Here is a fact that surprises most people who work outside drug regulatory affairs: hundreds of prescription products are actively sold in the United States right now without formal FDA approval. They are dispensed by pharmacists, billed to insurance, and prescribed by physicians who may not even know their patients are taking something the agency has never formally vetted. The FDA estimated back in 2006 that unapproved products accounted for as much as 2% of all U.S. prescriptions. [1] That sounds small until you apply it to the scale of the American drug market, at which point it becomes a remarkably large number of pills, tablets, and vials.
This is not a scandal waiting to happen. It is a business opportunity hiding in plain sight, and a relatively small number of pharmaceutical companies have learned to exploit it with devastating commercial efficiency. The mechanics are straightforward once you understand them, though the regulatory nuance is anything but simple. A company identifies an unapproved drug, files a New Drug Application via the Section 505(b)(2) hybrid pathway, wins formal FDA approval—often without conducting a single new clinical trial—and then watches as the FDA’s own enforcement machinery clears every competitor off the market. The result is a government-mandated monopoly on a product that may have been a low-cost commodity for decades.
The price increases that follow are not modest. A Vizient analysis of just five drugs that moved from unapproved to approved status found price jumps ranging from 72% to over 1,600%, producing an estimated $3 billion in additional healthcare spending. [2] The same analysis projected that 18 remaining unapproved drug candidates could add another $7.52 billion to U.S. healthcare costs if the pattern continued unchanged. [2] These are not rounding errors. They are strategic outcomes engineered by companies that understand regulatory arbitrage better than their competitors.
This article explains how that arbitrage works—mechanically, legally, and commercially—and what it takes to execute it. It covers the history of the unapproved drug market, the 505(b)(2) pathway in technical depth, the market exclusivity toolkit, a practical candidate-identification framework, the canonical case studies of colchicine and vasopressin, and the ethical and political headwinds any company in this space must take seriously. The goal is a clear-eyed picture, not a promotional one.
Part 1: How We Got Here—A Century of Regulatory Gaps
The Wild West Origins of U.S. Drug Law
The modern American drug approval system is only about 85 years old. Before the early 20th century, the federal government had no authority to review a medicine before it reached patients. Manufacturers sold products containing morphine, cocaine, and toxic industrial solvents openly, with marketing claims they invented at will. “Mrs. Winslow’s Soothing Syrup,” marketed to parents for teething infants, contained morphine. “Peter’s Specific, The Great Blood Purifier System Regulator” listed no ingredients worth discussing. [3]
Congress passed the original Food and Drugs Act in 1906, primarily in response to public horror at conditions in the food industry—Upton Sinclair’s ‘The Jungle’ played a documented role in generating political momentum. [4] The 1906 Act prohibited the interstate sale of adulterated or misbranded drugs, but it contained no pre-market review requirement. The government could act after a product was already harming people; it could not stop a dangerous product before it entered the market.
1938: The First Real Gate
That changed in 1937, when a Tennessee company killed more than 100 people—many of them children—by using diethylene glycol, a toxic industrial solvent, as the base for a liquid sulfa drug called Elixir Sulfanilamide. [5] The public outcry produced the Federal Food, Drug, and Cosmetic (FD&C) Act of 1938, which for the first time required manufacturers of new drugs to submit safety evidence to the FDA before marketing. [1]
The 1938 Act created the New Drug Application process. It also created the first large cohort of unapproved drugs that would persist for the next nine decades: drugs already on the market when the Act passed were grandfathered in and did not need to demonstrate safety. [6] That exemption was written to handle practical reality—you could not retroactively require everyone marketing a drug before 1938 to suddenly file an NDA—but it created a legacy that regulators are still wrestling with today.
1962: Efficacy Enters the Picture
The next major change came from Europe. Thalidomide, a sedative widely prescribed to pregnant women, caused severe birth defects in thousands of babies across the United Kingdom and Germany. The U.S. largely avoided the disaster—primarily because FDA reviewer Frances Oldham Kelsey refused to approve it despite substantial industry pressure—but the near-miss generated political will for stronger legislation. [4]
The Kefauver-Harris Amendments of 1962 added a second requirement to drug approval: manufacturers had to demonstrate not just safety, but effectiveness for the claimed indication. [1] This raised the bar substantially for new drugs going forward. For the enormous backlog of drugs approved between 1938 and 1962 on safety evidence alone, the amendments established the Drug Efficacy Study Implementation (DESI) review. The FDA contracted with the National Academy of Sciences to evaluate thousands of pre-1962 drugs for efficacy, and products found ineffective were supposed to be removed from the market. [1]
“Supposed to be” is doing a lot of work in that sentence. Some manufacturers never complied with DESI decisions. Others were overlooked in the review. Some products were copies of DESI drugs that had never been through any formal review at all. These gaps produced the persistent population of unapproved drugs that the FDA was still trying to address four decades later.
Grandfathering: What It Actually Means
Drug executives sometimes encounter the term “grandfathered drug” and assume it describes a legally acceptable product that requires no regulatory action. The FDA’s actual position is considerably narrower. To maintain a valid grandfathered status, a drug must be identical in composition, dosage form, route of administration, and labeling to what was marketed before the relevant Act. [6] The FDA has stated explicitly that it is unaware of any human prescription drug currently on the market that lawfully qualifies for this exemption, because it is extremely difficult to demonstrate that a drug has remained completely unchanged for 60 to 85 years. [6]
Similarly, “Generally Recognized as Safe and Effective” (GRASE) status sounds like an available workaround, but the evidentiary standard is equivalent to what a full NDA requires—widespread expert consensus supported by adequate, well-controlled studies. [5] GRASE is the exemption used for common OTC ingredients like aspirin and acetaminophen, not a regulatory escape hatch for unreviewed prescription drugs.
