Atossa Therapeutics Maintains Strong Market Position for (Z)-Endoxifen for Duchenne Muscular Dystrophy as Congress Reauthorizes Priority Review Voucher Program

Rhea-AI Summary

Atossa Therapeutics (NASDAQ: ATOS) reaffirmed its market position for (Z)-endoxifen in Duchenne muscular dystrophy (DMD) after Congress reauthorized the Rare Pediatric Disease Priority Review Voucher (PRV) program for five years on Feb 5, 2026. The drug holds Rare Pediatric Disease (RPD) designation and would be eligible for a PRV if FDA approval is obtained. PRVs can accelerate future reviews or be sold/transferred; disclosed PRV sales in the last 18 months ranged from $150–$200 million. Atossa cites emerging preclinical data and plans to advance the program toward clinical development for boys with DMD.

Positive

• RPD designation for (Z)-endoxifen makes the program eligible for a PRV upon FDA approval
• Congress reauthorized the PRV program for five years, preserving potential future value
• Market precedent: disclosed PRV sales ranged $150–$200 million in the last 18 months

Negative

• (Z)-endoxifen remains preclinical/early-stage for DMD and has not received FDA approval
• PRV benefit is contingent on eventual FDA approval and therefore uncertain in timing and outcome

Key Figures

PRV program duration: 5 years Recent PRV sale range: $150–$200 million Reference period: 18 months +1 more

4 metrics

PRV program duration 5 years Five-year reauthorization of Rare Pediatric Disease PRV Program

Recent PRV sale range $150–$200 million Disclosed PRV sale prices over last 18 months

Reference period 18 months Lookback window for disclosed PRV sale values

Pediatric age range Birth to 18 years Eligibility criteria for Rare Pediatric Disease designation

Market Reality Check

Vol: Volume 263,247 vs 20-day ...

normal vol

Volume Volume 263,247 vs 20-day average 203,971 (relative volume 1.29x). normal

Technical Price $5.27 trades below 200-day MA at $12.12, and 72.76% below 52-week high $19.35.

Peers on Argus

ATOS fell 4.34% with peers ADAG (-4.7%), ANRO (-5.97%), and MGNX (-1.14%) also d...

1 Up

ATOS fell 4.34% with peers ADAG (-4.7%), ANRO (-5.97%), and MGNX (-1.14%) also down, while PYXS (+1.34%) and SPRO (+1.33%) rose, indicating a mixed but generally weak biotech tape.

Historical Context

5 past events · Latest: Jan 21 (Positive)

Pattern 5 events

Date	Event	Sentiment	Move	Catalyst
Jan 21	Leadership recognition	Positive	+0.1%	CEO named among Top 50 Healthcare Technology CEOs, highlighting (Z)-endoxifen progress.
Jan 16	Orphan Drug status	Positive	+6.0%	FDA Orphan Drug Designation for (Z)-endoxifen in Duchenne muscular dystrophy.
Jan 06	Trial clearance	Positive	+7.0%	FDA “Study May Proceed” letter for metastatic breast cancer IND with (Z)-endoxifen.
Dec 17	R&D award	Positive	-1.5%	Clinical Trials Arena R&D Excellence Award for precision endocrine work on (Z)-endoxifen.
Dec 15	Clinical data update	Positive	-13.4%	Multiple breast cancer trial updates showing strong tolerability and biomarker responses.

Pattern Detected

Recent positive clinical and recognition news often produced mixed reactions, with several regulatory and data milestones sold off despite constructive fundamentals.

Recent Company History

Over the past few months, Atossa has repeatedly highlighted progress around (Z)-endoxifen. A January 6, 2026 FDA “Study May Proceed” letter for metastatic breast cancer was followed by a 7% gain, and Orphan Drug Designation for DMD on January 16, 2026 saw a 6.02% rise. However, strong breast cancer trial updates on December 15, 2025 led to a -13.37% move. Today’s PRV-focused DMD update fits the same theme of expanding (Z)-endoxifen’s regulatory and rare-disease optionality.

Market Pulse Summary

This announcement links Atossa’s Rare Pediatric Disease designation for (Z)-endoxifen in DMD to Cong...

Analysis

This announcement links Atossa’s Rare Pediatric Disease designation for (Z)-endoxifen in DMD to Congress’s five-year reauthorization of the PRV program, preserving eligibility for a future voucher that has recently sold for $150–$200 million. It extends a series of DMD- and oncology-focused milestones around (Z)-endoxifen. Investors may track progression into clinical DMD studies, additional regulatory designations, and how management balances oncology and rare-disease development priorities.

