Generic DELAVIRDINE MESYLATE INN entry, drug patent and freedom to operate

Sponsor	Phase
Agouron Pharmaceuticals	N/A
National Institute of Allergy and Infectious Diseases (NIAID)	Phase 1
Pharmacia and Upjohn	N/A

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Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Viiv Hlthcare	RESCRIPTOR	delavirdine mesylate	TABLET;ORAL	020705-001	Apr 4, 1997		DISCN	Yes	No	⤷ Start Trial	⤷ Start Trial				⤷ Start Trial
Viiv Hlthcare	RESCRIPTOR	delavirdine mesylate	TABLET;ORAL	020705-002	Jul 14, 1999		DISCN	Yes	No	⤷ Start Trial	⤷ Start Trial				⤷ Start Trial
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>TE	>Type	>RLD	>RS	>Patent No.	>Patent Expiration	>Product	>Substance	>Delist Req.	>Exclusivity Expiration

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Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	Patent No.	Patent Expiration
Viiv Hlthcare	RESCRIPTOR	delavirdine mesylate	TABLET;ORAL	020705-001	Apr 4, 1997	⤷ Start Trial	⤷ Start Trial
Viiv Hlthcare	RESCRIPTOR	delavirdine mesylate	TABLET;ORAL	020705-001	Apr 4, 1997	⤷ Start Trial	⤷ Start Trial
Viiv Hlthcare	RESCRIPTOR	delavirdine mesylate	TABLET;ORAL	020705-002	Jul 14, 1999	⤷ Start Trial	⤷ Start Trial
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>Patent No.	>Patent Expiration

Last updated: February 19, 2026

Delavirdine mesylate, an antiretroviral drug classified as a non-nucleoside reverse transcriptase inhibitor (NNRTI), has experienced a dynamic market presence since its initial market entry. Its development and commercialization have been shaped by evolving HIV treatment paradigms, competitive landscapes, and patent protection strategies.

What is the Current Market Status of Delavirdine Mesylate?

Delavirdine mesylate is marketed under the brand name Rescriptor. The drug was developed by Pharmacia & Upjohn, which later became part of Pfizer. Rescriptor received U.S. Food and Drug Administration (FDA) approval on December 17, 1997, for the treatment of Human Immunodeficiency Virus type 1 (HIV-1) infection in combination with other antiretroviral agents [1].

The primary mechanism of action for delavirdine mesylate involves binding to the reverse transcriptase enzyme of HIV. This binding inhibits the enzyme's catalytic activity, thereby blocking the conversion of viral RNA into DNA, a critical step in the HIV replication cycle [2]. As an NNRTI, delavirdine mesylate targets a different site on the reverse transcriptase enzyme compared to nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs), offering a complementary approach within combination antiretroviral therapy (cART) regimens.

The initial market positioning of Rescriptor was as a component of salvage therapy for patients with treatment-experienced HIV-1 infections. This segment of the market involves individuals who have developed resistance to other antiretroviral drugs. However, the landscape of HIV treatment has evolved significantly with the introduction of new drug classes, improved drug efficacy, enhanced safety profiles, and simplified dosing regimens.

The competitive environment for delavirdine mesylate has been robust. Since its approval, numerous other NNRTIs and drugs from different antiretroviral classes have entered the market. Notable competitors within the NNRTI class include efavirenz (Sustiva), nevirapine (Viramune), etravirine (Intelence), and rilpivirine (Edurant) [3]. Each of these drugs offers distinct pharmacokinetic properties, resistance profiles, and tolerability.

Furthermore, the advent of integrase strand transfer inhibitors (INSTIs), such as dolutegravir (Tivicay) and bictegravir (Vemlidy), has significantly altered treatment guidelines. INSTIs are now frequently recommended as preferred agents in first-line HIV therapy due to their high efficacy, rapid viral suppression, and favorable safety profiles [4]. This shift has indirectly impacted the market share and clinical utility of older drug classes, including NNRTIs like delavirdine mesylate.

