Copyright © DrugPatentWatch. Originally published at https://www.drugpatentwatch.com/blog/

The pharmaceutical industry is built on a foundation of high-risk, high-reward innovation. The traditional path of de novo drug discovery is a decathlon of endurance, demanding billions of dollars and over a decade of relentless effort, with a staggering rate of failure. Yet, hiding in plain sight, within the vast archives of approved medicines, failed clinical candidates, and shelved compounds, lies a powerful alternative strategy that is rapidly moving from the periphery to the core of modern R&D: drug repurposing. This is not merely about getting lucky; it’s about getting smart. Welcome to the repurposing renaissance.

Defining the Landscape: More Than Just Happy Accidents

At its heart, drug repurposing—also known as drug repositioning, reprofiling, or redirecting—is the strategic process of identifying, developing, and securing approval for new therapeutic uses for existing drugs outside the scope of their original medical indication.¹ The concept, which first emerged in scientific literature around 2004, has expanded significantly from its initial definition. It now encompasses a broad spectrum of assets:

• Approved Drugs: Finding new uses for medicines already on the market, including those that have become generics.
• Failed Clinical Candidates: Reviving compounds that were proven safe in humans but failed to show sufficient efficacy for their original intended use.
• Shelved or Discontinued Compounds: Re-evaluating assets that were abandoned for strategic or commercial reasons, not due to safety concerns.

It is critical to understand that true repurposing does not involve structurally modifying the drug molecule itself. Instead, it leverages the compound’s known biological properties—sometimes its primary mechanism of action in a new disease context, and other times, a previously known “side effect” that can be harnessed for therapeutic benefit.

Historically, repurposing was a story of serendipity. The infamous thalidomide, withdrawn in the 1960s for causing catastrophic birth defects, was later found by chance to be a powerful treatment for a complication of leprosy and, eventually, multiple myeloma.⁴ Sildenafil (Viagra), famously, was a failed angina medication before its surprising side effect created a multi-billion dollar market for erectile dysfunction.²

But the modern era of repurposing has evolved far beyond these happy accidents. It is now a systematic, intentional strategy, supercharged by advances in human genomics, network biology, chemoproteomics, and, most importantly, artificial intelligence.² We can now computationally screen vast libraries of known compounds against newly understood disease pathways, identifying promising candidates with a speed and precision that was unimaginable a decade ago. It has been shown that drugs targeting pathways supported by human genetics are twice as likely to succeed, providing a powerful rationale for this data-driven approach.

This strategic shift is reflected in the market’s explosive growth. The global drug repurposing market was valued at an impressive $34.98 billion in 2024. Projections show it rocketing to $59.30 billion by 2034, expanding at a compound annual growth rate (CAGR) of 5.42%. This is not a niche segment; repurposed drugs already account for an estimated 25% of the entire pharmaceutical industry’s annual revenue, a testament to their profound economic impact.⁸ While North America currently leads this charge, holding 47% of the market share, the fastest growth is anticipated in the Asia-Pacific region, signaling a global embrace of this efficient innovation model.⁷

The Unmistakable Economic Advantage: Faster, Cheaper, and De-Risked

Why has repurposing captured the attention of boardrooms and investors worldwide? The answer lies in its ability to fundamentally alter the brutal economics of drug development. It offers a compelling trifecta of advantages: speed, cost-efficiency, and a dramatically lower risk of failure.

Accelerated Timelines

The traditional journey from a new chemical entity (NCE) to an approved drug is a 10 to 15-year marathon. Drug repurposing is a sprint in comparison. By leveraging a compound’s existing preclinical and, crucially, human safety data, developers can often bypass the earliest, most time-consuming stages of development. On average, a repurposing strategy can slash 5 to 7 years from the typical drug development timeline. In a competitive market where time-to-market is paramount, this acceleration is a game-changing advantage.

Drastic Cost Reduction

The cost of bringing a novel drug to market is astronomical, with estimates frequently cited in the range of $2 to $3 billion after accounting for the cost of failures.⁴ Repurposing projects operate on a completely different financial scale. The estimated cost to develop a repurposed drug is around

$300 million, representing a staggering 50-60% reduction in overall development expenses.⁸ This efficiency stems directly from eliminating the need to repeat extensive preclinical toxicology studies and Phase I clinical trials, which have often already been completed for the drug’s original indication. This isn’t just about saving money; it’s about deploying capital more efficiently, enabling companies to pursue more projects and diversify their pipelines.

Higher Probability of Success

Perhaps the most powerful advantage of drug repurposing is the dramatic de-risking of the development process. The attrition rate for NCEs is brutal; less than 10% of candidates entering Phase I trials will ultimately gain FDA approval. The primary reason for this high failure rate is often unforeseen safety or toxicity issues that emerge in human trials.

Repurposed drugs have a significant head start. They are, by definition, compounds with a known human safety profile. This pre-existing knowledge base drastically reduces the risk of failure due to safety concerns. The impact on success rates is profound. For repurposed drugs that have already successfully completed Phase I, the probability of reaching market approval can be as high as 30%—a threefold improvement over the industry average for NCEs.⁸ This higher likelihood of success makes repurposing projects far more attractive from an investment perspective, offering a more predictable return on R&D capital.

To put these differences in stark relief, consider the following comparison:

Feature	Traditional De Novo Drug Discovery	Drug Repurposing
Average Time-to-Market	10–15 years	3–12 years (avg. 5-7 years shorter) 4
Average Development Cost	$2–3 billion	~$300 million (50-60% lower) 8
Probability of Success (from Phase I)	<10% 4	~30% 8
Key Development Stages Bypassed	None	Preclinical discovery, extensive toxicology, often Phase I safety trials
Primary IP Protection	Composition of Matter & Method of Use Patents	Primarily Method of Use; sometimes Formulation/Combination Patents
Commercial Exclusivity (US)	5 years (New Chemical Entity)	3 years (New Use/Formulation) or 7 years (Orphan Drug) 4

Beyond the Balance Sheet: Strategic Imperatives

The numbers are compelling, but the true strategic value of drug repurposing transcends simple cost and time savings. For a pharmaceutical company, embracing this strategy is about building a more resilient, efficient, and intelligent R&D engine.

The core value proposition is the conversion of a known safety profile into a tangible financial asset. In traditional drug development, uncertainty is the dominant variable, and safety is the biggest unknown. A repurposed drug flips this equation. The existing dossier of human safety data, pharmacology, and established manufacturing processes represents millions of dollars and years of R&D that a developer does not have to spend.¹ This isn’t just information; it’s a sunk cost for the original developer that becomes a massive capital efficiency gain for the repurposer. When a company in-licenses a shelved compound, it is not just buying a molecule; it is buying a significant measure of certainty. This certainty has a quantifiable value—a “de-risking premium”—that fundamentally alters the investment calculus, making repurposing projects far more palatable to venture capital and internal budget committees than their high-risk NCE counterparts.

Furthermore, for large pharmaceutical companies, a dedicated repurposing program is no longer a “side project” but a crucial portfolio management tool. It functions as a strategic hedge against the punishingly high attrition rates of an innovative pipeline. A big pharma pipeline is in a constant state of flux, threatened by clinical trial failures that can vaporize billions in investment and market capitalization overnight. Repurposing offers a parallel development track with a much higher probability of success and a shorter timeline.⁸ By systematically screening their own shelved assets or actively seeking external opportunities, companies can generate a steady stream of lower-risk, mid-to-late-stage assets. These assets can plug the gaps in the pipeline left by NCE failures, ensuring a more consistent flow of new products to market, smoothing revenue volatility, and satisfying shareholder expectations. In this context, repurposing evolves from an opportunistic tactic into an essential component of strategic risk management.

The Intellectual Property Labyrinth: Securing Your Commercial Future

In the world of drug repurposing, the scientific discovery is only the first step. The far more intricate challenge—and the one that ultimately determines commercial success—is navigating the intellectual property (IP) labyrinth. Unlike a novel compound, where a strong composition-of-matter patent can create a 20-year fortress of exclusivity, a repurposed drug starts with an inherent vulnerability: the molecule itself is already known. Therefore, building a defensible and profitable business requires a sophisticated, multi-layered IP strategy that goes far beyond the basics. How do you protect a new use for an old drug? And how do you do it in a way that can withstand legal challenges and deter generic competition?

