), and others. There are currently no prospective data on real-world standard-of-care (SOC) in patients who progress after PIs, IMiDs, and anti-CD38 mAbs. Here, we present interim results from LocoMMotion (NCT04035226), the first prospective efficacy and safety study of real-life SOC in patients with RRMM. Methods: Eligible patients (aged ≥18 years [y]) with a diagnosis of MM were enrolled between August 2019 and October 2020 from 75 sites across 9 European countries and the US. Patients were included if they received ≥3 prior lines of therapy or were double-refractory to a PI and IMiD, had measurable disease at screening, received at least a PI, an IMiD, and anti-CD38 mAb with documented progressive disease since their last line of therapy, and had an ECOG PS score of 0 or 1. Responses were assessed per International Myeloma Working Group response criteria. A Response Review Committee assessed the overall response rate (ORR, primary objective) of real-life current SOC. Secondary objectives of the study included additional efficacy and safety evaluation of real-life SOC. Results: The data cut-off was November 4, 2020 for the first interim analysis of 225 patients with a median follow-up of 3.7 months (range: 0–12.7), 22 (9.8%) patients were from the US and 203 (90.2%) were from Europe. Median age was 68 y (range: 41–89), 124 (55.1%) were male, 162 (72.0%) had a baseline ECOG PS score of 1, and median time since initial MM diagnosis was 6.0 y (range: 0.3–22.8). Patients had received a median of 4.0 (range: 2–13) prior lines of therapy; all patients were triple-class exposed, 166 (73.8%) were triple-class refractory, and 208 (92.4%) were refractory to last line of therapy. The ORR with real-life SOC salvage therapy was 20.1% (95% CI: 15.0–26.0) in the response-evaluable population (n = 219). Treatment-emergent adverse events (TEAEs) were reported in 148 (65.8%) patients, 95 (42.2%) were grade ≥3. The most common grade ≥3 TEAEs were anemia, thrombocytopenia, and neutropenia. Fifteen deaths (6.7%) occurred due to TEAEs during the study. Treatment is ongoing in 121 (53.8%) patients. Conclusions: The interim results of this first, prospective study of real-life SOC treatment in heavily pretreated, triple-class exposed patients with RRMM demonstrate that patients continue to progress after multiple lines of therapy and have poor outcomes. Therefore, there is a need for new treatments with novel mechanisms of action for this patient population. Clinical trial information: NCT04035226.

CARTITUDE-2: Efficacy and safety of ciltacabtagene autoleucel (cilta-cel), a BCMA-directed CAR T-cell therapy, in patients with progressive multiple myeloma (MM) after one to three prior lines of therapy

