Atossa Therapeutics Receives Positive FDA Feedback, Boosts Clinical Outlook with Strategic Advancements

Atossa Therapeutics has received positive FDA feedback for its clinical program for Z-endoxifen in ER+/HER2- metastatic breast cancer. The FDA has agreed to the proposed plans, deemed nonclinical safety data and cardiac safety assessment plan adequate, and validated key components of the clinical development strategy. Analyst Emily Bodnar from H.C. Wainwright maintains a Buy rating with a $7.00 price target.

Atossa Therapeutics (NASDAQ: ATOS) has received positive feedback from the U.S. Food and Drug Administration (FDA) regarding its clinical program for Z-endoxifen in treating estrogen receptor positive (ER+), human epidermal growth factor receptor 2 negative (HER2-) metastatic breast cancer. The FDA's responses affirm key elements of Atossa's clinical development plan, eliminating the need for a pre-Investigational New Drug (IND) meeting and accelerating the path toward an IND submission in Q4 2025.

The FDA has approved Atossa's dose optimization strategy, supported the scientific rationale for combining Z-endoxifen with standard-of-care therapies, and confirmed the adequacy of the existing nonclinical data package. The agency also agreed on the cardiac safety assessment plan for monotherapy, which includes serial electrocardiograms (ECGs) and QT interval monitoring.

Analyst Emily Bodnar from H.C. Wainwright maintains a Buy rating with a $7.00 price target, reflecting the positive impact of this regulatory milestone on Atossa's stock performance.

Atossa plans to submit an IND in Q4 2025 and will soon announce specific details about the target patient population and trial design. The development aligns with the FDA's Project Optimus initiative, which emphasizes data-driven dose exploration to maximize benefits while minimizing toxicity.

For ER+/HER2- metastatic breast cancer patients—who represent approximately 70% of all breast cancer cases—this development could eventually lead to an important new therapeutic option. Z-endoxifen, an active metabolite of tamoxifen, directly binds to estrogen receptors with potentially superior efficacy compared to current options.

The company now faces important upcoming decisions regarding patient population selection, combination therapy backbone, and overall trial design—all critical factors that will determine the ultimate clinical and commercial potential of this program.

References:

[1] https://www.stocktitan.net/news/ATOS/atossa-therapeutics-announces-positive-fda-feedback-advances-toward-pdh6ocu9e3nc.html
[2] https://www.marketscreener.com/news/atossa-therapeutics-announces-positive-fda-feedback-advances-toward-ind-for-z-endoxifen-clinical-ce7c5fd9de8cfe20
[3] https://www.prnewswire.com/news-releases/atossa-therapeutics-announces-positive-fda-feedback-advances-toward-ind-for-z-endoxifen-clinical-program-in-erher2--metastatic-breast-cancer-302516013.html