The Patent Playbook for Repurposed Drugs

The central IP challenge for any repurposed drug is establishing novelty and non-obviousness when the core active pharmaceutical ingredient (API) is in the public domain. This reality forces a strategic shift away from protecting the what (the compound) to protecting the how (the new application and its specific implementation).

Method-of-Use Patents: The Cornerstone of Protection

The primary and most fundamental tool in the repurposing IP arsenal is the method-of-use (MoU) patent. Also known as a “new use” patent, this legal instrument does not protect the drug itself but rather the specific method of using that drug to treat a new disease.¹⁴ The patent claim would be structured as, for example, “A method of treating Alzheimer’s disease, comprising administering a therapeutically effective amount of drug X.”

While absolutely essential, MoU patents are often considered a weaker form of protection compared to composition-of-matter patents. Their enforcement can be challenging. A physician prescribing a generic version of drug X for Alzheimer’s might be infringing the patent, but suing individual doctors is impractical and commercially toxic. The more significant challenge comes from “off-label” use, where a generic company can sell the drug for its original, off-patent indication, knowing that physicians will prescribe it for the new, patented use. This creates a significant commercial leak that can undermine the value of the repurposed product.

Strengthening the Moat: Formulation and Combination Patents

Because a standalone MoU patent can be a leaky vessel, a robust IP strategy must build a stronger, more defensible moat around the repurposed asset. This is achieved by creating new, patentable inventions related to the drug’s application.

• Formulation Patents: This is a powerful strategy for adding a layer of protection. A new formulation—such as an extended-release tablet, a transdermal patch, an injectable depot, or a novel nanoparticle delivery system—can be patented if it offers a demonstrable advantage for the new indication.¹⁴ This is a much stronger form of protection because it shifts the patentable invention back to a physical product. A generic competitor cannot simply use the old API; they would have to replicate the specific, patented formulation to be substitutable for the new use, which would constitute direct infringement.
• Combination Patents: Another effective approach is to patent a new combination of the repurposed drug with one or more other known drugs. If this new fixed-dose combination demonstrates unexpected synergy—where the combined effect is greater than the sum of the individual effects—it can be considered a non-obvious and highly valuable invention. This strategy not only creates strong IP but can also lead to a superior therapeutic product.
• Dosage and Regimen Patents: In some cases, the innovation may lie in a specific dosing schedule or a narrow therapeutic window that is critical for efficacy and/or safety in the new indication. Patenting a specific dosage (e.g., “a 37.5 mg tablet”) or a regimen (e.g., “administering drug X once weekly”) can provide an additional layer of protection, making it more difficult for a generic to be prescribed in a way that aligns with the approved label for the new use.

Navigating the “Obviousness” Hurdle

Simply finding a new use is not enough to secure a patent. The new use must be non-obvious to a “person having ordinary skill in the art”.¹⁴ This is often the highest bar to clear in repurposing. If the original patent, scientific literature, or clinical trial data for the drug hinted at its potential activity in the new disease area, a patent office may reject the application as obvious.

This is where the quality and nature of the discovery process become paramount. A discovery based on a clear, linear extension of a known mechanism (e.g., using a known anti-inflammatory drug for another inflammatory condition) may face a tough obviousness challenge. However, a discovery stemming from a complex, non-obvious connection—perhaps identified by an AI algorithm that found an unexpected link between a drug’s off-target effects and a disease’s genetic signature—is far more likely to be deemed non-obvious. Robust data demonstrating an unexpected or surprising result is the best defense against an obviousness rejection.

The “Evergreening” Controversy: Strategy or System-Gaming?

No discussion of follow-on pharmaceutical patents is complete without addressing the contentious practice of “evergreening.” The term, often used pejoratively by critics, refers to the collection of legal and business strategies used by pharmaceutical companies to extend patent protection and market exclusivity for a drug, often just as its original patents are set to expire.¹⁴ Repurposing, particularly the filing of new indication or formulation patents late in a drug’s lifecycle, is frequently cited as a key evergreening tactic.²⁰

The practice is at the center of a fierce debate, pitting the need for continued innovation against the demand for affordable generic medicines.

• The Critical View: Critics argue that evergreening is a way to “game the system”. They contend that many of these secondary patents are for minor, trivial modifications that offer little to no additional therapeutic benefit to patients. The primary goal, they argue, is to block or delay the entry of lower-cost generics, keeping drug prices artificially high and burdening healthcare systems.²² Dr. Joel Lexchin, a prominent academic and critic of industry practices, puts it bluntly:“Typically, when you evergreen something, you are not looking at any significant therapeutic advantage. You are looking at a company’s economic advantage.”
  This perspective sees evergreening as a perversion of the patent system’s intent, rewarding market manipulation over genuine breakthrough innovation.
• The Industry Defense: Pharmaceutical companies and their defenders reject the term “evergreening,” preferring the more neutral “lifecycle management”. They argue that this is not about gaming the system but about protecting legitimate, valuable, and often costly follow-on innovation. They make several key points:

• Recouping R&D Costs: The initial 20-year patent term is significantly eroded by the long development and regulatory review process, leaving an effective market life of often just 12-14 years. Secondary patents are seen as a necessary way to recoup the massive initial investment.
• Incremental Innovation has Value: A new formulation that improves patient adherence (e.g., moving from a twice-daily to a once-daily pill), a new delivery system that reduces side effects, or a new indication that serves a previously unmet need are all genuine innovations that benefit patients and deserve patent protection.
• Incentivizing Further Research: The possibility of securing new patents encourages companies to continue investing in a drug even after its initial approval, leading to the discovery of new uses and improvements that might otherwise never be explored.²²

The truth, as is often the case, lies somewhere in the middle. While some evergreening practices have involved trivial changes, many others, including legitimate repurposing efforts, have resulted in significant clinical advances. For the strategist, the key is to ensure that any lifecycle management strategy is built on a foundation of genuine, demonstrable patient benefit, which provides the strongest possible defense against both legal and public scrutiny.

Building an Impenetrable IP Fortress

A successful IP strategy for a repurposed drug is not about finding a single “silver bullet” patent. It is about architectural design—constructing a “patent thicket,” a dense and overlapping network of different patent types that creates multiple, formidable barriers to entry for would-be competitors. A single MoU patent is a picket fence; a patent thicket is a fortress.

Consider the strategic logic: a standalone MoU patent is vulnerable. A generic competitor can challenge its validity on grounds of obviousness. Even if the patent holds, they can launch with a “skinny label” for the off-patent indication and benefit from off-label prescribing, effectively circumventing the patent’s commercial power.² However, when you layer on a patent for a new extended-release formulation that is essential for the new indication’s safety profile, and another patent for its synergistic combination with a standard-of-care drug, the landscape for the generic challenger changes dramatically. Now, they must navigate or invalidate not one, but three or more patents. The legal cost, time, and risk of doing so increase exponentially. This multi-layered defense transforms a weak IP position into a strong one.

The ultimate IP strategy achieves a powerful symbiosis between patent protection and regulatory exclusivity. These are two distinct but complementary mechanisms. Patents protect the invention, while regulatory exclusivities (which we will explore in the next sections) protect the data submitted for approval.¹⁶ They operate on different timelines and provide different shields. A company might secure a repurposed drug’s approval for a rare disease, granting it 7 years of orphan drug exclusivity. This exclusivity provides a “safe harbor” where the company is protected from generic competition for that indication,

regardless of the patent status.¹³ A savvy strategist will meticulously time their patent filings and regulatory submissions to maximize the overlap and sequential application of these two forms of protection, creating a period of commercial exclusivity that is both longer and far more resilient than either could provide on its own. This integrated approach is the hallmark of a masterfully executed repurposing strategy.

U.S. Regulatory Pathways: The 505(b)(2) Superhighway

Once a promising new use for an existing drug has been identified and a nascent IP strategy is in place, the next critical phase is navigating the regulatory landscape to gain marketing approval. In the United States, the Food and Drug Administration (FDA) does not have a specific pathway labeled “for repurposed drugs.” Instead, it offers a uniquely flexible and powerful mechanism that has become the de facto superhighway for this type of innovation: the 505(b)(2) New Drug Application (NDA). Understanding the nuances of this pathway is not just a regulatory necessity; it is a core component of commercial strategy, as it directly influences development timelines, costs, and the potential for lucrative market exclusivity.

