Atossa Therapeutics Inc., a clinical-stage biopharmaceutical company, presented four clinical trial updates related to its investigational drug (Z)-endoxifen at the 2025 San Antonio Breast Cancer Symposium (SABCS), held December 9-12, 2025. The presentations included initial results from the RECAST DCIS multicenter platform trial, which is evaluating active surveillance and novel endocrine therapy agents for the management of ductal carcinoma in situ (DCIS). Early pharmacodynamic data indicated that 86% of patients achieved a Week 4 Ki-67 ≤10%, supporting the selection of 40 mg (Z)-endoxifen with ovarian function suppression for Phase II studies. The trial is also assessing whether short-term endocrine therapy combined with MRI response assessment can identify DCIS patients suitable for long-term active surveillance and potentially avoid surgery. The findings showed promising antiproliferative efficacy, good tolerability, and steady enrollment, with many patients choosing to continue active surveillance.