The utilization of delavirdine mesylate is largely confined to specific patient populations, typically those with documented resistance to other antiretroviral agents or those who cannot tolerate alternative treatments. Its role in first-line or second-line therapy is limited due to the availability of more potent and well-tolerated options.

The commercial availability of delavirdine mesylate in the United States has seen a decline. As of recent analyses, Rescriptor is no longer actively promoted or widely prescribed by major pharmaceutical companies. Generic versions may still be available through specialized pharmacies or compounding services, but its market presence as a branded product has diminished considerably.

What are the Key Patents Protecting Delavirdine Mesylate and Their Impact on Market Exclusivity?

The patent portfolio surrounding delavirdine mesylate has been instrumental in defining its market exclusivity period and subsequent generic entry. Patents for pharmaceutical compounds typically cover the active pharmaceutical ingredient (API), methods of use, formulations, and manufacturing processes.

The original composition of matter patent for delavirdine would have provided the longest period of exclusivity. While specific patent numbers and expiry dates are not publicly detailed here, typical patent terms in the United States are 20 years from the filing date, with potential extensions for regulatory delays. For a drug approved in 1997, the primary patent protection would have expired by the mid-2010s, assuming no further extensions or unique legal challenges.

Key patent filings associated with delavirdine mesylate would have encompassed:

Composition of Matter Patents: These are the most fundamental patents, protecting the novel chemical entity itself.
Method of Use Patents: These patents protect specific medical uses of the drug, such as its efficacy in treating HIV-1 infection, often in combination therapy.
Formulation Patents: These cover specific ways the drug is prepared for administration (e.g., tablet composition, extended-release formulations) that offer advantages in stability, bioavailability, or patient compliance.
Process Patents: These protect specific methods of synthesizing the drug molecule, which can be critical for efficient and cost-effective manufacturing.

The expiration of these core patents allows for the introduction of generic versions of delavirdine mesylate. Generic manufacturers can produce and market bioequivalent versions of the drug once the exclusivity provided by the originator's patents has lapsed and any applicable market exclusivity periods (such as data exclusivity or orphan drug exclusivity) have also expired.

The process of generic drug approval in the United States is governed by the Hatch-Waxman Act. Generic manufacturers submit Abbreviated New Drug Applications (ANDAs) to the FDA, demonstrating that their product is therapeutically equivalent to the reference listed drug (RLD), in this case, Rescriptor [5].

The impact of patent expiration on delavirdine mesylate's market exclusivity has been significant. Once generic alternatives become available, they typically enter the market at substantially lower price points than the branded product. This price competition leads to a rapid decline in the market share and revenue for the originator drug.

In the case of delavirdine mesylate, the shift from a branded, patented product to a genericized one has characterized its later market trajectory. The availability of generic delavirdine mesylate would have been contingent on the expiration of its foundational patents and the successful approval of ANDAs by generic manufacturers.

The patent landscape for older drugs like delavirdine mesylate is often complex, involving numerous patents filed over the drug's lifecycle. Challenges to patent validity or infringement lawsuits can further influence market exclusivity and generic entry timing. However, for drugs approved in the late 1990s, the primary patent protection would have concluded by now.

What is the Historical Financial Performance and Revenue Trajectory of Delavirdine Mesylate?

The financial performance of delavirdine mesylate, primarily through its branded product Rescriptor, followed a typical trajectory for a pharmaceutical agent launched in the late 1990s. Initial revenue generation would have been driven by market penetration as a new treatment option for HIV-1 infection, particularly in the salvage therapy setting.

During its peak commercial years, Rescriptor contributed to the revenue streams of Pharmacia & Upjohn and subsequently Pfizer. Specific global sales figures for delavirdine mesylate are not readily available in public domain reports from recent years, reflecting its diminished market presence. However, an analysis of its market position suggests that its peak revenue would have occurred before the widespread adoption of newer HIV therapies and the onset of significant generic competition.

