-- Median duration of response, progression free
survival, and overall survival rate not reached with median
follow-up after CART-ddBCMA (anito-cel) infusion of 26.5
months –
-- The estimated median progression free survival
by Kaplan-Meier is 28 months --
-- Oral presentation at ASH will be on
Monday, December 11, 2023 at
5 p.m. PT --
-- Company to host a live webcast event with an
expert panel of clinicians on Monday,
December 11 at 8 p.m. --
REDWOOD
CITY, Calif., Dec. 8, 2023
/PRNewswire/ -- Arcellx, Inc. (NASDAQ: ACLX), a biotechnology
company reimagining cell therapy through the development of
innovative immunotherapies for patients with cancer and other
incurable diseases, today announced new clinical data from its
Phase 1 expansion study of CART-ddBCMA, now known as anitocabtagene
autoleucel (anito-cel). Anito-cel utilizes a novel D-Domain BCMA
binder that is compact and stable, which results in a drug
product with a high proportion of CAR+ cells and high surface
expression, potentially enhancing antigen binding and more
efficient Multiple Myeloma cell killing.
The data continue to demonstrate robust long-term responses with
median duration of response, progression free survival (PFS), and
overall survival rate not reached. The data are from an
October 15, 2023 data cut, with
median follow-up after anito-cel infusion of 26.5 months. These
latest study findings will be presented as an oral presentation
during the 65th American Society of Hematology (ASH) Annual Meeting
and Exposition on Monday, December 11,
2023 at 5 p.m. PT. The company
also has a medical affairs booth (#748) in Hall E of the
San Diego Convention Center.
As of October 15, 2023, 38
patients were evaluable for efficacy and safety analysis based on a
median follow-up of 26.5 months following treatment. These
evaluable patients comprised the dose escalation cohorts for the
first dose level (100 (+/- 20) million CAR+ T cells, n=6) and the
second dose level (300 (+/- 20) million CAR+ T cells, n=6), and a
dose expansion cohort at 100 (+/- 20) million CAR+ T cells (n=26).
The median dose administered to patients in the first dose level
and dose expansion cohorts was 115 million CAR+ T cells. All
patients evaluable for this analysis have poor prognostic factors
with 38 of 38 (100%) patients triple-refractory, 26 of 38 (68%)
penta-refractory, and 34 of 38 (89%) refractory to last line of
treatment under International Myeloma Working Group (IMWG)
criteria. Additionally, 9 of 38 (24%) patients had high tumor
burden with >60% bone marrow plasma (BMPC) cells, 13 of 38 (34%)
patients had extra-medullary disease (EMD), and 11 of 38 (29%)
patients had high-risk cytogenetics (Del 17p, t(14;16), t(4;14)) at
screening/baseline. Further, 24 of 38 (63%) had at least one
high-risk clinical feature, defined as presence of EMD, BMPC
>60%, or Beta 2 microglobulin (B2M) >5.5 mg/L at
screening/baseline. All 38 patients had at least three prior lines
of therapy.
The interim anito-cel Phase 1 clinical results (October 15, 2023 cutoff date) demonstrate deep
and durable responses in patients with poor prognostic factors.
All Patients:
Of the 38 evaluable patients with a median follow-up of 26.5
months:
- 100% overall response rate (ORR) achieved in all patients per
IMWG criteria
- 29 of 38 evaluable patients achieved a complete response (CR)
or a stringent complete response (sCR) (>CR rate, 76%)
- 35 of 38 patients achieved a very good partial response or
higher (>VGPR rate, 92%)
Of those evaluable for MRD testing to date (n=28), 25 (89%) were
MRD-negative at a minimum of 10-5 sensitivity.
Median duration of response, progression free survival (PFS), and
overall survival were not reached at the time of the October 15, 2023 data cut. While median PFS is
yet to be reached, the estimated Kaplan-Meier median progression
free survival for the study population was 28 months at the time of
the data cut with 26.5 months of median follow-up.
