Atossa Receives FDA 'Study May Proceed' Approval for Metastatic Breast Cancer Study
Written by Emily J. Thompson, Senior Investment Analyst
Updated: Jan 06 2026
0mins
Should l Buy ATOS?
Source: PRnewswire
- Regulatory Milestone: Atossa Therapeutics announced that its study for (Z)-endoxifen in metastatic breast cancer received a 'Study May Proceed' letter from the FDA, marking a significant advancement in the development of new therapies and potentially offering new treatment options for resistant tumors.
- Drug Potential: (Z)-endoxifen is a potent Selective Estrogen Receptor Modulator with activity across multiple mechanisms, and Atossa believes it holds significant application potential in treating metastatic ER+/HER2- breast cancer, which could change existing treatment paradigms.
- Intellectual Property Support: The (Z)-endoxifen program is backed by a growing global intellectual property portfolio, including multiple recently issued U.S. patents, which lays a solid foundation for future market entry and competitive positioning.
- Clinical Development Outlook: With the FDA's approval, Atossa will accelerate its clinical research efforts, which is expected to create new growth opportunities for the company and potentially open new markets in oncology.
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Analyst Views on ATOS
Wall Street analysts forecast ATOS stock price to rise
4 Analyst Rating
4 Buy
0 Hold
0 Sell
Strong Buy
Current: 3.940
Low
4.00
Averages
6.33
High
8.00
Current: 3.940
Low
4.00
Averages
6.33
High
8.00
About ATOS
Atossa Therapeutics, Inc. is a clinical-stage biopharmaceutical company. It is engaged in developing medicines in areas of unmet medical need in oncology with a focus on women’s breast cancer and other breast conditions. Its lead drug candidate under development is oral (Z)-endoxifen, which it is developing for both the prevention and treatment of breast cancer. (Z)-endoxifen is the potent Selective Estrogen Receptor Modulator for estrogen receptor inhibition and causes estrogen receptor degradation. In addition to its potent anti-estrogen effects, (Z)-endoxifen has been shown to target PKCB1, a known oncogenic protein, at clinically attainable blood concentrations. It is developing a form of (Z)-endoxifen which is administered orally for the potential treatment of breast cancer and reduction of breast density. It has completed four Phase I clinical studies and two Phase II clinical studies with its proprietary (Z)-endoxifen (including oral and topical formulations).
About the author
Emily J. Thompson
Emily J. Thompson, a Chartered Financial Analyst (CFA) with 12 years in investment research, graduated with honors from the Wharton School. Specializing in industrial and technology stocks, she provides in-depth analysis for Intellectia’s earnings and market brief reports.
Atossa Therapeutics Provides Strategic Update on Clinical Progress and Future Directions
- FDA Meeting Outcomes: Atossa completed a Type C meeting with the FDA on November 17, 2025, clarifying accelerated development pathways for (Z)-endoxifen in breast cancer, which is expected to expedite clinical trials and regulatory reviews, thereby enhancing the company's competitive position in oncology.
- Clinical Trial Progress: In the I-SPY 2 studies, 20 women with newly diagnosed ER+/HER- breast cancer received (Z)-endoxifen monotherapy, with preliminary data indicating reductions in tumor activity markers like Ki-67% and functional tumor volume, suggesting good tolerability and potential efficacy, with more data expected in the second half of 2026.
- Intellectual Property Expansion: Atossa reinforced its intellectual property for (Z)-endoxifen by securing a new patent covering enteric oral formulations, supporting its unique oral delivery method that preserves drug efficacy and consistency, thus enhancing market protection.
- Financial Discipline: As of early 2026, Atossa holds over $40 million in cash and equivalents, projected to support more than a year of working capital, while the company executed a reverse stock split on February 2, 2026, to regain Nasdaq compliance, strengthening its future capital operations.
See More
Atossa Therapeutics Provides Update on Clinical Progress and FDA Feedback
- FDA Strategic Milestone: Atossa completed a Type C meeting with the FDA on November 17, 2025, receiving feedback on potential expedited pathways for (Z)-endoxifen in breast cancer treatment, thereby establishing a foundation for rapid development in oncology.