Part 2: The Unapproved Drugs Initiative—Good Intentions, Complicated Outcomes
What the UDI Was Supposed to Do
By 2006, the FDA estimated that thousands of unapproved drug products remained in active commerce in the U.S. [5] The agency responded by launching the Unapproved Drugs Initiative (UDI), a risk-based enforcement program designed to bring these legacy products under modern regulatory standards. The program’s stated logic was sensible: drugs that have not been formally reviewed for safety, efficacy, manufacturing quality, or accurate labeling represent a genuine public health risk, regardless of how long they have been in use. [7]
The UDI works through targeted enforcement. The FDA identifies a specific drug or class of drugs and issues either a warning letter or a Federal Register notice declaring all unapproved versions subject to enforcement action. Manufacturers typically get a one-year grace period to cease marketing and distribution of the unapproved product. [5] The first company to obtain an approved NDA for the targeted drug finds itself in a market that the FDA has effectively cleared. Competitors either exit or spend years preparing their own applications.
The mechanism is blunt and powerful. It was also, in retrospect, a template for one of the more consistently profitable regulatory strategies in modern pharmaceutical business development.
The Economic Consequences: Prices, Shortages, and Minimal New Science
The UDI has a measurable track record. A 2017 systematic review published in the Journal of Managed Care & Specialty Pharmacy examined 34 prescription drugs targeted by the initiative between 2006 and 2015. For the 26 drugs with available pricing data, the median average wholesale price increased by 37% in the two years following UDI action or approval. [8] For the 10 drugs where a manufacturer received a warning letter and subsequently gained approval, the median price increase immediately post-approval was 122%. [8] <blockquote> ‘A systematic review of all prescription drugs targeted by the UDI between 2006 and 2015 showed that the price of these drugs increased by a median of 37% after UDI regulatory action or approval. The number of drugs in shortage increased from 17 (50%) to 25 (74%) in the two years before and after UDI regulatory action or approval… Nearly 90% of previously unapproved drugs that received FDA approval through the UDI were supported by literature reviews or bioequivalence studies, not new clinical trial evidence.’ — Journal of Managed Care & Specialty Pharmacy, 2017 [8] </blockquote>
The shortage data is equally striking. Before UDI enforcement, 50% of targeted drugs were experiencing shortages. Afterward, that figure rose to 74%, and the median shortage duration increased from 31 days to 217 days—a nearly seven-fold increase. [8] Concentrating a market from multiple suppliers to one introduces fragility. That is not a controversial claim; it is basic supply chain logic.
The most damning critique of the UDI’s value proposition is the absence of new science it produces. Nearly 90% of drugs approved through the UDI process received approval on the basis of literature reviews or bioequivalence studies, not new sponsor-conducted clinical trials. [8] The program achieves price increases and supply disruptions largely without generating new evidence that the drugs are safer or more effective than decades of clinical use already suggested.
This is the specific combination of facts that makes the unapproved drug space commercially interesting. Low evidentiary bar to approval. High monopoly pricing power after approval. Government enforcement doing the competitive clearing for you.
The 2020 Termination and 2021 Reinstatement
In November 2020, the Trump administration’s Department of Health and Human Services announced it was rescinding the guidance documents underpinning the UDI. [9] The stated rationale was that the initiative created de facto market exclusivity that drove dramatic price increases without generating substantial new clinical data. The framing was explicitly pro-competition. HHS called the program’s consequences “laudable” in goal but counterproductive in effect. [9]
The Biden administration reversed this in May 2021, reinstating the UDI with language that called the 2020 rescission “legally and factually inaccurate” and inconsistent with the FD&C Act. The reinstatement notice argued that walking away from the program “could result in significant harm to public health by suggesting that unsafe or ineffective drugs could circumvent the drug approval process.” [10]
This whiplash captures the fundamental policy tension: a program designed to protect patients from unvetted drugs that also consistently produces monopolies and price spikes. The oscillation between administrations shows there is no clean resolution. For anyone building a business strategy around the unapproved drug market, this political history is not background noise—it is a key risk factor that affects how aggressive a pricing strategy the market will tolerate before generating legislative or regulatory backlash.
Part 3: The 505(b)(2) Pathway—The Strategic Core
Three Routes, One Ideal Choice
The Federal Food, Drug, and Cosmetic Act provides three primary pathways for approving small-molecule drugs. Understanding their differences is not just regulatory trivia; it determines the cost, timeline, and commercial upside of any development program.
The 505(b)(1) NDA is the traditional full application for a new chemical entity—a molecule the FDA has never before approved. Everything in a 505(b)(1) package must come from the applicant’s own studies: full nonclinical toxicology, Phase 1 through Phase 3 clinical data, manufacturing validation. The average cost to bring a drug to market via this route runs approximately $2.6 billion, and timelines of 10 to 15 years are typical. [11] The reward for surviving this process is five-year New Chemical Entity (NCE) exclusivity. This is the traditional innovation pathway, and it is designed for companies that have genuinely discovered something new.
The 505(j) ANDA covers generic drugs. It was created by the 1984 Hatch-Waxman Act specifically to enable the rapid, low-cost introduction of generic versions of branded drugs after their patents and exclusivities expire. [12] A generic applicant does not need to repeat the originator’s clinical trials—it only needs to demonstrate that its product is pharmaceutically equivalent to the Reference Listed Drug (RLD) and shows comparable bioavailability in a bioequivalence (BE) study. The 505(j) route is cheap and fast, but it carries one fundamental restriction: the product must be essentially identical to the RLD. Any meaningful difference—dosage form, strength, route of administration—puts the product outside the ANDA framework. Generics also carry no market exclusivity of their own beyond the 180-day first-filer period for successful patent challengers. [12]
The 505(b)(2) NDA occupies the strategically advantageous middle ground. It is a full NDA in legal status, requiring the same standard of evidence for safety and effectiveness as a 505(b)(1) application. [13] The critical difference is that the applicant can fulfill some of those data requirements by relying on investigations it did not conduct and does not have a right of reference to—specifically, FDA’s prior findings of safety and effectiveness for an approved RLD, and published scientific literature. [13] This hybrid structure, established by Hatch-Waxman, makes the 505(b)(2) pathway ideal for products that represent modifications of existing drugs: new dosage forms, different strengths, new routes of administration, new combinations, new indications, or, directly relevant to this discussion, legacy unapproved drugs with a body of existing clinical literature.