The Kaplan-Meier method estimated PFS rates for 6, 12, 18 and 24
months were 92%, 76%, 64% and 56%, respectively. Durable responses
were also observed in patients with high-risk features (EMD, BMPC
≥60%, or B2M ≥5.5 mg/L at baseline) and high-risk cytogenetics.
Estimated PFS rates at 6, 12, 18, and 24- months by Kaplan-Meier
method were:
PFS Rates
(%)
|
|
6-month
|
12-month
|
18-month
|
24-month
|
All dosed
(n=38)
|
92.1
|
75.9
|
63.7
|
56.0
|
Age ≥65 years
(n=20)
|
95.0
|
85.0
|
74.3
|
61.3
|
High Risk Features*
(n=24)
|
91.7
|
74.2
|
64.6
|
58.7
|
Extramedullary Disease
(n=13)
|
92.3
|
67.1
|
67.1
|
57.5
|
High Risk Cytogenetics
(n=11)
|
81.8
|
71.6
|
71.6
|
71.6
|
*High risk features defined as presence of EMD, BMPC ≥60, or B2M
≥5.5 mg/L. Note: increased from prior presentation from 22 to 24
subjects as a result of database update based on ongoing data
review.
Anito-cel dosed at RP2D (115 million (+/- 10) CAR+ T cells)
continues to be well-tolerated at the time of the October 15, 2023 data cut:
- Adverse events with anito-cel, including CRS and ICANS, were
manageable
- No cases of grade 3 (or greater) CRS and only one case (3%) of
grade 3 ICANS event with no additional cases from previously
reported
- No tissue-targeted toxicities were observed
- No cases of delayed neurotoxicity events or parkinsonian
symptoms were observed
Matthew J. Frigault, M.D.,
anito-cel study investigator, Clinical Director of the Cellular
Therapy Service at Mass General Cancer Center, and Assistant
Professor at Harvard Medical School
said, "It is encouraging to see continued deep and durable
responses with anito-cel. While access to CAR-T treatment options
for patients with multiple myeloma is expanding, it is still
limited, and additional therapeutics can help close the treatment
gap. In light of this encouraging clinical profile of anito-cel, I
look forward to continuing to enroll patients in the iMMagine-1
study."
Arcellx's Chairman and Chief Executive Officer, Rami Elghandour continued, "This latest data set
further underscores our confidence in the potential of anito-cel to
become a best-in-class treatment option for patients with relapsed
or refractory multiple myeloma. Building on this momentum, we look
forward to completing enrollment in our iMMagine-1 study and
planning for commercial launch with our partners at
Kite."
ASH Presentation Details:
Title: Phase 1
Study of CART-ddBCMA for the Treatment of Patients with Relapsed
and/or Refractory Multiple Myeloma: Results from at Least 1-Year
Follow-up in All Patients
Speaker: Matthew J. Frigault, M.D., Clinical
Director of the Cellular Therapy Service at Mass General Cancer
Center, and Assistant Professor at Harvard
Medical School
Session Name: 704. Cellular Immunotherapies: Early Phase
and Investigational Therapies: CAR-T Cell Therapies for Multiple
Myeloma and B Cell Lymphomas
Session Date: Monday, December 11,
2023
Session Time: 4:30 - 6:00 p.m.
PT (Oral presentation for anito-cel will be at 5 p.m. PT)
Location: San Diego
Convention Center, Room 6A, San Diego,
California
Publication Number: 1023
A copy of the presentation can be accessed from Arcellx's
website at www.arcellx.com on the Scientific Publications page.
Webcast Event:
Arcellx will host a live webcast event
with an expert panel of clinicians to discuss the clinical results
on Monday, December 11, 2023 at
8 p.m. PT. The event will be
accessible from Arcellx's website at www.arcellx.com in
the Investors section. A replay of the webcast will be archived and
available for 30 days following the event.
About Multiple Myeloma
Multiple Myeloma (MM) is a type of hematological cancer in which
diseased plasma cells proliferate and accumulate in the bone
marrow, crowding out healthy blood cells and causing bone lesions,
loss of bone density, and bone fractures. These abnormal plasma
cells also produce excessive quantities of an abnormal
immunoglobulin fragment, called a myeloma protein (M protein),
causing kidney damage and impairing the patient's immune function.
