Evaluable for efficacy and safety analysis were 31 patients, based on follow-up of at least one month, following treatment. These evaluable patients comprised the dose escalation cohorts for the first dose level (100 million CAR+ T cells, n=6), the second dose level (300 million CAR+T cells, n=6), and a dose expansion cohort at the recommended Phase 2 dose (RP2D) of 100 million CAR+T cells (n=19). All patients enrolled in the study have poor prognostic factors with 21 of 31 (68%) patients penta-refractory, 12 of 31 (39%) extramedullary disease (EMD), and all 31 patients having had at least three prior treatments.

The interim CART-ddBCMA clinical results (May 3, 2022 cutoff date) demonstrate deep and durable responses in patients with poor prognostic factors.

• Of the 31 evaluable patients with median follow-up of 12.1 months
  • 100% overall response rate (ORR) achieved in all patients per International Myeloma Working Group criteria
  • 22 of 31 (71%) evaluable patients achieved complete response (CR) or a stringent complete response (sCR)
  • 29 of 31 (94%) patients achieved > very good partial response (VGPR)
  • 2 of 31 (6%) patients achieved a partial response (PR)
  • 12 of 31 (39%) with extramedullary disease
• 13 of 16 patients (81%) dosed more than 12 months ago reached CR/sCR; 8 (50%) with EMD; 9 (56%) remain in ongoing response with a median follow up of 17.7 months
• Conversions to sCR have occurred as early as 1 month and also at ≥12 months
• CART-ddBCMA dosed at RP2D (100 million CAR+T cells) continues to be well-tolerated
  • Toxicities including CRS and ICANS have been manageable, and all resolved with standard management at both dose levels
  • No cases of delayed neurotoxicity events or parkinsonian symptoms
  • No cases of grade 3 (or greater) CRS and only one case (4%) of grade 3 ICANS event with no additional cases from previously reported.