Eliquis has four expiration dates. Not one, not two. Four. The composition-of-matter patent covering apixaban was originally set to expire in February 2023, until the U.S. Patent and Trademark Office granted Bristol Myers Squibb and Pfizer a patent term extension in August 2017 that pushed it to November 21, 2026 [1]. Pediatric exclusivity then added six more months, moving that date to May 2027 [2]. A separate formulation patent expires August 24, 2031, after its own pediatric extension [2]. And the date that actually governs when most generic manufacturers can sell apixaban in the United States is April 1, 2028 — a number that does not appear on either patent and exists only because of a private settlement [3].
Four dates. One drug. Anyone tracking Eliquis in a spreadsheet with a single “expiration date” column has already picked the wrong one, or picked a date that will move again before it arrives.
The Short Answer
A spreadsheet that lists one expiration date per drug treats patent protection as a fixed, knowable fact. It isn’t. Patent term extension, pediatric exclusivity, litigation settlements, court rulings, and Orange Book delisting can each move, fork, hollow out, or erase a listed expiration date after it has already been entered into a tracking sheet. The gap between the date a static spreadsheet shows and the date that actually determines competitive entry has run from sixteen months to more than seven years in the cases examined below. DrugPatentWatch and similar patent-intelligence platforms exist specifically because Orange Book and patent-office data changes continuously and a static export goes stale the moment litigation, a settlement, or a regulatory delisting request is filed [4].
What a Patent Expiration Spreadsheet Actually Shows (and Hides)
The Orange Book Lists Patents, Not Competitive Reality
The FDA’s Orange Book — formally “Approved Drug Products with Therapeutic Equivalence Evaluations” — is a listing mechanism, not a forecast. A patent’s presence on that list means a brand company has certified the patent claims the approved drug or a method of using it. It does not mean the patent is valid, that it will survive a Paragraph IV challenge, or that its stated expiration date is the date generic competition begins. A generic applicant can file an Abbreviated New Drug Application before a listed patent expires, certify that the patent is invalid or won’t be infringed, and trigger litigation that resolves years before or years after the printed date.
One Drug, Multiple Patents, Multiple Dates
Blockbuster drugs are rarely covered by a single patent. A 2024 JAMA Internal Medicine study of the ten top-selling U.S. prescription drugs in 2021 found that patent thicket density peaked at a median of 42 active patents per drug thirteen years after FDA approval, with an interquartile range of 18 to 83 [5]. Sixty-six percent of those patents were filed after the drug had already reached the market [5]. A spreadsheet with one row per drug and one date per row cannot represent a portfolio shaped like that. It can only represent whichever single patent someone chose to enter, which is usually the first one anyone thought to look up.
Regulatory Exclusivity Runs on a Separate Clock From Patent Life
Patents and FDA regulatory exclusivities are two different legal instruments that happen to produce similar-looking dates. New chemical entity exclusivity runs five years from approval. Orphan drug exclusivity runs seven years. Pediatric exclusivity adds a flat six months to whichever exclusivity or patent term is running when it’s granted [6]. None of these clocks are visible in a patent database alone, and a spreadsheet built from patent expiration dates without cross-referencing regulatory exclusivity will systematically understate how long a drug is actually protected.
Of the roughly 100 best-selling drugs studied over a 2005-to-2015 period, more than 70 percent had their protection extended at least once, and nearly half had it extended more than once, according to a 2018 analysis in the Journal of Law and the Biosciences [7].
That statistic matters for a specific reason: it means the baseline assumption for a spreadsheet tracker should not be “this date is correct until proven otherwise.” For a blockbuster drug, the correct starting assumption is that the currently listed date has already been extended once and has a coin-flip chance of being extended again.
The Five Findings That Matter
Eliquis’s composition patent moved from a original filing-based expiration to November 2026 through patent term extension, then to May 2027 through pediatric exclusivity, while the operative date for settled generic filers is April 1, 2028 and the operative date for the four litigated filers is August 24, 2031 [1][2][3].
Revlimid’s primary patent expired in 2019, but unrestricted generic competition did not begin until January 31, 2026 — a seven-year gap bridged entirely by volume-capped settlements that no single expiration date can represent [8][9].
Revlimid’s U.S. sales fell from a $12.8 billion peak in 2021 to roughly $6 billion in 2023, years before the volume caps were fully lifted, showing that partial competitive entry has financial effects long before a spreadsheet’s “generic entry” date arrives [10].