Unlike a generic, a 505(b)(2) product is a new, branded drug eligible for its own market exclusivity. That is the commercial distinction that drives the entire business model.
The 505(b)(2) Pathway in Technical Practice
Building on Published Literature
For many legacy unapproved drugs, the published medical literature is the foundation of the development program. A drug that has been prescribed by physicians for 40 years generates an enormous body of observational data, case series, retrospective analyses, and sometimes prospective controlled studies. A 505(b)(2) applicant can compile this literature systematically and use it to support the safety and effectiveness claims in the NDA.
The qualification is important: the FDA does not simply accept any body of literature. The agency requires “adequate and well-controlled investigations” to support efficacy claims, and much of the older literature was not conducted to modern standards. A thorough gap analysis—identifying what the existing data supports and where the evidentiary holes are—is prerequisite work before any development program begins. [14]
The Scientific Bridge
Relying on external data requires establishing what FDA guidance calls a “scientific bridge” between the applicant’s specific product and the reference information it relies on. [11] The bridge demonstrates that it is scientifically justified to extrapolate from the RLD data or published literature to the new product.
The nature of the bridge depends entirely on how different the new product is from the reference:
If the product is pharmacologically very similar to an RLD (e.g., a different salt of the same active moiety), a standard bioavailability/bioequivalence study typically constitutes a sufficient bridge.
If the differences are more substantive—a new dosage form, a different delivery mechanism, a modified release profile—more extensive bridging work is needed. This can include pharmacokinetic studies, targeted nonclinical toxicology, or small clinical safety studies with the new formulation.
The bridge is where 505(b)(2) programs most commonly run into trouble. Underestimating the FDA’s expectations for bridging data is the single most common source of Complete Response Letters in this pathway. [15]
Chemistry, Manufacturing, and Controls
A persistent misconception about the 505(b)(2) route is that the lower development burden on the clinical side somehow extends to manufacturing. It does not. The FDA holds all NDAs to the same manufacturing quality standards, regardless of whether they are 505(b)(1) or 505(b)(2) applications. Inadequate Chemistry, Manufacturing, and Controls (CMC) data is one of the most frequent causes of 505(b)(2) CRLs. [15] A company that cuts corners on manufacturing validation to save cost will discover that this is not where the savings should be taken.
Comparative Pathway Summary
Feature
505(b)(1) NDA
505(b)(2) NDA
505(j) ANDA
Primary use
New chemical entity
Modifications; legacy unapproved drugs
Generic copy of RLD
Data source
Applicant’s own investigations only
Applicant’s data + FDA RLD findings + literature
Bioequivalence to RLD
Typical cost
~$2.6 billion
$15M–$100M
Low (BE study focused)
Typical timeline
10–15 years
3–5 years
Tied to patent/exclusivity expiry
Exclusivity potential
5-year NCE, 3-year new clinical, 7-year orphan
3-year new clinical, 7-year orphan
180-day first-filer only
Innovation requirement
High—new molecule
Moderate—meaningful modification
None—replication
Part 4: Market Exclusivity—The Actual Prize
Patents vs. Exclusivity: A Distinction That Matters
These two forms of market protection are frequently conflated, and conflating them is expensive. Patents are granted by the U.S. Patent and Trademark Office and protect an invention—a specific molecule, a formulation, a method of manufacture—for approximately 20 years from the filing date. Exclusivity is granted by the FDA at product approval and prevents the agency itself from approving certain competing applications for a defined period. [16]
The practical difference is in enforcement. Patent rights are enforced by the holder through litigation in federal court. Regulatory exclusivity is enforced by the FDA administratively—no lawsuit required. If a product has 3-year new clinical investigation exclusivity, the FDA simply will not approve a generic or 505(b)(2) competitor referencing the same data during that period, regardless of the patent situation. These two systems run in parallel and provide complementary, layered protection. [16]
For a company pursuing an unapproved drug approval, regulatory exclusivity is often more immediately reliable than patent protection, because the active ingredient is almost certainly not patentable—it has been known and used for decades. The patents available to this strategy tend to cover specific formulations, manufacturing processes, or methods of use. Regulatory exclusivity, by contrast, requires only successful completion of the right kind of development program.
The Four Types of FDA Exclusivity Relevant to 505(b)(2) Strategy
New Chemical Entity Exclusivity (5 years). This applies to drugs containing an active moiety the FDA has never before approved in any Section 505(b) application. [16] For most legacy unapproved drugs, this is not available—the active ingredient has been known for decades. Exceptions exist. The trace mineral product selenious acid received 5-year NCE exclusivity when it went through the UDI approval process, because the FDA had never formally approved its specific active moiety before. [2] These cases are uncommon but worth analyzing during due diligence.
New Clinical Investigation Exclusivity (3 years). This is the most accessible and most commercially important form of exclusivity for the unapproved drug strategy. It requires that the NDA (or a supplement to an existing NDA) contain reports of new clinical investigations that were conducted or sponsored by the applicant and that were essential to the approval decision. [13] The investigations must be clinical—bioavailability and bioequivalence studies do not qualify. [16]
Three-year exclusivity protects the specific change or innovation supported by the new clinical data. If a sponsor gets a legacy drug approved for a new indication based on a new clinical trial, competitors are barred for three years from winning approval for that same indication via an ANDA or a 505(b)(2) referencing the same clinical data. The commercial implication is significant: this exclusivity is earned by conducting a targeted clinical study, not by discovering a new molecule.
Orphan Drug Exclusivity (7 years). The Orphan Drug Act grants seven years of market exclusivity to drugs approved for conditions affecting fewer than 200,000 Americans. [16] If a legacy unapproved drug can be approved for a designated orphan indication, the sponsor gets the longest statutory exclusivity period available under this framework. Dehydrated alcohol received 7-year orphan exclusivity through the UDI process for treatment of a severe cardiac condition. [2] For drugs with mechanisms applicable to rare diseases, the orphan route is the most powerful exclusivity strategy available.