8013

Background: Cilta-cel is a CAR T-cell therapy expressing two BCMA-targeting, single-domain antibodies designed to confer avidity. The multicohort, phase 2 CARTITUDE-2 study (NCT04133636) is evaluating cilta-cel safety and efficacy in various clinical settings for patients (pts) with MM and exploring suitability of outpatient administration. Here, we present initial results from Cohort A. Methods: Cohort A pts had progressive MM after 1–3 prior lines of therapy (LOT), including a proteasome inhibitor (PI) and immunomodulatory drug (IMiD), were lenalidomide refractory, and had no prior exposure to BCMA-targeting agents. A single cilta-cel infusion (target dose: 0.75×106 CAR+ viable T cells/kg) was given 5–7 days (d) after start of lymphodepletion (daily cyclophosphamide [300 mg/m2] and fludarabine [30 mg/m2] for 3 d). The primary objective was minimal residual disease (MRD) 10-5 negativity. Secondary outcomes were response rates (IMWG) and safety (per CTCAE; CRS and ICANS by ASTCT). Results: As of Feb 2021 data cutoff (median follow-up: 5.8 months [mo]; range: 2.5–9.8 mos), 20 pts (65% male; median age 60 years [38–75]) received cilta-cel; 1 pt was treated in an outpatient setting. Pts received a median of 2 prior LOT (1–3); 12 pts received < 3 prior lines and 8 received 3 prior LOT. All pts were exposed to PI, IMiD, and dexamethasone, 95% to alkylating agents, and 65% to daratumumab. The majority (95%) were refractory to the last LOT; 40% were triple refractory. Overall response rate was 95% (95% CI: 75–100), 75% (95% CI: 51–91) achieved stringent CR/CR, and 85% (95% CI: 62–97) achieved ≥VGPR. Median time to first response was 1.0 mo (0.7–3.3); median time to best response was 1.9 mo (0.9–5.1). Median duration of response was not reached. All pts (n = 4) with MRD-evaluable samples at 10-5 at data cutoff were MRD-negative. Hematologic AEs ≥20% were neutropenia (95%; gr 3/4: 90%), thrombocytopenia (80%; gr 3/4: 35%), anemia (65%; gr 3/4: 40%), lymphopenia (60%; gr 3/4: 55%), and leukopenia (55%; all gr 3/4). CRS occurred in 85% of pts; 10% were gr 3/4. Median time to CRS onset was 7 d (5–9), with a median duration of 3.5 d (2–11). CAR T-cell neurotoxicity occurred in 20% of pts (all gr 1/2). Three pts had ICANS (1 gr 1; 2 gr 2); median time to onset was 8 d (7–11) and median duration was 2 d (1–2). One pt had gr 2 facial paralysis; time to onset was 29 d with a duration of 51 d. One death occurred due to COVID-19 (assessed as treatment (tx)-related by investigator). Safety profile was manageable in the pt treated in an outpatient setting. Conclusions: A single cilta-cel infusion at the recommended phase 2 dose led to early and deep responses with a manageable safety profile in pts with MM who had 1–3 prior LOT. Updated efficacy and safety findings will inform suitability of outpatient tx in this and other cohorts of CARTITUDE-2 as well as the CARTITUDE-4 study. Clinical trial information: NCT04133636.

Safety and efficacy of daratumumab-based regimens in elderly (≥75 y) patients (Pts) with relapsed or refractory multiple myeloma (RRMM): Subgroup analysis of POLLUX and CASTOR

8033

Background: Daratumumab (D) plus lenalidomide and dexamethasone (Rd; POLLUX) or with bortezomib and dexamethasone (Vd; CASTOR) demonstrated prolonged PFS and tolerability compared with Rd and Vd alone, respectively, in RRMM pts. We examined the safety and efficacy profiles of DRd and DVd in elderly (≥75 y) pts from these phase 3 studies. Methods: Pts with ≥1 prior line of therapy were enrolled. All pts in POLLUX were treated until progression; CASTOR pts received 8 cycles of Vd ± daratumumab. Different D (16 mg/kg) dosing schedules were used in POLLUX (qw for cycles 1-2, q2w for cycles 3-6, and q4w thereafter) and CASTOR (qw in Cycles 1-3, q3w for Cycles 4-8, and q4w thereafter). Elderly pts received a reduced dexamethasone dose (20 mg once weekly). Results: In POLLUX, 29/286 (DRd) and 35/283 (Rd) were ≥75 y, with 86% and 91% having ECOG status ≤1, respectively. With 17.3 months of median follow up, 10% in DRd and 11% in Rd discontinued due to treatment-emergent adverse events (TEAEs). Common (>10%) grade 3/4 TEAEs for DRd included neutropenia and hypokalemia (Table). Twelve (41%) DRd pts experienced infusion-related reactions (IRR) and 4 (14%) experienced grade 3/4 IRR; none discontinued due to IRR. Median PFS was not reached (NR) in DRd vs 11.4 months in Rd (HR 0.19; 95% CI, 0.06-0.55; P=0.0007), and ≥CR % was significantly higher with DRd vs Rd (52% vs 9%; P=0.0002). In CASTOR, 23/251 (DVd) and 35/247 (Vd) were ≥75 y, with 100% and 94% having ECOG status ≤1, respectively. With 13.0 months of median follow up, rates of discontinuation due to TEAEs were similar (15% vs 20%). Thrombocytopenia, fatigue, and pneumonia were common grade 3/4 TEAEs for DVd (Table). Thirteen (65%) pts reported IRR (10% grade 3/4) and no pts discontinued due to IRR. Median PFS was NR in DVd vs 8.1 months in Vd (HR 0.27; 95% CI, 0.12-0.61; P=0.0007), and significantly higher ≥CR % was observed in DVd vs Vd (25% vs 3%; P=0.0154). Conclusions: The safety and efficacy profiles in elderly pts were generally comparable with the overall population in each study. Clinical trial information: NCT02136134 and NCT02076009. [Table: see text]

