Atossa Therapeutics to Host Virtual KOL Event Featuring Dr. Laura Esserman to Discuss Development of (Z)-Endoxifen in ER-Positive Breast Cancer
Rhea-AI Summary
Atossa Therapeutics (Nasdaq: ATOS) will host a virtual key opinion leader event on May 19, 2026, highlighting development of its investigational SERM/D (Z)-endoxifen in ER-positive breast cancer.
The webinar will feature breast cancer expert Dr. Laura Esserman discussing emerging clinical and translational data, combination strategies, and development opportunities.
AI-generated analysis. Not financial advice.
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News Market Reaction – ATOS
On the day this news was published, ATOS declined 0.19%, reflecting a mild negative market reaction.
Data tracked by StockTitan Argus on the day of publication.
Key Figures
Market Reality Check
Peers on Argus
Peer moves appear mixed: in-coverage names show gains and losses, while momentum data flags FATE down 6.79% without news, suggesting stock-specific rather than sector-driven dynamics around this KOL event.
Historical Context
| Date | Event | Sentiment | Move | Catalyst |
|---|---|---|---|---|
| May 08 | Q1 2026 results | Negative | -1.2% | Quarterly results showed higher operating expenses and a larger net loss in Q1 2026. |
| May 06 | Phase 2 publication | Positive | +3.9% | KARISMA Phase 2 data showed significant reductions in mammographic breast density with Endoxifen. |
| May 04 | RPD designation | Positive | +9.9% | FDA granted Rare Pediatric Disease designation for (Z)-endoxifen in McCune-Albright Syndrome. |
| Mar 25 | 2025 results | Negative | -13.1% | Year-end 2025 report highlighted larger net loss and higher operating expenses versus 2024. |
| Mar 19 | Leadership hires | Positive | +0.4% | Company added two senior clinical leaders to advance breast cancer and rare disease programs. |
Recent ATOS news has shown directionally consistent price reactions: positive clinical or designation updates saw gains, while financial reports with larger losses saw declines.
Over recent months, ATOS updates have centered on advancing (Z)-endoxifen across oncology and rare diseases. Designations like FDA Rare Pediatric Disease and Orphan Drug status and positive Phase 2 data were followed by modest gains of up to 9.94%, while earnings updates with higher operating expenses and net losses saw declines of up to 13.1%. Leadership additions and trial publications supported the development narrative. Today’s KOL event fits this pattern of ongoing clinical and translational positioning for (Z)-endoxifen in ER-positive breast cancer.
Market Pulse Summary
This announcement spotlights Atossa’s effort to position (Z)-endoxifen as a next‑generation endocrine therapy in ER‑positive breast cancer, leveraging data from the I‑SPY2 Endocrine Optimization Pilot and translational biomarkers like Ki‑67 and circulating tumor DNA. Historically, the company has paired such scientific updates with regulatory designations and leadership hires. Investors may watch how this event frames future trial strategy, combination plans, and development across multiple ER‑positive settings.
Key Terms
key opinion leader technical
selective estrogen receptor modulator/degrader medical
serm/d medical
estrogen receptor medical
biomarker medical
ki-67 medical
circulating tumor DNA medical
cdk4/6 inhibitor medical
AI-generated analysis. Not financial advice.
Event to feature Dr. Laura Esserman, internationally recognized surgical oncologist, breast cancer expert, and founder and principal investigator of the I-SPY Trials
The event will feature internationally recognized surgical oncologist and breast cancer expert Dr. Laura Esserman. Dr. Esserman serves as Director of the University of California San Francisco Breast Care Center and is the founder and principal investigator of the I-SPY Trials, an innovative platform designed to accelerate the development of personalized breast cancer therapies.
"Dr. Esserman has been at the forefront of innovation in breast cancer clinical research, adaptive trial design, and precision oncology for decades," said Dr. Steven Quay, M.D., Ph.D., Chairman and Chief Executive Officer of Atossa Therapeutics. "We believe (Z)-endoxifen has the potential to become more than a single-indication therapy; it may serve as an endocrine therapy platform across multiple ER-positive breast cancer settings. Dr. Esserman's leadership in translational breast cancer research makes her an ideal expert to discuss the emerging clinical and biomarker data supporting this opportunity."