Understanding the 505(b)(2) New Drug Application (NDA)

The 505(b)(2) pathway was created as part of the landmark Drug Price Competition and Patent Term Restoration Act of 1984, better known as the Hatch-Waxman Amendments.¹³ It was designed to create a more efficient approval process for certain drugs by avoiding the unnecessary duplication of studies that had already been conducted. It occupies a strategic middle ground between the two other main pathways:

• 505(b)(1) NDA: The traditional pathway for a New Chemical Entity (NCE). This is a “stand-alone” application that must contain full reports of all preclinical and clinical studies conducted by the sponsor to establish the drug’s safety and efficacy.
• 505(j) ANDA (Abbreviated New Drug Application): The pathway for generic drugs. This application relies on the FDA’s previous finding of safety and effectiveness for the innovator drug and primarily requires the sponsor to demonstrate bioequivalence.

The 505(b)(2) pathway is a hybrid. Like a 505(b)(1), it is an NDA for a new drug approval. However, its defining feature is that it allows a sponsor to rely, at least in part, on data not their own.⁹ This external data can come from two main sources:

1. The FDA’s previous findings of safety and/or efficacy for an approved drug (referred to as the “listed drug” or “reference listed drug”).
2. Data from published scientific literature.

The “Bridge” is the Key to Success

The core task for a 505(b)(2) applicant is to provide a “scientific bridge” that justifies their reliance on the existing data for the listed drug. The sponsor must conduct whatever studies are necessary to link their new product to the reference product. For example, if a company is repurposing an approved oral tablet into a new topical cream, they cannot rely on the oral drug’s efficacy data. However, they can likely rely on much of its existing systemic safety and toxicology data, provided they conduct bridging studies (e.g., pharmacokinetic studies) to show how much of the drug is absorbed through the skin compared to the oral route. The nature and extent of this “bridge” is the central strategic and scientific challenge of any 505(b)(2) program and is highly dependent on the specific product and indication.

This pathway is tailor-made for drug repurposing and other forms of incremental innovation. It is the ideal route for products that represent a change to a previously approved drug, such as:

• New Indications (the classic repurposing scenario)
• New Dosage Forms (e.g., tablet to liquid)
• New Routes of Administration (e.g., oral to injectable)
• New Dosing Regimens
• New Formulations (e.g., immediate-release to extended-release)
• New Combinations of two or more approved drugs ²⁸

A textbook example of the pathway’s power is the approval of Spravato (esketamine). Ketamine has been used for decades as an anesthetic. Johnson & Johnson developed a nasal spray formulation of esketamine (a component of ketamine) for treatment-resistant depression. By using the 505(b)(2) pathway, they were able to rely on the extensive existing safety data for ketamine, dramatically streamlining the development process for a breakthrough therapy in mental health.

The Strategic Advantages and Exclusivities of 505(b)(2)

For a business strategist, the 505(b)(2) pathway offers two irresistible advantages: a reduced development burden and the potential for valuable, patent-independent market exclusivity.

The ability to leverage existing data means that a 505(b)(2) program typically requires fewer, smaller, and less expensive clinical trials than a full 505(b)(1) program.⁹ This is the regulatory mechanism that enables the dramatic time and cost savings that make repurposing so economically attractive.

Even more importantly from a commercial standpoint, a successful 505(b)(2) application can be granted its own period of market exclusivity. This exclusivity prevents the FDA from approving certain other applications for a set period, providing a crucial window to establish market share and recoup investment. The types of exclusivity available are:

• 3-Year New Use/Product Exclusivity: This is the most common form for repurposed drugs. It is granted if the application required the conduct of new clinical investigations (other than bioavailability studies) that were essential for approval. This three-year period blocks the FDA from approving a 505(j) generic application that relies on the innovator’s new data.⁴
• 5-Year New Chemical Entity (NCE) Exclusivity: This is granted to the first drug approved containing an active moiety that has never before been approved by the FDA. This is less common for repurposing but can be highly valuable if the repurposed compound was a shelved asset that never reached the market.
• 7-Year Orphan Drug Exclusivity (ODE): If the repurposed drug is developed to treat a designated rare disease, it is eligible for this powerful seven-year period of exclusivity, which provides a formidable barrier to competition.

The strategic appeal of this pathway is undeniable and is reshaping development trends. In a striking shift, 505(b)(2) approvals in 2024 accounted for 40% of all new FDA approvals, outpacing even the number of generic drug approvals and demonstrating the industry’s widespread adoption of this efficient, hybrid approach.

Reading Between the Regulatory Lines

While the 505(b)(2) pathway is often framed as a streamlined accelerator, its reality is more complex. It is a powerful tool, but its very sophistication creates a significant barrier to entry, particularly for the academic and non-profit researchers who are often the source of initial repurposing discoveries. The design of the “scientific bridge” requires deep and nuanced regulatory expertise, knowledge of FDA precedents, and the capital to fund the necessary bridging studies.²⁹ These are resources that “nontraditional developers” typically lack. The FDA itself has acknowledged that the pathway was designed with industry sponsors in mind.

Consequently, the 505(b)(2) pathway functions as a strategic filter. Promising academic research often reaches a chasm—the infamous “valley of death”—because the researchers who made the discovery cannot single-handedly navigate this complex regulatory process. This reality necessitates a partnership with a commercial entity that possesses the requisite experience and resources. The ultimate decision to pursue an approval, therefore, often hinges not just on the scientific merit or patient need, but on the commercial viability of the project. This structural barrier is a key reason why many promising repurposing opportunities, especially for off-patent generic drugs, never result in a formal label change and broader patient access.

Another critical strategic consideration is the interplay between the 505(b)(2) pathway and patent protection, particularly concerning the “skinny label” loophole. As discussed, a method-of-use patent for a new indication is vulnerable to generic competition, as a generic can launch with a label that “carves out” the patented indication. Physicians can then prescribe the cheaper generic off-label, undermining the innovator’s market. The 2018 court case involving Pfizer’s Lyrica (pregabalin) highlighted this vulnerability, where the court ruled that pharmacists could dispense generic pregabalin for neuropathic pain (a patented use) without being liable for infringement, assuming it was impractical for them to inquire about the prescribed indication.

A sophisticated 505(b)(2) strategy anticipates and closes this loophole. The key is to ensure that the new, repurposed product is not just a new use, but a new product with a patented feature that is essential for that new use. For example, if the new indication for Disease X requires a novel, patented extended-release formulation to maintain therapeutic blood levels and minimize toxicity, the generic’s immediate-release version is not therapeutically equivalent for that specific use. A physician cannot ethically or effectively substitute the generic. This inextricably links the method (treating Disease X) to the form (the patented formulation), making the IP position vastly more defensible and forcing a generic competitor to either infringe the formulation patent or be locked out of the new market. This transforms the 505(b)(2) application from a simple label extension into a tool for creating a truly differentiated and protectable product.

The European Approach: Navigating the EMA Framework

While the United States offers a powerful, industry-centric pathway for drug repurposing, the regulatory landscape in the European Union presents a different, and in some ways more structured, set of opportunities and challenges. The European Medicines Agency (EMA), in concert with national competent authorities, has established a framework that explicitly acknowledges the unique nature of repurposing and has made deliberate efforts to support non-commercial entities. However, this system comes with its own complexities, including a unique set of exclusivity rules and a critical dependency on the cooperation of commercial marketing authorisation holders.

