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

ABSTRACT

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 MRDevaluable, 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 lenrefractory. 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.