Atossa Therapeutics Inc (ATOS)

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Atossa Therapeutics’ Phase 2 Endoxifen Breast Cancer Study Produces Substantially Positive Results Allowing Study to be Halted Early

SEATTLE, Feb. 02, 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 with a current focus on breast cancer and COVID-19, today announces that based on substantially positive results achieved with the patients enrolled to date in its Australian open-label Phase 2 clinical study of oral Endoxifen administered in the “window of opportunity” between diagnosis of breast cancer and surgery, Atossa has halted the study and is accelerating its Endoxifen program in the United States.

“It is a welcome event to halt an ongoing clinical trial because the results are so overwhelmingly positive,” commented Steven Quay, M.D., Ph.D., Atossa’s President and Chief Executive Officer. “Data from the first six patients in our Australian Phase 2 window of opportunity study shows a 74% average reduction in Ki-67, which is a common measure of tumor cell activity, and that at the time of surgery all patients had Ki-67 levels lower than 25%, which is an important threshold to improve long-term survival as identified in studies by others. We believe that additional enrollment will not alter these positive results so we are terminating the study early. This saves at least a year on the development time line allowing us to accelerate clinical development in the Unites States. We look forward to reporting final data from all patients in the study and sharing our continued progress in the development of oral Endoxifen.”

The study enrolled seven 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 received 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 Phase 2 study was conducted on behalf of Atossa by Avance Clinical, a leading Australian CRO.

The American Cancer Society (ACS) estimates that in 2020, 276,480 women will be diagnosed with breast cancer in the U.S. Every two minutes an American woman is diagnosed with breast cancer and 42,170 die each year.

Atossa is 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.

https://atossatherapeutics.com/atossa-therapeutics-phase-2-endoxifen-breast-cancer-study-produces-substantially-positive-results-allowing-study-to-be-halted-early/