Regulatory Pathways for Repurposing in the EU

The foundation of the EU’s approach is Directive 2001/83/EC, which provides several avenues for adding a new indication to an already authorised medicinal product. These options offer a more granular approach than the singular 505(b)(2) pathway in the US :

1. New Indication with Significant Clinical Benefit: If a company develops a new indication for its drug that provides a significant clinical benefit over existing therapies, and does so within the first eight years of the drug’s initial authorisation, it can be rewarded with one additional year of market protection. This is a direct, albeit modest, incentive for repurposing on-patent drugs.²⁵
2. Established Active Substance (EAS): For drugs with a well-established history of use in the EU (defined as a minimum of 10 years), an applicant can seek approval for a new indication by relying heavily on published scientific literature to support the application, reducing the need for extensive new trials.
3. Authorisation under Exceptional Circumstances: This pathway can be used for drugs treating very rare diseases where the applicant is unable to provide comprehensive data on efficacy and safety under normal conditions of use, simply because the patient population is too small to conduct a full-scale clinical trial.
4. Conditional Marketing Authorisation: For medicines that address a serious or life-threatening unmet medical need, the EMA can grant a conditional approval based on less comprehensive clinical data than normally required. The approval is contingent on the sponsor providing more complete data post-authorisation.
5. Orphan Medicinal Product Authorisation: A dedicated and highly incentivized pathway for drugs intended to treat rare diseases, which offers significant periods of market exclusivity.

The EMA Pilot Program: A Noble Experiment

Recognizing that commercial incentives are often lacking for repurposing off-patent, genericized medicines, the EMA, in collaboration with the Heads of Medicines Agencies (HMA), launched a pilot project in 2021.³⁴ The program’s goal was to support academic institutions and not-for-profit organizations—dubbed “champions”—in their efforts to get new uses for old drugs formally authorised. The pilot provided these non-commercial sponsors with free, tailored scientific advice and regulatory support to help them generate a data package robust enough to support a marketing authorisation application.

However, the results of the pilot, as detailed in a 2025 EMA report, were a sobering reality check. The agency concluded that the pilot had “limited success”. The academic and non-profit champions faced significant hurdles, including:

• Data Interpretation: Difficulty in appropriately describing and synthesizing available data to meet the rigorous standards required for a regulatory benefit-risk assessment.³⁴
• Clinical Trial Design: Frequent scientific issues with trial design, such as defining appropriate patient inclusion/exclusion criteria and choosing the right primary endpoints.
• Engaging Commercial Partners: A major roadblock was the difficulty in engaging with the commercial Marketing Authorisation Holders (MAHs) or generic manufacturers who are ultimately required to submit the application for the new indication.
• Resource Intensity: The process of providing such tailored, hands-on support was found to be extremely resource-intensive for both the applicants and the regulatory agencies themselves.

Despite these challenges, the pilot was a valuable learning experience, highlighting the specific support non-commercial entities need and revealing the structural barriers that still exist within the EU system.

Data and Market Exclusivity: The “8+2+1” Rule

The EU’s system of market protection is fundamentally different from that of the US. It is based on a defined, time-based framework of data and market exclusivity that runs concurrently with any patent protection the drug may have.²⁵ This system is often referred to as the “8+2+1” rule:

• 8 Years of Data Exclusivity: For the first eight years after a drug receives its initial marketing authorisation, its preclinical and clinical trial data are protected. During this period, a generic or biosimilar company cannot use or reference the originator’s data to support their own application.²⁵
• +2 Years of Market Protection: Following the 8-year data exclusivity period, there is an additional two-year period of market protection. During these two years (years 9 and 10 of the drug’s life), a generic company can submit its application and reference the originator’s data, and the EMA can review and even grant a marketing authorisation. However, the generic product cannot be legally placed on the market until the full 10-year period has expired. This guarantees the innovator a minimum of a decade of market exclusivity.
• +1 Year for New Indications: This is the key incentive for repurposing. If the originator company gains approval for one or more new therapeutic indications that bring a “significant clinical benefit” over existing therapies, and they do so within the first eight years of the drug’s life, the 10-year market protection period can be extended by one additional year, to a maximum of 11 years.²⁵

Comparing the Transatlantic Playing Fields: EMA vs. FDA

When developing a global repurposing strategy, it is crucial to understand the key differences between the US and EU regulatory environments. While both agencies share the goal of ensuring drug safety and efficacy, their philosophies, processes, and incentives diverge in important ways.

Feature	U.S. Food and Drug Administration (FDA)	European Medicines Agency (EMA)
Primary Repurposing Pathway	505(b)(2) NDA: A flexible, hybrid pathway allowing reliance on external data.	Multiple options under Directive 2001/83/EC, including variations for new indications and the Established Active Substance (EAS) pathway.
Philosophy	A pragmatic, industry-oriented “tool” that favors entities with regulatory expertise and resources.30	A more structured “ecosystem” approach with explicit support mechanisms (e.g., pilot program) for non-commercial entities.33
Key Exclusivity for New Use	3 years for new clinical investigations; 7 years for orphan drugs.	1 extra year of market protection (up to 11 total) if new indication with significant benefit is approved within first 8 years.
Approval Authority	Directly grants marketing approval.	Provides a scientific opinion/recommendation; the European Commission grants the final marketing authorisation.
Support for Non-Profits	Limited direct support; pathway is challenging for “nontraditional developers”.	Formal pilot program offering free scientific advice and tailored support, though with limited success to date.
Harmonization	High concordance (95%) in approval decisions for generic applications submitted to both agencies, though timelines differ.	Actively engaged in harmonization efforts but significant procedural and legal differences remain.

The regulatory landscapes on either side of the Atlantic reflect fundamentally different philosophies. The EU is actively trying to build a supportive infrastructure to address the market failure of off-patent drug repurposing, as evidenced by its pilot program. It is a top-down attempt to create an ecosystem. In contrast, the US provides a powerful and flexible tool—the 505(b)(2) pathway—that is agnostic as to the user but, in practice, heavily favors experienced industry players who can meet its complex technical and financial demands. This dictates different engagement strategies. In the EU, a non-profit might find a more structured and supportive, if bureaucratic, path for initial regulatory engagement. In the US, the path to approval is more direct but almost invariably requires a commercial partner from the very beginning.

However, the EMA’s noble experiment with its pilot program revealed a critical, structural flaw in the European system: the “MAH Veto.” Under current EU law, only the Marketing Authorisation Holder—the commercial entity that owns the license to market the drug—can submit an application to vary the product license and add a new indication.³⁶ The pilot confirmed that engaging these MAHs was a primary obstacle for the academic champions. A for-profit company often has zero commercial incentive to invest the time and resources to file for a new indication for a cheap, off-patent, genericized drug.⁴¹ This creates a frustrating paradox: a non-profit can spend years and millions in philanthropic funding to generate positive Phase III data, receive favorable scientific advice from the EMA, and still be completely blocked if the MAH simply refuses to file the paperwork. This “MAH Veto” is the Achilles’ heel of non-profit-led repurposing in Europe. The ongoing discussions around EU legislative reform, which could potentially empower non-profit champions to initiate the regulatory process themselves, are therefore not just a procedural tweak. They represent a potentially revolutionary change that could unlock a wealth of new treatments currently stranded in the valley of death.

The Orphan Drug Act: A Lifeline for Rare Disease Repurposing

While repurposing drugs for common diseases presents a complex web of commercial and IP challenges, there is one area where the strategy not only thrives but is actively encouraged by a powerful set of legislative incentives: rare diseases. The U.S. Orphan Drug Act (ODA) of 1983 was a landmark piece of legislation designed to solve a fundamental market failure. In doing so, it created a fertile ground for drug repurposing, providing the missing financial motivation to develop therapies for patients with the greatest unmet needs. For the savvy strategist, the ODA is not just a public health initiative; it is a powerful commercial toolkit.

The Commercial Logic of the Orphan Drug Act (ODA)

Prior to 1983, patients with rare diseases were largely “economic orphans” in the eyes of the pharmaceutical industry. Developing a drug for a condition affecting only a few thousand people was commercially unviable; the potential market was simply too small to ever recoup the enormous costs of R&D.²⁷ The ODA was enacted to change this economic equation by offering a suite of compelling incentives to companies willing to invest in this space.

In the United States, a rare disease is legally defined as a condition that affects fewer than 200,000 people.²⁷ A drug can also be granted “orphan” status if it treats a larger population but for which there is no reasonable expectation that the development and sales costs will be recovered from the U.S. market.⁴³

This framework is a perfect match for drug repurposing. It allows a company to take an existing compound—often one that is off-patent or has a weak IP position—and gain a strong, government-granted period of market exclusivity simply by proving its effectiveness in a small, underserved patient population.¹⁴ This transforms a potentially unprofitable academic exercise into a commercially attractive venture. The success of the Act is undeniable: before its passage, only 10 drugs for rare diseases were on the market; as of 2015, the FDA had approved over 550 orphan drugs for 277 different rare diseases.