Pediatric Exclusivity (6 months). When the FDA issues a Written Request for pediatric studies and the sponsor completes them, the agency extends all existing patent and exclusivity periods by six months. [16] This attaches to whatever protection already exists, making it an incremental benefit rather than a standalone strategy.
‘De Facto’ Exclusivity: What the UDI Actually Provides
Beyond statutory exclusivity, the UDI creates something the HHS rescission notice in 2020 explicitly called “de facto market exclusivity.” [9] When the FDA issues an enforcement action clearing unapproved versions of a drug from the market, the first approved product faces no competitors for at least the one-year grace period. In practice, this monopoly period extends much longer. It takes years for a competitor to identify the opportunity, prepare a complete NDA, submit it, and survive the 10-month review cycle. By the time a second approved competitor reaches the market, the first mover may have accumulated several years of unchallenged revenue.
This de facto exclusivity runs concurrent with, not in place of, statutory exclusivity. A company that earns 3-year new clinical investigation exclusivity on top of the UDI’s market-clearing effect can reasonably expect a protected market window of 5 to 7 years from launch, sometimes longer if patent protection is also in play.
Part 5: Finding the Opportunity—A Practical Candidate Identification Framework
The Search Process
Identifying actionable unapproved drug candidates is a data problem. The raw material is public, but the analysis required to convert it into prioritized leads is not trivial.
Step 1: The NDC Directory as Universe
Every drug product legally marketed in the U.S. must be listed with the FDA and assigned a National Drug Code (NDC) number. [7] The NDC identifies the labeler, the product, and the package. The NDC Directory is therefore the closest thing to a master list of all marketed U.S. drugs, approved and unapproved alike. It is the starting universe.
Step 2: Orange Book Cross-Reference
The FDA’s Orange Book—formally ‘Approved Drug Products with Therapeutic Equivalence Evaluations’—is the definitive list of FDA-approved drug products with their associated patents and exclusivity periods. [17] Any product that appears in the NDC Directory but not in the Orange Book is, by definition, a potential unapproved drug. This cross-referencing step generates the initial list of leads.
The logic is simple. The execution is tedious at scale, which is why automated tools have a material advantage over manual search.
Step 3: Drugs@FDA for Depth
The Drugs@FDA database provides access to the regulatory history behind each approved product: original approval letters, scientific reviews, labeling, and correspondence. [7] For any candidate generated by the Orange Book cross-reference, Drugs@FDA confirms that no approved NDA or ANDA exists, and it helps identify related approved products that could serve as RLDs for a potential 505(b)(2) application.
Step 4: Specialized Intelligence Platforms
Manual searching of public databases is feasible for an initial scan but impractical for systematic ongoing surveillance. This is where platforms like DrugPatentWatch become operationally important. DrugPatentWatch maintains curated lists of unapproved drugs, including those subject to historical DESI review, and integrates regulatory data from the FDA with patent data from the USPTO, international patent offices, clinical trial registries, and Paragraph IV litigation records. [18]
The practical advantage is not just breadth—it is the ability to set up automated monitoring. A firm can configure alerts for specific active ingredients, companies, or patent filings and receive notification when something changes. In a space where being the first to file can mean years of unchallenged market position, real-time intelligence on competitive activity matters.
DrugPatentWatch also supports Freedom to Operate analysis by integrating patent data with regulatory status information in a single interface, reducing the research time required to assess whether a candidate has blocking patents that would prevent market entry.
The Due Diligence Framework
A raw list of unapproved drugs is not a business strategy. Each candidate requires systematic evaluation across four dimensions.
Commercial Potential
Is there a real market here? The analysis should quantify the patient population, assess the current standard of care, and evaluate the pricing environment. A drug used in 500,000 patients annually with no adequate approved alternative is a categorically different opportunity from one used in a few thousand patients with multiple competing therapies.
The most commercially powerful scenario is a drug that can be positioned for an orphan indication. Orphan drugs command premium pricing, receive 7-year exclusivity, and often face no generic entry during that window. Even if a drug has historically been used primarily for a non-orphan condition, the existence of a rare disease with a plausible mechanistic fit is worth investigating systematically during due diligence.
Regulatory Feasibility
The key questions are whether sufficient published literature exists to support the 505(b)(2) submission and what bridging studies the FDA will require. A preliminary literature review and gap analysis—ideally conducted or reviewed by a regulatory expert with 505(b)(2) experience—should be completed before any significant capital commitment.
The absence of an RLD is a complicating factor that adds both regulatory risk and development cost. Without an established FDA-vetted data anchor, the submission must rely entirely on published literature and the applicant’s own bridging studies. That is manageable, but it requires more rigorous scientific justification throughout the application.
Patent Landscape
Freedom to Operate analysis is non-negotiable. The active ingredient of a legacy unapproved drug is almost certainly not patentable—it is prior art many times over. But specific formulations, dosage forms, manufacturing processes, delivery devices, and methods of use can all be patented, and any of these could create blocking positions for a new entrant. A single valid patent held by a competitor can make an otherwise attractive candidate commercially impossible.
This analysis must go beyond searching active ingredient names. It requires a systematic review of formulation and method-of-use patents, with attention to the claim scope and expiration dates of anything potentially relevant. DrugPatentWatch’s integrated patent and regulatory database can substantially reduce the time required to build this picture.
Competitive Intelligence
How many manufacturers currently sell unapproved versions of this drug? Are any of them likely preparing their own NDA? A market with three small manufacturers is easier to dominate after FDA clearance than one with ten established players, some of whom may have already begun regulatory preparations. This information is rarely published, but it can be triangulated from NDC Directory listings, manufacturing capacity data, and company pipeline disclosures.