Key Terms

rare pediatric disease designation, priority review voucher, duchenne muscular dystrophy, neuromuscular diseases, +3 more

7 terms

rare pediatric disease designation regulatory

"Atossa's Rare Pediatric Disease Designation for (Z)-endoxifen in neuromuscular diseases"

A rare pediatric disease designation is an official regulatory status given to a drug or therapy that targets a serious or life‑threatening condition primarily affecting children and is uncommon in the population. It matters to investors because the status often brings financial and development perks — such as tax credits, reduced fees, faster review and periods of market protection — which can lower costs, speed approval and improve the commercial outlook; think of it as a VIP pass that makes bringing a scarce, child‑focused treatment to market easier and potentially more profitable.

priority review voucher regulatory

"Reauthorizes Priority Review Voucher Program"

A priority review voucher is a transferable regulatory incentive that lets a company move a future drug or device application to the front of the review line, shortening the review period by several months. For investors it matters because the voucher can speed up market access for a high-value product or be sold to other companies for significant cash, acting like a tradable fast-pass that can accelerate revenue or create immediate financial upside.

duchenne muscular dystrophy medical

"strong market position around its Duchenne Muscular Dystrophy (DMD) program"

A rare, inherited condition that progressively weakens muscles, Duchenne muscular dystrophy causes the body’s muscle fibers to break down over time, often leading to severe disability. For investors, it matters because the small, well-defined patient population, high unmet medical need and complex regulatory and pricing dynamics mean successes or failures in clinical trials, approvals, or therapies can have outsized effects on a company’s valuation and future revenue prospects.

neuromuscular diseases medical

"Rare Pediatric Disease Designation for (Z)-endoxifen in neuromuscular diseases"

Neuromuscular diseases are a group of medical conditions that damage the nerves controlling muscles or the muscles themselves, causing weakness, poor coordination, or loss of movement—think of it as problems with the wiring or motors that make the body move. They matter to investors because they often involve clear unmet medical needs, long-term care or durable treatments, and focused patient populations, which can drive drug development, pricing power, and regulatory attention in the healthcare market.

u.s. food and drug administration regulatory

"upon the U.S. Food and Drug Administration's ("FDA") approval"

The U.S. Food and Drug Administration is the federal agency that evaluates and enforces safety, effectiveness and labeling standards for medicines, medical devices, vaccines, food and related products before they reach consumers. For investors it matters because FDA approvals, warnings or recalls determine whether a product can be sold, how quickly it reaches the market and how costly compliance will be—changes that directly affect a company’s revenue, costs and stock value.

rpd designation regulatory

"following the FDA granting Rare Pediatric Disease ("RPD") designation"

A Rare Pediatric Disease (RPD) designation is a regulatory label granted by the U.S. FDA to investigational drugs or biologics targeting serious or life‑threatening diseases that primarily affect children and meet rarity criteria. For investors it matters because approval tied to an RPD can earn the sponsor a transferable “priority review” voucher — like a sellable fast‑pass for future FDA review — which can speed a product’s path to market or be sold for substantial cash value.

ind clearance regulatory

"Having previously secured IND clearance for what is now the DMD treatment"

IND clearance is regulatory authorization that allows a company to begin testing an experimental drug in human clinical trials. Think of it as a safety-passport from regulators confirming enough preclinical evidence exists to move from lab work to people; for investors it marks a major development milestone that de-risks the program’s path to approval, unlocks value-driving data milestones, and often influences funding, partnerships, and stock value.

AI-generated analysis. Not financial advice.

Atossa's Rare Pediatric Disease Designation for (Z)-endoxifen in neuromuscular diseases qualifies for a future PRV upon FDA approval

SEATTLE, Feb. 5, 2026 /PRNewswire/ -- Atossa Therapeutics, Inc. (Nasdaq: ATOS) ("Atossa" or the "Company"), a clinical-stage biopharmaceutical company developing novel therapies in oncology and other areas of high unmet clinical need, today reaffirmed its strong market position around its Duchenne Muscular Dystrophy (DMD) program following  yesterday's congressional announcement that it had passed a five-year reauthorization of the Rare Pediatric Disease Priority Review Voucher ("PRV") Program. The program extends the Company's ability to be eligible to receive a future PRV upon the U.S. Food and Drug Administration's ("FDA") approval following the FDA granting Rare Pediatric Disease ("RPD") designation to (Z)-endoxifen for the treatment of DMD late last year.

RPD designation is granted to drug candidates intended to treat serious or life-threatening diseases that primarily affect individuals from birth to 18 years of age. Upon approval of a qualifying marketing application, drugs with RPD designation may be eligible for a PRV, which can be used to obtain priority review for a future application or may be sold or transferred to another sponsor. In the last 18 months, disclosed PRV sales have ranged from $150–$200 million.

"The renewal of the PRV program represents an important signal from Congress that it understands the complexities and financial burden on the drug development industry. The program's continuation, along with the RPD designation, underscores the validation of the science supporting the potential of (Z)-endoxifen as a treatment for Duchenne Muscular Dystrophy," said Steven Quay, M.D., Ph.D., Atossa Therapeutics President and Chief Executive Officer. "DMD is one of the most devastating childhood diseases. Families urgently need better options beyond steroids and gene-targeted approaches. While oncology remains our core focus, this milestone highlights (Z)-endoxifen's potential as a platform therapy in both cancer and rare diseases, opening the door to potential non-dilutive value creation through the Rare Pediatric Disease program."

