Atossa Therapeutics Announces Final Data from Phase 2 Endoxifen Breast Cancer Study Primary Endpoint Met: 65.1% Reduction in Biomarker Ki-67; Secondary Endpoint Met: Endoxifen Safe and Well Tolerated

About this update from Atossa Therapeutics, Inc.

[{"type":"text","content":"SEATTLE, June 09, 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 announced the following final data from its Phase 2 clinical study of oral Endoxifen administered in the “window of opportunity” between diagnosis of breast cancer and surgery. Primary Endpoint Met: Reduction in Ki-67 was achieved. Ki-67, a common measure of tumor cell activity, was reduced from an average of 25.6% at screening to 6% on the day of surgery, a 65.1% reduction. Ki-67 was reduced below 25% for all patients, which is potentially clinically meaningful because studies by others have shown that a reduction below 25% improves long term survival. Secondary Endpoints Were as Follows: Safety and tolerability: All adverse events were mild and considered related to the study drug. There were no abnormal laboratory findings (serum chemistry, hematology, coagulation, urinalysis) and no differences in vital signs, physical examinations and ECGs. Based on these results, Endoxifen was considered safe and well tolerated in this study. No adverse events led to discontinuation of the study. Other Results: Estrogen receptor expression decreased from 100% at screening to 88.6% on the day of surgery and progesterone receptor expression increased from 84.3% at screening to 92.9% on the day of surgery. No correlation between Ki-67 expression and Endoxifen levels was observed. “Based on these favorable results, we are taking a number of steps to quickly advance our development of Endoxifen,” commented Steven Quay, M.D., Ph.D., Atossa’s President and Chief Executive Officer. “We have begun the formal non-clinical toxicology program that will be needed for a New Drug Application to seek marketing approval for Endoxifen and plan to apply to the U.S. FDA for approval to conduct a clinical study here in the United States as soon as possible. We expect the next clinical study to measure pathological complete response in the neoadjuvant setting. Although there are several FDA-approved neoadjuvant therapies for breast cancers that are not estrogen receptor positive (ER+), currently there are very few approved therapies for the approximately 78% of breast cancers, which ar...

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