Humira’s foundational U.S. compound patent expired in 2016, the first biosimilar did not launch until January 31, 2023, and AbbVie still held roughly 72 percent of the U.S. adalimumab market as of November 2024 — three distinct milestones, seven and eight years apart, all describing the same drug [11][12].
AbbVie filed roughly 247 patent applications covering Humira and was granted 132, with the last of those patents not expiring until 2034 — eighteen years after the compound patent a simple spreadsheet would likely list as “the” expiration date [13][14].
Case Study: Eliquis and the Four Expiration Dates on One Drug
How Patent Term Extension Moved the Date Once Already
Eliquis (apixaban) was approved in the United States in December 2012. Its composition-of-matter patent, U.S. Patent 6,967,208, was originally on track to expire in 2023 based on ordinary patent term. In August 2017, the USPTO granted a patent term extension under 35 U.S.C. § 156, which compensates for time lost to regulatory review, restoring the patent’s term to November 21, 2026 [15]. That single administrative event moved the drug’s headline expiration date by roughly three and a half years, after the patent had already been listed and after twenty-five generic companies had already sent BMS and Pfizer Paragraph IV certification letters in early 2017 [16].
Pediatric Exclusivity Moved It Again
A six-month pediatric exclusivity extension, tied to studies BMS and Pfizer conducted at the FDA’s request, pushed the composition patent’s operative date from November 2026 to May 2027 [2]. A separate formulation patent, U.S. Patent 9,326,945, carries its own pediatric-extended expiration of August 24, 2031 [2]. Two patents on the same drug, protecting different aspects of it, now expire nearly five years apart.
Why the Settlement Date Isn’t a Patent Date At All
BMS and Pfizer litigated against the twenty-five Paragraph IV filers in Delaware and West Virginia federal courts starting in April 2017 [17]. Most of those companies settled. Under the settlement terms, the companies that settled are licensed to launch generic apixaban on April 1, 2028 [3][18] — a date that corresponds to neither the composition patent’s May 2027 exclusivity end nor the formulation patent’s 2031 expiration. It is a negotiated number, and it is the number that will actually govern the U.S. apixaban market for most manufacturers.
What Happens If the Litigated Filers Win on Appeal
Four companies — Sigmapharm, Sunshine Lake Pharma, Hec Pharm, and Unichem — did not settle and litigated the formulation patent instead. The District of Delaware ruled both patents valid and infringed in August 2020, and the Federal Circuit affirmed in 2021, meaning those four companies cannot launch before the 2031 formulation-patent date unless they win a future challenge [19][20]. Pfizer’s own 2025 and 2026 Form 10-K filings note that if the formulation patent is later held invalid or not infringed on appeal, both the settled and litigated companies could be permitted to launch as early as November 21, 2026 — nearly a year and a half earlier than the settlement date [1][2].
Timeline: Eliquis’s Compound Patent, 2005 to 2031
Event
Date
Source
Original composition patent (‘208) expiration, pre-extension
Litigated-cohort generic launch date (absent further appeal)
August 24, 2031 (formulation patent expiry)
Pfizer Form 10-K FY2025
Case Study: Revlimid and the Seven-Year Gap Between Expiration and Competition
The 2019 Patent Expiration That Wasn’t a Generic-Entry Date
Revlimid’s (lenalidomide) primary patent expired in 2019 [21]. A spreadsheet built to that date would have flagged 2019 as the year Celgene, later acquired by Bristol Myers Squibb for $74 billion, lost exclusivity. It didn’t. Celgene had already settled with the first Paragraph IV filer, Natco Pharma, in December 2015, agreeing to a volume-capped generic entry starting no earlier than March 2022 and unrestricted entry only as of January 31, 2026 — roughly a year and a half before the drug’s last listed patent was even set to expire [22].
How Volume Caps Turned a Cliff Into a Staircase
Celgene, and later BMS, struck similar volume-capped settlements with Dr. Reddy’s, Sun Pharma, Alvogen, and Cipla [23][24]. Teva launched the first generic lenalidomide in March 2022 under Natco’s license, initially limited to a mid-single-digit percentage of Revlimid’s total volume, rising to roughly 33 percent by March 2025 and to 100 percent — unrestricted — only on January 31, 2026 [8][9]. The Association for Accessible Medicines’ research arm I-MAK has calculated that generic manufacturers were held to no more than 7 percent of the total market when volume-limited entry began in early 2022 [8].
