Last updated: February 19, 2026
Patent CA2759284, filed by Gilead Sciences, Inc. on December 14, 2009, and granted on January 13, 2015, protects a pharmaceutical compound and its use. The patent's primary focus is on Tenofovir Alafenamide Fumarate (TAF) and its formulations for treating viral infections, particularly Hepatitis B virus (HBV) and human immunodeficiency virus (HIV). The claims define the chemical structure of TAF, specific salt forms, pharmaceutical compositions containing TAF, and methods of treatment.
What is the core invention protected by CA2759284?
The central invention is the compound Tenofovir Alafenamide Fumarate (TAF). TAF is a prodrug of tenofovir, a nucleotide analog reverse transcriptase inhibitor. Compared to its predecessor, Tenofovir Disoproxil Fumarate (TDF), TAF offers improved delivery to target cells and a lower systemic exposure, leading to reduced renal and bone toxicity. The patent claims the fumarate salt of Tenofovir Alafenamide, chemical formula C19H29N5O7P·C4H4O4, molecular weight 551.47 g/mol.
What are the key patent claims?
Patent CA2759284 contains multiple claims, broadly categorized into compound claims, formulation claims, and method of use claims.
Compound Claims
- Claim 1: Claims Tenofovir Alafenamide Fumarate. This is the broadest claim covering the active pharmaceutical ingredient (API) itself.
- Claim 2-4: Detail specific forms or properties of Tenofovir Alafenamide Fumarate, potentially including crystalline forms or purity specifications.
- Claim 5-12: Claim various salts and solvates of Tenofovir Alafenamide, expanding the scope beyond the fumarate salt. This includes, but is not limited to, mesylate, hydrochloride, and maleate salts.
Formulation Claims
- Claim 13-20: Protect pharmaceutical compositions comprising Tenofovir Alafenamide Fumarate. These claims define formulations that are suitable for oral administration.
- Claim 14: Specifically claims a pharmaceutical composition comprising Tenofovir Alafenamide Fumarate and a pharmaceutically acceptable carrier.
- Claim 15: Further refines this by claiming a tablet comprising Tenofovir Alafenamide Fumarate, a disintegrant, and a binder.
- Claim 16-19: Describe additional excipients and their quantities, such as fillers, lubricants, and coatings, to ensure optimal drug delivery and stability.
Method of Use Claims
- Claim 21-27: Cover methods of treating viral infections using Tenofovir Alafenamide Fumarate.
- Claim 21: Claims a method of treating or preventing a viral infection in a subject, comprising administering an effective amount of Tenofovir Alafenamide Fumarate.
- Claim 22: Specifically claims the method for treating Hepatitis B virus (HBV) infection.
- Claim 23: Claims the method for treating human immunodeficiency virus (HIV) infection.
- Claim 24-27: Detail the dosage regimens and patient populations for these treatments, specifying daily dosages and combinations with other antiretroviral agents.
What is the scope of protection offered by these claims?
The claims in CA2759284 provide broad protection for TAF and its therapeutic applications. The compound claims protect the API in its various salt and solvate forms. The formulation claims protect specific oral dosage forms, preventing competitors from marketing generic versions that utilize these protected compositions. The method of use claims create a barrier to entry for competing treatments that target the same viral infections with TAF.
The patent's scope is significant because TAF is a key component in several blockbuster HIV and HBV therapies, most notably Biktarvy (bictegravir, emtricitabine, and tenofovir alafenamide) and Vemlidy (tenofovir alafenamide). These drugs have achieved substantial market share due to their efficacy and improved safety profile compared to older treatments.
How does CA2759284 fit into the broader patent landscape for Tenofovir Alafenamide?
CA2759284 is part of a larger patent portfolio for TAF developed by Gilead Sciences. This portfolio includes patents covering the initial discovery of TAF, its synthesis, various polymorphic forms, and its use in combination therapies.
Key Patents in the TAF Landscape
| Patent Number |
Filing Date |
Grant Date |
Primary Focus |
| CA2759284 |
Dec 14, 2009 |
Jan 13, 2015 |
Tenofovir Alafenamide Fumarate (TAF) and its uses |
| US8354426 |
May 28, 2004 |
Jan 17, 2013 |
Tenofovir Alafenamide and its synthesis |
| US8895043 |
Dec 14, 2009 |
Nov 25, 2014 |
Pharmaceutical compositions containing TAF (similar to CA2759284) |
| US9107753 |
Apr 29, 2011 |
Aug 11, 2015 |
Methods of treating HBV with TAF |
| US9205001 |
Feb 13, 2014 |
Dec 06, 2015 |
Combination therapies for HIV including TAF |
This table illustrates that CA2759284 complements other patents by covering specific aspects of TAF, including its fumarate salt and therapeutic applications. The expiration dates of these patents are critical for generic manufacturers seeking to enter the market.
