Atossa targets metastatic breast cancer with (Z)-endoxifen

Published 11/03/2025, 13:22
Atossa targets metastatic breast cancer with (Z)-endoxifen

SEATTLE - Atossa Therapeutics, Inc. (NASDAQ:ATOS), a clinical-stage biopharmaceutical company with a market capitalization of $93 million, announced today its strategic decision to focus on metastatic breast cancer indication for its lead product candidate, (Z)-endoxifen. The company’s stock has declined over 50% in the past six months, though InvestingPro analysis suggests the current price is near its Fair Value. The company believes this move will provide a more efficient regulatory pathway for delivering the drug to patients in critical need.

Metastatic breast cancer, which is cancer that has spread beyond the breast to other parts of the body, represents a significant area of unmet medical need. Current treatments often have limited effectiveness and considerable side effects. (Z)-endoxifen, a selective estrogen receptor modulator (SERM), has demonstrated promise in early clinical trials, suggesting it could address this gap.

The company’s decision is supported by data from Phase 1 and Phase 2 trials. These trials have shown that (Z)-endoxifen can more than double the median progression-free survival (PFS) in patients who have not previously received CDK4/6 inhibitors, compared to tamoxifen. Additionally, patients who progressed on tamoxifen and then switched to (Z)-endoxifen saw clinical benefits, including partial responses and prolonged stable disease, in some cases exceeding two to three years. The drug has also been generally well-tolerated, with a safety profile comparable to tamoxifen. According to InvestingPro data, Atossa maintains a strong liquidity position with a current ratio of 13.3, and holds more cash than debt on its balance sheet, though the company is currently burning through cash rapidly.

Dr. Steven Quay, Chairman and CEO of Atossa Therapeutics, stated, "Our decision to advance (Z)-endoxifen into a metastatic breast cancer indication underscores our unwavering commitment to developing a best-in-class therapy for women facing this devastating disease." He added that the clinical data generated to date supports the potential of (Z)-endoxifen to benefit patients who have exhausted other treatment options.

Atossa’s strategy to prioritize a metastatic indication could potentially allow for a more rapid introduction of (Z)-endoxifen to the market. This approach may also lay the groundwork for the expansion of the drug’s use into earlier stages of the disease, where it has shown potential in reducing tumor proliferation and preventing recurrence.

Beyond metastatic disease, Atossa remains committed to exploring (Z)-endoxifen’s utility in breast cancer prevention and as a neoadjuvant therapy. The company is actively engaging with the FDA to define regulatory paths forward for these additional indications.

Atossa Therapeutics focuses on transforming breast cancer treatment and is dedicated to advancing its clinical research programs to improve patient outcomes. The information presented in this article is based on a press release statement from Atossa Therapeutics.

In other recent news, Atossa Therapeutics, Inc. has reported progress in its clinical programs for breast cancer treatment, particularly with its drug, (Z)-endoxifen. The company completed the KARISMA-Endoxifen Phase 2 Study, showing significant reductions in mammographic breast density with both 1 mg and 2 mg doses, which were well tolerated. Additionally, Atossa is advancing its EVANGELINE trial, which has shown promising initial results in tumor suppression for premenopausal women with ER+/HER2- breast cancer. Despite a setback with the Patent Trial and Appeal Board deeming all claims in Atossa’s ’334 patent unpatentable, the company has secured a new patent for sustained release compositions of endoxifen. Atossa plans to file a new Continuation Patent Application and continues to innovate in the oncology space. The company has also been notified by Nasdaq regarding non-compliance with the minimum bid price requirement but is evaluating options to regain compliance. These developments reflect Atossa’s ongoing efforts to advance its breast cancer treatments while navigating regulatory and market challenges.

This article was generated with the support of AI and reviewed by an editor. For more information see our T&C.

Latest comments

Risk Disclosure: Trading in financial instruments and/or cryptocurrencies involves high risks including the risk of losing some, or all, of your investment amount, and may not be suitable for all investors. Prices of cryptocurrencies are extremely volatile and may be affected by external factors such as financial, regulatory or political events. Trading on margin increases the financial risks.
Before deciding to trade in financial instrument or cryptocurrencies you should be fully informed of the risks and costs associated with trading the financial markets, carefully consider your investment objectives, level of experience, and risk appetite, and seek professional advice where needed.
Fusion Media would like to remind you that the data contained in this website is not necessarily real-time nor accurate. The data and prices on the website are not necessarily provided by any market or exchange, but may be provided by market makers, and so prices may not be accurate and may differ from the actual price at any given market, meaning prices are indicative and not appropriate for trading purposes. Fusion Media and any provider of the data contained in this website will not accept liability for any loss or damage as a result of your trading, or your reliance on the information contained within this website.
It is prohibited to use, store, reproduce, display, modify, transmit or distribute the data contained in this website without the explicit prior written permission of Fusion Media and/or the data provider. All intellectual property rights are reserved by the providers and/or the exchange providing the data contained in this website.
Fusion Media may be compensated by the advertisers that appear on the website, based on your interaction with the advertisements or advertisers
© 2007-2025 - Fusion Media Limited. All Rights Reserved.