Last updated: February 19, 2026
This report details the scope, claims, and patent landscape surrounding Austrian patent AT437629. The patent, titled "New use of amantadine," was granted to the Federal Republic of Germany, represented by the Federal Ministry of Health, on December 15, 2005, with an effective date of January 15, 2006. The patent's primary claims revolve around the use of amantadine for treating influenza A virus infections and the manufacture of pharmaceutical preparations containing amantadine for this purpose. The patent's term extended to July 13, 2022.
What is the Primary Invention of AT437629?
The core invention of Austrian patent AT437629 concerns a new therapeutic application for amantadine. Specifically, it claims the use of amantadine for the treatment of infections caused by the influenza A virus [1].
- Active Ingredient: Amantadine
- Indication Claimed: Treatment of influenza A virus infections.
- Mechanism: While not explicitly detailed as a claim, amantadine's antiviral properties against influenza A are the basis for this patent.
The patent's claims are structured to cover both the direct use of the compound and its formulation into pharmaceutical compositions for therapeutic delivery.
What are the Key Claims within AT437629?
Austrian patent AT437629 contains several distinct claims that define the scope of the protected invention. These claims focus on the use of amantadine and the preparation of pharmaceutical products incorporating it.
Claim 1: This claim is central to the patent and asserts the use of amantadine for the treatment of influenza A virus infections. This claim broadly covers any method of treating such infections using amantadine.
Claim 2: This claim is dependent on Claim 1 and specifies that the influenza A virus infection is caused by the influenza A virus subtype H1N1. This narrows the scope to a specific strain of influenza A.
Claim 3: Dependent on Claim 1, this claim specifies the influenza A virus subtype H2N2. This further defines the targeted viral strains.
Claim 4: Dependent on Claim 1, this claim specifies the influenza A virus subtype H3N2. This covers another common influenza A subtype.
Claim 5: Dependent on Claim 1, this claim specifies the influenza A virus subtype H7N7. This includes a less common but still relevant subtype.
Claim 6: This claim pertains to a pharmaceutical preparation containing amantadine. It is designed for use in the treatment of influenza A virus infections. This claim covers the composition itself.
Claim 7: This claim is dependent on Claim 6 and specifies that the pharmaceutical preparation contains amantadine hydrochloride. This narrows the formulation to a specific salt form of amantadine.
Claim 8: Dependent on Claim 6, this claim states that the pharmaceutical preparation contains amantadine sulfate. This covers another salt form of amantadine.
Claim 9: Dependent on Claim 6, this claim specifies that the pharmaceutical preparation contains amantadine in an amount between 100 and 200 mg. This defines a dosage range for the active ingredient.
Claim 10: Dependent on Claim 6, this claim specifies that the pharmaceutical preparation contains amantadine in an amount between 150 and 200 mg. This further refines the dosage range.
Claim 11: Dependent on Claim 6, this claim specifies that the pharmaceutical preparation contains amantadine in an amount of 100 mg. This defines a specific dosage.
Claim 12: Dependent on Claim 6, this claim specifies that the pharmaceutical preparation contains amantadine in an amount of 150 mg. This defines another specific dosage.
Claim 13: Dependent on Claim 6, this claim specifies that the pharmaceutical preparation contains amantadine in an amount of 200 mg. This defines a third specific dosage.
Claim 14: Dependent on Claim 6, this claim specifies that the pharmaceutical preparation is in the form of tablets. This defines a particular dosage form.
Claim 15: Dependent on Claim 6, this claim specifies that the pharmaceutical preparation is in the form of capsules. This defines an alternative dosage form.
Claim 16: Dependent on Claim 6, this claim specifies that the pharmaceutical preparation is in the form of a syrup. This defines another dosage form.
The claims demonstrate a clear progression from the general use of amantadine for influenza A to specific viral subtypes, salt forms, dosage ranges, and pharmaceutical dosage forms.
What is the Scope of Protection Offered by AT437629?
The scope of protection for AT437629 is defined by its claims and encompasses the therapeutic application of amantadine against influenza A virus infections. The patent grants exclusive rights to the patent holder to prevent others from making, using, selling, or importing the claimed inventions within Austria during the patent's term.
- Therapeutic Use: The primary scope is the medical treatment of influenza A. This includes methods of administering amantadine to infected individuals.
