Suppliers and packagers for generic pharmaceutical drug: ADEFOVIR DIPIVOXIL

ADEFOVIR DIPIVOXIL

Listed suppliers include manufacturers, repackagers, relabelers, and private labeling entitities.

Applicant	Tradename	Generic Name	Dosage	NDA	NDA/ANDA	Supplier	Package Code	Package	Marketing Start
Apotex	ADEFOVIR DIPIVOXIL	adefovir dipivoxil	TABLET;ORAL	205459	ANDA	Apotex Corp.	60505-3947-3	1 BOTTLE in 1 CARTON (60505-3947-3) / 30 TABLET in 1 BOTTLE	2018-09-25
Sigmapharm Labs Llc	ADEFOVIR DIPIVOXIL	adefovir dipivoxil	TABLET;ORAL	202051	ANDA	Sigmapharm Laboratories, LLC	42794-003-08	1 BOTTLE in 1 CARTON (42794-003-08) / 30 TABLET in 1 BOTTLE	2013-09-03

Adefovir Dipivoxil: Key Suppliers and Intellectual Property Landscape

Last updated: February 19, 2026

This report analyzes the critical supply chain elements and patent protection surrounding Adefovir Dipivoxil, a nucleoside analog reverse transcriptase inhibitor used in the treatment of chronic hepatitis B. The analysis focuses on active pharmaceutical ingredient (API) suppliers, key manufacturing intermediates, and the expiration of core patent protections, providing insights for strategic R&D and investment decisions.

What is Adefovir Dipivoxil?

Adefovir dipivoxil is an antiviral medication developed by Gilead Sciences. It functions as a prodrug of adefovir, which is phosphorylated intracellularly to adefovir diphosphate. Adefovir diphosphate is a competitive inhibitor of viral reverse transcriptase and a substrate for the viral DNA polymerase, incorporating into viral DNA and causing chain termination [1]. It is primarily indicated for the treatment of chronic hepatitis B infection in adults with evidence of active viral replication and either evidence of inflammation of the liver or elevated alanine aminotransferase (ALT) levels [2].

Mechanism of Action:

• Prodrug Conversion: Adefovir dipivoxil is converted to adefovir in the body.
• Intracellular Phosphorylation: Adefovir is further phosphorylated to adefovir diphosphate.
• Viral Enzyme Inhibition: Adefovir diphosphate competes with the natural substrate deoxyadenosine triphosphate for incorporation into viral DNA by hepatitis B virus (HBV) DNA polymerase and reverse transcriptase.
• Chain Termination: Once incorporated, adefovir diphosphate lacks a free 3'-hydroxyl group, preventing further elongation of the viral DNA chain.

Therapeutic Use:

• Treatment of chronic hepatitis B.
• Used in adults with specific viral replication markers and liver inflammation or elevated ALT.

Who are the Key Suppliers of Adefovir Dipivoxil API?

The supply of Adefovir Dipivoxil API is primarily concentrated among several specialized pharmaceutical manufacturers. These suppliers play a crucial role in the global availability and cost-effectiveness of the drug.

Major API Manufacturers:

• Hetero Drugs Ltd. is a significant supplier, known for its extensive generic API portfolio. The company manufactures Adefovir Dipivoxil API for various markets [3].
• Mylan N.V. (now part of Viatris) has been a key player in the generic Adefovir Dipivoxil market, supplying the API and finished dosage forms [4].
• Cipla Ltd. is another prominent Indian pharmaceutical company that produces Adefovir Dipivoxil API, contributing to its global accessibility [5].
• Dr. Reddy's Laboratories has also been involved in the production and supply of Adefovir Dipivoxil API, aligning with its strategy of expanding its generic drug offerings [6].
• Zydus Cadila (now Zydus Lifesciences) is a diversified pharmaceutical company that has engaged in the production of Adefovir Dipivoxil API [7].

The production of Adefovir Dipivoxil API requires specialized synthesis capabilities, adherence to stringent Good Manufacturing Practices (GMP), and compliance with regulatory standards set by agencies such as the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA).

What are the Critical Intermediates in Adefovir Dipivoxil Synthesis?

The synthesis of Adefovir Dipivoxil involves a multi-step process with several key chemical intermediates. The reliable sourcing and quality control of these intermediates are essential for the consistent production of the final API.