- Clinical Trial Progress: In the I-SPY 2 study, 20 newly diagnosed ER+/HER- breast cancer women received (Z)-endoxifen monotherapy, with preliminary data indicating significant reductions in tumor activity markers like Ki-67% and tumor volume, with more combination therapy data expected in the second half of 2026 to further drive clinical applications.
- Expansion Beyond Oncology: Atossa received dual FDA designations for (Z)-endoxifen in treating Duchenne Muscular Dystrophy, highlighting its potential in non-oncology areas, which may provide strategic benefits such as market exclusivity and a Priority Review Voucher.
- Team Strengthening and Financial Discipline: In 2025, Atossa added experienced leaders to enhance clinical execution and entered 2026 with over $40 million in cash, ensuring operational funding for over a year and bolstering commercial readiness and market competitiveness.
See More
Atossa Receives Rare Pediatric Disease Designation for (Z)-endoxifen
- PRV Program Reauthorization: The U.S. Congress has passed a five-year reauthorization of the Rare Pediatric Disease Priority Review Voucher (PRV) program, enabling Atossa to qualify for a future PRV upon FDA approval, signaling strong support for the drug development industry.
- Potential of (Z)-endoxifen: Atossa's (Z)-endoxifen has received Rare Pediatric Disease (RPD) designation for treating Duchenne Muscular Dystrophy (DMD), providing new opportunities for the company in both cancer and rare diseases, potentially leading to non-dilutive value creation.
- Strong Market Demand: DMD is a fatal childhood disease, and families urgently need treatment options beyond steroids and gene-targeted therapies; the development of (Z)-endoxifen aims to offer a broader treatment approach to meet significant unmet medical needs.
- Positive Preclinical Data: Atossa is optimistic about the emerging preclinical data for (Z)-endoxifen and plans to advance it to clinical trials, aiming to provide more effective treatment options for DMD patients and further solidify the company's market position in the biopharmaceutical sector.
See More
Atossa Therapeutics CEO Steven Quay Named One of Top 50 Healthcare Technology CEOs of 2025
- Leadership Recognition: Atossa Therapeutics' Founder and CEO Steven Quay has been named one of the Top 50 Healthcare Technology CEOs of 2025, highlighting his exceptional leadership in biotechnology innovation and team building, which enhances the company's reputation in the industry.
- Precision Therapy Advancement: Under Quay's leadership, Atossa's lead product (Z)-endoxifen is being optimized across multiple Phase 2 clinical trials, aiming to provide consistent systemic treatment for breast cancer patients, which is expected to significantly improve patient outcomes.
- Multiple Indication Exploration: The company is exploring the application of (Z)-endoxifen for Duchenne Muscular Dystrophy (DMD), which, if successful, will further expand its market potential and strengthen the company's competitiveness in the rare disease sector.
- Strategic Investment Focus: Atossa emphasizes a disciplined capital allocation strategy in clinical development, concentrating on projects that can support future regulatory submissions and commercialization, ensuring sustainable growth in the biopharmaceutical industry.
See More
Atossa Therapeutics CEO Steven Quay Recognized as Top 50 Healthcare Technology CEO of 2025
- Leadership Recognition: Atossa Therapeutics' Founder and CEO Steven Quay has been named one of the Top 50 Healthcare Technology CEOs of 2025, highlighting his exceptional leadership in advancing biotechnology innovation and building a high-performing, people-centered organization.
- Precision Therapy Advancement: Under Quay's guidance, Atossa's lead product (Z)-endoxifen is being optimized across multiple Phase 2 clinical trials, aiming to provide a unique selective estrogen receptor modulator/degrader that significantly enhances breast cancer treatment outcomes.
- Exploration of Multiple Indications: Atossa is also investigating the application of (Z)-endoxifen for Duchenne Muscular Dystrophy (DMD), showcasing its potential to address high unmet clinical needs and potentially open new market opportunities for the company.
- Strategic Investment Focus: The company emphasizes disciplined capital allocation in clinical development, concentrating on projects that can support future regulatory submissions and commercialization, ensuring sustained competitiveness and innovation in the biopharmaceutical sector.