The Pre-IND Meeting: The Single Most Important Step
Before spending real money on development activities, any company pursuing a 505(b)(2) unapproved drug opportunity should request a Pre-IND meeting with the FDA. This formal meeting is the opportunity to present the development strategy—proposed indication, literature review summary, gap analysis, and planned bridging study designs—and receive early, non-binding feedback from the agency. [14]
A Pre-IND meeting that produces FDA alignment on the development approach can save tens of millions of dollars in misdirected effort. A development program that proceeds without FDA alignment can waste several years and the same amount of money, only to receive a Complete Response Letter explaining that the bridging studies were inadequate or the literature package did not meet the required evidentiary standard.
This is not a bureaucratic formality. It is the most important risk-mitigation step in the entire process.
Part 6: Case Studies—The Playbook in Action
Colchicine: The Drug That Made Everyone Pay Attention
Colchicine is derived from the autumn crocus and has been used to treat gout for centuries. By the mid-2000s, it was sold in the U.S. by multiple manufacturers as a low-cost, unapproved commodity at approximately $0.09 per tablet. [19]
URL Pharma saw the opportunity the FDA’s new Unapproved Drugs Initiative created. The company ran a 505(b)(2) development program for colchicine, conducting the clinical studies needed to formally establish its safety and efficacy for gout treatment. This was not novel science—physicians had been using the drug safely and effectively for decades. It was regulatory navigation.
In 2009, the FDA approved URL Pharma’s branded version, Colcrys, and granted it three years of new clinical investigation exclusivity based on the clinical data submitted. [19] Following its own UDI policy, the agency then ordered all other manufacturers of unapproved colchicine products to cease marketing. Overnight, a decades-old generic commodity became a government-protected monopoly.
URL Pharma priced Colcrys at approximately $5.00 per tablet—an increase of more than 5,000% from the pre-approval commodity price. [19] The commercial outcome was straightforward and substantial. The public health outcome was equally obvious and controversial, generating significant backlash from patients, physicians, and members of Congress who found themselves paying Medicare and Medicaid dollars for a drug that had cost almost nothing a year earlier.
The colchicine case did not establish wrongdoing. It established a template. The UDI, combined with the 505(b)(2) pathway and 3-year new clinical investigation exclusivity, is a legally compliant mechanism that produces this exact result. URL Pharma’s approach was creative, well-executed, and controversial in roughly equal measure. It became the most cited example of UDI-driven price inflation.
Vasopressin: The Advanced Playbook
If colchicine was the proof of concept, vasopressin was the masterclass. The drug is a peptide hormone that has been used in critical care medicine since 1928, primarily to treat life-threatening vasodilatory shock. Like colchicine, it had never received formal FDA approval.
In 2012, JHP Pharmaceuticals submitted a 505(b)(2) application for vasopressin based entirely on published literature. No new clinical trials were conducted. [20] Par Pharmaceutical acquired JHP and took the approval across the finish line in 2014, launching the branded product Vasostrict. [20] What followed was a more sophisticated multi-pronged strategy to lock in and extend market dominance.
The pricing move. Par raised the wholesale acquisition cost of vasopressin dramatically. Annual U.S. spending on the drug, which had been approximately $30.8 million before the monopoly, rose to an estimated $791 million by 2020. [2] This occurred during the COVID-19 pandemic, when vasopressin and similar critical care drugs were in high demand, adding both practical significance and political visibility to the price increase.
The patent thicket. This is where Par’s strategy went beyond what URL Pharma accomplished with colchicine. Despite vasopressin being a century-old molecule, Par filed patents on its specific formulation and manufacturing process. By 2022, the company had listed 14 separate patents with the FDA, with the last expiring in 2035. [20] Building this “patent thicket” around an ancient drug requires genuine IP creativity—finding aspects of the specific commercial product that represent protectable innovations—but it can substantially extend the effective monopoly period beyond whatever statutory exclusivity the FDA grants.
Blocking compounded alternatives. When hospitals sought cheaper compounded versions of vasopressin to avoid Par’s prices, Par sued the FDA to prevent it. The agency ultimately determined there was no “clinical need” for compounded vasopressin, a finding upheld in court that eliminated the primary workaround available to cost-sensitive hospital formulary managers. [20]
Par maintained its monopoly for approximately eight years. The first generic competitor was not approved until late 2021, after a federal court ruled it did not infringe on Par’s patents. [20] By that point, the cumulative healthcare spending impact was estimated at nearly $19.9 billion. [2]
The Broader Pattern: Five Drugs, $25 Billion in Impact
The colchicine and vasopressin cases are the most visible, but they are representative rather than exceptional. A Vizient analysis of five UDI-affected drugs quantified the financial scale:
Drug
Use
Spending Increase
Vasopressin
Vasodilatory shock
$30.8M to $791M annually; estimated $19.9B total
Colchicine
Gout
Unit price increased over 5,000%
Neostigmine Methylsulfate
Anesthesia reversal
$60.6M to $205.8M annually; estimated $876M total
Dehydrated Alcohol
Nerve pain treatment
$28M to $215M annually; estimated $937M total
Selenious Acid
Nutritional deficiency
$8.52M to $84.9M annually; estimated $389M total
Sources: [2, 8]
The cumulative estimated impact from just these five products runs into tens of billions of dollars. Each case followed essentially the same pattern: unapproved commodity drug, 505(b)(2) NDA filed with limited or no new clinical data, FDA approval, market clearance under UDI, aggressive pricing.
Part 7: The ROI Calculation
Development Costs vs. Traditional R&D
The financial case for pursuing unapproved drug opportunities is strongest when you compare the investment required against the revenue it can generate.
Traditional 505(b)(1) development for a new chemical entity runs approximately $2.6 billion over 10 to 15 years, and that figure assumes success—the failure rates across Phase 1 through Phase 3 make the risk-adjusted cost of successfully marketed drugs considerably higher. [11] A 505(b)(2) program for a legacy drug, by contrast, typically costs in the range of $15 million to $100 million and takes 3 to 5 years. [11] The ceiling on that range reflects programs requiring more substantial bridging studies or new clinical trials to earn 3-year exclusivity; many programs come in well below $50 million.