The Powerful Incentives of Orphan Drug Designation (ODD)

Obtaining Orphan Drug Designation from the FDA’s Office of Orphan Products Development (OOPD) unlocks a treasure trove of benefits that significantly de-risk and subsidize the development process. While the financial incentives are substantial, the most valuable prize is the period of market exclusivity it confers upon approval.

The Crown Jewel: 7-Year Market Exclusivity

This is the most powerful incentive in the ODA and the primary driver of commercial interest. Upon receiving FDA approval, a drug with orphan designation is granted seven years of market exclusivity for the approved orphan indication.²⁷ During this seven-year period, the FDA is legally barred from approving another application for the

same drug for the same rare disease. This protection is ironclad and applies even if the drug is an old, off-patent molecule and a generic version is widely available for other uses.⁴⁴ The only way a competitor can break this exclusivity is by proving their version of the drug is “clinically superior” to the approved orphan drug—a very high bar to clear. This government-sanctioned monopoly allows the sponsor to command premium pricing and provides a clear path to recouping their investment.

A Suite of Financial and Regulatory Support

Beyond market exclusivity, the ODA provides a range of other benefits that lower the financial and logistical barriers to development ¹⁴:

• Tax Credits: Sponsors can claim tax credits for up to 50% of their qualified clinical testing expenses incurred in the U.S..⁴³
• Waiver of FDA Fees: Orphan drugs are exempt from the substantial Prescription Drug User Fee Act (PDUFA) fees that must be paid when submitting a New Drug Application, a saving that can amount to millions of dollars.⁴³
• Grant Funding: The OOPD provides grant funding to support clinical trials for orphan products, offering a source of non-dilutive capital to advance development.⁴³
• Regulatory Assistance: The FDA provides enhanced and more frequent guidance and support to sponsors of orphan drugs, helping them navigate the complex development and approval process more efficiently.

Strategic Considerations and Potential Pitfalls

The Orphan Drug Act fundamentally reshapes the strategic calculus for repurposing. It provides a robust, patent-independent form of monopoly that can make a project commercially viable even when its underlying patent position is weak or non-existent. For a generic drug, a method-of-use patent is often the only IP protection available, and as we’ve seen, it can be difficult to enforce.⁴ This IP weakness is a major deterrent to investment. Orphan Drug Exclusivity (ODE) effectively solves this problem. It creates a 7-year legal barrier to competition that is not based on patents but on regulatory law. This guaranteed period of monopoly provides the commercial certainty needed to attract investment and justify the cost of the necessary clinical trials. In essence, ODE acts as a powerful substitute for a strong patent, making the business case for repurposing in rare diseases vastly more compelling than in common diseases where such protection is unavailable.

However, the very power of the ODA has also led to controversy and accusations of strategic exploitation. While the Act was designed to incentivize development for truly neglected diseases, there are concerns that it is sometimes used as a loophole to gain financial advantages for drugs that are not, in a commercial sense, true “orphans.”

One such strategy is known as “salami slicing.” Because the FDA grants exclusivity for a specific, narrowly defined “use or indication,” it is theoretically possible for a company to gain multiple, sequential periods of exclusivity for the same drug by testing it in different, but related, rare diseases. A company might get a 7-year ODE for a drug in one rare type of pediatric leukemia, and then, a few years later, seek another 7-year ODE for the same drug in a different rare lymphoma.

A more significant concern is the use of the ODA as a strategic launchpad for drugs that ultimately achieve blockbuster status in common diseases. A company can develop a drug for a rare cancer subtype, benefiting from all the ODA incentives, and then, after approval, conduct further trials to expand the label into much larger cancer populations like breast or lung cancer. A 2021 study noted that of the 73 top-selling orphan drugs, 34 were also approved to treat common diseases, suggesting these products can be incredibly lucrative. While this label expansion is perfectly legal and often clinically beneficial, critics argue it goes against the spirit of the Act, using incentives meant for rare diseases to subsidize the development of highly profitable mainstream drugs. This creates both a reputational risk for companies and the potential for a legislative backlash that could reform the Act to close these perceived loopholes.

Lessons from the Field: Case Studies in Success and Failure

Theory and strategy are essential, but the true test of any business approach lies in its real-world application. The history of drug repurposing is rich with stories of both brilliant successes that have changed medicine and created billions in value, and instructive failures that offer crucial, hard-won lessons. By dissecting these cases, we can move from abstract principles to concrete, actionable insights. We will examine three landmark examples: the commercial and IP masterclass of sildenafil, the dramatic redemption of thalidomide, and the cautionary tale of losartan in Duchenne muscular dystrophy.

The Blockbuster Serendipity: The Repurposing of Sildenafil (Viagra)

The story of sildenafil is perhaps the most famous example of drug repurposing, a perfect storm of accidental discovery, scientific insight, and, most importantly, a brilliantly executed intellectual property and commercial strategy.

The Accidental Discovery

In the early 1990s, researchers at Pfizer were developing a compound, then known as UK-92480, as a potential treatment for hypertension and angina.¹¹ The drug worked by inhibiting an enzyme called phosphodiesterase type 5 (PDE-5), which was thought to help relax blood vessels. During early Phase I clinical trials in healthy male volunteers, the drug showed disappointing efficacy for its intended cardiovascular purpose. However, it produced a consistent and rather surprising side effect: penile erections.⁵ Pfizer’s leadership made a bold and now legendary strategic pivot, abandoning the angina indication and redirecting the entire development program to focus on what was then a little-discussed condition: erectile dysfunction (ED).

A Masterclass in IP and Lifecycle Management

The discovery was serendipitous, but Pfizer’s subsequent commercial success was anything but. It was the result of a multi-pronged, sophisticated strategy to maximize and extend the drug’s market exclusivity, a case study still taught in business schools today.

1. Layered Patenting: Pfizer’s masterstroke was securing two distinct sets of patents for the same molecule. They had an early patent (US5250534) covering the sildenafil compound and its use for cardiovascular conditions, which was later marketed as Revatio for pulmonary arterial hypertension. Crucially, they also filed a separate, later patent (US6469012) specifically protecting the method of use for treating erectile dysfunction. This second patent, for Viagra, had a much later expiration date, initially set for 2019. This layering strategy immediately extended their control over the most lucrative application of the molecule.
2. Strategic Patent Term Extension: Pfizer didn’t stop there. They cleverly leveraged regulatory mechanisms to push the patent cliff out even further. By conducting pediatric studies for Revatio’s effect on pulmonary hypertension in children, they earned a six-month pediatric exclusivity extension, which, due to the way the regulations work, applied to the Viagra patent as well. This single move pushed the final expiration of their core US patent to April 2020, adding hundreds of millions of dollars in sales.
3. Controlled Generic Entry through Litigation and Settlement: When Teva Pharmaceuticals filed to launch a generic version, Pfizer sued for patent infringement. Despite winning the initial court case, which would have blocked Teva until 2019, Pfizer made a calculated strategic decision. In 2013, they settled the lawsuit. The confidential agreement allowed Teva to launch its generic in December 2017—more than two years before the patent was set to expire—but in exchange, Teva had to pay Pfizer a royalty for a license. This move may seem counterintuitive, but it was brilliant. It allowed Pfizer to trade a shorter period of absolute monopoly for a longer period of controlled, profitable competition. They controlled the exact timing of the first generic entry and guaranteed themselves a revenue stream from their own competitor.
4. The Authorized Generic Gambit: Pfizer’s final move was its most innovative. On the very same day that Teva launched its licensed generic, Pfizer launched its own generic version through its subsidiary, Greenstone. This “authorized generic” was identical to branded Viagra but sold at a significant discount. This had two profound effects: first, it immediately captured a large portion of the price-sensitive market, keeping that revenue within the Pfizer corporate family. Second, it completely diluted the value of the 180-day market exclusivity that the first generic filer (Teva) would normally enjoy. Instead of a six-month head start against all other generics, Teva immediately faced competition from the original manufacturer.