See More
Atossa Therapeutics Receives FDA Orphan Drug Designation, Stock Rises Nearly 13%
- FDA Orphan Drug Designation: Atossa Therapeutics (ATOS) announced that its (Z)-endoxifen received Orphan Drug Designation from the FDA, leading to a 12.98% stock increase to $0.69, marking a significant milestone in the treatment of Duchenne muscular dystrophy and expected to drive future R&D progress.
- Clinical Trial Progress: ImmunityBio (IBRX) reported that over 85% of the study population has been enrolled in its registrational trial QUILT-2.005 for BCG-naïve non-muscle-invasive bladder cancer, with stock rising 9.43% to $6.04, and full enrollment anticipated by Q2 2026, enhancing market confidence.
- NASDAQ Compliance Extension: Femasys (FEMY) received NASDAQ approval for a 180-day extension to meet the minimum $1.00 bid price requirement, with stock climbing 10.68% to $0.72, providing the company until July 13, 2026, to regain compliance, alleviating investor concerns.
- Successful Financing: Foghorn Therapeutics (FHTX) closed a $50 million registered direct financing at a 30% premium, resulting in a 4.02% stock increase to $6.26, demonstrating market confidence and support for its future development.
See More
Atossa Therapeutics Provides Strategic Update on Clinical Progress and Future Directions
- FDA Meeting Outcomes: Atossa completed a Type C meeting with the FDA on November 17, 2025, clarifying accelerated development pathways for (Z)-endoxifen in breast cancer, which is expected to expedite clinical trials and regulatory reviews, thereby enhancing the company's competitive position in oncology.
- Clinical Trial Progress: In the I-SPY 2 studies, 20 women with newly diagnosed ER+/HER- breast cancer received (Z)-endoxifen monotherapy, with preliminary data indicating reductions in tumor activity markers like Ki-67% and functional tumor volume, suggesting good tolerability and potential efficacy, with more data expected in the second half of 2026.
- Intellectual Property Expansion: Atossa reinforced its intellectual property for (Z)-endoxifen by securing a new patent covering enteric oral formulations, supporting its unique oral delivery method that preserves drug efficacy and consistency, thus enhancing market protection.
- Financial Discipline: As of early 2026, Atossa holds over $40 million in cash and equivalents, projected to support more than a year of working capital, while the company executed a reverse stock split on February 2, 2026, to regain Nasdaq compliance, strengthening its future capital operations.
See More
Atossa Therapeutics Provides Update on Clinical Progress and FDA Feedback
- FDA Strategic Milestone: Atossa completed a Type C meeting with the FDA on November 17, 2025, receiving feedback on potential expedited pathways for (Z)-endoxifen in breast cancer treatment, thereby establishing a foundation for rapid development in oncology.
- Clinical Trial Progress: In the I-SPY 2 study, 20 newly diagnosed ER+/HER- breast cancer women received (Z)-endoxifen monotherapy, with preliminary data indicating significant reductions in tumor activity markers like Ki-67% and tumor volume, with more combination therapy data expected in the second half of 2026 to further drive clinical applications.
- Expansion Beyond Oncology: Atossa received dual FDA designations for (Z)-endoxifen in treating Duchenne Muscular Dystrophy, highlighting its potential in non-oncology areas, which may provide strategic benefits such as market exclusivity and a Priority Review Voucher.
- Team Strengthening and Financial Discipline: In 2025, Atossa added experienced leaders to enhance clinical execution and entered 2026 with over $40 million in cash, ensuring operational funding for over a year and bolstering commercial readiness and market competitiveness.
See More
Atossa Receives Rare Pediatric Disease Designation for (Z)-endoxifen
- PRV Program Reauthorization: The U.S. Congress has passed a five-year reauthorization of the Rare Pediatric Disease Priority Review Voucher (PRV) program, enabling Atossa to qualify for a future PRV upon FDA approval, signaling strong support for the drug development industry.