The FDA’s review timeline for a 505(b)(2) application is the same as for a 505(b)(1)—a standard 10-month PDUFA review cycle for applications without priority review designation. [15] The time savings come entirely from the shorter development program that precedes submission, not from any expedited FDA review.
If the post-approval price dynamics resemble those seen in the vasopressin or colchicine cases, a product that generates $200 million in annual revenue during a 5-year exclusivity window represents a cumulative return of $1 billion against a development investment that may have been $30 to $60 million. No other segment of pharmaceutical investment produces that ratio reliably.
The “AB” Rating Strategy
An underappreciated tactical play involves the FDA’s Therapeutic Equivalence (TE) coding system. Products in the Orange Book receive TE codes indicating whether they can be automatically substituted at the pharmacy. A code beginning with “A” indicates therapeutic equivalence and interchangeability; a code beginning with “B” indicates the opposite. [21]
For a 505(b)(2) product, securing an “AB” rating creates a specific barrier to future generic entry. Any generic applicant wishing to reference the “AB”-rated 505(b)(2) product must use it as the Reference Listed Drug for their own bioequivalence study—meaning they have to acquire and test against the marketed product, adding both time and cost to their development program. This delays generic entry beyond the expiration of statutory exclusivity periods.
An analysis of 505(b)(2) approvals found that 35 out of 83 products with assigned TE codes obtained “AB” ratings. [21] The products varied across dosage forms, from solid oral tablets to topicals. The implication is that this outcome is achievable across a range of product types, not limited to a specific formulation category. Building for an “AB” rating should be a standard consideration during the development program design phase.
Advanced Revenue Strategy: Combination Plays
The most sophisticated operators in this space do not limit themselves to straight approval of a drug’s historical indication. They design programs to generate:
Statutory exclusivity through new clinical investigation data, protecting the specific approval from generic competition for three years
Orphan designation where applicable, providing 7-year exclusivity and premium pricing justification
New patents on the specific formulation or delivery system used in the commercial product
An “AB” rating to extend effective market protection beyond the exclusivity period
Each of these elements is additive. A program that captures all four creates a protection stack that can extend a product’s commercial lifecycle well beyond any single exclusivity period. The total investment is higher than a bare-minimum compliance-focused filing, but the protected revenue window can be 10 to 15 years rather than 3 to 5.
The combination approach also affects how the product is positioned with payers. A drug that enters the market as “the compliant version of an old commodity” has a fundamentally different reimbursement conversation than one entering as “a newly approved product with clinical data, orphan designation, and a differentiated formulation.” The latter justifies significantly higher pricing without the same degree of payer resistance.
Part 8: Risks, Ethics, and the Policy Outlook
The Reputational Arithmetic
The business case is real. The risks attached to it are also real, and underestimating them is a strategic mistake that several companies in this space have made.
The central ethical problem is not subtle. Taking a drug that patients have relied on for decades as an affordable commodity, obtaining regulatory approval with minimal new science, and then pricing it 5x to 1,600x higher is a sequence of events that is legally permissible and commercially rational but that most people outside the industry—including patients, physicians, hospital administrators, and legislators—find straightforwardly objectionable.
Colchicine and vasopressin both generated congressional scrutiny and media coverage that damaged the companies involved. The vasopressin situation was particularly damaging because it involved a critical care drug used in ICUs during the COVID-19 pandemic, and hospitals reported making access decisions based on cost. [20] The reputational consequences were not merely abstract—they affected stock prices, investor sentiment, and executive tenure.
Any company entering this space needs a pricing strategy that accounts for what the market will politically tolerate, not just what the economics can sustain. The two numbers are not the same. A price increase of 200% rather than 1,200% may leave substantial profit on the table relative to the theoretical maximum, but it also leaves the company out of congressional testimony and off the front page of the Washington Post.
Political Risk and Regulatory Reform
The oscillation between the 2020 UDI termination and the 2021 reinstatement is a preview of how politically sensitive this territory is. The UDI exists at the intersection of drug pricing politics and regulatory integrity, two areas that reliably generate legislative attention.
Proposed reforms that have been discussed in policy circles include:
Requiring manufacturers to commit to supply guarantees and pricing agreements in exchange for the de facto exclusivity the UDI creates
Directing the FDA to review multiple applications for the same unapproved drug simultaneously, enabling competition rather than monopoly
Waiving or reducing NDA user fees for legacy unapproved drug applications to lower barriers for additional entrants
None of these reforms has been enacted as of April 2026, but the political trajectory suggests that at least some regulatory adjustment is likely. Companies building long-term business plans around UDI-driven monopolies should stress-test those plans against scenarios where post-approval pricing power is constrained by regulatory or legislative action.
The core legal framework—the FD&C Act’s requirement that all drugs be proven safe and effective—is not at risk. The FDA is not going to stop requiring approval for unapproved drugs. What is at risk is the degree of pricing freedom the first mover enjoys in the post-approval monopoly window.
The Generic Entry Problem
Statutory and de facto exclusivity both expire. When they do, the generic filing window opens, and the economics of the product shift dramatically. Companies that have built their entire business case around the monopoly period need a post-exclusivity strategy.
The patent thicket approach Par used with vasopressin is one model, but it requires that there be patentable aspects of the specific commercial product. Not every unapproved drug presents these opportunities. The “AB” rating approach, as described above, is another tool for extending competitive advantage. Lifecycle management through new indications, dosage forms, or reformulations—each potentially earning its own 3-year exclusivity—is a third.
The worst position is to have invested in an unapproved drug approval without any plan for the post-exclusivity period and then watch revenue collapse when generics enter.
Part 9: The Intelligence Infrastructure
What Good Market Intelligence Looks Like
The difference between a well-executed unapproved drug strategy and a failed one often comes down to the quality of intelligence used to select and evaluate candidates. This is a space where information asymmetry is real and persistent. The public FDA databases are available to everyone, but synthesizing them into actionable business intelligence requires work that most organizations do not do systematically.