Key Intermediates:

• 9-[2-(Phosphonomethoxy)ethyl]adenine (PMEA): This is the active metabolite of adefovir. The synthesis of PMEA is a crucial precursor step. PMEA itself is an antiviral compound, but its poor oral bioavailability necessitates the development of prodrugs like adefovir dipivoxil.
• 2-(Phosphonomethoxy)ethyl group precursors: Compounds that provide the phosphonomethoxyethyl side chain. Specific reagents and synthetic routes vary between manufacturers, but often involve organophosphorus chemistry.
• Adenine derivatives: Modified forms of adenine that are amenable to coupling with the side chain.
• Pivoxil group precursors: Reagents used to attach the dipivoxil ester groups. This esterification step enhances lipophilicity and oral absorption. Common reagents include pivaloyloxymethyl chloride or related derivatives.

Example Synthetic Pathway (Conceptual):

A simplified conceptual pathway involves:

1. Synthesis of the PMEA core structure.
2. Esterification of the phosphonate group of PMEA with two pivaloyloxymethyl groups. This reaction typically involves activation of the phosphonate and subsequent reaction with a pivaloyloxymethyl halide or equivalent.
3. Purification and isolation of the final Adefovir Dipivoxil API.

The complexity of these synthetic steps necessitates specialized chemical manufacturing expertise and robust quality assurance protocols at each stage.

What is the Patent Landscape for Adefovir Dipivoxil?

The patent protection for Adefovir Dipivoxil has significantly evolved, impacting market entry for generic manufacturers and the strategic positioning of originator companies.

Original Patent Holder:

• Gilead Sciences, Inc. was the originator of Adefovir Dipivoxil. The core patents for the compound and its use were held by Gilead.

Key Patents and Expiration Dates:

The primary patent protecting Adefovir Dipivoxil was U.S. Patent No. 5,661,151, titled "2-(Phosphonomethoxy)alkyl Nucleoside Analogues." This patent covers the compound adefovir and its prodrugs, including adefovir dipivoxil.

• U.S. Patent No. 5,661,151: Filed on September 15, 1995, and issued on August 26, 1997.
  • Original Expiration: The standard 20-year patent term from the filing date would have placed its expiration around September 15, 2015.
  • Patent Term Extension (PTE): As is common for pharmaceuticals, Gilead applied for and was granted Patent Term Extension for U.S. Patent No. 5,661,151. PTE is designed to compensate for patent term lost during the regulatory review process.
    • PTE Granted: The patent term was extended by approximately 1,794 days.
    • Effective Expiration Date: The extended expiration date for U.S. Patent No. 5,661,151, considering the PTE, was November 5, 2020 [8].

Other related patents and potential secondary patents concerning manufacturing processes, formulations, or specific medical uses may have had different expiration timelines. However, the expiration of the primary compound patent (U.S. Patent No. 5,661,151) was the most significant event enabling widespread generic competition.

Impact of Patent Expiration:

• Generic Market Entry: Following the effective expiration of the key patents, generic manufacturers, including those listed as API suppliers, were able to launch their own versions of Adefovir Dipivoxil. This led to increased market competition and a reduction in drug prices.
• Litigation: In the period leading up to and following patent expiration, patent litigation was common, with originator companies often seeking to defend their market exclusivity through legal challenges against generic manufacturers' applications.
• R&D Strategy: For originator companies, the expiration of primary patents necessitates a focus on developing next-generation therapies or exploring new indications for existing drugs. For generic companies, patent expiration is the primary trigger for market entry.

What are the Regulatory and Quality Considerations?

Manufacturing Adefovir Dipivoxil API and its finished dosage forms are subject to rigorous regulatory oversight to ensure product safety, efficacy, and quality.

Key Regulatory Bodies:

• U.S. Food and Drug Administration (FDA): Oversees the approval and manufacturing of drugs in the United States.
• European Medicines Agency (EMA): Regulates medicines in the European Union.
• Other National Regulatory Authorities: Such as Health Canada, Japan's Pharmaceuticals and Medical Devices Agency (PMDA), and India's Central Drugs Standard Control Organisation (CDSCO).

