Atossa Therapeutics Inc., a clinical-stage biopharmaceutical company focused on developing innovative treatments for breast cancer, has announced the full results from the I-SPY 2 Endocrine-Optimization Sub-Study evaluating low-dose (Z)-endoxifen. The Phase 2 trial assessed the compound as a neoadjuvant treatment in 20 women with stage II/III estrogen-receptor-positive, HER2-negative breast cancer. Key findings revealed rapid Ki-67 suppression and significant MRI-confirmed tumor shrinkage with a favorable safety profile. Atossa's (Z)-endoxifen, which shows potential bone-protective effects and minimal endometrial activity, is being further evaluated in ongoing trials, including its combination with the CDK4/6 inhibitor abemaciclib. The company is actively enrolling participants for additional cohorts in the I-SPY 2 trial, prioritizing the development of (Z)-endoxifen for metastatic breast cancer treatment.