Shares of Atossa Therapeutics, Inc. (ATOS) are up 12% in pre-market trading today, as investors continue to focus on the company's advancing (Z)-endoxifen program and regulatory and clinical milestones expected in 2026.
Atossa is a clinical-stage biopharmaceutical company developing innovative oncology therapies, with a primary focus on breast cancer. Its lead program, (Z)-endoxifen, is a next-generation selective estrogen receptor modulator/degrader (SERM/D) designed to overcome limitations of tamoxifen and other endocrine therapies.
The therapy has shown encouraging activity across multiple early- and mid-stage studies, including signals of improved progression-free survival and durable disease control in estrogen receptor-positive breast cancer.
Atossa is now advancing (Z)-endoxifen through several Phase 2 programs, including the EVANGELINE study in early-stage breast cancer and the RECAST platform trial in ductal carcinoma in situ. In metastatic breast cancer, the program is being developed for patients with estrogen receptor-positive disease who have progressed on prior endocrine therapy, a population with limited treatment options.
With the FDA now issuing a "Study May Proceed" letter for (Z)-endoxifen in metastatic breast cancer, the company is preparing to advance the program into its next clinical phase as part of a broader development strategy aimed at generating NDA-enabling data in 2026.
ATOS has traded between $0.55 and $1.29 over the past year. The stock is currently trading in the pre-market at $0.65, up 12.05%.
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