The Outcome: A Controlled Descent

The result of this multi-faceted strategy was that the dreaded “patent cliff” for Viagra never materialized as a catastrophic fall. Instead, Pfizer engineered a slow, controlled, and highly profitable descent. They managed the timing of generic entry, earned royalties from their first competitor, and became a major player in the generic market themselves from day one. Years after the first generic launch, the “Viagra franchise” (branded plus authorized generic) still commanded a massive share of the ED market, a testament to a strategy that turned an accidental discovery into a durable commercial empire.

Redemption of a Pariah: The Rebirth of Thalidomide

If sildenafil is a story of commercial brilliance, thalidomide is a story of scientific redemption. Its journey from a symbol of pharmaceutical tragedy to an indispensable tool in the fight against cancer is one of the most dramatic and instructive in modern medicine.

A Tragic Past and a Regulatory Revolution

Marketed in the late 1950s as a safe, non-addictive sedative and a highly effective treatment for morning sickness, thalidomide became a global bestseller. The subsequent discovery in 1961 that the drug caused horrific congenital disabilities—phocomelia, or “flipper limbs,” and other severe malformations—in thousands of babies led to its immediate withdrawal and a global scandal.⁴ The tragedy became a catalyst for change, directly leading to the passage of the Kefauver-Harris Amendment in the US, which for the first time required drug manufacturers to prove not only safety but also efficacy before a drug could be approved. This laid the foundation for the modern FDA and drug safety regulations worldwide.⁴⁵

Serendipity, Science, and a Second Chance

For years, thalidomide was a pariah. Yet, its revival began, once again, with a moment of serendipity. In 1964, an Israeli physician, Dr. Jacob Sheskin, gave the drug as a sedative to a patient suffering from a severe and painful inflammatory complication of leprosy called erythema nodosum leprosum (ENL). To his astonishment, the patient’s debilitating skin lesions resolved almost overnight.⁵ This observation was confirmed in subsequent studies, and thalidomide became the standard of care for ENL.

This unexpected success spurred a wave of new research to understand how the drug actually worked. Scientists soon discovered that thalidomide’s effects had nothing to do with sedation. Instead, it possessed two powerful biological properties:

1. Immunomodulatory Effects: It was a potent inhibitor of tumor necrosis factor-alpha (TNF-α), a key cytokine that drives inflammation.
2. Anti-Angiogenic Effects: It was found to be a powerful inhibitor of angiogenesis, the formation of new blood vessels.⁵¹ Researchers hypothesized that this anti-angiogenic property was the very mechanism that caused the birth defects—by starving the developing fetal limb buds of their blood supply.

Triumph in Oncology and a New Regulatory Paradigm

The discovery of its anti-angiogenic properties immediately suggested a new and compelling application: cancer. Many tumors, particularly blood cancers like multiple myeloma, are highly dependent on angiogenesis to grow and spread. In 1999, clinical trials showed that thalidomide had remarkable activity in patients with advanced, refractory multiple myeloma. This led to its landmark FDA approval for this indication in 2006, completing its remarkable renaissance.⁵¹

The re-approval of a drug with such a notorious history was a major regulatory challenge. It was made possible only through the creation of an unprecedentedly strict risk management program: the System for Thalidomide Education and Prescribing Safety (S.T.E.P.S.). This program requires that every physician who prescribes the drug, every pharmacy that dispenses it, and every patient who takes it be registered in a central system. It mandates strict pregnancy testing and contraceptive use to eliminate the risk of fetal exposure. The S.T.E.P.S. program became a new paradigm for the FDA, creating a pathway to approve drugs with profound benefits but also profound risks, ensuring that access could be provided to those who need it while protecting those who could be harmed.

A Bridge Too Far? The Instructive Failure of Losartan for DMD

Not all repurposing stories end in success, and the failures are often just as instructive. The attempt to repurpose losartan, a common blood pressure medication, for Duchenne muscular dystrophy (DMD) is a critical cautionary tale about the complexities of disease biology and the limitations of even the most logical scientific rationale.

The Scientific Rationale

DMD is a devastating and fatal genetic disorder that causes progressive muscle degeneration. A key feature of the disease is fibrosis, the replacement of muscle tissue with non-functional scar tissue. One of the master regulators of fibrosis is a signaling molecule called transforming growth factor-beta (TGF-β). Losartan, an angiotensin II receptor blocker (ARB), was known to inhibit the activity of TGF-β. Early preclinical studies in young mdx mice, the standard animal model for DMD, were highly promising, showing that losartan could reduce fibrosis and improve muscle function. This created enormous excitement and hope that a safe, cheap, and widely available drug could treat a currently incurable disease.

The Disappointing Clinical Reality

To better model the long-term progression of the human disease, researchers conducted a two-year study of losartan in aged mdx mice. The results were a stark disappointment. While the drug did show a significant benefit in preserving heart function and reducing mortality (as cardiomyopathy is also a major feature of DMD), it had absolutely no effect on skeletal muscle. The trial failed to meet its primary endpoints for muscle function, morphology, and fibrosis. Another anti-inflammatory drug, montelukast, similarly failed to show benefit in preclinical DMD models.

The Strategic Lesson: Biology is Boss

Why did such a promising and logical idea fail? The most likely reason is that the biology of DMD is far more complex than a single pathway. While the TGF-β pathway targeted by losartan may be a key driver of fibrosis in the early stages of the disease (as seen in the young mice), it is likely that in the chronic, advanced stages of the disease, other, redundant fibrotic pathways become dominant. The therapeutic window for that specific mechanism in skeletal muscle had likely closed. The heart, however, with its different cellular makeup and response to injury, still benefited.

The losartan story provides a crucial lesson for all repurposing strategists: a compelling mechanism of action is necessary, but not sufficient. Success requires a deep and nuanced understanding of the disease pathology at different stages. It underscores the risk of extrapolating from simple or early-stage animal models to complex, chronic human diseases. While the trial was a failure in one sense, it provided invaluable knowledge, preventing a costly and ultimately futile human clinical trial and redirecting research efforts toward other, more promising pathways. It demonstrates that even a failed repurposing project can create value by de-risking the future development landscape.

The Competitive Edge: Leveraging Patent Intelligence

In the high-stakes arena of pharmaceutical development, knowledge is not just power—it is the currency of competitive advantage. While serendipity and scientific brilliance can spark a repurposing idea, transforming that idea into a durable commercial success requires a deep understanding of the competitive landscape. The most valuable, and often underutilized, source of this strategic knowledge is patent data. Systematically monitoring and analyzing patent filings provides an unparalleled early-warning system, offering a window into your competitors’ R&D strategies years before they become public knowledge. For the repurposing strategist, mastering the art of patent intelligence is essential for identifying opportunities, mitigating risks, and outmaneuvering the competition.

From Data to Decisions: The Role of Competitive Intelligence (CI)

Pharmaceutical competitive intelligence is the systematic process of gathering, analyzing, and transforming information about rival companies into actionable insights that drive strategic decisions.⁵⁵ It goes far beyond simple market research, encompassing a deep dive into competitors’ R&D pipelines, clinical trial designs, regulatory strategies, IP portfolios, and commercial capabilities.

Patent filings are a uniquely powerful source of CI for one simple reason: they are, by their nature, a forward-looking declaration of a company’s inventive activity. Due to patent law requirements, applications are typically published 18 months after their initial filing date. This creates a predictable timeline for disclosure, allowing a vigilant company to learn about a competitor’s new technology, novel compound, or, crucially for our purposes, a new use for an existing drug, long before that project is ever announced in a press release or registered as a clinical trial. This 18-month head start is an invaluable period for strategic planning, allowing you to assess the threat, identify weaknesses in their approach, and formulate a counter-strategy.