- Potential of (Z)-endoxifen: Atossa's (Z)-endoxifen has received Rare Pediatric Disease (RPD) designation for treating Duchenne Muscular Dystrophy (DMD), providing new opportunities for the company in both cancer and rare diseases, potentially leading to non-dilutive value creation.
- Strong Market Demand: DMD is a fatal childhood disease, and families urgently need treatment options beyond steroids and gene-targeted therapies; the development of (Z)-endoxifen aims to offer a broader treatment approach to meet significant unmet medical needs.
- Positive Preclinical Data: Atossa is optimistic about the emerging preclinical data for (Z)-endoxifen and plans to advance it to clinical trials, aiming to provide more effective treatment options for DMD patients and further solidify the company's market position in the biopharmaceutical sector.
See More
Atossa Therapeutics CEO Steven Quay Named One of Top 50 Healthcare Technology CEOs of 2025
- Leadership Recognition: Atossa Therapeutics' Founder and CEO Steven Quay has been named one of the Top 50 Healthcare Technology CEOs of 2025, highlighting his exceptional leadership in biotechnology innovation and team building, which enhances the company's reputation in the industry.
- Precision Therapy Advancement: Under Quay's leadership, Atossa's lead product (Z)-endoxifen is being optimized across multiple Phase 2 clinical trials, aiming to provide consistent systemic treatment for breast cancer patients, which is expected to significantly improve patient outcomes.
- Multiple Indication Exploration: The company is exploring the application of (Z)-endoxifen for Duchenne Muscular Dystrophy (DMD), which, if successful, will further expand its market potential and strengthen the company's competitiveness in the rare disease sector.
- Strategic Investment Focus: Atossa emphasizes a disciplined capital allocation strategy in clinical development, concentrating on projects that can support future regulatory submissions and commercialization, ensuring sustainable growth in the biopharmaceutical industry.
See More
Atossa Therapeutics CEO Steven Quay Recognized as Top 50 Healthcare Technology CEO of 2025
- Leadership Recognition: Atossa Therapeutics' Founder and CEO Steven Quay has been named one of the Top 50 Healthcare Technology CEOs of 2025, highlighting his exceptional leadership in advancing biotechnology innovation and building a high-performing, people-centered organization.
- Precision Therapy Advancement: Under Quay's guidance, Atossa's lead product (Z)-endoxifen is being optimized across multiple Phase 2 clinical trials, aiming to provide a unique selective estrogen receptor modulator/degrader that significantly enhances breast cancer treatment outcomes.
- Exploration of Multiple Indications: Atossa is also investigating the application of (Z)-endoxifen for Duchenne Muscular Dystrophy (DMD), showcasing its potential to address high unmet clinical needs and potentially open new market opportunities for the company.
- Strategic Investment Focus: The company emphasizes disciplined capital allocation in clinical development, concentrating on projects that can support future regulatory submissions and commercialization, ensuring sustained competitiveness and innovation in the biopharmaceutical sector.
See More
Atossa Therapeutics Receives FDA Orphan Drug Designation, Stock Rises Nearly 13%
- FDA Orphan Drug Designation: Atossa Therapeutics (ATOS) announced that its (Z)-endoxifen received Orphan Drug Designation from the FDA, leading to a 12.98% stock increase to $0.69, marking a significant milestone in the treatment of Duchenne muscular dystrophy and expected to drive future R&D progress.
- Clinical Trial Progress: ImmunityBio (IBRX) reported that over 85% of the study population has been enrolled in its registrational trial QUILT-2.005 for BCG-naïve non-muscle-invasive bladder cancer, with stock rising 9.43% to $6.04, and full enrollment anticipated by Q2 2026, enhancing market confidence.
- NASDAQ Compliance Extension: Femasys (FEMY) received NASDAQ approval for a 180-day extension to meet the minimum $1.00 bid price requirement, with stock climbing 10.68% to $0.72, providing the company until July 13, 2026, to regain compliance, alleviating investor concerns.
- Successful Financing: Foghorn Therapeutics (FHTX) closed a $50 million registered direct financing at a 30% premium, resulting in a 4.02% stock increase to $6.26, demonstrating market confidence and support for its future development.
See More
