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Phase 2Data readout

(Z)-Endoxifen (Estrogen Modulator)

Metastatic Breast Cancer

ATOSAtossa Therapeutics
Expected catalystDecember 31, 2026Company guidance: Dec 31, 2026

Catalyst overview

Event details

Drug or asset
(Z)-Endoxifen (Estrogen Modulator)
Development stage
Phase 2
Event type
Data readout
Indication
Metastatic Breast Cancer

Research summary

What is being tracked?

This catalyst tracks a Phase 2 data readout for (Z)-Endoxifen (Estrogen Modulator) in Metastatic Breast Cancer. The expected timing is based on the latest available company guidance and may change.

Development notes

11/12/25:- Planning IND for Ph2 metastatic breast cancer Q4 2025 with topline data in 2026. 12/15/25:- ESR1 mutant breast cancer data showed strong ERα antagonism and reversal of oncogenic transcriptional signatures. 01/06/26:- FDA issued Study May Proceed for metastatic Ph2; topline data still expected in 2026. 03/25/26:- Company reiterates focus on (Z)-endoxifen metastatic program; no new data or timing changes disclosed. 05/08/26:- Q1 update: metastatic program progressing; higher R&D spend; new breast oncology lead; no new trial data. 05/27/26:- ASCO 2026 abstract shows (Z)-endoxifen ER inhibition across ESR1 mutations. 08/07/26:- ASCO ESR1 mutation data reiterated; 2026 Ph2 topline timing unchanged.

Verification

Primary source

Confirm timing and program details against the company announcement or filing.

Open source

Company

Atossa Therapeutics

ATOS · NasdaqCM
Industry
Biotechnology
Pipeline assets
7
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Updated Aug 23, 2026. Dates can change; this is not investment advice.

Disclaimer: Biotech Stock Intel is an independent research platform. Information is provided for informational purposes only and is not investment or medical advice. Always verify catalyst dates against primary sources and conduct your own research.
Biotech Stock Intel© 2026 Biotech Stock Intel
AboutMethodologyTermsPrivacy