Atossa Therapeutics, Inc. (NASDAQ:
ATOS), a
clinical-stage biopharmaceutical company seeking to discover and
develop innovative medicines in areas of significant unmet medical
need with a current focus on breast cancer and COVID-19, today
announced positive interim results from its Phase 2 study of oral
Endoxifen to treat breast cancer in the window of opportunity
between diagnosis of breast cancer and surgery. A statistically
significant (p = 0.031) reduction of about 74% in tumor cell
proliferation was achieved over the 22 days of dosing.
Proliferation was measured by Ki-67, a recognized standard
measurement of breast cancer cell proliferation.
Window of Opportunity Phase 2 Study Interim
Results
The purpose of this study is to determine if Atossa’s oral
Endoxifen reduces breast cancer tumor cell proliferation as
measured by several biomarkers, including Ki-67. The open-label
study was designed to permit an interim analysis of the Ki-67
change. The requirement was to achieve a meaningful Ki-67 change in
at least two of eight patients. All patients (N=6) experienced a
significant reduction in Ki-67. A summary of these results
includes:
- Ki-67 was reduced by more than 50% in every patient in the
window of opportunity between initial biopsy and surgery, with an
overall reduction of 74%.
- All six patients had a Ki-67 below 25% after treatment. In a
paper entitled, “Prognostic value of different cut-off levels of
Ki-67 in breast cancer: a systematic review and meta-analysis of
64,196 patients,” Ki-67 was an independent prognostic value for
predicting overall survival in ER+ breast cancer patients. Ki-67
levels below 25% were associated with the lowest risk of death in
this systematic review and meta-analysis.
- Treatment ranged from 16-40 days with an average of 22
days.
- There were no safety or tolerability issues, including
vasomotor symptoms such as hot flashes and night sweats, which are
often a tolerability challenge for patients on tamoxifen.
“These are the most significant and exciting results achieved in
any of our Endoxifen clinical studies to date,” commented Steven C.
Quay, Ph.D., M.D., Atossa’s CEO and President. “In designing the
study, we had hoped that we could reduce tumor cell proliferation
in at least two out of the first eight patients. The results
surpassed our expectations with a substantial reduction in tumor
cell activity in every one of the six patients treated. This has
the potential to validate the role of Endoxifen in reducing tumor
proliferation between diagnosis and surgery. We are evaluating the
role that Endoxifen therapy in the window of opportunity might play
in helping some patients avoid or defer surgery, improving surgical
outcomes by avoiding mastectomy and improving cosmetic results, and
potentially replacing other pre-surgical chemotherapies or
endocrine therapies with Endoxifen.”
"I have been very impressed with the rapid impact Endoxifen has
had on tumor proliferation in these patients in the neoadjuvant
setting and also the absence of certain side effects, like hot
flashes,” commented Vinod Ganju, MBBS, FRACP, principal
investigator. “It is my pleasure to be playing a role in developing
a much-needed therapy that could improve outcomes for breast cancer
patients. Given the results to date, we are interested in expanding
the use of Endoxifen to other clinical settings, for example, to
metastatic breast cancer patients."
Results of the study are consistent with the results in a recent
compassionate use, or expanded access, single-patient study with
oral Endoxifen. At the end of 2018, the FDA approved a single
patient IND for a breast cancer patient to receive our oral
Endoxifen in the window of opportunity. That patient experienced a
50% reduction in Ki-67 after taking daily doses for 20 days prior
to her surgery. Based on these results, an additional compassionate
use approval was granted by the FDA for the same patient, who has
continued to take oral Endoxifen for over a year in the adjuvant
setting following her surgery.
Based on these positive results, Atossa is continuing to enroll
the remaining 19 patients in the study and will then seek
regulatory approval to move into a Phase 3 study.