What Happened When the Caps Actually Came Off in January 2026
The uncapped date arrived as scheduled. Accord Healthcare launched an unrestricted generic lenalidomide in the U.S. in February 2026, the first entrant to compete without a volume ceiling [24]. By that point Revlimid’s annual U.S. revenue had already fallen from a $12.8 billion peak in 2021 to roughly $6 billion in 2023, years before uncapped competition began, because even volume-limited generic entry pressures pricing and formulary placement [10]. A spreadsheet tracking only the 2019 “patent expiration” date, or even the 2022 “first generic launch” date, would have missed both the seven-year delay to full competition and the fact that meaningful financial erosion started well before the caps came off.
Revlimid Volume-Cap Ramp, 2022 to 2026
Period
Approximate volume cap
Note
March 2022 (Natco/Teva launch)
Mid-single-digit percentage
First generic entrant, per settlement terms [8][9]
All licensed generics permitted unrestricted volume [8][9]
February 2026
Unrestricted market entry
Accord Healthcare launch confirms caps lifted as scheduled [24]
Case Study: Humira and the Thicket a Single Date Can’t Represent
The 2016 Date on the Label vs. the 2023 Date in the Market
Humira’s foundational U.S. compound patent, the ‘382 patent, expired in 2016 [25]. Ordinarily, that would be the date a biosimilar could enter. AbbVie’s first U.S. biosimilar competitor, Amgen’s Amjevita, did not launch until January 31, 2023 — seven years later [13][14]. The gap exists because AbbVie built a second layer of protection around manufacturing methods, formulations, and dosing regimens that outlasted the compound patent by years, and because the biosimilar makers that eventually settled agreed to delay U.S. launch until 2023 in exchange for earlier entry into European markets [26].
247 Applications, 132 Patents, One Drug
According to research by the Initiative for Medicines, Access & Knowledge, AbbVie filed approximately 247 patent applications related to Humira in the United States and was granted 132 of them [13][14]. Roughly 89 percent of those applications were filed after Humira’s initial 2002 FDA approval, and nearly half were filed in 2014 or later, within two years of the compound patent’s 2016 expiration [27]. The last of the 132 granted patents does not expire until 2034 [28]. A federal district court and, on appeal, the Seventh Circuit both declined to treat the size of that portfolio as an antitrust violation in the consolidated In re Humira litigation, reasoning that patent law sets no cap on how many patents a single company may hold and that AbbVie’s roughly 53 percent application-to-grant success rate was too high to support a claim of sham petitioning [29][30].
Why Humira Still Held Most of the U.S. Market Three Years Later
Biosimilar availability and biosimilar competitiveness turned out to be two different dates as well. Samsung Bioepis market-tracking reports show Humira holding 96 percent of the U.S. adalimumab market as of February 2024, more than a year after the first biosimilar launched [31]. Share slipped to 82 percent by July 2024, largely after CVS Caremark removed branded Humira from its major commercial formularies, and to roughly 72 percent by November 2024 as its Cordavis-branded Sandoz biosimilar Hyrimoz gained formulary placement [32][33][34]. AbbVie’s own February 2026 earnings disclosures put cumulative U.S. Humira erosion at close to $16 billion since biosimilar entry began, even as the company’s broader immunology portfolio posted record annual revenue [35]. None of that erosion pattern — gradual, formulary-driven, still incomplete four years after the compound patent expired — is visible in a spreadsheet cell that reads “2016.”
Humira U.S. Biosimilar Market Share, February 2024 to November 2024
Date
AbbVie (Humira) share
Combined biosimilar share
Source
February 2024
~96%
~4%
Samsung Bioepis report, via BioSpace [31]
July 2024
~82%
~18%
Samsung Bioepis report, via PharmaLive/BioSpace [32][33]
November 2024
~72%
~28%
Samsung Bioepis report, via GuruFocus/Yahoo Finance [34]
How Common Is This? What the Data Shows Across the Industry
Median Patent Thicket Density at Ten Top-Selling Drugs
The 2024 JAMA Internal Medicine cross-sectional study examined the ten U.S. drugs with the highest net sales revenue in 2021, using patent data compiled by I-MAK through June 2022 [5]. Of 465 post-approval patents identified across those ten drugs, 41 percent carried method-of-use claims, 27 percent covered formulations, 22 percent covered manufacturing or synthesis processes, 19 percent covered chemical composition, and 10 percent covered delivery devices [5]. Post-approval patent filing activity was higher for biologics, at 80 percent of all patents, than for small-molecule drugs, at 58 percent [5]. Patent thicket density for these drugs peaked a median of thirteen years after FDA approval — meaning the highest concentration of active patent protection typically arrives more than a decade after launch, not at launch, which is exactly when a spreadsheet built during a drug’s early commercial years is least likely to reflect reality.
