Atossa Therapeutics shares rise 10.76% premarket after FDA clears (Z)-endoxifen study for metastatic breast cancer.

Atossa Therapeutics (NASDAQ: ATOS) surged 10.76% in premarket trading after receiving a "Study May Proceed" letter from the FDA for its (Z)-endoxifen investigational new drug application in metastatic ER+/HER2- breast cancer. This regulatory clearance allows the company to advance clinical trials for the drug candidate, which targets tumors resistant to other endocrine therapies and the PKCβ1 pathway. The FDA approval is a key milestone, positioning (Z)-endoxifen as a potential new treatment option in a high-unmet-need oncology space. The news aligns with Atossa's strategy to expand its drug's development across oncology indications, supported by its growing intellectual property portfolio and differentiated pharmacology profile.