Background
CARTITUDE-4 was a phase III randomized open-label trial evaluating ciltacabtagene autoleucel (cilta-cel), a BCMA-directed CAR-T cell therapy, versus standard of care (investigator's choice of pomalidomide-bortezomib-dexamethasone [PVd] or daratumumab-pomalidomide-dexamethasone [DPd]) in patients with relapsed/refractory multiple myeloma who had received 1–3 prior lines of therapy and were lenalidomide-exposed. CARTITUDE-4 was the first Phase III trial to demonstrate superiority of CAR-T therapy over standard salvage regimens in relatively early-relapse myeloma, a clinically transformative finding given prior CAR-T trials (CARTITUDE-1, KarMMa) had focused on heavily pretreated patients.
Interventions and follow up
Arm A (SOC): Investigator's choice standard-of-care: pomalidomide-bortezomib-dexamethasone (PVd) or daratumumab-pomalidomide-dexamethasone (DPd) until progression
Arm B (cilta-cel): Ciltacabtagene autoleucel — single infusion 0.75 × 10⁶ CAR-T cells/kg after lymphodepleting chemotherapy (fludarabine + cyclophosphamide); bridging therapy permitted
Primary endpoint: Progression-free survival (PFS) per IMWG criteria assessed by IRC
Secondary: ORR, sCR, MRD negativity, OS
mFollow-up: 15.9 months
Arm B (cilta-cel): Ciltacabtagene autoleucel — single infusion 0.75 × 10⁶ CAR-T cells/kg after lymphodepleting chemotherapy (fludarabine + cyclophosphamide); bridging therapy permitted
Primary endpoint: Progression-free survival (PFS) per IMWG criteria assessed by IRC
Secondary: ORR, sCR, MRD negativity, OS
mFollow-up: 15.9 months
Results
12-mo PFS: 75.9% vs 48.6% (HR 0.26, 95% CI 0.18–0.38, P<.001)
ORR: 84.6% vs 67.3%
sCR: 73.1% vs 21.8%
MRD negativity (10⁻⁵): 60.6% vs 15.6%
OS: data immature; 12-mo OS 89.3% vs 85.6%
ORR: 84.6% vs 67.3%
sCR: 73.1% vs 21.8%
MRD negativity (10⁻⁵): 60.6% vs 15.6%
OS: data immature; 12-mo OS 89.3% vs 85.6%
Adverse events
Overall: Grade ≥3 AEs 96.6% (cilta-cel) vs 94.2% (SOC); 1 treatment-related death in each arm
CAR-T-specific: CRS 76.1% (Grade ≥3: 4.6%); neurotoxicity (ICANS) 4.8% Grade ≥3; movement and neurocognitive toxicities (MNTs) 2.4%
Hematologic: cytopenias Grade ≥3 prolonged in cilta-cel arm
Infectious: infections Grade ≥3 26.6% vs 23.6%
CAR-T-specific: CRS 76.1% (Grade ≥3: 4.6%); neurotoxicity (ICANS) 4.8% Grade ≥3; movement and neurocognitive toxicities (MNTs) 2.4%
Hematologic: cytopenias Grade ≥3 prolonged in cilta-cel arm
Infectious: infections Grade ≥3 26.6% vs 23.6%
Conclusions
Cilta-cel produced a 74% reduction in risk of progression or death (HR 0.26) compared to standard salvage regimens in lenalidomide-exposed relapsed/refractory myeloma with 1–3 prior lines, with dramatically higher sCR (73% vs 22%) and MRD negativity rates, establishing single-infusion CAR-T therapy as a paradigm-changing approach in early-relapse myeloma.
Key Limitations
Open-label; leukapheresis and manufacturing time (median ~47 days) necessitates bridging therapy and logistically complex delivery; CRS management requires REMS certification; movement and neurocognitive toxicities (MNTs) are class-specific BCMA CAR-T toxicities requiring vigilance; OS data immature at primary analysis; cilta-cel access is limited by manufacturing capacity and specialized center requirements; 27% of cilta-cel arm received prior daratumumab — subgroup analysis showed maintained benefit; no comparison to other BCMA-directed therapies (belantamab mafodotin, teclistamab); long-term durability beyond 2 years not yet established; MNT risk demands careful patient selection.
Clinical Context
CARTITUDE-4 led to FDA approval of cilta-cel for R/R MM after ≥1 prior line including an IMiD and PI in April 2024, expanding the label from heavily pretreated (≥4 prior lines, CARTITUDE-1) to early-relapse settings. This is clinically transformative: moving CAR-T from last resort to standard second-line therapy in lenalidomide-refractory patients. The CARTITUDE-4 HR of 0.26 is among the strongest ever seen in a myeloma Phase III trial. Competing BCMA-directed strategies (belantamab mafodotin, teclistamab, elranatamab) serve patients who cannot access or tolerate CAR-T. The optimal sequencing of CAR-T, bispecific antibodies, and salvage chemotherapy in the modern myeloma landscape is an active area of clinical investigation per ASCO/ESMO guidance.