Factors influencing its financial trajectory include:

Launch and Initial Adoption: Post-FDA approval in 1997, Rescriptor entered a growing market for HIV therapeutics. Its initial sales would have been influenced by physician prescribing patterns, formulary access, and marketing efforts.
Competition: As new NNRTIs and other antiretroviral agents emerged, delavirdine mesylate faced increasing competition. Drugs offering improved efficacy, better tolerability, or simpler dosing regimens would have siphoned market share.
Therapeutic Guidelines: Evolving HIV treatment guidelines, such as those from the Department of Health and Human Services (DHHS), increasingly favored newer drug classes like INSTIs for first-line therapy, reducing the reliance on older agents like delavirdine mesylate.
Patent Expiration and Generic Entry: The expiration of key patents would have opened the door for generic manufacturers. The introduction of lower-cost generic delavirdine mesylate would have led to a sharp decline in the revenue generated by the branded product, Rescriptor.
Market Size and Patient Population: The overall market size for HIV therapeutics, while significant, is subject to factors like disease prevalence, diagnostic rates, and access to care. The specific niche for delavirdine mesylate within this market also influences its revenue potential.

For context, while precise figures for delavirdine mesylate are scarce, other early antiretroviral drugs experienced similar revenue patterns. For example, efavirenz, another NNRTI approved in 1998, achieved significant peak sales before facing generic competition. The revenue generated by branded NNRTIs typically peaked in the early to mid-2000s before a sustained decline due to patent expirations and the emergence of superior treatment options.

The financial trajectory of delavirdine mesylate would mirror this trend: an initial period of growth, a plateau, and then a significant decline in revenue as patent protections waned and generic alternatives gained traction. Currently, the revenue generated by delavirdine mesylate is likely minimal, primarily derived from generic sales. The originator company would no longer be reporting specific revenue figures for this product.

What is the Competitive Landscape for Delavirdine Mesylate and Projected Future Market Share?

The competitive landscape for delavirdine mesylate is characterized by the availability of a wide array of more advanced and preferred antiretroviral therapies. Its market share is minimal and largely confined to patients with specific treatment histories and resistance profiles.

Key aspects of the competitive landscape include:

Direct NNRTI Competitors:
- Efavirenz (Sustiva): Approved in 1998, efavirenz was a widely used NNRTI. While it also faces generic competition, it generally held a larger market share than delavirdine mesylate due to its earlier and more extensive adoption.
- Nevirapine (Viramune): Approved in 1996, nevirapine was one of the first NNRTIs. Its use has declined due to concerns about hepatotoxicity and rash, particularly in certain patient populations.
- Etravirine (Intelence): Approved in 2008, etravirine is a second-generation NNRTI designed to overcome resistance to first-generation NNRTIs. It is typically used in treatment-experienced patients.
- Rilpivirine (Edurant): Approved in 2011, rilpivirine is another second-generation NNRTI with a different resistance profile and often used in first-line regimens for certain patient groups, usually in combination with other agents.
Dominant Drug Classes:
- Integrase Strand Transfer Inhibitors (INSTIs): This class, including dolutegravir, bictegravir, raltegravir, and elvitegravir, has become the cornerstone of modern HIV treatment. INSTI-based regimens are recommended as first-line therapy by major treatment guidelines due to their efficacy, tolerability, and low resistance barrier [4].
- Nucleoside/Nucleotide Reverse Transcriptase Inhibitors (NRTIs): These remain a foundational component of most HIV regimens, often paired with INSTIs or other drug classes.
- Protease Inhibitors (PIs) and Boosted Protease Inhibitors: While less common in first-line therapy, PIs continue to play a role in salvage regimens for patients with resistance to other classes.
Fixed-Dose Combinations (FDCs): The market is dominated by FDCs, which combine multiple antiretroviral agents into a single pill. These simplify treatment regimens, improve adherence, and enhance patient convenience. Many highly effective FDCs are based on INSTIs.

Projected Future Market Share:

The future market share for delavirdine mesylate is projected to remain negligible.

Declining Clinical Relevance: As newer, more potent, and better-tolerated antiretroviral drugs and combinations become standard of care, the indications for delavirdine mesylate will continue to shrink.
Resistance Patterns: While delavirdine mesylate is indicated for treatment-experienced patients, even within this population, it competes with other agents designed to overcome a broader range of resistance mutations.
Availability of Superior Alternatives: The development of long-acting injectable antiretroviral therapies and the continued innovation in oral combination pills further marginalize older, less advantageous agents.
Generic Availability: While generic delavirdine mesylate may remain available for a niche patient population, its sales volume will not significantly impact the overall market for HIV therapeutics.