About the Endoxifen Window of Opportunity Phase 2
Study
Atossa’s Phase 2 study of its oral Endoxifen in the window of
opportunity between diagnosis of breast cancer and surgery is being
conducted in Australia. The study will enroll up to 25
newly-diagnosed patients with ER+ and human epidermal growth factor
receptor 2 negative (HER2-) stage 1 or 2 invasive breast cancer,
requiring mastectomy or lumpectomy. Patients receive Atossa’s
proprietary oral Endoxifen for at least 14 days from the time of
diagnosis up to the day of surgery. The primary endpoint is to
determine if the administration of oral Endoxifen reduces the tumor
activity as measured by Ki-67. The secondary endpoints are safety
and tolerability and assessment of the study drug on expression
levels of both estrogen and progesterone receptors. The impact on
additional markers of cellular activity will also be explored. The
Phase 2 study is being conducted on behalf of Atossa by Avance
Clinical, which successfully completed four Phase 1 studies of
Atossa’s Endoxifen.
About Window of Opportunity Therapy
The goal of pharmaceutical treatment in patients with
non-metastatic breast cancer after surgery (also called adjuvant
therapy), for example by chemotherapy or hormone therapy, is
typically to reduce the risk of the cancer recurring. Administering
therapy in the window of opportunity prior to surgery (also called
neoadjuvant therapy) may also reduce the risk of recurrence;
however, the primary goal in this setting is typically to downstage
the tumor and provide information regarding treatment response.
Downstaging the tumor may convert a large, inoperable tumor in
selected frail patients into an operable tumor that may allow
breast conserving surgery in place of mastectomy. This may also
improve cosmetic outcomes, and reduce postoperative complications
such as lymphedema. Successful neoadjuvant therapy may allow some
patients to avoid surgery altogether or defer surgery under a
“watch and wait” strategy. The results of neoadjuvant therapy may
also be used to guide adjuvant treatment recommendations as the
therapy can provide the opportunity to obtain imaging studies,
tumor specimens, and blood samples prior to and after the
neoadjuvant treatment, which may assist in the identification of
tumor or patient specific adjuvant therapies.
Based on these strong study results, Atossa will be evaluating a
number of potential clinical benefits and potential indications for
its oral Endoxifen in the window of opportunity setting. These may
include avoidance of surgery in some patients, such as older and/or
frail patients, allowing for breast conservation surgery, and use
of Endoxifen in place of other neoadjuvant therapies such as
chemotherapy, aromatase inhibitors and other endocrine therapies
like tamoxifen. Reduction in Ki-67 in and of itself may not,
however, be an indication that the FDA or other regulatory
authorities will approve. Atossa plans to seek input from
regulatory authorities about potential approvable indications for
Endoxifen in the window of opportunity and the design of future
clinical studies.
About Atossa Therapeutics
Atossa Therapeutics, Inc., is a clinical-stage biopharmaceutical
company seeking to discover and develop innovative medicines in
areas of significant unmet medical need with a current focus on
breast cancer and COVID-19. For more information, please visit
www.atossatherapeutics.com.
Forward-Looking Statements
Forward-looking statements in this press release, which Atossa
undertakes no obligation to update, are subject to risks and
uncertainties that may cause actual results to differ materially
from the anticipated or estimated future results, including the
risks and uncertainties associated with any variation between
interim and final clinical results, actions and inactions by the
FDA, the outcome or timing of regulatory approvals needed by Atossa
including those needed to commence studies such as the COVID-19
HOPE Study, lower than anticipated rate of patient enrollment,
estimated market size of drugs under development, the safety and
efficacy of Atossa's products, performance of clinical research
organizations and investigators, obstacles resulting from
proprietary rights held by others such as patent rights, whether
reduction in Ki-67 or any other result from a neoadjuvant study is
an approvable endpoint for oral Endoxifen, and other risks detailed
from time to time in Atossa's filings with the Securities and
Exchange Commission, including without limitation its periodic
reports on Form 10-K and 10-Q, each as amended and supplemented
from time to time.
Atossa Therapeutics Company Contact:
Atossa Therapeutics, Inc.Kyle GuseCFO and General Counsel(O)
800-351-3902kyle.guse@atossainc.com
Investor Relations Contact:
CoreIROffice: 516.222.2560IR@atossainc.com
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