A Practical Guide: Using Patent Databases for Repurposing

Harnessing the power of patent data requires a systematic approach, leveraging both public patent databases and specialized commercial platforms. Services like DrugPatentWatch are specifically designed to provide this kind of pharmaceutical business intelligence, offering curated data and analytical tools to track patent expirations, monitor competitor portfolios, and identify new market opportunities.⁵⁸ An effective monitoring program involves several key steps :

1. Define Your Strategic Objectives: Before you begin searching, you must know what you are looking for. Are you conducting a broad search for “white space”—areas of unmet need with little patent activity? Are you assessing the freedom-to-operate (FTO) for a specific repurposing project you are considering? Or are you engaged in targeted surveillance of a key competitor’s activities in your therapeutic area? Your objective will define the scope and nature of your search.
2. Establish Systematic Monitoring Systems: Create a structured surveillance program. This involves establishing search parameters using relevant keywords (e.g., disease names, biological targets, drug classes), international patent classification (IPC) codes, and the names of competitor companies. Set up automated alerts within your chosen platform to notify you immediately when a new patent application matching your criteria is published.
3. Analyze the Landscape and Identify Key Signals: The goal is not just to collect patents but to interpret what they mean. When screening for repurposing opportunities, look for these critical signals:

• Identifying “White Space”: Map the patent landscape for a disease of interest. If you find a well-understood biological target with strong clinical rationale but surprisingly little patent activity around it, you may have discovered an overlooked opportunity for repurposing a drug known to modulate that target.
• Tracking Competitor Pivots: A sudden flurry of new method-of-use or formulation patents from a competitor for one of their established, on-market drugs is a five-alarm fire. It is one of the strongest possible indicators that they are actively pursuing a repurposing or lifecycle management strategy for that asset.
• Finding In-Licensing and Acquisition Targets: The most innovative repurposing ideas often originate in academia or small biotech companies. By monitoring patents filed by these smaller entities, you can identify novel, high-potential assets with strong IP positions long before they appear on the radar of larger pharmaceutical companies, creating opportunities for early and advantageous in-licensing or acquisition deals.
• Conducting Freedom-to-Operate (FTO) Analysis: Before you invest a single dollar in lab work for a new repurposing project, a thorough FTO analysis is non-negotiable. This involves a comprehensive search to ensure that your proposed product and its new use do not infringe on any existing, valid patents held by others—including not just method-of-use patents, but also potentially blocking formulation, dosage, or combination patents.

Unlocking Deeper Strategic Insights

The true masters of competitive intelligence go beyond simply tracking what competitors are doing. They use patent data to understand how and why they are doing it, and even to infer where they have failed.

A sophisticated analysis of a competitor’s patent portfolio can reveal their entire strategic blueprint. By grouping their patents by technology type, you can map their core R&D platforms—for example, a specific drug delivery technology or a proprietary screening method—that they are leveraging across multiple programs. The breadth and language of their patent claims can signal their strategic intent: broad, aggressive claims suggest an ambition to dominate a new field, while narrow, defensive claims may indicate a more cautious or incremental approach.

Most powerfully, patent data can be a map of a competitor’s failures. A series of patent applications filed around a specific biological target, followed by a period of silence with no corresponding clinical trial registrations or publications, is a strong signal that the program was terminated internally. The detailed experimental data included within those patent applications—required by law to demonstrate the invention—can provide invaluable clues as to why it failed. Did they encounter unexpected toxicity? Were they unable to achieve a stable formulation? This is priceless negative data that can save your organization from wasting time and resources repeating the same mistakes.

Ultimately, the most powerful competitive intelligence emerges from integrating these patent insights with other disparate data sources. A platform like DrugPatentWatch can serve as the central hub for IP and regulatory data, but its strategic value is magnified exponentially when its findings are cross-referenced with other intelligence streams. Patent filings tell you what a company wants to protect. Clinical trial registries like ClinicalTrials.gov tell you what they are actively testing in humans. Scientific publications and conference abstracts reveal the underlying science and may disclose early discoveries before a patent is even filed. And financial documents like SEC filings and investor calls tell you where the company is allocating its capital and what strategic narrative it is presenting to Wall Street.

By weaving these threads together, you can build a multi-dimensional, validated picture of the competitive landscape. A single patent filing is an interesting signal. But a patent filing, followed six months later by the registration of a Phase II trial for that new indication, followed by the CEO mentioning a new “lifecycle management program” on an earnings call, is a confirmed strategic initiative. This integrated approach is what transforms raw data into the kind of actionable intelligence that wins markets.

The Future is Now: AI, Big Data, and the Next Wave of Repurposing

If the first era of drug repurposing was defined by serendipity and keen clinical observation, the current era is being defined by a revolutionary shift toward systematic, predictive, and data-driven discovery. We are at the dawn of a new wave of innovation, powered by the convergence of artificial intelligence (AI), machine learning (ML), and the unprecedented explosion of biological and clinical “big data.” This computational revolution is transforming repurposing from a largely reactive strategy into a proactive and highly efficient engine for therapeutic discovery, capable of uncovering non-obvious connections at a scale and speed previously confined to science fiction.

Moving Beyond Serendipity: The Computational Revolution

The modern life sciences are drowning in data. The sequencing of the human genome opened the floodgates to a deluge of information from genomics, proteomics, transcriptomics, and metabolomics—collectively known as “omics” data.² Simultaneously, the digitization of healthcare has created vast repositories of real-world data, including millions of electronic health records (EHRs) and insurance claims.² This data contains the hidden patterns and subtle correlations that are the raw material for the next generation of repurposing discoveries. The sheer volume and complexity of this information, however, make manual analysis impossible.

This is where AI and machine learning come in. These advanced computational tools are capable of sifting through these massive, multi-dimensional datasets to identify potential drug-disease relationships that would be invisible to the human eye. By training algorithms on this data, researchers can build predictive models that systematically screen thousands of existing drugs against hundreds of diseases, generating and prioritizing high-probability repurposing hypotheses for subsequent experimental validation.

Key Computational Approaches and Their Impact

A variety of sophisticated computational methods are now being deployed to accelerate repurposing, each leveraging different types of data to uncover new therapeutic links:

• Signature-Based Methods: This approach works on a simple but powerful premise: if a drug’s effect on gene expression in cells is the “opposite” of the gene expression signature caused by a disease, that drug may have a therapeutic effect on the disease. By comparing thousands of drug-induced gene signatures against thousands of disease signatures, these methods can rapidly identify promising repurposing candidates.³
• Network Biology and Pathway Analysis: Diseases are rarely caused by a single faulty gene; they are often the result of disruptions in complex biological networks and pathways. Network-based approaches map these intricate protein-protein and gene-gene interaction networks and then look for existing drugs that are known to modulate key nodes or choke points within a disease-relevant pathway.
• Drug-Target Interaction (DTI) Prediction: Many drugs have “off-target” effects, meaning they interact with proteins other than their primary intended target. While sometimes the cause of side effects, these off-target interactions can also be therapeutically beneficial. Machine learning models, particularly deep learning, can analyze the 3D chemical structure of a drug and the structure of a disease-related protein to predict the likelihood of a previously unknown interaction, thereby identifying a novel mechanism for repurposing.
• Real-World Evidence (RWE) Mining: This is one of the most exciting frontiers. By applying algorithms to massive, anonymized datasets of EHRs and insurance claims, researchers can conduct virtual population studies. The algorithm might, for example, identify a statistically significant signal that patients taking a specific diabetes drug have a much lower incidence of developing Parkinson’s disease over a ten-year period.² This generates a powerful, human-data-based hypothesis that can then be tested in a formal clinical trial.

These computational approaches offer immense advantages in terms of speed, cost-effectiveness, and the ability to generate truly novel hypotheses. However, they are not a panacea. Their predictions are only as good as the quality and completeness of the input data, and they are prone to generating false positives. It is absolutely critical to remember that any in silico prediction is merely a starting point; it must always be followed by rigorous experimental validation in the lab and, ultimately, in clinical trials.

The Strategic Implications of a Computational Future

The integration of AI and big data into the repurposing workflow has profound strategic implications that extend beyond the lab and into the realms of intellectual property and commercial strategy.

First, AI is becoming the ultimate “non-obviousness engine.” As we’ve discussed, the biggest legal hurdle in securing a strong method-of-use patent is demonstrating that the new use is non-obvious. An AI platform that identifies a therapeutic link between a drug and a disease through a complex, multi-layered, and completely unexpected biological pathway provides a powerful argument against obviousness. The very nature of the discovery process—driven by an algorithm finding a non-linear relationship in a vast dataset—is inherently non-obvious. The data generated to validate this AI-driven hypothesis can then be used as compelling evidence in a patent application, significantly strengthening the patent’s defensibility. In this sense, AI becomes a tool not just for scientific discovery, but for forging stronger intellectual property.

