Phase 3 ALLELE Study in EBV+ PTLD Demonstrates
50% Objective Response Rate, Consistent with Previous Results
At Least 11 of 19 Responders had a Duration of
Response (DOR) Lasting More Than Six Months with Median Time to
Response in All Patients of Just 1.1 Months
One-year Survival Rate of 89.2% for Patients
Responding to Tab-cel Compared with 32.4% Among Non-Responders
Atara Biotherapeutics, Inc. (Nasdaq: ATRA), a leader in T-cell
immunotherapy, leveraging its novel allogeneic Epstein-Barr virus
(EBV) T-cell platform to develop transformative therapies for
patients with cancer and autoimmune diseases, today announced
efficacy and safety results from its Phase 3 multicenter ALLELE
study investigating tabelecleucel (tab-cel®) for the treatment of
Epstein-Barr virus positive post-transplant lymphoproliferative
disease (EBV+ PTLD) following solid organ transplant (SOT) or
hematopoietic cell transplant (HCT). These findings, along with
combined long-term survival data from Phase 2 and multicenter
Expanded Access Protocol (EAP) studies of tab-cel were featured as
oral presentations at the 63rd American Society of Hematology (ASH)
Annual Meeting.
“Patients with EBV+ PTLD face a poor prognosis with survival
measured in weeks to months if initial treatment is unsuccessful.
There are no approved treatment options for this devastating
disease, underscoring the critical unmet need that exists,” said
Jakob Dupont, MD, Head of Global Research & Development at
Atara. “Our conviction that tab-cel, recently filed with the EMA,
is a potential first-in-class treatment option for transplant
recipients that develop EBV+ PTLD is validated by almost 90% of
patients responding to treatment surviving after one year, and a
similar two-year survival benefit of over 86% in patients who
achieved a complete or partial response from Phase 2 and EAP
studies.”
Poor patient survival in relapsed or refractory EBV+ PTLD
underscores the significant need for effective, safe, and
fast-acting new therapeutic options as highlighted in two
additional posters presented at ASH. Patients suffer from poor
median survival of 0.7 months (n=81) and 4.1 months (n=86) for HCT
and SOT, respectively, reported in EBV+ PTLD patients for whom
rituximab ± chemotherapy failed.
In the ongoing Phase 3 ALLELE study, 38 evaluable patients as of
May 2021 — 24 EBV+ PTLD patients following SOT after failure of
rituximab ± chemotherapy and 14 EBV+ PTLD patients following HCT
after failure of rituximab monotherapy — were treated with tab-cel
and had the opportunity for a six-month follow-up after response.
The median age of evaluable patients for both SOT and HCT was 52.9
years (3.2–81.5) who had tried a median of 1 (range: 1-5) prior
systemic treatments including rituximab monotherapy, chemotherapy
or immunotherapy.
As measured by independent oncologic response adjudication
(IORA) assessment, an ORR of 50% (19/38, 95% CI: 33.4, 66.6) was
observed for both HCT and SOT groups. For patients with EBV+ PTLD
following SOT, an ORR of 50.0% (12/24, 95% CI: 29.1, 70.9) was
observed and similarly, for patients with EBV+ PTLD following HCT,
an ORR of 50.0% (7/14, 95% CI: 23.0, 77.0) was observed, with a
best overall response of Complete Response (CR; 26.3%; n=10; n=5,
SOT, n=5, HCT) or Partial Response (PR; 23.7%; n=9; n=7, SOT, n=2,
HCT). The median time to response (TTR) in all patients was 1.1
months (0.7-4.7). In the study, 11 of 19 responders had a duration
of response (DOR) lasting more than six months and median DOR has
not yet been reached. Of the remaining eight responders, four had
events due to IORA-assessed progressive disease (PD) or death and
four patients were alive and censored for the DOR at the time of
the data cut.
Patients responding to tab-cel had longer survival compared to
the non-responders, with a median overall survival (OS) not
evaluable (NE) (95% CI: 16.4, NE) and a one-year survival rate of
89.2% (95% CI: 63.1, 97.2) versus non-responders’ OS of 5.7 months
(95% CI: 1.8, 12.1) and one-year survival rate of 32.4% (95% CI:
12.1, 54.9).
Safety was consistent with previously published data, and no new
safety signals or concerns were reported. There were no reports of
tumor flare reaction, infusion reactions, cytokine release
syndrome, transmission of infectious diseases, including
cytomegalovirus, and no events of graft versus host disease (GvHD)
or organ rejection related to tab-cel. Overall, tab-cel was
well-tolerated in treatment-refractory and immunocompromised
patients.
Atara also reported combined long-term survival data from Phase
2 and multicenter EAP studies of tab-cel in a second oral
presentation. Results show that across studies, patients who
responded to tab-cel for treatment of EBV+ PTLD experienced a
long-term survival benefit with a median OS of 54.6 months (95% CI:
14.8, 115.0) reported in all patients (n=76). An ORR of 63.2%
(48/76) was observed in all patients with a best overall response
of CR (42.1%; n=32) or PR (21.1%; n=16). Two-year survival rates
were 86.2% (95% CI: 67.0, 94.6) and 86.5% (95% CI: 55.8, 96.5) for
patients with CR and PR, respectively. Importantly, patients who
achieved a PR with tab-cel derived similar OS benefit to those who
achieved a CR. Treatment was well tolerated in refractory and
immunocompromised patients and there were no fatal events reported
related to tab-cel. There were no reports of tumor flare reaction,
cytokine release syndrome, organ/marrow rejection, or transmission
of infectious diseases and cytomegalovirus. There is no evidence of
GvHD or infusion-related reaction risks attributable to
tabelecleucel based on current data.
