Arcellx (ACLX) Status Update summary

Key clinical results and efficacy

• Phase I follow-up showed a 100% overall response rate and 79% complete response rate, with median PFS of 34 months for CR patients and 30 months for the whole population.

• iMMagine-1 phase II study reported a 97% overall response rate and 62% complete/strict complete response rate at a median follow-up of 9.5 months, with 93.1% achieving MRD negativity among those tested.

• Median progression-free survival and overall survival were not reached; 12-month PFS and OS rates were 78.5% and 96.5%, respectively.

• Deep and durable responses were observed in high-risk, heavily pretreated patients, including triple- and penta-refractory cases.

• 93% of evaluable patients achieved MRD negativity at 10^-5 sensitivity, with a median time to MRD negativity of one month.

Safety and tolerability profile

• 86% of patients had ≤Grade 1 CRS, 17% had no CRS; 91% had no ICANS, and all ICANS cases resolved without sequelae.

• No delayed or non-ICANS neurotoxicities, including Parkinsonism, cranial nerve palsies, or Guillain-Barré syndrome, observed in over 150 patients.

• Three deaths occurred due to adverse events, with no secondary T-cell malignancies or replication-competent lentivirus detected.

• Most common Grade ≥3 adverse events were cytopenias: neutropenia (54%), thrombocytopenia (20%), and anemia (22%).

• Safety profile is considered predictable and manageable, with no evidence of product-specific delayed neurotoxicity seen in some other CAR-Ts.

Manufacturing, logistics, and commercial outlook

• Anito-cel manufacturing success rate was 99% in phase II, with <17-day turnaround and >96% reliability.

• Kite's global footprint includes over 500 ATCs, supporting broad access and scalability.

• Commercial opportunity estimated at $12B for second line plus, $20B+ for front line plus, and $3.5B for fourth line plus.

• Favorable reimbursement in over 80% of CAR-T cases, regardless of inpatient or outpatient administration.

• Outpatient dosing is expected to increase due to favorable safety and late-onset CRS, potentially reducing readmissions and hospital resource utilization.