Master Protocol for the Phase 1 Study of Cell Therapies in Multiple Myeloma ACLX-001

What's the purpose of this trial?

Master protocol for cell therapy, Phase 1 proof-of-concept studies in relapsed and refractory multiple myeloma and includes long-term safety follow-up.

ARM 1 is a, non-randomized, open label, multi-site Phase 1 study. ACLX-001 is a BCMA directed CAR with a non-scFv binding domain that has been deimmunized.

This trial is currently open and accepting patients.

What will happen during the trial?

Additional Trial Information

Phase 1

Enrollment: 65 patients (estimated)

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Published Results

Phase 1 Study of CART-Ddbcma for the Treatment of Subjects with Relapsed and /or Refractory Multiple Myeloma

November 15, 2022

At the last data-cut performed on May 3, 2022, 37 patients (pts, median age 66 (range: 44-76)) were enrolled, 33 received CART-ddBCMA and 31 were evaluable for initial safety and clinical response. Median follow-up after CART-ddBCMA infusion was 12.1 months. 27 subjects received DL1 (6 in dose escalation and 21 in dose expansion, 25 evaluable) and 6 received DL2 (all evaluable). CAR+ cells comprised median 72% (48-87%) of total CD3+ T cells; median VCN was 2.2 copies/cell (1.1-3.5); median cell viability was 99% (91-100%), and median cell manufacturing yield was 1159 million cells (470-1626).

Subjects had a median of 5 (3-16) prior lines of therapy. Twenty-four pts (77%) were "triple-refractory," and 21 (68%) were "penta-refractory"; 12 pts (39%) had high tumor burden with ≥ 50% bone marrow plasma cells; and 12 (39%) pts (50%) had extramedullary disease at baseline. CRS was seen in 28/31 (90%) pts but only 1 subject (in DL2) had grade (G) 3 CRS and all other cases were G≤2. ICANS was seen in 7 subjects (5, G≤2; 2, G3), with 1 G3 case in each DL. All cases resolved without sequalae with standard management. No cases of off-tumor cell mediated toxicity, no delayed neurotoxicity events (i.e., occurring after day 28), and no Parkinsonian-like symptoms.

All 31 evaluable subjects demonstrated clinical response per IMWG criteria (ORR, 100%) with 22 sCR/CR (≥CR rate, 71%), 7 VGPR (≥VGPR rate, 94%), and 2 PR. Responses deepened over time and conversion to CR/sCR was observed with longer follow-up (as late as month 12). Of those evaluable for MRD testing to date (n=22), 19 (86%) were MRD-neg at 10-5 or lower.

Median duration of response, PFS & OS were not evaluable at the time of data-cut because 22 of 31 evaluable subjects (71%) had ongoing response. In the patients with ≥12 months follow-up (n=16), which included 8 (50%) patients with EMD, ORR was 100%, ≥CR rate was 81% (13/16) and ≥VGPR rate was 88% (14/16). CART-ddBCMA product characteristics were consistent with the specifications in all the lots and there were no manufacturing failures.

Arcellx Presents Continued Robust Long-Term Responses From Its CART-DdBCMA Phase 1 Expansion Trial In Patients With Relapsed Or Refractory Multiple Myeloma At The 2022 ASCO Annual Meeting

June 03, 2022

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.
Arcellx Announces Presentation of Positive Clinical Results from Ongoing Phase 1 Study of CART-ddBCMA at the 2021 ASCO Annual Meeting

June 04, 2021

As previously announced, as of the April 14, 2021 data cutoff:

  • 12 of 12 patients achieved responses per IMWG criteria (median follow-up of 197 days; (Min – Max) 29-449 days)
    • 5 patients achieved stringent complete responses (sCR)
    • 1 patient achieved a complete response (CR)
    • 3 patients achieved very good partial responses (VGPR)
    • 3 patients achieved partial responses (PR)
  • One patient achieved VGPR despite prior progression on BCMA-targeted therapy
  • Responses in 11 patients are ongoing, with evidence that responses deepen over time

All patients enrolled in the study have poor prognostic factors with 10 of 12 patients penta-refractory and all 12 patients having had at least three prior treatments.

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Trial Locations

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Massachusetts General Hospital

Boston, MA

Open and Accepting

Beth Israel Deaconess Medical Center

Boston, MA

Open and Accepting
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