About Tabelecleucel
Tabelecleucel (tab‐cel) is an off-the-shelf, allogeneic T-cell
immunotherapy in development for the treatment of Epstein-Barr
virus-positive post-transplant lymphoproliferative disease (EBV+
PTLD). EBV+ PTLD is a type of lymphoma (cancer) that may occur
after a solid organ transplant (SOT) or allogeneic hematopoietic
cell transplant (HCT). There are currently no approved treatments
indicated to treat PTLD and if left untreated, PTLD can have
life-threatening consequences.
Tab-cel is currently being investigated in the Phase 3
registration-enabling ALLELE study to assess efficacy and safety
for the treatment of EBV+ PTLD in SOT and HCT after failure of
standard of care. These data support the recent EMA-validated
Marketing Authorization Application for tab-cel as the first
off-the-shelf allogeneic T-cell therapy ever to be reviewed by a
regulatory agency. The EMA’s Committee for Medicinal Products for
Human Use (CHMP) granted tab-cel Accelerated Assessment and an EU
approval decision is anticipated for second half of 2022.
Tab-cel has been granted Breakthrough Therapy Designation for
EBV+ PTLD following allogeneic HCT by the U.S. Food and Drug
Administration (FDA) and PRIME designation by the European
Medicines Agency (EMA) for the same indication. Tab-cel has orphan
drug designation in the U.S. and EU.
About Atara Biotherapeutics, Inc.
Atara Biotherapeutics, Inc. (@Atarabio) is a pioneer in T-cell
immunotherapy leveraging its novel allogeneic EBV T-cell platform
to develop transformative therapies for patients with serious
diseases including solid tumors, hematologic cancers and autoimmune
disease. With our lead program in Phase 3 clinical development and
currently under review to support registration in Europe, Atara is
the most advanced allogeneic T-cell immunotherapy company and
intends to rapidly deliver off-the-shelf treatments to patients
with high unmet medical need. Our platform leverages the unique
biology of EBV T cells and has the capability to treat a wide range
of EBV-associated diseases, or other serious diseases through
incorporation of engineered CARs (chimeric antigen receptors) or
TCRs (T-cell receptors). Atara is applying this one platform, which
does not require TCR or HLA gene editing, to create a robust
pipeline including: tab-cel in Phase 3 development for Epstein-Barr
virus-driven post-transplant lymphoproliferative disease (EBV+
PTLD) and other EBV-driven diseases; ATA188, a T-cell immunotherapy
targeting EBV antigens as a potential treatment for multiple
sclerosis; and multiple next-generation chimeric antigen receptor
T-cell (CAR-T) immunotherapies for both solid tumors and
hematologic malignancies. Improving patients’ lives is our mission
and we will never stop working to bring transformative therapies to
those in need. Atara is headquartered in South San Francisco and
our leading-edge research, development and manufacturing facility
is based in Thousand Oaks, California. For additional information
about the company, please visit atarabio.com and follow us on
Twitter and LinkedIn.
Forward-Looking Statements
This press release contains or may imply "forward-looking
statements" within the meaning of Section 27A of the Securities Act
of 1933 and Section 21E of the Securities Exchange Act of 1934. For
example, forward-looking statements include statements regarding:
the potential benefits, safety and efficacy of tab-cel®; the timing
and progress of tab-cel®, including (i) data and analyses from
ALLELE study, the investigator-initiated Phase 2 study, and the
EAP; (ii) tab-cel® clinical trials, and (iii) Atara’s ability to
successfully advance the development of tab-cel®. Because such
statements deal with future events and are based on Atara’s current
expectations, they are subject to various risks and uncertainties
and actual results, performance or achievements of Atara could
differ materially from those described in or implied by the
statements in this press release. These forward-looking statements
are subject to risks and uncertainties, including, without
limitation, risks and uncertainties associated with the costly and
time-consuming pharmaceutical product development process and the
uncertainty of clinical success; the ongoing COVID-19 pandemic,
which may significantly impact (i) our business, research, clinical
development plans and operations, including our operations in South
San Francisco and Southern California and at our clinical trial
sites, as well as the business or operations of our third-party
manufacturer, contract research organizations or other third
parties with whom we conduct business, (ii) our ability to access
capital, and (iii) the value of our common stock; the sufficiency
of Atara’s cash resources and need for additional capital; and
other risks and uncertainties affecting Atara’s and its development
programs, including those discussed in Atara’s filings with the
Securities and Exchange Commission (SEC), including in the “Risk
Factors” and “Management’s Discussion and Analysis of Financial
Condition and Results of Operations” sections of the Company’s most
recently filed periodic reports on Form 10-K and Form 10-Q and
subsequent filings and in the documents incorporated by reference
therein. Except as otherwise required by law, Atara disclaims any
intention or obligation to update or revise any forward-looking
statements, which speak only as of the date hereof, whether as a
result of new information, future events or circumstances or
otherwise.
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version on businesswire.com: https://www.businesswire.com/news/home/20211213005973/en/
INVESTORS & MEDIA: Investors Eric Hyllengren
805-395-9669 ehyllengren@atarabio.com
Media Alex Chapman 805-456-4772 achapman@atarabio.com
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