The firms that do this well maintain ongoing surveillance of the unapproved drug landscape rather than running a one-time search. They track NDC Directory changes, FDA warning letters, Federal Register notices, and Orange Book updates in real time. They monitor competitor pipeline activity through ANDA filings, Pre-IND meeting requests (where publicly disclosed), and clinical trial registrations. They run patent landscape analyses that are updated quarterly, not once during initial diligence.
DrugPatentWatch provides the infrastructure for this kind of continuous monitoring. The platform’s curated DESI and unapproved drug lists eliminate the most labor-intensive step in the initial search process, and its alert functionality converts the search from a periodic manual exercise into an automated surveillance capability. [18] For organizations making significant investment decisions based on regulatory intelligence, the cost of a professional-grade data platform is a rounding error relative to the value of better decisions made earlier.
The patent component of the intelligence stack deserves particular attention. The Orange Book lists only patents that manufacturers voluntarily submit for inclusion, and the criteria for listing have been subject to ongoing legal disputes. A patent that is not listed in the Orange Book can still be enforced against an infringer—it just does not trigger the automatic 30-month stay that Orange Book-listed patents confer. Understanding the full patent landscape for a target drug, including unlisted patents, requires searching the USPTO directly. Platforms that integrate USPTO data with FDA regulatory information reduce the time and error rate of this process.
Part 10: Beyond Compliance—Finding Hidden Value in Legacy Drugs
The Better Opportunity
The simplest version of the unapproved drug strategy is a pure regulatory play: identify an unprotected drug, file a 505(b)(2) NDA, wait for the FDA to clear competitors, raise the price. This works, as the case studies demonstrate. But it is not the most defensible version of the strategy, either commercially or reputationally.
The more sophisticated approach treats the unapproved drug as starting material rather than the end product. The question is not “can we get this drug approved?” but “can we make this drug meaningfully better, and can we get that improved version approved?” Framing the development program around a genuine product improvement changes multiple things at once.
Consider a legacy drug with known bioavailability problems. A 505(b)(2) program that addresses those problems with a new formulation—perhaps a modified-release system or a prodrug approach—creates a product that is genuinely differentiated from what physicians previously used. That differentiation can be documented in new clinical studies, which qualifies the product for 3-year new clinical investigation exclusivity. Those studies generate data that can support premium pricing conversations with payers. The formulation innovation itself may be patentable, adding IP protection that extends beyond the exclusivity period. And the company has a cleaner story to tell about why this drug deserves a higher price than its unapproved predecessor.
The same logic applies to repurposing. A drug with a well-characterized mechanism that has been used off-label for a rare disease may qualify for orphan designation, which provides 7-year exclusivity and a pricing environment that is dramatically more favorable than the commodity drug market. This is not hypothetical—dehydrated alcohol and selenious acid both received significant exclusivity periods through the UDI process after being positioned for specific indications. [2]
The Formulation Innovation Play
Several specific categories of formulation innovation are worth considering as part of a 505(b)(2) unapproved drug development program:
Extended-release or modified-release formulations can convert a drug requiring multiple daily doses into a once-daily product, improving patient adherence and creating a product differentiation that supports the new clinical investigation exclusivity requirement. The clinical study demonstrating comparable efficacy and safety with the new dosing regimen qualifies.
Alternative dosage forms can address historical barriers to use. A drug available only as a solid oral tablet that has been used off-label in pediatric patients with swallowing difficulties could be developed as a liquid formulation with appropriate taste masking, with a pediatric clinical study generating both the required clinical data and a Written Request that leads to 6-month pediatric exclusivity.
Combination products that pair an unapproved drug with a complementary therapy can create a fixed-dose combination that is genuinely more convenient than separate tablets, qualifying for its own exclusivity if the combination has not previously been approved.
None of these strategies is guaranteed to work for any specific drug. The feasibility depends on the drug’s pharmacology, the manufacturing complexity involved, and what the published literature already supports. But the principle—using the 505(b)(2) development program to create a product that is better rather than simply compliant—consistently produces more defensible competitive positions.
Conclusion
The unapproved drug market is not a niche regulatory curiosity. It is a multi-billion-dollar commercial opportunity with a government enforcement mechanism built into it. The FDA’s Unapproved Drugs Initiative, whatever its public health merits, functions as a market-clearing machine that rewards the first company to obtain a formal NDA. The 505(b)(2) pathway makes that NDA achievable in 3 to 5 years for tens of millions of dollars rather than the 10 to 15 years and billions required for a traditional drug approval. The market exclusivity framework provides statutory protection for the resulting monopoly. And the UDI’s de facto exclusivity extends that protection further.
The case studies of colchicine and vasopressin demonstrate what this playbook looks like when executed aggressively. The price increases are real, the profits are substantial, and the political and reputational consequences are also real. The companies that navigate this space most successfully will be those that treat the pricing strategy and the development strategy as equally important variables—not just maximizing the technical monopoly but calibrating the commercial execution to avoid the kind of political reaction that generates congressional hearings and policy reforms.
The fundamental legal structure creating this opportunity is not going away. Unapproved drugs will continue to exist, the FDA will continue to enforce approval requirements, and the first mover in each targeted drug will continue to have a period of unchallenged market position. The opportunity is real. So are the requirements to execute it well: rigorous candidate selection, expert regulatory navigation, comprehensive patent analysis, and a pricing strategy that the company can defend publicly.
Key Takeaways
The unapproved drug market is a persistent, government-created commercial opportunity. The FDA’s Unapproved Drugs Initiative clears competitors from the market for any drug it targets, directly benefiting the first company to obtain a formal NDA.
The 505(b)(2) pathway is the essential tool. It allows approval based partly on existing literature and FDA findings for a Reference Listed Drug, reducing development costs to $15 million–$100 million and timelines to 3–5 years—a fraction of what traditional 505(b)(1) development requires.
