Understanding Breast Cancer

Breast Cancer Across the Continuum

Breast cancer spans a continuum from elevated risk to localized disease to metastatic disease. Approximately 70–80% of breast cancers express the estrogen receptor, making endocrine biology central to prevention and treatment strategies.

Atossa is studying (Z)-endoxifen across selected points in this continuum. In women at elevated risk, the company is evaluating low-dose approaches and mammographic breast density as a biomarker of biological activity. In women with newly diagnosed ER-positive/HER2-negative disease, neoadjuvant studies are evaluating tumor and biomarker response before surgery. Earlier studies in metastatic disease provide additional evidence of anti-estrogen activity.

The long-term objective is to determine where direct administration of (Z)-endoxifen can provide clinically meaningful activity, consistent exposure, and acceptable tolerability relative to existing endocrine approaches.

Risk Reduction for High-Risk Women

For women and men with dense breast tissue or inherited genetic mutations, the risk of developing breast cancer can be significantly higher.

Atossa Therapeutics is advancing endocrine-based approaches designed to modulate estrogen activity earlier, offering the potential to reduce risk through targeted hormonal intervention.

This work builds on decades of endocrine science while aiming to improve tolerability and adherence of treatment.

When breast cancer is diagnosed, treatment may begin prior to surgery.

Our neoadjuvant program aims to reduce tumor burden before surgical intervention by precisely targeting estrogen receptor activity to improve surgical outcomes and expand treatment options for patients following diagnosis.

Following surgery, residual cancer cells may remain.

Adjuvant endocrine therapies are used to help reduce the risk of recurrence.

Atossa Therapeutics is focused on delivering consistent exposure to active therapy, with the goal of improving tolerability while maintaining effectiveness during this defining phase of care.

For patients with metastatic breast cancer, treatment focuses on disease control and quality of life.

Clinical data suggest that next-generation selective estrogen receptor modulators (SERM/Ds), including (Z)-endoxifen, may offer meaningful benefit, even in patients who have progressed on prior therapies. These therapies maintain activity across resistance pathways and are being studied for their potential to prolong the time a patient’s condition remains stable.