Daratumumab, bortezomib and dexamethasone (DVd) vs bortezomib and dexamethasone (Vd) in relapsed or refractory multiple myeloma (RRMM): Efficacy and safety update (CASTOR)

8036

Background: Daratumumab (D), a human, CD38-targeting mAb, is well tolerated and induces deep and durable responses in patients (pts) with RRMM. We provide an update of CASTOR (NCT02136134), a multicenter, phase 3, randomized study of DVd vs Vd in RRMM. Methods: All pts received ≥1 prior line of therapy (LOT) and were administered 8 cycles (Q3W) of Vd (1.3 mg/m2 SC bortezomib on days 1, 4, 8, and 11; 20 mg PO/IV dexamethasone on days 1-2, 4-5, 8-9, and 11-12) ± D (16 mg/kg IV once weekly in Cycles 1-3, every 3 weeks for Cycles 4-8, then every 4 weeks until progression). Bortezomib-refractory pts were ineligible. Minimal residual disease (MRD) was assessed upon suspected CR and at 6 and 12 months following the first dose at sensitivities of 10–4, 10–5, and 10–6using the ClonoSEQ assay (Adaptive Biotechnologies, Seattle, WA). Results: Pts received a median (range) of 2 (1-10) prior LOTs. 66% were previously treated with bortezomib and 21% were refractory to lenalidomide in their last prior LOT. After a median follow-up of 13.0 months, PFS was significantly prolonged with DVd vs Vd (median: not reached vs 7.1 months; HR, 0.33; 95% CI, 0.26-0.43; P< 0.0001). This PFS benefit was seen regardless of number of prior LOTs received, with greatest benefit observed in 1 prior line pts (median: not reached vs 7.9 months; HR, 0.22; 95% CI, 0.14-0.34; P< 0.0001). ORR was also significantly higher for DVd vs Vd (84% vs 63%), along with ≥VGPR (62% vs 29%) and ≥CR (26% vs 10%; P< 0.0001 for all). MRD-negative rates were ≥4-fold higher at all three sensitivity thresholds with DVd vs Vd (10% vs 2% at 10–5 threshold). Pts who achieved MRD negativity demonstrated prolonged PFS compared with MRD-positive pts. 37 (15%) and 58 (24%) deaths were observed in DVd vs Vd, respectively, and follow up is ongoing. The most common grade 3/4 TEAE was thrombocytopenia (45% vs 33%). Updated efficacy and safety data will be presented. Conclusions: DVd provided significant benefits with respect to PFS, ORR, depth of response, and MRD-negative rate vs Vd. No new safety signals were reported. These data continue to support the use of DVd in RRMM pts and indicate that pts with 1 prior LOT will derive the most benefit. Clinical trial information: NCT02136134.

Efficacy of daratumumab in combination with lenalidomide plus dexamethasone (DRd) or bortezomib plus dexamethasone (DVd) in relapsed or refractory multiple myeloma (RRMM) based on cytogenetic risk status