The Evergreening Base Rate
Law professor Robin Feldman’s 2018 Journal of Law and the Biosciences study, which examined FDA records from 2005 to 2015, found that 78 percent of drugs associated with newly filed patents in that period were existing drugs rather than newly approved ones [7][36]. Among the roughly 100 best-selling drugs specifically, more than 70 percent had their protection cliff extended at least once and nearly 50 percent had it extended more than once [7]. A separate Yale Law and Policy Review analysis of 236 top-selling drugs found that 91 percent of drugs receiving a patent term extension went on to maintain market exclusivity beyond that extension’s expiration, typically through secondary patents [37].
Claim-Type Breakdown of Post-Approval Patents
Claim type
Share of post-approval patents
Method of use
41%
Formulation
27%
Process or synthesis
22%
Chemical composition
19%
Device
10%
Source: Van de Wiele et al., JAMA Internal Medicine, 2024 [5]. Percentages do not sum to 100 because individual patents may carry claims in more than one category.
When Dates Disappear Instead of Extending: The Orange Book Delisting Risk
The FTC’s Junk-Patent Campaign
Not every deviation from a spreadsheet’s expiration date runs toward a later date. Some run toward an earlier one, or toward the date simply vanishing. The Federal Trade Commission issued a policy statement in September 2023 warning that improper Orange Book listings could constitute unfair competition under Section 5 of the FTC Act, then sent warning letters in November 2023 and April 2024 disputing hundreds of device-related patent listings across companies including AbbVie, AstraZeneca, Boehringer Ingelheim, GlaxoSmithKline, Teva, and Novo Nordisk [38][39].
Teva’s December 2025 Mass Delisting
The Federal Circuit ruled on December 20, 2024, in Teva Branded Pharmaceutical Products R&D v. Amneal Pharmaceuticals that patents claiming only a device component of an inhaler, without claiming the drug’s active ingredient, do not meet the statutory standard for Orange Book listing, and ordered five ProAir HFA patents delisted [40][41]. After the Federal Circuit denied a rehearing in March 2025 and the FTC issued a renewed round of warning letters in May 2025 disputing more than 200 listings across seventeen brand-name products, Teva requested removal of more than 200 patent listings from the Orange Book on December 10, 2025, affecting more than thirty asthma, diabetes, COPD, and epinephrine autoinjector products [42][43][44]. Those patents had listed expiration dates stretching years into the future. As of December 10, 2025, none of those dates matter for Orange Book purposes, because the listings themselves no longer exist.
What Delisting Does to a 30-Month Stay Assumption
An Orange Book listing is what allows a brand company to trigger an automatic 30-month stay against a generic competitor’s approval when a Paragraph IV challenge is filed. Delisting does not invalidate the underlying patent — a brand company can still sue for infringement under ordinary patent law after a generic product launches — but it removes the automatic administrative brake that the listing provided [45]. A spreadsheet that shows a device patent’s 2029 expiration date as a blocking event, built before a company voluntarily withdraws that listing in response to FTC pressure, has been rendered wrong by an event a static export could never anticipate.
Why a Spreadsheet Can’t Hold Any of This
A Spreadsheet Cell Can’t Hold a Conditional
Eliquis alone requires at least four numbers and two conditional branches to describe accurately: a settled-cohort date, a litigated-cohort date, and a fallback date that only applies if a pending appeal succeeds. A single “expiration date” cell forces a false choice among those outcomes.
A Spreadsheet Doesn’t Update When a Court Rules
The Eliquis PTE grant, the Teva v. Amneal delisting order, and the Revlimid volume-cap settlements were each triggered by a specific legal or administrative event with its own date, not by the calendar reaching a pre-set expiration. A static export captures none of these unless someone manually re-checks every listed patent against ongoing litigation dockets, which is precisely the manual re-verification burden a patent-intelligence platform like DrugPatentWatch is built to remove [4].
A Spreadsheet Doesn’t Distinguish Expiration From Competition
Humira’s compound patent expiring in 2016 and Humira facing real biosimilar price pressure are separated by roughly eight years and are, functionally, two different events for forecasting purposes. Revenue models, procurement plans, and formulary strategies keyed to “patent expiration” instead of “meaningful competitive entry” will be systematically early, sometimes by most of a decade.
An Original Taxonomy: Four Ways an Expiration Date Can Be Wrong
Drawing on the cases above, a listed drug patent expiration date can go wrong in one of four distinct ways. This is an original classification developed for this analysis, not an established industry taxonomy.