Second, the future of repurposing is personalized. The next evolution of this strategy will move beyond finding a new use for a single disease and toward finding a new use for a specific, biomarker-defined sub-population of patients with that disease. By training AI models on multi-omics data from diverse patient populations, it becomes possible to identify the specific genetic signatures or protein expression patterns that predict which patients will respond to a given drug.

This will revolutionize both clinical development and commercialization. Instead of running a large, expensive trial for all “breast cancer” patients, a company could run a smaller, faster, and much more likely to succeed trial exclusively in “HER2-negative breast cancer patients with a specific PIK3CA mutation.” Commercially, this enables the co-development of a companion diagnostic test alongside the repurposed drug. This creates a highly differentiated, precision medicine product with an incredibly strong value proposition for physicians, patients, and payers, who are increasingly demanding evidence of targeted efficacy. This is the ultimate evolution of the repurposing strategy: from finding new uses for old drugs to finding the right drug for the right patient, regardless of its original label.

Conclusion and Key Takeaways

Drug repurposing has firmly transitioned from a niche strategy of opportunistic discoveries to a central pillar of modern, efficient pharmaceutical R&D. It represents a paradigm shift, offering a faster, cheaper, and significantly de-risked alternative to the formidable challenges of de novo drug development. For the strategic leaders in the biopharmaceutical industry, mastering the intricate interplay of intellectual property law, complex regulatory pathways, and cutting-edge computational science is no longer optional—it is essential for building a resilient and competitive pipeline.

The economic case is undeniable. With the potential to cut development timelines by half and reduce costs by more than 60%, all while tripling the probability of success, repurposing offers a compelling solution to the industry’s pressing R&D productivity crisis. Yet, the path to commercial success is fraught with unique challenges. The inherent weakness of traditional IP for known compounds demands a sophisticated, multi-layered approach, creating a “patent thicket” of method-of-use, formulation, and combination patents that can effectively deter generic competition.

Navigating the global regulatory landscape requires a dual-track mindset. In the U.S., the 505(b)(2) pathway serves as a powerful superhighway to market, but its complexity favors experienced industry players and demands a commercial partner from the outset. In the E.U., the framework is more supportive of non-commercial research, but the “MAH Veto” remains a critical bottleneck that can strand promising therapies. For rare diseases, the Orphan Drug Act provides a lifeline, offering powerful market exclusivity incentives that can transform a scientifically interesting project into a commercially viable asset.

As we look to the future, the integration of AI and big data promises to unlock the next wave of repurposing innovation, moving the field toward a predictive, systematic, and ultimately personalized paradigm. The companies that will lead in this new era will be those that not only embrace these new technologies for discovery but also understand how to translate those discoveries into defensible intellectual property and navigate the complex global pathways to patients. Repurposing is more than a cost-saving measure; it is a strategic imperative that, when executed with expertise and foresight, can deliver immense value to patients, healthcare systems, and shareholders alike.

Key Takeaways

• Repurposing is a Core Economic Driver: Drug repurposing is a multi-billion dollar market segment that significantly reduces drug development timelines (by 5-7 years), costs (by ~60%), and risk (tripling the success rate to ~30%), making it an essential strategy for R&D productivity.
• IP Strategy Must Be Multi-Layered: A single method-of-use patent is vulnerable. A robust IP fortress requires a “patent thicket” combining new use, formulation, dosage, and combination patents to effectively block generic competition and close loopholes like “skinny labeling.”
• Master the 505(b)(2) Pathway in the U.S.: The FDA’s 505(b)(2) pathway is the primary vehicle for repurposed drug approval in the U.S. Success hinges on building a strong “scientific bridge” to existing data and leveraging the pathway to secure valuable 3-year (new use) or 7-year (orphan drug) market exclusivities.
• Navigate the EU’s Unique Landscape and the “MAH Veto”: The EMA offers more structured support for non-profits but requires engagement with the Marketing Authorisation Holder (MAH), who has the final say on filing for a new indication—a critical bottleneck for off-patent drugs.
• Leverage the Orphan Drug Act for Rare Diseases: The ODA provides powerful, patent-independent 7-year market exclusivity and significant financial incentives, making it the most potent tool for turning a scientifically promising but commercially challenging rare disease project into a viable asset.
• Use Patent Intelligence as a Strategic Weapon: Systematically monitoring patent databases with tools like DrugPatentWatch provides an early warning system for competitor activities and helps identify “white space” opportunities, in-licensing targets, and freedom-to-operate risks.
• Embrace the Computational Revolution: The future of repurposing is being driven by AI and big data analytics, which are moving the field from serendipity to systematic, predictive discovery. These tools not only identify novel candidates but can also generate the “non-obvious” data needed to secure stronger patents.

Frequently Asked Questions (FAQ)

1. Our company is considering repurposing an off-patent, generic drug for a new indication in a common disease. What is the single biggest hurdle to commercial viability, and how can it be overcome?

The single biggest hurdle is the lack of robust market exclusivity. Since the drug is generic, there is no composition-of-matter patent, and a method-of-use (MoU) patent for the new indication is vulnerable to being undermined by the off-label use of cheap generics. The most effective way to overcome this is to create a new, patentable invention that is inextricably linked to the new use. The gold standard is developing a novel, patented formulation (e.g., an extended-release version, a new delivery system) that is clinically superior or essential for the new indication’s safety or efficacy profile. This forces competitors to either infringe your new formulation patent or market a product that is not therapeutically equivalent for the new use, effectively closing the “skinny label” loophole and creating a defensible market.

2. We are a small biotech with a promising AI-driven repurposing discovery. How should we approach partnership discussions with a large pharmaceutical company?

Come to the table with more than just an idea; bring a de-risked asset. Before approaching a potential partner, invest in generating strong, compelling preclinical validation data for your AI-generated hypothesis. Crucially, file for provisional patents on the new method of use, and if applicable, any novel formulations or combinations you’ve conceptualized. This demonstrates that you have not only a scientific discovery but also the beginnings of a protectable commercial asset. In negotiations, focus on the value of your “de-risking premium”—the time, cost, and uncertainty you have already removed from the project. Frame the partnership not as them taking a risk on your idea, but as them acquiring a late-stage, de-risked asset with a clear IP and regulatory path forward.

3. What is the most common mistake companies make when pursuing a 505(b)(2) strategy for a repurposed drug?

The most common mistake is underestimating the complexity and strategic importance of the “scientific bridge.” Many companies focus heavily on the efficacy data for the new indication but fail to adequately plan the specific pharmacokinetic, bioavailability, or toxicology studies needed to scientifically justify their reliance on the reference drug’s data. This can lead to unexpected requests from the FDA for additional, costly, and time-consuming studies late in the development process. A successful 505(b)(2) strategy requires early and deep engagement with regulatory experts to meticulously map out the bridging plan, anticipate FDA questions, and design the development program specifically to meet the unique requirements of the pathway.

4. If a repurposed drug fails its clinical trial for a new indication, is all the investment lost?

Not necessarily. As the losartan case study for Duchenne muscular dystrophy demonstrates, even a “failed” trial can generate immensely valuable data. While losartan failed to improve skeletal muscle function, it showed a clear benefit for cardiac function and mortality. This negative data for skeletal muscle is valuable because it de-risks the field, saving other companies from pursuing the same failed hypothesis and redirecting resources toward more promising avenues. The positive cardiac data, meanwhile, could potentially support a different, more narrowly focused repurposing effort for DMD-associated cardiomyopathy. A strategic mindset views every clinical trial, success or failure, as an opportunity to generate knowledge that informs the next wave of R&D decisions.

5. With the rise of AI, will human-led, serendipitous discovery in drug repurposing become obsolete?

Unlikely. While AI and systematic screening will undoubtedly become the dominant engine for generating repurposing leads, they will not replace the role of astute clinical observation and scientific creativity. AI models are trained on existing data; they are excellent at finding patterns within what is already known. True serendipity—like the observation of sildenafil’s effects in a trial for a completely different disease—often comes from unexpected human contexts that are not captured in structured datasets. The future is likely a hybrid model where computational approaches generate hundreds of high-probability hypotheses, while physicians, patients, and bench scientists continue to be a source of truly novel, “out-of-the-box” discoveries that can then be fed back into the computational models for deeper exploration.

References |

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