Arcellx Presents Robust and Continued 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

— 100% TRO at both dose levels; Profound and Long-Lasting Responses Seen in Patients with Poor Prognostic Factors —

— 22 of 31 (71%) evaluable patients achieved CR/CRS —

— 13 of the 16 patients (81%) treated more than 12 months ago achieved CR/CRS; 8 (50%) with EMD; 9 (56%) remain in continuous response with a median follow-up of 17.7 months —

— No cases of CRS grade ≥ 3 and no delayed neurotoxicity or parkinsonian-like events observed at RP2D (n=25) —

— Pivotal Phase 2 study on track to start by YE 2022 —

— Management will host a live webcast event on Sunday, June 5, 2022at 7:00 p.m. CDT to discuss new positive CART-ddBCMA data with a panel of clinical experts —

FOSTER CITY, Calif., June 3, 2022 /PRNewswire/ — Arcellx, Inc. (NASDAQ: ACLX), a biotechnology company reinventing cell therapy by developing innovative immunotherapies for patients with cancer and other terminal diseases, today announced positive new clinical data from the ongoing Phase 1 expansion study of its new autologous CART-ddBCMA therapy for the treatment of patients with relapsed or refractory multiple myeloma. The clinical results are presented in an oral presentation at the 2022 Annual Meeting of the American Society of Clinical Oncology (ASCO).

31 patients were evaluable for analysis of efficacy and safety, based on a follow-up of at least one month after treatment. These evaluable patients included 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 dose Phase 2 Dose (RP2D) of 100 million CAR+T cells (n=19). All patients included in the study have poor prognostic factors with 21 of 31 (68%) penta-refractory patients, 12 of 31 (39%) patients with extramedullary disease (EMD) and the 31 patients having had at least three previous treatments.

The interim clinical results of the CART-ddBCMA (May 3, 2022 cut-off date) demonstrate profound and durable responses in patients with poor prognostic factors.

  • Among 31 evaluable patients with a median follow-up of 12.1 months
    • 100% overall response rate (TRO) achieved in all patients according to the criteria of the International Myeloma Working Group
    • 22 of 31 (71%) evaluable patients achieved complete response (CR) or strict 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%) treated more than 12 months ago achieved CR/CRS; 8 (50%) with EMD; 9 (56%) remain in continuous response with a median follow-up of 17.7 months
  • Conversions to SCR 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 were manageable and all resolved with standard management at both dose levels
    • No cases of delayed neurotoxicity events or parkinsonian symptoms
    • No cases of CRS grade 3 (or higher) and one case (4%) of ICANS grade 3 event with no additional cases previously reported.

Matthieu J. FrigaultMD, CART-ddBCMA Study Investigator and Deputy Director of Cell Therapy at Mass General Cancer Center and Instructor at Harvard Medical School said: “The demand for clinically meaningful and safe CAR-T therapies exceeds what is currently available for patients with multiple myeloma. It is encouraging to see that these data continue to demonstrate profound answers and provide benefit to patients. patients. I look forward to enrolling patients in the pivotal Phase 2 study.”

“We are excited about these long-term results, particularly given the challenging patient demographics, and believe these promising results reflect the potential of our lead program, CART-ddBCMA, to be a best-in-class treatment for patients with multiple myeloma. ,” said Rami Elghandour, Chairman and CEO of Arcellx. “We believe there is a significant unmet need for cell therapies and are committed to providing physicians with a safe and effective treatment option for patients with multiple myeloma. We are honored to have our data presented to ASCO by Dr. Frigault and look forward to commencing enrollment in our pivotal Phase 2 study by the end of this year as the next step on the road to approval. regulatory. »

The presentation can be viewed on the company’s website here.