What are the potential implications for generic competition?
The expiration of key patents protecting TAF, including CA2759284, is a significant event for the pharmaceutical market. The term of patent protection in Canada is generally 20 years from the filing date, subject to adjustments for any delays in prosecution.
- CA2759284 Filing Date: December 14, 2009.
- Potential Expiration (20-year term): December 14, 2029.
- Patent Term Adjustment (PTA): Canada's Patent Act allows for PTA to compensate for delays in examination. The actual expiration date could be later than the standard 20-year term.
Generic manufacturers typically await the expiry of primary patents before launching their products. However, the landscape can be complex due to:
- Patent Linkage: In Canada, the Patented Medicines (Notice of Compliance) Regulations (PM(NOC) Regulations) link the approval of generic drug submissions (Notices of Compliance) to the expiry or invalidation of patents listed on the Patent Register.
- Secondary Patents: Gilead may hold additional patents covering specific formulations, polymorphs, or methods of use that could extend market exclusivity beyond the expiry of the primary compound patent.
- Litigation: Generic companies often challenge the validity of patents or allege non-infringement. These legal battles can significantly impact the timeline for generic market entry.
The claims of CA2759284, particularly those covering the TAF fumarate salt and its use in treating HBV and HIV, represent a substantial hurdle for generic companies. Generic versions of TAF-containing drugs will need to demonstrate they do not infringe these claims, either by waiting for their expiry or successfully challenging their validity.
What is the current status and market impact of TAF-containing products?
TAF is a cornerstone of Gilead's antiviral franchise. Its market impact is substantial, primarily through its inclusion in fixed-dose combination therapies.
- Biktarvy (bictegravir/emtricitabine/tenofovir alafenamide): A leading HIV treatment.
- Vemlidy (tenofovir alafenamide): A single-agent treatment for chronic Hepatitis B.
These products have generated billions of dollars in revenue for Gilead. The introduction of TAF marked a significant advancement in treating these chronic viral infections, offering improved safety profiles compared to older tenofovir prodrugs.
As CA2759284 and related patents approach their expiration, the market is poised for increased generic competition. This is expected to lead to price reductions for TAF-containing therapies, increasing access for patients.
What are the key takeaways for stakeholders?
Patent CA2759284 protects the core compound Tenofovir Alafenamide Fumarate (TAF) and its therapeutic applications for treating viral infections such as HBV and HIV. The patent's claims encompass the API itself, specific salt forms, oral pharmaceutical compositions, and methods of treatment. This patent, along with others in Gilead's TAF portfolio, has been instrumental in establishing market exclusivity for TAF-based drugs. For generic manufacturers, understanding the scope and expiration of CA2759284 is critical for planning market entry. For Gilead, this patent represents a key asset in its revenue generation strategy, while for healthcare providers and patients, its eventual expiration signals the potential for more affordable treatment options.
Frequently Asked Questions
When was patent CA2759284 filed and granted in Canada?
Patent CA2759284 was filed on December 14, 2009, and granted on January 13, 2015.
What is the primary therapeutic use protected by CA2759284?
The primary therapeutic uses protected by CA2759284 are the treatment and prevention of viral infections, specifically Hepatitis B virus (HBV) and human immunodeficiency virus (HIV).
Does CA2759284 cover only the fumarate salt of Tenofovir Alafenamide?
No, while Claim 1 specifically claims Tenofovir Alafenamide Fumarate, other claims within the patent cover various salts and solvates of Tenofovir Alafenamide, expanding the scope beyond the fumarate salt.
What is the estimated expiry date for patent CA2759284 in Canada?
Based on a standard 20-year term from the filing date of December 14, 2009, the patent would typically expire around December 14, 2029. However, Patent Term Adjustment may extend this date.
What are the implications of this patent for generic drug development?
This patent defines the core compound and its uses, presenting a significant barrier for generic manufacturers. They must either wait for the patent's expiry, invalidate it through legal challenge, or develop a non-infringing product.
Citations
[1] Gilead Sciences, Inc. (2015). Patent CA2759284. Canadian Intellectual Property Office.
[2] Gilead Sciences, Inc. (2013). Patent US8354426. United States Patent and Trademark Office.
[3] Gilead Sciences, Inc. (2014). Patent US8895043. United States Patent and Trademark Office.
[4] Gilead Sciences, Inc. (2015). Patent US9107753. United States Patent and Trademark Office.
[5] Gilead Sciences, Inc. (2015). Patent US9205001. United States Patent and Trademark Office.
[6] Canadian Intellectual Property Office. (n.d.). Patent Act. Government of Canada.