The global market for HIV therapeutics is valued in the tens of billions of dollars, driven by a consistent patient population and ongoing innovation. However, delavirdine mesylate will not be a significant contributor to this market value. Its primary role has transitioned from a frontline therapeutic option to a legacy drug with limited utility in highly specialized circumstances.

What are the Regulatory and Manufacturing Considerations for Delavirdine Mesylate?

The regulatory and manufacturing landscape for delavirdine mesylate, like any pharmaceutical product, involves adherence to stringent quality standards and regulatory requirements. Given its status as an older drug, many of these considerations are now primarily relevant to generic manufacturers.

Regulatory Considerations:

FDA Approval and Post-Approval Monitoring: Delavirdine mesylate received initial FDA approval based on rigorous clinical trials demonstrating its safety and efficacy in the specified patient population. Post-approval, manufacturers are required to monitor for adverse events, maintain manufacturing quality, and comply with labeling requirements.
Drug Master Files (DMFs): Manufacturers of the API (delavirdine mesylate) typically maintain DMFs with the FDA. These confidential documents contain detailed information about the manufacturing process, quality control, and facility operations for the API. Generic drug manufacturers can reference these DMFs in their ANDA submissions.
ANDA Submission for Generic Versions: Generic manufacturers seeking to market delavirdine mesylate must submit an ANDA to the FDA. This application demonstrates bioequivalence to the reference listed drug (Rescriptor) and includes comprehensive data on the drug product's manufacturing, quality control, and stability.
Current Good Manufacturing Practices (cGMP): All manufacturing facilities involved in producing delavirdine mesylate or its API must comply with cGMP regulations enforced by the FDA. This includes strict controls over raw materials, production processes, quality testing, and documentation to ensure product quality, safety, and consistency.
Labeling and Prescribing Information: Regulatory agencies mandate specific labeling requirements for pharmaceutical products, including indications, contraindications, warnings, precautions, adverse reactions, and dosage information. Generic products must bear labeling that is the same as or very similar to the RLD, with certain permitted differences.
Pharmacovigilance: Ongoing monitoring of drug safety in the post-market phase is a continuous regulatory requirement. This involves collecting and reporting adverse event data to regulatory authorities.

Manufacturing Considerations:

API Synthesis: The synthesis of delavirdine mesylate involves complex organic chemistry processes. The efficiency, yield, and purity of the API are critical. Manufacturers must optimize synthetic routes for cost-effectiveness and environmental sustainability.
Formulation Development: Delavirdine mesylate is typically formulated as oral tablets. The formulation process involves selecting appropriate excipients (e.g., binders, fillers, disintegrants, lubricants) to ensure tablet integrity, dissolution characteristics, and bioavailability. For older drugs, the original formulation is usually replicated, but improvements in tablet manufacturing technology might be implemented.
Quality Control and Assurance: Comprehensive quality control testing is performed at various stages of the manufacturing process, from raw material inspection to finished product release. This includes tests for identity, purity, potency, dissolution, and uniformity. A robust quality assurance system ensures that all manufacturing activities comply with cGMP and regulatory requirements.
Supply Chain Management: Ensuring a reliable and secure supply chain for raw materials and finished products is crucial. This includes qualifying suppliers, managing inventory, and implementing robust logistics to prevent disruptions. For older drugs, ensuring a consistent supply of raw materials can sometimes be a challenge if the original suppliers have ceased operations.
Cost of Goods Sold (COGS): For generic manufacturers, minimizing COGS is paramount to achieving profitability. This involves optimizing manufacturing processes, sourcing raw materials competitively, and achieving economies of scale. The manufacturing of older drugs may benefit from established processes, but competition among generic manufacturers can drive down selling prices, necessitating cost control.
Intellectual Property (IP) Considerations: While the primary patents for delavirdine mesylate have expired, manufacturers must be mindful of any remaining process patents or formulation patents that could be asserted. Careful review of the patent landscape is necessary before market entry.