8006

Background: In 2 randomized phase 3 trials of RRMM patients (pts), DRd (POLLUX) or DVd (CASTOR) significantly improved PFS and deepened responses compared with Rd or Vd alone, respectively. The novel mechanism of action of daratumumab (D) may improve the poor prognosis associated with high-risk cytogenetic abnormalities in RRMM. Therefore, we examined the efficacy of DRd and DVd among RRMM pts with standard (std) or high cytogenetic risk status. Methods: Bone marrow aspirates were collected at screening and assessed centrally via next generation sequencing (NGS). Pts with high-risk cytogenetics included those who had ≥1 of the following abnormalities: t(4;14), t(14;16), or del17p; std-risk pts were defined as those confirmed negative for these abnormalities. Efficacy analyses included PFS and ORR. Results: Samples from 311/569 pts in POLLUX and 353/498 pts in CASTOR were assessed via NGS. In POLLUX, the median duration of follow-up was 17.3 months. Significantly longer median PFS and numerically higher ORR were observed with DRd vs Rd among high-risk patients, and significant improvements in these outcomes were observed in std-risk patients (Table). In CASTOR, the median duration of follow-up was 13.0 months. Significantly longer median PFS and higher ORR were observed with DVd vs Vd among both high- and std-risk pts (Table). Concordance rates for t(4;14), t(14;16), and del17p were high (88%-98%) between NGS and FISH. Updated data, including subgroup analyses, will be presented. Conclusions: In RRMM pts, the addition of D to standard-of-care regimens improved outcomes regardless of cytogenetic risk status. Targeting CD38 by combining D with Rd or Vd appears to improve the poor outcomes associated with high-risk cytogenetic status. See table. Clinical trial information: NCT02136134 and NCT02076009. [Table: see text]

Phase III randomized controlled study of daratumumab, bortezomib, and dexamethasone (DVd) versus bortezomib and dexamethasone (Vd) in patients (pts) with relapsed or refractory multiple myeloma (RRMM): CASTOR study

LBA4

Background: Daratumumab (D), a human anti-CD38 IgGκ mAb, induces deep and durable responses with a favorable safety profile in RRMM pts. We report a pre-specified interim analysis of the first randomized controlled study of D (CASTOR; NCT02136134). Methods: Pts with ≥1 prior line of therapy were randomized (1:1) to 8 cycles (q3w) of bortezomib (V)/dexamethasone (d) (V: 1.3 mg/m2sc on Days 1, 4, 8, 11; d: 20 mg po on Days 1, 2, 4, 5, 8, 9, 11, 12) ± D (16 mg/kg iv qw in Cycles 1-3, Day 1 of Cycles 4-8, then q4w until progression). Primary endpoint was PFS. Results: 498 pts (DVd, 251; Vd, 247) were randomized. Baseline demographics and disease characteristics were well balanced. Pts received a median of 2 prior lines of therapy (range 1-10). 66% received prior V; 76% received prior IMiD; 48% received prior PI and IMiD; 33% were IMiD-refractory; 32% were refractory to last line of prior therapy. With median follow-up of 7.4 months, D significantly improved median PFS (61% reduction in risk of progression) and TTP for DVd vs Vd (Table). D significantly increased ORR (83% vs 63%, P <0.0001), and doubled rates of ≥VGPR (59% vs 29%, P <0.0001), and ≥CR (19% vs 9%, P= 0.0012) for DVd vs Vd, respectively; median duration of response was NR vs 7.9 months, respectively. Most common (>25%) AEs (DVd/Vd) were thrombocytopenia (59%/44%), peripheral sensory neuropathy (47%/ 38%), diarrhea (32%/22%) and anemia (26%/31%). Most common grade 3/4 AEs (>10%) were thrombocytopenia (45%/33%), anemia (14%/16%), neutropenia (13%/4%). 7%/9% of pts discontinued due to a TEAE. D-associated infusion-related reactions (45% of pts) mostly occurred during the first infusion; most were grade 1/2 (grade 3/4, 9%/0%). Conclusions: D significantly improved PFS, TTP, and ORR in combination with Vd vs Vd alone. DVd doubled both VGPR and sCR/CR rates vs Vd alone. Safety of DVd is consistent with the known safety profile of D and Vd. The addition of D to Vd should be considered a new standard of care for RRMM pts currently receiving Vd alone. Clinical trial information: NCT02136134. [Table: see text]