Details of the oral presentation:

Title: Phase 1 study of CART-ddBCMA in relapsed or refractory multiple myeloma
Speaker: Matthieu J. FrigaultMD, assistant director of the cell therapy service at the Mass General Cancer Center and instructor at Harvard Medical School
Session Type/Title: Oral Summary Session/Hematologic Malignancies—Plasma Cell Dyscrasia
Date of the session: Sunday, June 5, 2022
session time: 8:00 a.m.11:00 a.m. CDT
Location: McCormick Place Convention Center, ChicagoIllinois
Abstract number: 8003

Webcast event:

Arcellx will host a live webcast event with an expert panel of clinicians to discuss clinical results on Sunday, June 5, 2022at 7:00 p.m. CDT. The event will be accessible from the Arcellx website at www.arcellx.com in the Investors section. A replay of the webcast will be archived and available for 30 days after the event.

About Multiple Myeloma

Multiple myeloma (MM) is a type of blood cancer in which diseased plasma cells proliferate and accumulate in the bone marrow, crowding out healthy blood cells and causing bone damage, loss of bone density and bone fractures. These abnormal plasma cells also produce excessive amounts of an abnormal immunoglobulin fragment, called myeloma protein (M protein), causing kidney damage and impairing the patient’s immune function. Multiple myeloma is the third most common hematological malignancy United States and Europe, accounting for approximately 10% of all cases of hematological cancers and 20% of deaths due to hematological malignancies. The median age of patients at diagnosis is 69 years with a third of patients diagnosed at an age of at least 75 years. Because MM tends to affect patients late in life, patients often have multiple comorbidities and toxicities that can quickly escalate and be life-threatening.

About CART-ddBCMA

CART-ddBCMA is Arcellx’s BCMA-specific CAR-modified T-cell therapy using the Company’s novel BCMA-targeting binding domain for the treatment of patients with relapsed or refractory multiple myeloma. CART-ddBCMA is currently in a Phase 1 study. Arcellx’s proprietary binding domains are novel synthetic proteins designed to bind to specific therapeutic targets. CART-ddBCMA has been granted Fast Track, Orphan Drug, and Regenerative Medicine Advanced Therapy designations by the United States Food and Drug Administration.

About Arcellx, Inc.

Arcellx, Inc. is a clinical-stage biotechnology company reinventing cell therapy by designing innovative immunotherapies for patients with cancer and other life-threatening diseases. Arcellx believes that cell therapies are one of the advanced pillars of medicine and Arcellx’s mission is to advance humanity by developing safer, more effective and more widely available cell therapies. Arcellx’s lead product candidate, CART-ddBCMA, is being developed for the treatment of relapsed or refractory multiple myeloma (r/r MM) in an ongoing Phase 1 study. CART-ddBCMA has been granted Fast Track, Orphan Drug, and Regenerative Medicine Advanced Therapy designations by the United States Food and Drug Administration.

Arcellx is also advancing its doseable and controllable CAR-T therapy, ARC-SparX, through two programs: a Phase 1 study of ACLX-001 for r/r MM, initiated in the second quarter of 2022; and ACLX-002 in relapsed or refractory acute myeloid leukemia and high-risk myelodysplastic syndrome, which is expected to enter the clinic in the second half of 2022.

Visit www.arcellx.com for more information.

Forward-looking statements
This press release contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. All statements in this press release that are not purely historical are forward-looking statements. The forward-looking statements contained herein are based on Arcellx’s current expectations and involve assumptions which may never materialize or may prove to be incorrect. These forward-looking statements are neither promises nor guarantees and are subject to a variety of risks and uncertainties, including those set forth in Part I, Section 1A (Risk Factors) of Arcellx’s Annual Report on Form 10- K and in other reports, such as Quarterly Reports on Form 10-Q and Current Reports on Form 8-K, which Arcellx may file from time to time with the Securities and Exchange Commission. These forward-looking statements are made as of the date of this press release, and Arcellx undertakes no obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise, except if required by law.

Investor contacts:
Myesha Lacy
Arcellx, Inc.
[email protected]
510-418-2412

Media Contact
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Sam Brown Inc.
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SOURCEArcellx, Inc