Atara Biotherapeutics, Inc. (Nasdaq:ATRA), a leading off-the-shelf
T-cell immunotherapy company developing novel treatments for
patients with cancer, autoimmune and viral diseases, today
announced that the Company's collaborating investigators presented
updated, positive interim results for tabelecleucel (formerly known
as ATA129) from a multicenter expanded access protocol (EAP) study
for patients with EBV associated cancers. The findings were
reported at the ongoing 59th American Society of Hematology (ASH)
Annual Meeting, taking place in Atlanta, GA, December 9-12, 2017.
Tabelecleucel is Atara's off-the-shelf T-cell immunotherapy in
development for the treatment of Epstein-Barr virus (EBV)
associated post-transplant lymphoproliferative disorder (EBV+PTLD),
as well as other EBV associated hematologic and solid tumors.
“We are gratified to see that the multicenter clinical findings
in patients with EBV+PTLD are consistent with the tabelecleucel
profile observed in the Phase 2 studies conducted at Memorial Sloan
Kettering Cancer Center,” said Chris Haqq M.D., Ph.D., Executive
Vice President of Research and Development and Chief Scientific
Officer of Atara Biotherapeutics. “We look forward to initiating
Phase 3 clinical studies with tabelecleucel by the end of this
year, which are expected to enroll the same EBV+PTLD patient
populations as presented at ASH.”
Updated efficacy findings were presented:
- In 6 patients with rituximab-refractory EBV+PTLD following
solid organ transplant (SOT) the Objective Response Rate (ORR) was
83%, with 5 of 6 patients responding to treatment.
- Additionally, in 5 patients with rituximab-refractory EBV+PTLD
following allogeneic hematopoietic cell transplant (HCT) an ORR of
80% was observed, with 4 of 5 patients responding to
treatment.
- An additional patient with EBV+PTLD following HCT remains
alive, but was not evaluable due to lack of post-baseline
assessment.
- The estimated one-year overall survival for the 12
tabelecleucel treated patients with EBV+PTLD following HCT or SOT,
was 90.9% [95% confidence interval (50.8%, 98.7%)].
Updated safety findings were reported for a total of 23
patients, including an additional 11 patients with other EBV
associated cancers who were included in the safety analysis:
- Tabelecleucel was generally well-tolerated in this study
population, which comprised quite ill, mostly immunosuppressed
patients with multiple comorbidities.
- 5 patients experienced treatment-related serious adverse events
(SAEs).
- One HCT patient died due to PTLD disease progression.
- Two possibly related cases of graft-versus-host disease (GvHD)
in patients with EBV+PTLD following HCT were reported.
- A tumor flare was observed in one patient with EBV+
HIV-associated plasmablastic lymphoma that resolved without
clinical sequelae.
Atara’s collaborating investigators at Memorial Sloan Kettering
Cancer Center presented updated results for ATA230, an allogeneic
T-cell immunotherapy targeting antigens expressed by
cytomegalovirus (CMV), from 50 post-transplant patients with
refractory CMV viremia and disease, including those with disease in
the CNS. The reported response rate of 64% in all patients was
similar in those with CMV viremia and disease. Patients who
responded to ATA230 showed improved 6-month survival of 81.3%
versus 33.3% in patients who did not respond to treatment. One of
the 32 patients who responded to ATA230 died of CMV disease.
ATA230 was generally well-tolerated. Five patients experienced
grade 4 or 5 serious adverse events deemed possibly related to
ATA230.
About EBV+PTLDSince its discovery as the first
human oncovirus, Epstein-Barr virus (EBV) has been implicated in
the development of a wide range of lymphoproliferative disorders,
including lymphomas and other cancers. EBV is widespread in all
human populations and persists as a lifelong, asymptomatic
infection. In immunocompromised patients, such as those undergoing
allogeneic hematopoietic cell transplants (HCT) or solid organ
transplants (SOT), EBV associated post-transplant
lymphoproliferative disorder (EBV+PTLD), represents a
life-threatening condition. Median overall survival in patients
with EBV+PTLD following HCT who have failed rituximab-based first
line therapy is 16-56 days. In EBV+PTLD following SOT, patients
failing rituximab experience increased chemotherapy-induced
treatment-related mortality compared to other lymphoma patients.
One- and two-year survival in patients with high-risk EBV+PTLD
following SOT is 36% and 0%, respectively.
About tabelecleucel (formerly known as ATA129)
Atara's most advanced T-cell immunotherapy in development,
tabelecleucel, is a potential treatment for patients with
rituximab-refractory Epstein-Barr virus (EBV) associated
post-transplant lymphoproliferative disorder (EBV+PTLD), as well as
other EBV associated hematologic and solid tumors, including
nasopharyngeal carcinoma (NPC). In February 2015, FDA granted
tabelecleucel Breakthrough Therapy Designation for EBV+PTLD
following allogeneic hematopoietic cell transplant (HCT) and in
October 2016, tabelecleucel was accepted into the EMA Priority
Medicines (PRIME) regulatory pathway for the same indication,
providing enhanced regulatory support. Atara also received
positive regulatory feedback from Health Canada in September 2017
supporting the submission of tabelecleucel for an expedited
approval pathway. In addition, tabelecleucel has orphan status in
the U.S. and EU. Phase 3 studies of tabelecleucel in EBV+PTLD
following HCT (MATCH study) or solid organ transplant (ALLELE
study) are expected to start in 2017, and a Phase 1/2 study in NPC
is planned for 2018. Tabelecleucel is also available to eligible
patients with EBV associated hematologic and solid tumors through
an ongoing multicenter expanded access protocol (EAP) clinical
study.