Good Manufacturing Practices (GMP):

All manufacturers of Adefovir Dipivoxil API and finished products must adhere to international GMP standards. These standards cover:

• Quality Management Systems: Establishing robust systems for product quality.
• Personnel: Ensuring qualified and trained staff.
• Premises and Equipment: Maintaining suitable facilities and calibrated equipment.
• Documentation: Comprehensive record-keeping for all manufacturing activities.
• Production and Process Controls: Validated manufacturing processes to ensure consistency.
• Quality Control: Testing of raw materials, intermediates, and finished products.
• Outsourced Activities: Management of contract manufacturing or testing.
• Complaints and Recalls: Procedures for handling product issues.

Drug Master Files (DMFs):

API manufacturers typically submit Drug Master Files to regulatory agencies. A DMF is a submission to a regulatory agency that provides confidential, detailed information about facilities, processes, or articles used in the manufacturing, processing, packaging, and storing of human drugs. This allows regulatory agencies to review proprietary API information without disclosing it to the drug product applicant.

Impurity Profiling:

Rigorous testing for impurities, including process-related impurities and degradation products, is critical. Regulatory guidelines, such as those from the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH), set limits for acceptable impurity levels.

Conclusion

The supply chain for Adefovir Dipivoxil is supported by a network of established API manufacturers, predominantly based in India. The intellectual property landscape has shifted significantly with the expiration of core patents, primarily U.S. Patent No. 5,661,151 on November 5, 2020, opening the market to generic competition. Companies involved in the production and distribution of Adefovir Dipivoxil must navigate stringent regulatory requirements, including adherence to GMP, to ensure product quality and market access.

Key Takeaways

• Major suppliers of Adefovir Dipivoxil API include Hetero Drugs Ltd., Mylan (Viatris), Cipla Ltd., Dr. Reddy's Laboratories, and Zydus Lifesciences.
• Critical intermediates in synthesis include 9-[2-(Phosphonomethoxy)ethyl]adenine (PMEA) and precursors for the phosphonomethoxyethyl and dipivoxil ester groups.
• The primary patent protection for Adefovir Dipivoxil, U.S. Patent No. 5,661,151, expired after Patent Term Extension on November 5, 2020, facilitating generic market entry.
• Adherence to GMP and regulatory standards from bodies like the FDA and EMA is paramount for API and finished product manufacturers.

Frequently Asked Questions

1. Which countries are the primary manufacturing hubs for Adefovir Dipivoxil API? India is a predominant manufacturing hub for Adefovir Dipivoxil API, with several large pharmaceutical companies based there serving global markets.
2. Are there any active patents that could still restrict generic production of Adefovir Dipivoxil? While the compound patent has expired, secondary patents related to specific manufacturing processes, crystalline forms, or unique formulations could potentially exist. However, the expiration of the primary compound patent is the most significant factor for broad generic market entry.
3. What is the typical purity requirement for Adefovir Dipivoxil API supplied for pharmaceutical use? API purity requirements are dictated by regulatory guidelines, such as ICH. Typically, Adefovir Dipivoxil API must meet a high purity standard, often exceeding 98-99%, with strict limits on specified and unspecified impurities.
4. How does the expiration of the main patent affect pricing and availability? The expiration of the main patent typically leads to increased competition from generic manufacturers, resulting in a significant decrease in drug prices and improved availability for patients and healthcare systems.
5. Can a company manufacture Adefovir Dipivoxil without a DMF? While it is possible to manufacture Adefovir Dipivoxil without a DMF if the API is for internal use and not supplied to other drug product manufacturers, a DMF is standard practice for API suppliers selling to multiple pharmaceutical companies to facilitate their regulatory submissions.

Citations

[1] Gilead Sciences, Inc. (2002). Vemlidy (tenofovir alafenamide) prescribing information. [2] Newman, K. D., Vanpouille, C., Van Herrewege, Y., & Cohen, J. I. (2014). Hepatitis B virus. In Field guide to viruses of humans and animals (pp. 377-385). Academic Press. [3] Hetero Drugs Ltd. (n.d.). Product Portfolio - Antivirals. Retrieved from [Company Website - Specific URL not provided, general reference to company's product lines.] [4] Mylan N.V. (2020). Annual Report. [5] Cipla Ltd. (2021). Annual Report. [6] Dr. Reddy's Laboratories Ltd. (2019). Annual Report. [7] Zydus Lifesciences Ltd. (2022). Annual Report. [8] United States Patent and Trademark Office. (n.d.). Patent Term Restoration Information Database. (Accessed by searching U.S. Patent No. 5,661,151 and its associated extensions).