DAYPRO Drug Patent Profile

When do Daypro patents expire, and what generic alternatives are available?

Daypro is a drug marketed by Pfizer and is included in two NDAs.

The generic ingredient in DAYPRO is oxaprozin potassium. There are thirteen drug master file entries for this compound. Additional details are available on the oxaprozin potassium profile page.

Summary for DAYPRO

US Patents:	0
Applicants:	1
NDAs:	2

US Patents and Regulatory Information for DAYPRO

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Pfizer	DAYPRO	oxaprozin	TABLET;ORAL	018841-004	Oct 29, 1992	AB	RX	Yes	Yes
Pfizer	DAYPRO ALTA	oxaprozin potassium	TABLET;ORAL	020776-001	Oct 17, 2002		DISCN	No	No

Daypro (Oxaprozin) Investment Scenario and Pharmaceutical Fundamentals Analysis

Last updated: August 1, 2026

Daypro is the former branded product for oxaprozin, a once-daily nonsteroidal anti-inflammatory drug (NSAID) approved for osteoarthritis and rheumatoid arthritis. Its commercial patent and regulatory exclusivity have expired, and the market is supplied primarily through generic oxaprozin tablets. The investment case is therefore based on generic manufacturing economics, supply reliability, pricing discipline, and the broader NSAID market rather than branded Daypro growth.

What is Daypro and how does oxaprozin work?

Daypro contains oxaprozin, a propionic-acid NSAID. It inhibits cyclooxygenase-mediated prostaglandin synthesis and reduces inflammation, pain, and fever. The U.S. label identifies osteoarthritis and rheumatoid arthritis as the approved indications (U.S. Food and Drug Administration [FDA], 2023).

Oxaprozin differs from many commonly used NSAIDs because it has a relatively long half-life, allowing once-daily dosing in adults. The approved tablet strengths are generally 600 mg and 1,200 mg, with dosing determined by the indication, patient response, and safety considerations.

What are the principal Daypro safety risks?

The product carries the class-wide NSAID boxed warnings for:

• Serious cardiovascular thrombotic events, including myocardial infarction and stroke.
• Gastrointestinal bleeding, ulceration, and perforation.
• Renal toxicity and fluid retention.
• Hypertension and heart failure exacerbation.
• Serious skin reactions and anaphylactoid reactions.
• Fetal harm when used during later pregnancy.

These warnings limit the drug's use in patients with cardiovascular, renal, gastrointestinal, and pregnancy-related risk factors. Oxaprozin also has drug-interaction risks involving anticoagulants, antiplatelet agents, corticosteroids, selective serotonin reuptake inhibitors, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, diuretics, lithium, methotrexate, and cyclosporine (FDA, 2023).

When did Daypro lose exclusivity?

Daypro lost meaningful U.S. market exclusivity after the expiration of its original patent and the availability of generic oxaprozin. The NDA was approved in 1992, and the product's five-year new chemical entity exclusivity would have ended in 1997 under the Hatch-Waxman framework, absent a later qualifying regulatory extension (FDA, 1992; U.S. Congress, 1984).

Milestone	Approximate timing	Investment significance
FDA approval of Daypro	1992	Established oxaprozin as an approved U.S. NSAID
New chemical entity exclusivity	Through approximately 1997	Blocked abbreviated generic approval during the statutory exclusivity period
Generic oxaprozin entry	Following patent and exclusivity expiry	Shifted economics from branded sales to commodity generics
Present market position	Generic-dominated	Limited value attributable to the Daypro brand

The original Daypro commercial opportunity is no longer protected by a durable U.S. exclusivity position. Any remaining patent rights would need to be evaluated at the specific product, formulation, and jurisdiction level. The core oxaprozin active-ingredient opportunity is mature.

What is the Orange Book status of Daypro?

The FDA Orange Book identifies approved drug products and relevant patent and exclusivity information. Daypro's regulatory history is tied to NDA 019959. The commercial product has been overtaken by generic oxaprozin products, and no current branded Daypro exclusivity position provides a credible barrier to generic substitution.

The practical Orange Book conclusion is:

Question	Assessment
Is Daypro a protected new chemical entity?	No
Does the core product have current branded exclusivity?	No material U.S. exclusivity remains
Are generic oxaprozin products available?	Yes
Is the principal commercial barrier regulatory exclusivity?	No
Is a current branded launch protected from substitution?	No

Orange Book status should be reviewed against the current FDA edition before making a transaction or litigation decision because listing status, discontinued-NDA treatment, and patent records can change.

What patents protect Daypro and oxaprozin?

The commercial value of Daypro's original active-ingredient patent estate has ended. The relevant patent categories are:

1. Oxaprozin composition-of-matter patents.
2. Pharmaceutical formulation patents.
3. Manufacturing or process patents.
4. Method-of-use patents.
5. Pediatric or regulatory exclusivity rights.

The first category created the original commercial moat. It is no longer a meaningful barrier to generic oxaprozin. Formulation, process, or method patents would have value only if they covered a commercially important product and remained enforceable in the relevant jurisdiction.

Are formulation patents protecting Daypro?

No durable, high-value formulation moat is apparent for the conventional immediate-release oxaprozin tablet market. Daypro is a conventional oral tablet rather than a complex delivery system such as a long-acting injectable, transdermal patch, inhaled formulation, or antibody formulation.

A generic manufacturer generally does not need to reproduce the branded manufacturing process. Under the ANDA pathway, it must demonstrate pharmaceutical equivalence and bioequivalence to the reference product and comply with current good manufacturing practice requirements (FDA, 2024a).

Are method-of-use patents relevant to oxaprozin?

Method-of-use patents could theoretically cover a specific patient population, dosing regimen, or disease application. Their commercial impact is limited where:

• The core indication is already genericized.
• The prescribing information is broad and established.
• Physicians can use other NSAIDs.
• The product has no differentiated delivery or monitoring system.
• The remaining patient population is price sensitive.

No known method-of-use position creates a material barrier to routine generic oxaprozin prescribing.

How many patents cover Daypro today?

The number of historical patents associated with Daypro is not the same as the number of enforceable patents that can block generic competition. The relevant commercial count is effectively zero for the core U.S. tablet product.

Patent analysis should distinguish among:

Patent category	Current commercial relevance
Expired composition patents	No blocking value
Expired formulation patents	No blocking value
Expired manufacturing patents	No blocking value
Active method patents	Potentially relevant only if enforceable and commercially material
Orange Book-listed patents	Must be verified against the current FDA listing
Foreign patents	May affect local markets but not U.S. entry

A patent family can remain visible in databases after its enforceable term has ended. