Atossa Therapeutics Announces Plans to Pursue Metastatic Breast Cancer Indication for (Z)-Endoxifen and Continued Engagement with FDA on Additional Indications

Core Viewpoint - Atossa Therapeutics is strategically pursuing a metastatic breast cancer indication for (Z)-endoxifen, believing it offers a more efficient regulatory pathway to address urgent medical needs in this area [1][4]. Group 1: Unmet Medical Need - Metastatic breast cancer presents a significant unmet medical need, with current treatments often having limited durability and substantial side effects [2]. - (Z)-endoxifen is a selective estrogen receptor modulator (SERM) that has shown promising results in previous clinical trials, indicating its potential to address this treatment gap [2]. Group 2: Clinical Trial Data - Early-stage trials of (Z)-endoxifen have demonstrated encouraging results, reinforcing its potential as a transformative therapy for breast cancer [3]. - Key findings include: - In CDK4/6i-naïve patients, (Z)-endoxifen more than doubled the median progression-free survival (PFS) compared to tamoxifen (7.2 months vs. 2.4 months) [5]. - Patients who progressed on tamoxifen and switched to (Z)-endoxifen experienced clinical benefits, including prolonged stable disease exceeding 2-3 years in some cases [5]. - (Z)-endoxifen has a favorable safety profile, showing no unexpected safety concerns beyond those typically seen with tamoxifen [5]. Group 3: Strategic Advantages - Pursuing an initial approval in metastatic breast cancer is seen as an efficient regulatory and clinical path to market, potentially allowing for quicker access to patients in need [4]. - This strategy also lays the groundwork for expanding (Z)-endoxifen's role in earlier-stage disease settings, where it has shown promise in reducing tumor proliferation and preventing recurrence [4]. Group 4: Broader Indications - Atossa is committed to demonstrating the broad clinical utility of (Z)-endoxifen across the breast cancer treatment spectrum, including prevention and neoadjuvant therapy [5][6]. - Prior studies suggest that (Z)-endoxifen can significantly reduce breast tissue density and estrogen receptor activity, which are key risk factors for developing breast cancer [6]. - Data from early-stage patients indicate that (Z)-endoxifen may effectively reduce tumor proliferation, leading to improved surgical outcomes and long-term prognosis [7]. Group 5: Company Overview - Atossa Therapeutics is a clinical-stage biopharmaceutical company focused on transforming breast cancer treatment through innovative science and patient-centered solutions [8]. - The company's lead product candidate, (Z)-endoxifen, is designed for use across the breast cancer spectrum, including prevention, neoadjuvant, adjuvant, and metastatic settings [8].