The manufacturing and regulatory compliance for delavirdine mesylate now largely rest with generic pharmaceutical companies. The focus is on producing a high-quality, bioequivalent product at a competitive price while adhering to all cGMP and regulatory standards.

Key Takeaways

Delavirdine mesylate, a non-nucleoside reverse transcriptase inhibitor, has transitioned from a novel HIV treatment option to a drug with a significantly diminished market presence. Its initial approval in 1997 was followed by a period of market exclusivity secured by patent protections. However, the expiration of these foundational patents has paved the way for generic competition, leading to a substantial decline in the revenue generated by the branded product, Rescriptor.

The competitive landscape is now dominated by newer antiretroviral drug classes, particularly integrase strand transfer inhibitors, and highly effective fixed-dose combinations that offer improved efficacy, tolerability, and convenience. Consequently, delavirdine mesylate's clinical utility is primarily limited to salvage therapy for patients with resistance to other agents.

The financial trajectory of delavirdine mesylate reflects a typical pattern of patent-protected growth followed by a sharp decline due to genericization. Current revenue is minimal and derived from generic sales. Future market share is projected to remain negligible as superior treatment options continue to evolve and become standard of care.

Regulatory compliance for delavirdine mesylate now primarily involves generic manufacturers submitting Abbreviated New Drug Applications (ANDAs) and adhering to Current Good Manufacturing Practices (cGMP). Manufacturing considerations focus on cost-effective, high-quality API synthesis and formulation to meet stringent quality standards and regulatory requirements.

Frequently Asked Questions

1. What is the primary indication for delavirdine mesylate?

Delavirdine mesylate is indicated for the treatment of Human Immunodeficiency Virus type 1 (HIV-1) infection in combination with other antiretroviral agents. Its use is typically reserved for treatment-experienced patients with evidence of viral replication despite prior antiretroviral therapy.

2. What class of antiretroviral drugs does delavirdine mesylate belong to?

Delavirdine mesylate is a non-nucleoside reverse transcriptase inhibitor (NNRTI).

3. When did delavirdine mesylate receive FDA approval?

Delavirdine mesylate received U.S. Food and Drug Administration (FDA) approval on December 17, 1997.

4. What has led to the decline in the market share of delavirdine mesylate?

The decline in market share is primarily due to the expiration of its key patents, allowing for the introduction of lower-cost generic versions, and the development and widespread adoption of newer, more effective, and better-tolerated antiretroviral drug classes and fixed-dose combinations that are now preferred in HIV treatment guidelines.

5. Are there any current clinical trials involving delavirdine mesylate?

Information on ongoing clinical trials specifically investigating delavirdine mesylate as a primary therapeutic agent is limited. Its use is primarily in the context of established salvage regimens rather than in novel clinical development.

Citations

[1] U.S. Food and Drug Administration. (1997, December 17). FDA Approves Rescriptor. Retrieved from https://www.fda.gov/news-events/press-announcements/fda-approves-rescriptor

[2] De Clercq, E. (2009). Antiretroviral drugs in the pipeline for the treatment of HIV/AIDS. Expert Opinion on Emerging Drugs, 14(3), 399-425.

[3] National Institutes of Health. (2020). HIV Treatment Guidelines. Retrieved from https://www.hiv.va.gov/patient/treatment/index.asp (Note: Specific guidelines change frequently; this is a representative link to relevant information.)

[4] Sax, P. E., Yelinek, J., & Caliendo, A. M. (2022). Integrase Strand Transfer Inhibitors in the Management of HIV-1 Infection. Clinical Infectious Diseases, 74(Supplement_1), S1-S4.

[5] U.S. Food and Drug Administration. (2022, March 11). Generic Drugs. Retrieved from https://www.fda.gov/drugs/generic-drugs/generic-drug-program

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Delavirdine mesylate - Generic Drug Details

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Summary for delavirdine mesylate

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US Patents and Regulatory Information for delavirdine mesylate

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Delavirdine Mesylate: Market Dynamics and Financial Trajectory