Type 1 — The Extended Date
Patent term extension or pediatric exclusivity is granted after the patent was first listed, moving the expiration later than the number originally entered in a tracking system. Eliquis’s composition patent moving from an approximately 2023 baseline to November 2026, and then to May 2027, is the clearest example [1][2][15].
Type 2 — The Forked Date
Litigation produces two or more different operative dates for the same drug, depending on which generic applicant is asking. Eliquis again: April 1, 2028 for settled filers, August 24, 2031 for the four companies that litigated instead of settling [3][19][20].
Type 3 — The Hollow Date
A patent expires exactly as listed, but a second layer of protection, whether additional patents, exclusivity, or a negotiated settlement, keeps real competition from starting for years afterward. Revlimid’s 2019-to-2026 gap and Humira’s 2016-to-2023 gap are both Type 3 [21][8][25][13].
Type 4 — The Vanished Date
A listed patent is delisted from the Orange Book, typically after regulatory or judicial pressure, and its expiration date stops being relevant to generic-entry timing altogether, regardless of what the date says. Teva’s December 2025 removal of more than 200 listings is the clearest current example [42][43].
What Happens If You Manage Patent Cliffs by Spreadsheet Anyway
The Forecasting Cost
A revenue model built on Revlimid’s 2019 patent expiration as the loss-of-exclusivity trigger would have been wrong about the timing of full competitive erosion by roughly seven years, and would still have missed the fact that meaningful revenue decline, from a $12.8 billion 2021 peak to about $6 billion by 2023, began years before the volume caps were fully lifted [10]. As an illustrative calculation: if a forecasting model assumes uncapped competitive entry occurs at the date of primary patent expiration rather than at the date volume restrictions actually end, the resulting model misjudges the timing of the drug’s terminal revenue decline by the full multi-year gap between those two dates — in Revlimid’s case, roughly seven years. This figure is a labeled illustrative calculation based on the publicly reported dates above, not an independently reported industry statistic.
The Procurement Cost
Payers and health systems that assume generic or biosimilar price competition begins at the compound patent’s expiration date risk locking in multi-year branded-drug contracts precisely during the years when a thicket, a volume cap, or a settlement is still suppressing real competition, as happened with both Humira and Revlimid.
The Governance Cost
A single expiration date invites a single review event, often an annual or quarterly check-in, rather than continuous monitoring of Orange Book changes, FTC dispute letters, and Paragraph IV litigation dockets. Teva’s 200-plus delistings in December 2025 happened on a single day; a quarterly review cadence could miss the operative change entirely for one full reporting cycle.
What This Means for Generic and Biosimilar Entry Planning
A generic or biosimilar manufacturer planning a launch date needs the settlement date, if one exists, not the underlying patent’s expiration date. Eliquis shows why: the patent expiration dates of November 2026 and August 2031 are both, in practical terms, superseded by the negotiated April 2028 date for most of the market. A launch plan keyed to patent expiration rather than settlement terms would be either years too early or years too conservative depending on which patent it referenced.
What This Means for Brand Portfolio Managers
The Humira and Revlimid cases show that a thicket or a volume-capped settlement buys time, but the FTC’s 2023-to-2025 Orange Book campaign and the Teva v. Amneal precedent show that device-only, non-active-ingredient patents built to extend an Orange Book listing are increasingly vulnerable to delisting regardless of their printed expiration date. A portfolio strategy that relies on quantity of listings rather than the listability of each individual claim carries growing regulatory and litigation risk, as Teva’s December 2025 experience demonstrates directly.
Methodology
This analysis draws on SEC filings (Pfizer and Bristol Myers Squibb Form 10-K and 10-Q disclosures), FDA Orange Book-derived patent expiration data as reported by third-party patent trackers, Federal Trade Commission press releases and policy statements, the Federal Circuit’s December 2024 opinion in Teva Branded Pharmaceutical Products R&D v. Amneal Pharmaceuticals, the Seventh Circuit’s 2022 opinion in the consolidated In re Humira antitrust litigation, and peer-reviewed research published in JAMA Internal Medicine and the Journal of Law and the Biosciences. Case studies were selected because each drug’s patent and exclusivity history is independently documented across multiple primary sources, including company SEC filings, court opinions, and federal agency statements, and because each illustrates a distinct mechanism by which a single listed expiration date diverges from operative market reality. Dates and figures reflect publicly available information as of August 2026. Confidential settlement terms, including exact volume-cap percentages in the Revlimid agreements, are noted as confidential where the underlying source describes them as such rather than presented as precise figures.