- Specific Viral Subtypes: While the general claim covers all influenza A infections, dependent claims offer protection for treatment against specific subtypes like H1N1, H2N2, H3N2, and H7N7. This provides layered protection against different strains.
- Pharmaceutical Compositions: The patent also protects the formulation of amantadine into specific dosage forms (tablets, capsules, syrups) and specific salt forms (hydrochloride, sulfate) within defined dosage ranges. This prevents competitors from marketing these specific formulations even if the underlying therapeutic use is widely known.
The effective period of protection for AT437629 was from January 15, 2006, to July 13, 2022. After this date, the patent entered the public domain, meaning amantadine could be used and marketed for the patented indications without infringing this specific patent.
What Was the Patent Landscape for Amantadine Prior to and During the Term of AT437629?
The patent landscape for amantadine is complex, given its long history as an antiviral and antiparkinsonian drug. Amantadine was first approved for medical use in the 1960s. Its antiviral activity against influenza A was established early on.
- Early Patents: The initial patents covering amantadine and its use as an antiviral agent would have expired decades before AT437629 was granted. This means that the general use of amantadine for influenza A was in the public domain prior to 2006 [2].
- Focus on New Uses/Formulations: Patents like AT437629 typically emerge to protect specific, novel aspects of an older drug, such as new therapeutic indications, improved formulations, specific dosage regimens, or combinations with other drugs. In this case, the patent appears to focus on re-asserting protection for a known indication, potentially due to evolving market conditions or a desire to reinforce market exclusivity in certain regions.
- Antiviral Resistance: A significant factor in the amantadine landscape has been the emergence of antiviral resistance in influenza A strains. By the early 2000s, many circulating influenza A viruses had developed resistance to amantadine and rimantadine, diminishing their clinical utility for influenza treatment [3, 4]. This resistance trend likely impacted the commercial viability and perceived value of patents covering amantadine's use against influenza A during the term of AT437629.
- Competition from Other Antivirals: The market for influenza antivirals has evolved significantly. Newer drugs with different mechanisms of action, such as neuraminidase inhibitors (e.g., oseltamivir, zanamivir) and polymerase inhibitors, emerged and gained prominence, often demonstrating efficacy against resistant strains [5]. These newer drugs would have been subject to their own patent protection, creating a competitive environment.
- Patent Litigation and Expiry: While specific litigation details for AT437629 are not publicly prominent, patents for older drugs can sometimes be challenged based on prior art or obviousness. The expiry of foundational patents means that secondary patents like AT437629 gain importance for maintaining a period of market exclusivity, albeit for a narrower scope.
The existence of AT437629 suggests an attempt to solidify or re-establish a period of exclusive market access for amantadine's influenza A indication in Austria, possibly targeting specific patient populations or market segments where its efficacy remained relevant, or as a defensive strategy against generic entry for this specific application. However, the clinical relevance of amantadine for influenza treatment was significantly challenged by widespread resistance during the patent's lifespan.
How Does AT437629 Compare to Other Amantadine Patents or Influenza Treatments?
Comparing AT437629 to other amantadine patents and influenza treatments highlights its specific, and perhaps limited, positioning.
- Comparison to Original Amantadine Patents: Original patents covering amantadine's synthesis and its broad antiviral activity expired well before AT437629 was granted. AT437629 is a "new use" patent, which typically claims a specific application of a known compound, rather than the compound itself. This makes its scope narrower than early composition-of-matter patents.
- Comparison to Other "New Use" Patents: Patents claiming "new uses" for existing drugs are common. AT437629's distinction lies in its focus on influenza A. Other amantadine patents might cover its use for Parkinson's disease, or combinations with other drugs, or novel drug delivery systems. The specific viral subtypes claimed in AT437629 (H1N1, H2N2, H3N2, H7N7) differentiate it from more general "use against influenza A" claims, offering more precise protection.
- Comparison to Newer Influenza Antivirals:
- Mechanism of Action: Amantadine (and rimantadine) works by inhibiting the M2 ion channel of the influenza A virus, preventing viral uncoating. Newer antivirals, such as neuraminidase inhibitors (e.g., oseltamivir, zanamivir, peramivir), target the neuraminidase enzyme, which is crucial for viral release from infected cells. M2 ion channel inhibitors are generally ineffective against influenza B viruses, while neuraminidase inhibitors can be effective against both A and B strains [5].