About CMVIn patients with weakened immune
systems, including bone marrow and solid organ transplant
recipients, newborns with immature immune systems and those with
human immunodeficiency virus (HIV), cytomegalovirus (CMV) can cause
potentially life-threatening disease or may result in blindness,
brain damage, and deafness. While small molecule antiviral drugs
are approved to treat and prevent CMV infection, there remains a
high unmet need due to viral resistance, modest neurodevelopmental
activity and adverse effects, such as toxicity and reduction in
white blood cell count impairing the ability to fight other
infections, with these agents.
About ATA230ATA230, an allogeneic T-cell
immunotherapy targeting antigens expressed by cytomegalovirus
(CMV), has been investigated in one Phase 1 and two Phase 2
clinical studies in immunocompromised patients with CMV viremia or
disease who are refractory or resistant to antiviral drug treatment
in the post-transplant setting. In October 2017, Atara announced
that ATA230 was granted Rare Pediatric Disease Designation by the
FDA for the treatment of congenital CMV infection, and in September
2017, ATA230 received orphan drug designation in the U.S. for the
treatment of CMV viremia and disease in immunocompromised
patients. The European Medicines Agency (EMA) in October 2016
also issued a positive orphan drug designation opinion for ATA230
for the treatment of CMV infection in patients with impaired
cell-mediated immunity. Atara intends to further evaluate ATA230
development plans with the FDA and other global health authorities
following the initiation of tabelecleucel EBV+PTLD Phase 3
studies.
About Atara Biotherapeutics, Inc. Atara
Biotherapeutics, Inc. (@Atarabio) is a leading T-cell immunotherapy
company developing novel treatments for patients with cancer,
autoimmune and viral diseases. The Company's off-the-shelf, or
allogeneic, T-cells are bioengineered from donors with healthy
immune function and allow for rapid delivery from inventory to
patients without a requirement for pretreatment. Atara's T-cell
immunotherapies are designed to precisely recognize and eliminate
cancerous or diseased cells without affecting normal, healthy
cells. Atara's most advanced T-cell immunotherapy in development,
tabelecleucel (formerly known as ATA129), is being developed for
the treatment of patients with rituximab-refractory Epstein-Barr
virus (EBV) associated post-transplant lymphoproliferative disorder
(EBV+PTLD), as well as other EBV associated hematologic and solid
tumors, including nasopharyngeal carcinoma (NPC). Phase 3 studies
of tabelecleucel in EBV+PTLD following an allogeneic hematopoietic
cell transplant (MATCH study) or solid organ transplant (ALLELE
study) are expected to start in 2017, and a Phase 1/2 study of
tabelecleucel in combination with Merck's anti-PD-1 (programmed
death receptor-1) therapy, KEYTRUDA® (pembrolizumab), in patients
with platinum-resistant or recurrent EBV associated NPC is planned
for 2018. Tabelecleucel is also available to eligible patients with
EBV associated hematologic and solid tumors through an ongoing
multicenter expanded access protocol (EAP) clinical study.
Allogeneic ATA188 and autologous ATA190, the Company's T-cell
immunotherapies using a complementary targeted antigen recognition
technology, target specific EBV antigens believed to be important
for the potential treatment of multiple sclerosis (MS). A Phase 1
clinical study of autologous ATA190 in patients with progressive MS
is ongoing. Atara also initiated a multinational, multicenter Phase
1 allogeneic ATA188 clinical study in patients with progressive or
relapsing-remitting MS in October 2017. Atara's clinical pipeline
also includes ATA520 targeting Wilms Tumor 1 (WT1) and ATA230
directed against cytomegalovirus (CMV).
Forward-Looking StatementsThis 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
Company’s intention to start Phase 3 studies of tabelecleucel in
EBV+PTLD following a hematopoietic cell transplant or solid organ
transplant in 2017 and a Phase 1/2 study of tabelecleucel in
combination with Merck's anti-PD-1 therapy, KEYTRUDA®, in patients
with platinum-resistant or recurrent EBV associated NPC in 2018;
and the Company’s intention to further evaluate ATA230 development
plans with the FDA and other global health authorities following
the initiation of the tabelecleucel EBV+PTLD Phase 3 studies.
Because such statements deal with future events and are based on
Atara Biotherapeutics’ current expectations, they are subject to
various risks and uncertainties and actual results, performance or
achievements of Atara Biotherapeutics 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 those discussed under the heading "Risk
Factors" in Atara Biotherapeutics’ quarterly report on Form 10-Q
filed with the Securities and Exchange Commission (SEC) on November
9, 2017, including the documents incorporated by reference therein,
and subsequent filings with the SEC. Except as otherwise required
by law, Atara Biotherapeutics 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.
INVESTOR & MEDIA CONTACTS:
Investors: John Craighead, Atara
Biotherapeutics 650-410-3012 jcraighead@atarabio.com
Steve Klass, Burns McClellan 212-213-0006 x331
sklass@burnsmc.com
Media: Justin Jackson, Burns McClellan
212-213-0006 x327 jjackson@burnsmc.com
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