Market exclusivity is the commercial foundation. Three-year new clinical investigation exclusivity requires new clinical data but provides statutory protection. Seven-year orphan exclusivity is available for rare disease indications. Both run on top of whatever de facto exclusivity the UDI’s market-clearing actions provide.
Candidate identification is a data problem. Public FDA databases (NDC Directory, Orange Book, Drugs@FDA) provide the raw material for identifying unapproved drug leads. Platforms like DrugPatentWatch integrate regulatory, patent, and litigation data to accelerate that analysis and enable ongoing competitive surveillance.
The better strategy is product improvement, not just compliance. Development programs designed around genuine formulation innovations or new indications generate 3-year exclusivity, patentable IP, cleaner payer conversations, and a more defensible pricing narrative than straight compliance filings.
Pricing strategy is as important as regulatory strategy. The colchicine and vasopressin cases show what maximum pricing power looks like. They also show the political consequences. Companies that calibrate pricing to avoid congressional scrutiny while capturing substantial returns will outperform those that optimize only for short-term monopoly revenue.
The Pre-IND meeting is the single most important risk-mitigation step. Regulatory miscalculation—particularly around bridging study requirements—is the primary cause of 505(b)(2) CRLs. Getting FDA alignment before committing to a development program saves more money than any other single decision in the process.
FAQ
1. What distinguishes a 505(b)(2) NDA from a generic drug application, and why does the distinction matter commercially?
A 505(j) ANDA (generic) requires the applicant’s product to be essentially identical to the Reference Listed Drug—same active ingredient, dosage form, strength, and route of administration. It relies on the RLD’s existing safety and efficacy data without requiring any new evidence. A 505(b)(2) NDA is a full New Drug Application that can incorporate differences from the RLD—new dosage forms, strengths, routes, or indications—and can be based partly on published literature rather than only on data the applicant generated. The commercial difference is categorical: generics receive no market exclusivity of their own (beyond the 180-day first-filer period), while 505(b)(2) products are eligible for 3-year new clinical investigation exclusivity, 7-year orphan exclusivity, and pediatric exclusivity extensions. In the unapproved drug context, this distinction determines whether a company can legally prevent generic competitors from entering the market for several years after approval.
2. How does a company know whether the FDA will require new clinical trials or whether published literature will suffice for a 505(b)(2) submission?
There is no categorical rule. The FDA’s expectations depend on the specific drug, the proposed indication, the quality and volume of the existing literature, and the nature of any differences between the applicant’s product and any available RLD. A preliminary gap analysis—examining what the published data supports, where the methodological gaps are, and what bridging studies the differences from any RLD might require—is the starting point. But the only reliable way to get FDA’s actual position before committing resources is to request a Pre-IND meeting. At that meeting, the agency can indicate whether the proposed development plan is adequate or what additional studies it would expect. This meeting is not binding, but its output is the closest thing to de-risked regulatory guidance available at the early development stage.
3. What specific characteristics make an unapproved drug a strong 505(b)(2) candidate versus a weak one?
Strong candidates typically have several features: a substantial body of published clinical literature, ideally including some well-controlled studies; a patient population large enough to sustain premium pricing without significant payer resistance; no compelling approved alternative (which would make it harder to argue for premium pricing); and either a plausible orphan indication or a specific product improvement opportunity that could justify 3-year new clinical investigation exclusivity. Weak candidates tend to have thin literature requiring extensive new clinical work (which erases the cost advantage of the pathway), patent blocking positions held by competitors, highly price-sensitive payer environments, or approved therapeutic alternatives that payers can mandate substitution to. Drugs with known safety problems in the historical literature are particularly risky—the FDA may require more extensive new clinical data than a pure compliance filing would normally need.
4. How durable is the monopoly position that the UDI creates, and what typically ends it?
The de facto monopoly has two components: the statutory exclusivity period (if earned) and the time required for any competitor to prepare and win approval for a competing product. Statutory exclusivity—whether 3-year or 7-year—creates a firm legal barrier during which the FDA will not approve a qualifying competing application. After that period, the market opens to ANDA or 505(b)(2) competition, and the only remaining protection is patents. The vasopressin case shows what sustained monopoly looks like when patent protection is layered on top of statutory exclusivity—Par maintained market control for approximately eight years. The colchicine case, where exclusivity was shorter and patent protection less extensive, saw competition return faster. The practical timeline from initial UDI targeting to the arrival of a generic competitor averages several years even without extensive patent protection, because the preparation and review of a competing NDA takes time.
5. How should a company think about the ethics of raising prices significantly on a legacy drug that patients have relied on affordably for decades?
This question does not have a clean answer, and any company that pretends it does is either not thinking carefully or not being candid. The legal framework permits the pricing strategies used in cases like colchicine and vasopressin. Shareholder obligations in public companies create pressure to capture available pricing power. These facts do not resolve the ethical question.
The more useful framing for business decision-making is not “is it ethical?” but “what are the consequences, and are we prepared for them?” Companies that have pursued maximum pricing in this space have faced congressional testimony, investigative journalism, payer formulary exclusions, and sustained reputational damage. Par Pharmaceutical’s vasopressin strategy was profitable, but it also produced years of negative press, multiple lawsuits, and regulatory scrutiny that imposed real costs. A pricing strategy calibrated to generate substantial returns while avoiding the political threshold that triggers these consequences is both more defensible and, over a realistic time horizon that accounts for reputational costs, likely more profitable. Companies should model the full scenario including political and reputational risk, not just the revenue curve under a pricing-power assumption.
References
[1] Government Accountability Office. (2006). Prescription drugs: FDA’s oversight of the use of clonidine in children. U.S. Government Accountability Office. [Cited for FDA’s 2% prescription market estimate for unapproved drugs.]
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[9] U.S. Department of Health and Human Services. (2020). FAQs: Unapproved drugs initiative announcement. HHS. https://www.hhs.gov/sites/default/files/covid-19-unapproved-drugs-initiative.pdf
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