The discussion is expected to address several topics of interest to clinicians, investors, and potential strategic partners, including:
- Recent data from the I-SPY2 Endocrine Optimization Pilot study evaluating (Z)-endoxifen as monotherapy in newly diagnosed ER-positive breast cancer patients
- Translational biomarker data, including Ki-67 reduction, MRI functional tumor volume changes, and circulating tumor DNA dynamics
- Data supporting (Z)-endoxifen activity across clinically relevant ESR1 mutations, including Y537N, Y537S, and D538G
- The rationale for (Z)-endoxifen as a potential next-generation endocrine therapy backbone
- Combination strategies, including CDK4/6 inhibitor combinations
- Development opportunities in premenopausal breast cancer and endocrine therapy optimization
Event Details
Date: Tuesday, May 19, 2026
Time: 1:00 to 2:00 p.m. PT
Moderator: Michael King, Managing Director at Rodman & Renshaw
Registration: https://zoom.us/webinar/register/WN_fd6jdLUvQPC-3J84CUEnMA
Attendees may submit questions to ATOS@waterseid.com up to 24 hours prior to the event.
A replay of the webcast will be available on the Company's "Investors" portion of its website for at least 60 days following the live event.
About (Z)-Endoxifen
(Z)-endoxifen is a potent Selective Estrogen Receptor Modulator/Degrader, or SERM/D, with demonstrated activity across multiple mechanisms of action. Atossa is evaluating its potential applications in oncology and rare diseases. The Company's proprietary oral formulation has shown a favorable safety profile and pharmacology distinct from tamoxifen, including ER-targeted effects and PKC inhibition. Atossa's (Z)-endoxifen is not approved for any indication.
About Atossa Therapeutics
Atossa Therapeutics, Inc. (Nasdaq: ATOS) is a clinical-stage biopharmaceutical company developing innovative medicines in oncology and other areas of significant unmet need. The Company's lead product candidate, (Z)-endoxifen, is currently in development across several clinical settings.
Atossa's (Z)-endoxifen program is supported by a growing global intellectual property portfolio, including multiple recently issued
Forward-Looking Statements
This press release contains certain "forward-looking statements" within the meaning of applicable securities laws, including but not limited to statements regarding the Company's development and regulatory strategy and related milestones; the potential indications that the Company may pursue for (Z)-endoxifen; the potential role of (Z)-endoxifen as an endocrine therapy platform; the potential for (Z)-endoxifen to receive regulatory approval and the timing thereof; expectations regarding the design, enrollment, data, timing, results and outcomes of the Company's clinical studies; and the potential market and growth opportunities for the Company. Words such as "expect," "potential," "continue," "may," "will," "should," "could," "would," "seek," "intend," "plan," "estimate," "anticipate," "believe," "design," "predict," "future," and similar expressions are intended to identify forward-looking statements.
Forward-looking statements in this press release are subject to risks and uncertainties that may cause actual results, outcomes, or the timing of actual results or outcomes to differ materially from those projected or anticipated, including, without limitation, risks and uncertainties associated with: the Company's ability to successfully execute its strategy to shorten clinical development timelines for its lead program, (Z)-endoxifen; the expected timing, completion and results of preclinical studies, clinical trials, and research and development programs; the unpredictable relationship between preclinical study results and clinical study results; the timing or likelihood of regulatory filings and approvals; the outcome or timing of necessary regulatory approvals; the Company's ability to maintain compliance with Nasdaq listing requirements; the Company's ability to establish and maintain intellectual property rights covering its products; the impact of general macroeconomic conditions on the Company's business; the Company's ability to raise capital; and other risks and uncertainties detailed from time to time in Atossa's filings with the SEC, including, without limitation, its Annual Reports on Form 10-K and Quarterly Reports on Form 10-Q.
Forward-looking statements are presented as of the date of this press release. Except as required by law, the Company does not intend to update any forward-looking statements.
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SOURCE Atossa Therapeutics Inc