"The passage the PRV reauthorization is a win for all children with serious and rare diseases," said Janet Rea, MSPH, Senior Vice President of Research and Development at Atossa. "We are very encouraged by emerging preclinical data with (Z)-endoxifen and its potential in DMD, and we look forward to advancing this program to the clinic for boys living with DMD. Unlike more recent therapeutic approaches, (Z)-endoxifen does not target specific exon defects, thus potentially offering a broader and more accessible treatment approach for this patient population. Having previously secured IND clearance for what is now the DMD treatment, EXONDYS 51® (eteplirsen), I am excited to further Atossa's DMD (Z)-endoxifen program."

About Rare Pediatric Disease Designation

The FDA's Rare Pediatric Disease designation is reserved for serious or life-threatening diseases that primarily affect individuals from birth to 18 years old and that meet the definition of a rare disease or condition within the meaning of Section 526 of the Federal Food, Drug & Cosmetic Act ("FD&C Act"). Drugs granted RPD designation may be eligible for a PRV upon FDA approval of a qualifying New Drug Application or Biologics License Application, provided it meets all statutory criteria under Section 529(a)(4) of the FD&C Act. A PRV may be used by the sponsor or sold or transferred to another company.

About Duchenne Muscular Dystrophy

Duchenne Muscular Dystrophy is a rare, progressive, X-linked neuromuscular disorder caused by one or more mutation in the dystrophin gene. Symptoms typically emerge in early childhood and include progressive muscle weakness, loss of ambulation, respiratory compromise, and cardiomyopathy. DMD is uniformly fatal, often in early adulthood, and despite recent therapeutic advances, there remains a substantial unmet medical need for safe, effective, and accessible treatments.

About (Z)-Endoxifen

(Z)-endoxifen is a potent Selective Estrogen Receptor Modulator/Degrader (SERM/D) with demonstrated activity across multiple mechanisms of interest. 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.

Atossa's (Z)-endoxifen program is supported by a growing global intellectual property portfolio, including multiple recently issued U.S. patents and numerous pending applications worldwide.

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. More information is available at https://atossatherapeutics.com.

Forward-Looking Statements

This press release contains certain "forward-looking statements" within the meaning of applicable securities laws, including but not limited to, our expectations regarding the Company's development and regulatory strategy and related milestones, the potential indications that the Company may pursue for (Z)-endoxifen, the potential for (Z)-endoxifen to receive regulatory approval and the timing thereof, the potential extension of the RPD Priority Review Voucher program and the Company's potential eligibility for and value of a future Priority Review Voucher, 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," or other similar expressions or statements regarding intent, belief or current expectations, are 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: our ability to successfully execute our strategy to shorten our clinical development timelines and pursue a metastatic breast cancer indication, DMD indication or other indications for our lead program, (Z)-endoxifen; expected timing, completion and results of our 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; our ability to regain and maintain compliance with Nasdaq listing requirements; our ability to establish and maintain intellectual property rights covering our products; the impact of general macroeconomic conditions on our business; our 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.

The market value of a Priority Review Voucher is variable and subject to a number of factors beyond our control and reported past PRV sale amounts are not necessarily indicative of PRV sale amounts in the future.

Forward-looking statements are presented as of the date of this press release. Except as required by law, we do not intend to update any forward-looking statements.

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SOURCE Atossa Therapeutics Inc

FAQ

What does the PRV reauthorization mean for Atossa (ATOS) and (Z)-endoxifen eligibility?

It preserves Atossa's potential to receive a PRV if (Z)-endoxifen gains FDA approval. According to the company, RPD designation plus the PRV reauthorization keeps eligibility intact and could allow priority review or sale of a voucher after approval.

How much value have PRVs recently generated that could benefit ATOS shareholders?

Disclosed PRV sales have recently ranged from $150–$200 million. According to the company, that market precedent shows a potential non-dilutive value avenue if (Z)-endoxifen ultimately secures FDA approval and a PRV.

What is the current development stage of Atossa's DMD program for (Z)-endoxifen?

The DMD program is at the preclinical/early development stage and advancing toward the clinic. According to the company, emerging preclinical data support progression but no marketing approval has been obtained yet.

How could a PRV practically affect Atossa's strategy if (Z)-endoxifen is approved?

A PRV could be used to obtain priority review for another application or be sold/transferred to a third party. According to the company, this offers a potential non-dilutive financing or acceleration mechanism for future programs.

Does (Z)-endoxifen target specific DMD exon defects like some gene therapies?

No; (Z)-endoxifen does not target specific exon defects and may offer broader applicability. According to the company, this could make the approach accessible to a wider DMD patient population compared with exon-specific therapies.