Atossa Therapeutics Announces Receipt of FDA Safe to Proceed Letter for Treatment of an Ovarian Cancer Patient with Oral Endoxifen Under Expanded Access Pathway

Seattle, Washington, UNITED STATES

SEATTLE, March 11, 2021 (GLOBE NEWSWIRE) -- Atossa Therapeutics, Inc. (Nasdaq: ATOS), a clinical-stage biopharmaceutical company seeking to discover and develop innovative medicines in areas of significant unmet medical need in oncology and infectious diseases today announced the FDA has issued a “Safe to Proceed” letter under their Expanded Access Pathway, permitting the use of Atossa’s oral Endoxifen as a treatment in an ovarian cancer patient. The patient is being treated at the University of Washington Medical Center by Dr. Barbara Goff, Surgeon-in-Chief.

“Dr. Goff recently contacted Atossa with an interest in gaining access to our Endoxifen under the FDA’s expanded access, or compassionate use, program for one of her patients,” commented Steven Quay, M.D., Ph.D., Atossa’s President and CEO. “The patient has recurrent ovarian cancer and recently underwent functional molecular genomic testing, using 3D tumor organoid cultures grown in the laboratory from the patient’s tumor. The organoid testing revealed that the combination of Endoxifen and alpelisib produced an exceptional tumor response. We are gratified to be able to help this patient and are anxious to follow her response to this drug combination. If the drug combination shows promise in this patient, Atossa will consider doing additional clinical studies in patients with ovarian cancer.”

Under the FDA expanded access program, the use of Atossa's proprietary oral Endoxifen is restricted solely to this patient. Approval from the Institutional Review Board (IRB) must be obtained prior to providing oral Endoxifen to this patient.

About FDA Expanded Access

Sometimes called "compassionate use," expanded access is a potential pathway for a patient with serious disease or condition, or an immediately life-threatening condition, to gain access to an investigational medical product (drug, biologic, or medical device) for treatment outside of clinical trials when no comparable or satisfactory alternative therapy options are available. For more information about this process, please see the FDA website: FDA Expanded Use Website

About Atossa's Proprietary Endoxifen

Endoxifen is an active metabolite of tamoxifen, which is an FDA-approved drug to treat ovarian and breast cancer. Tamoxifen itself must be broken down by the liver into active compounds (metabolites), of which Endoxifen is the most active. In third party preclinical studies, endocrine-sensitive and letrozole-resistant breast tumors, Z-endoxifen resulted in robust antitumor and antiestrogenic activity compared to tamoxifen and aromatase inhibitor monotherapy.

Atossa has been developing its proprietary oral Endoxifen for breast cancer and other breast conditions and has successfully completed five clinical studies with this drug, including an expanded access study of a female breast cancer patient who has been taking oral Endoxifen for over two years, with no recurrence to date.

About Ovarian Cancer

In 2021 ovarian cancer will be diagnosed in about 21,400 women in the United States and about 13,770 women will die from the disease. Ovarian cancer ranks fifth in cancer deaths among women, accounting for more deaths than any other cancer of the female reproductive system.

About Alpelisib

Alpelisib was approved in the United States in 2019 for use in combination with the endocrine therapy fulvestrant, to treat postmenopausal women, and men, with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative, PIK3CA-mutated, advanced or metastatic breast cancer following progression on or after an endocrine-based regimen. PIK3 is a family of lipid kinases and one of them, PIK3CA, has mutations or gene amplification detected in 30.5% of all ovarian cancers and 45% of the endometrioid and clear cell subtypes. Alpelisib is marketed by Novartis under the brand name of Piqray.

About Atossa Therapeutics

Atossa Therapeutics, Inc. (Nasdaq: ATOS) is a clinical-stage biopharmaceutical company seeking to discover and develop innovative medicines in areas of significant unmet medical need in oncology and infectious diseases, with a current focus on breast cancer and COVID-19. For more information, please visit

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 development plans, any variation between interim, preliminary 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 of AT-H201, AT-301 and Endoxifen, 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, whether change in mammographic breast density is an approvable end point 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.

Company Contact:
Atossa Therapeutics, Inc.
Kyle Guse, CFO and General Counsel
Office: (866) 893-4927

Investor Relations Contact:
Core IR
Office:(516) 222-2560

Source: Atossa Therapeutics, Inc.

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