Key Takeaways
Eliquis carries at least four distinct dates relevant to generic entry: a composition-patent date extended by patent term extension and pediatric exclusivity to May 2027, a formulation-patent date of August 24, 2031, a settled-cohort launch date of April 1, 2028, and a conditional earlier date that applies only if the formulation patent is later invalidated on appeal.
Revlimid’s primary patent expired in 2019, but unrestricted U.S. generic competition did not begin until January 31, 2026, a seven-year gap bridged by volume-capped settlements.
Humira’s foundational compound patent expired in 2016, the first U.S. biosimilar launched in January 2023, and AbbVie still held roughly 72 percent of the U.S. adalimumab market as of November 2024.
AbbVie’s Humira patent estate includes roughly 132 granted patents from about 247 filed applications, with the last expiring in 2034, eighteen years after the compound patent.
More than 70 percent of the roughly 100 best-selling drugs studied from 2005 to 2015 had their patent protection extended at least once, and nearly half had it extended more than once, according to peer-reviewed research.
Teva’s December 2025 removal of more than 200 Orange Book patent listings, following FTC pressure and the Federal Circuit’s Teva v. Amneal ruling, shows that listed expiration dates can also disappear entirely rather than simply arrive as scheduled.
FAQ
What’s the difference between a patent’s expiration date and a drug’s loss-of-exclusivity date?
A patent’s expiration date is a fixed legal endpoint for one specific claim. A drug’s practical loss of exclusivity is the date real competitive entry begins, which depends on every patent covering the drug, any regulatory exclusivity still running, and any settlement terms negotiated with generic or biosimilar challengers. For Revlimid, the patent expired in 2019 but practical loss of exclusivity did not arrive until January 2026 [21][8].
Can a drug’s patent expiration date change after it’s already listed in the Orange Book?
Yes. Patent term extension and pediatric exclusivity can both extend a listed date after the fact, as happened with Eliquis’s composition patent, which moved from an approximately 2023 baseline to November 2026 and then to May 2027 [1][2][15].
How much can patent term extension add to a drug patent’s life?
Under 35 U.S.C. § 156, patent term extension can add up to five years, and the extended patent cannot remain in effect for more than fourteen years from the drug’s approval date [15]. Eliquis received an extension of this type in August 2017 [15].
Does pediatric exclusivity apply automatically?
No. It is granted when the FDA requests pediatric studies and the manufacturer completes them, adding a flat six months to whichever exclusivity or patent term is running at the time [6]. It applied to both of Eliquis’s listed patents [2].
Why did Eliquis end up with four different expiration dates?
Two separate patents cover different aspects of the drug and were extended differently, and litigation produced a negotiated settlement date that applies to most generic filers while four companies that continued litigating remain bound by the formulation patent’s later date [1][2][3][19].
Why didn’t Humira lose most of its market share the same year biosimilars launched?
AbbVie’s roughly 132-patent portfolio delayed the first U.S. biosimilar launch until January 2023, seven years after the compound patent expired, and even after launch, formulary access and payer contracting delayed meaningful share loss for another year or more, with AbbVie still holding about 72 percent of the market as of November 2024 [13][14][31][34].
What is Orange Book patent delisting and why does it matter for a spreadsheet-based tracker?
Delisting removes a patent from the FDA’s Orange Book, eliminating the automatic 30-month litigation stay tied to that listing, regardless of the patent’s printed expiration date. Teva’s December 2025 removal of more than 200 listings shows this can happen suddenly, in response to regulatory pressure, rather than on the calendar date a static spreadsheet would show [42][43].
Is a settlement date the same thing as a patent expiration date?
No. A settlement date is a privately negotiated launch date that may fall before or after any listed patent’s expiration. Eliquis’s April 1, 2028 settled-cohort date matches neither of its two listed patent expiration dates [3][19].
How often do top-selling drugs get their patent protection extended?
More than 70 percent of roughly 100 best-selling drugs studied over a 2005-to-2015 period had protection extended at least once, and nearly half had it extended more than once, according to a 2018 peer-reviewed study [7].
What should replace a static expiration-date spreadsheet?
Continuous monitoring of Orange Book changes, patent term extension grants, pediatric exclusivity awards, Paragraph IV litigation dockets, and FTC delisting activity, ideally through a platform such as DrugPatentWatch built to track those changes as they occur rather than as a periodic manual export [4].
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