Atossa Therapeutics Announces Expanded Research Agreement with Weill Cornell Medicine to Further Evaluate Synergy Between Antibody Drug Conjugates (ADCs) and (Z)-Endoxifen

SEATTLE, April 29, 2024 (GLOBE NEWSWIRE) -- Atossa Therapeutics, Inc. (Nasdaq: ATOS) (“Atossa” or the “Company”) today announced an expanded research agreement with Weill Cornell Medicine to explore the potential synergy between antibody drug conjugates (ADCs) and (Z)-endoxifen. Atossa is a clinical stage biopharmaceutical company developing innovative medicines in areas of significant unmet medical need in oncology with a focus on breast cancer.

The expanded research agreement with Weill Cornell will build on previously conducted in silico research that determined a strong clinically relevant anti-tumor effect when combining ADCs and (Z)-endoxifen. Specifically, the artificial intelligence modeling showed that the combination of (Z)-endoxifen with ADCs will enhance the pro-apoptotic effects seen after administration of either therapy alone. This computer-based analysis was further validated by previously published preclinical studies looking at the effect of selective estrogen receptor modulator (SERM) and chemotherapy combination strategies. Seven key opinion leaders also confirmed the strong scientific rationale and proposed efficacy of combining (Z)-endoxifen with ADCs in patients with advanced breast cancer.

ADCs are a specially designed class of therapeutics that target cancer cells expressing specific antigens using directed antibody-drug delivery. The therapies bind to targets on the cell, causing the release of a cytotoxic drug designed to kill the cancer cell. The Weill Cornell research will focus on the combination of (Z)-endoxifen and two FDA-approved ADCs, TRODELVY® and ENHERTU®. Both are currently approved as monotherapies to treat metastatic breast cancer. Additionally, TRODELVY is approved to treat adults with metastatic bladder and urinary tract cancers.

“The in silico modeling analysis identified multiple synergistic mechanism of actions of ADCs and (Z)-endoxifen, including cell cycle arrest and upregulation of pro-apoptotic mechanisms,” said Dr. Steven Quay, Atossa’s President and Chief Executive Officer. “This means that the combination may be far greater than the sum of the individual parts. The work we are doing with Weill Cornell is designed to validate the in silico modeling in well-established cell culture models of breast cancer. Once we have this data, we expect to move quickly into a clinical study investigating a (Z)-endoxifen / ADC combination in patients with late-line metastatic breast cancer.”

About (Z)-Endoxifen
(Z)-endoxifen is the most potent Selective Estrogen Receptor Modulator (SERM) for estrogen receptor inhibition and also causes estrogen receptor degradation. It has also been shown to have efficacy in the setting of patients with tumor resistance to other hormonal treatments. In addition to its potent anti-estrogen effects, (Z)-endoxifen has been shown to target PKCβ1, a known oncogenic protein, at clinically attainable blood concentrations. Finally, (Z)-endoxifen appears to deliver similar or even greater bone agonistic effects while resulting in little or no endometrial proliferative effects compared with standard treatments, like tamoxifen.

Atossa is developing a proprietary oral formulation of (Z)-endoxifen that does not require liver metabolism to achieve therapeutic concentrations and is encapsulated to bypass the stomach, as acidic conditions in the stomach convert a significant proportion of (Z)-endoxifen to the inactive (E)-endoxifen. Atossa’s (Z)-endoxifen has been shown to be well tolerated in Phase 1 studies and in a small Phase 2 study of women with breast cancer. (Z)-endoxifen is currently being studied in four Phase 2 trials: one in healthy women with measurable breast density, one in women diagnosed with ductal carcinoma in situ, and two other studies including the EVANGELINE study in women with ER+/HER2- breast cancer. Atossa’s (Z)-endoxifen is protected by three issued U.S. patents and numerous pending patent applications.

About Atossa Therapeutics
Atossa Therapeutics, Inc. is a clinical-stage biopharmaceutical company developing innovative medicines in areas of significant unmet medical need in oncology with a focus on using (Z)-endoxifen to prevent and treat breast cancer. For more information, please visit www.atossatherapeutics.com. 

TRODELVY® and ENHERTU® are registered trademarks of Gilead Sciences and Daiichi Sankyo Company, Limited, respectively.

Contact:
Eric Van Zanten
VP, Investor and Public Relations
610-529-6219
eric.vanzanten@atossainc.com 

FORWARD LOOKING STATEMENTS
This press release contains certain information that may constitute forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. We may identify these forward-looking statements by the use of words such as “expect,” “potential,” “continue,” “may,” “will,” “should,” “could,” “would,” “seek,” “intend,” “plan,” “estimate,” “anticipate,” “believe,” “future,” or other comparable words. Forward-looking statements in this press release are subject to risks and uncertainties that may cause actual results, outcomes, or the timing of actual results or outcomes, including the timing of data related to the (Z)-endoxifen program, the potential of (Z)-endoxifen as a breast cancer prevention and treatment agent, and the potential safety and tolerability profile of (Z)-endoxifen, to differ materially from those projected or anticipated, including risks and uncertainties associated with: macroeconomic conditions and increasing geopolitical instability; the expected timing of releasing data; any variation between interim and final clinical results; actions and inactions by the FDA and foreign regulatory bodies; the outcome or timing of regulatory approvals needed by Atossa, including those needed to continue our planned (Z)-endoxifen trials; our ability to satisfy regulatory requirements; our ability to comply with the continued listing requirements of the Nasdaq Stock Market; our ability to successfully develop and commercialize new therapeutics; the success, costs and timing of our development activities, including our ability to successfully initiate or complete our clinical trials, including our (Z)-endoxifen trials; our anticipated rate of patient enrollment; our ability to contract with third-parties and their ability to perform adequately; our estimates on the size and characteristics of our potential markets; our ability to successfully defend litigation and other similar complaints and to establish and maintain intellectual property rights covering our products; whether we can successfully complete our clinical trial of oral (Z)-endoxifen in women with mammographic breast density and our trials of (Z)-endoxifen in women with breast cancer, and whether the studies will meet their objectives; our expectations as to future financial performance, expense levels and capital sources, including our ability to raise capital; our ability to attract and retain key personnel; our anticipated working capital needs and expectations around the sufficiency of our cash reserves; and other risks and uncertainties detailed from time to time in Atossa’s filings with the Securities and Exchange Commission, including without limitation its Annual Reports on Form 10-K and Quarterly Reports on 10-Q. Forward-looking statements are presented as of the date of this press release. Except as required by law, we do not intend to update any forward-looking statements, whether as a result of new information, future events or circumstances or otherwise.