Multiple myeloma is the third most common hematological malignancy
in the United States and
Europe, representing approximately
10% of all hematological cancer cases and 20% of deaths due to
hematological malignancies. The median age of patients at diagnosis
is 69 years with one-third of patients diagnosed at an age of at
least 75 years. Because MM tends to afflict patients at an advanced
stage of life, patients often have multiple co-morbidities and
toxicities that can quickly escalate and become
life-endangering.
About anito-cel
Anito-cel, formerly known as CART-ddBCMA is Arcellx's BCMA-specific
CAR-modified T-cell therapy utilizing the company's novel
BCMA-targeting binding domain for the treatment of patients with
relapsed or refractory multiple myeloma. Anito-cel is currently in
a Phase 2 study. Arcellx's proprietary binding domains are novel
synthetic proteins designed to bind specific therapeutic targets.
Anito-cel has been granted Fast Track, Orphan Drug, and
Regenerative Medicine Advanced Therapy Designations by the U.S.
Food and Drug Administration.
About Arcellx, Inc.
Arcellx, Inc. is a clinical-stage biotechnology company reimagining
cell therapy by engineering innovative immunotherapies for patients
with cancer and other incurable diseases. Arcellx believes that
cell therapies are one of the forward pillars of medicine and
Arcellx's mission is to advance humanity by developing cell
therapies that are safer, more effective, and more broadly
accessible. Arcellx's lead product candidate, anito-cel, is being
developed for the treatment of relapsed or refractory multiple
myeloma (rrMM) in a Phase 2 pivotal trial. Anito-cel has been
granted Fast Track, Orphan Drug, and Regenerative Medicine Advanced
Therapy designations by the U.S. Food and Drug
Administration.
Arcellx is also developing its dosable and controllable CAR T
therapy, ARC-SparX, through two Phase 1 programs, ACLX-001 for rrMM
and ACLX-002 in relapsed or refractory acute myeloid leukemia and
high-risk myelodysplastic syndrome. For more information on
Arcellx, please visit www.arcellx.com. Follow Arcellx on
X (Twitter) at @arcellx and LinkedIn.
About Arcellx and Kite Collaboration
Arcellx and Kite, a Gilead Company, formed a global strategic
collaboration to co-develop and co-commercialize Arcellx's
anito-cel candidate for the treatment of patients with relapsed or
refractory multiple myeloma currently in a pivotal Phase 2 study.
Kite and Arcellx will jointly advance and commercialize the
anito-cel asset in the United
States, and Kite will commercialize the product outside the
U.S. In November 2023, Arcellx
and Kite announced that the companies expanded the scope of the
strategic collaboration. Closing of the transaction is subject to
expiration or termination of the waiting period under the
Hart-Scott-Rodino Antitrust Improvement Act and other customary
conditions.
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, including Arcellx's plans for the
clinical development of its product candidates, including
enrollment in its iMMagine-1 trial; Arcellx and Kite's plans to
advance and commercialize anito-cel; the expected closing of the
expanded strategic collaboration with Kite; and the potential
impact of Arcellx's product candidates and platforms on patients
and cell therapy. The forward-looking statements contained herein
are based upon Arcellx's current expectations and involve
assumptions that 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 risks that may be found in the section
entitled Part II, Item 1A (Risk Factors) in the Quarterly Report on
Form 10-Q for the quarter ended September
30, 2023, filed with the Securities and Exchange Commission
(SEC) on November 13, 2023 and the
other documents that Arcellx may file from time to time with the
SEC. These forward-looking statements are made as of the date of
this press release, and Arcellx assumes no obligation to update or
revise any forward-looking statements, whether as a result of new
information, future events or otherwise, except as required by
law.
Contacts:
Investors:
Myesha Lacy
Arcellx, Inc.
ir@arcellx.com
510-418-2412
Media:
Andrea Cohen
Sam Brown Inc.
andreacohen@sambrown.com
917-209-7163
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SOURCE Arcellx, Inc.