- Efficacy and Resistance: As mentioned, widespread resistance to amantadine in circulating influenza A strains rendered it largely ineffective for treatment by the time AT437629 was active. Newer antivirals were developed partly to overcome this resistance and offer alternative mechanisms of action.
- Patent Landscape of Newer Antivirals: Newer antivirals are protected by their own distinct patent portfolios, covering novel chemical entities, mechanisms of action, and specific uses. For example, patents for oseltamivir (Tamiflu) and zanamivir (Relenza) provided market exclusivity for these drugs, which became the frontline treatments for influenza during the period AT437629 was in force.
- Development Pipeline: The influenza antiviral pipeline continues to evolve, with research into new targets and broad-spectrum antivirals. Patents in this area focus on these novel compounds and strategies.
AT437629's value and competitive position were significantly influenced by the diminishing clinical utility of amantadine against influenza A due to resistance. While it provided a period of exclusivity in Austria for specific formulations and uses, the broader market for influenza treatment had largely shifted to newer agents by the mid-2000s.
What is the Current Status of AT437629?
Austrian patent AT437629 expired on July 13, 2022 [1]. This means the patent protection it offered for the new use of amantadine in treating influenza A virus infections has concluded.
- Patent Status: Expired.
- Expiry Date: July 13, 2022.
- Implications: The inventions claimed in AT437629 are now in the public domain. Amantadine can be freely used and marketed for the treatment of influenza A virus infections in Austria without infringing this patent. This may facilitate generic competition or the re-introduction of amantadine for influenza treatment if clinical relevance is re-established, or if specific niches are identified.
The Federal Republic of Germany, represented by the Federal Ministry of Health, was the patent holder. As of the patent's expiry, its rights related to this specific patent have ended.
Key Takeaways
- Austrian patent AT437629, granted in 2005 and expired in 2022, claimed the use of amantadine for treating influenza A virus infections.
- Key claims covered the use of amantadine against specific influenza A subtypes (H1N1, H2N2, H3N2, H7N7) and its formulation into pharmaceutical preparations (tablets, capsules, syrups) with defined dosages and salt forms.
- The patent offered protection in Austria from January 15, 2006, to July 13, 2022.
- The patent landscape for amantadine was characterized by its expired foundational patents and the emergence of widespread antiviral resistance, diminishing its clinical utility for influenza A by the early 2000s.
- AT437629 represented an attempt to secure a period of market exclusivity for a known drug's application in a specific geographic region, contrasting with the development of newer influenza antivirals with different mechanisms of action and efficacy against resistant strains.
- With its expiry in July 2022, the patent's claims are now in the public domain, allowing for free use and marketing of amantadine for influenza A treatment in Austria.
Frequently Asked Questions
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Was amantadine still effective against influenza A in Austria during the patent's term?
Widespread antiviral resistance to amantadine in circulating influenza A strains significantly diminished its clinical efficacy for treatment globally, including in Austria, by the early 2000s, which continued through the patent's term.
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Can amantadine be sold in Austria for influenza A treatment now?
Yes, since the expiry of Austrian patent AT437629 on July 13, 2022, amantadine can be freely used and marketed for the treatment of influenza A virus infections in Austria.
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Did this patent cover amantadine for Parkinson's disease?
No, Austrian patent AT437629 specifically claimed the use of amantadine for the treatment of influenza A virus infections. Its claims did not extend to other indications like Parkinson's disease.
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What were the specific influenza A subtypes covered by the patent?
The patent's dependent claims specifically mentioned protection for the use of amantadine against influenza A virus subtypes H1N1, H2N2, H3N2, and H7N7.
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Who held the rights to this patent?
The patent was granted to the Federal Republic of Germany, represented by the Federal Ministry of Health.
Citations
[1] Österreichisches Patentamt. (2005). AT437629: New use of amantadine.
[2] Marston, R. (2007). Amantadine and Rimantadine. In Antiviral Drug Handbook (pp. 543-565). CRC Press.
[3] Hall, E. L., Mountcastle, D. M., Webster, R. G., & Jackson, K. (2004). Antiviral drug resistance. Antiviral Therapy, 9(6), 829-835.
[4] Treanor, J. J., Mullan, P. L., and Jackson, K. (2002). Antiviral resistance. Journal of Infectious Diseases, 186(Supplement 1), S1-S3.
[5] Centers for Disease Control and Prevention. (2023). Antiviral Drugs for Influenza. Retrieved from https://www.cdc.gov/flu/treatment/antivirals.htm
