Atossa Therapeutics Announces Positive FDA Feedback, Advances Toward IND for (Z)-Endoxifen Clinical Program in ER+/HER2- Metastatic Breast Cancer

Core Viewpoint - Atossa Therapeutics has received positive feedback from the FDA regarding its proposed dose optimization trial for (Z)-endoxifen, aimed at treating ER+/HER2- metastatic breast cancer, which is a significant milestone for the company [1][2][3] FDA Feedback and Clinical Development - The FDA's constructive responses affirm key elements of Atossa's clinical development plan, eliminating the need for a virtual pre-IND meeting and facilitating a potential IND submission by Q4 2025 [2][3] - The FDA supports Atossa's dose optimization strategy and agrees with the existing nonclinical data package, enhancing confidence in the company's regulatory approach [3][7] Dose Optimization Strategy - The FDA has confirmed that existing clinical and nonclinical data are sufficient to initiate Part A (monotherapy) of the proposed dose optimization study, providing guidance on study design enhancements [7] - Atossa plans to explore multiple dose levels in its upcoming clinical study to define the optimal dose for combination therapy, aligning with the FDA's Project Optimus initiative [6][7] Combination Study Support - The FDA agrees with the scientific rationale for combining (Z)-endoxifen with standard-of-care therapies for breast cancer, which helps narrow the strategic approach for the potential IND [7] Cardiac Safety and Nonclinical Data - The FDA has confirmed that Atossa's cardiac safety assessment plan, including ECGs and QT interval monitoring, is sufficient for the monotherapy portion of the trial [7] - The existing nonclinical safety data package is deemed adequate, allowing Atossa to proceed without additional toxicity studies [7] Next Steps and Strategic Momentum - Atossa will announce plans for the target patient population, combination backbone, and overall trial design for the upcoming dose-ranging study in the coming weeks [7] - The company is positioned to maintain strategic momentum and meet regulatory milestones, aiming to deliver (Z)-endoxifen to patients and enhance shareholder value [5][10] About (Z)-Endoxifen - (Z)-endoxifen is a potent Selective Estrogen Receptor Modulator (SERM) that inhibits and potentially degrades estrogen receptors, showing activity in tumors resistant to other therapies [8][10] - Atossa is developing an oral formulation of (Z)-endoxifen that is enteric-coated to ensure optimal bioavailability and therapeutic integrity [9] Clinical Trials and Intellectual Property - Atossa is prioritizing (Z)-endoxifen for metastatic breast cancer, currently evaluating it in three Phase 2 trials [10] - The program is supported by a growing global intellectual property portfolio, including recently issued U.S. patents [10]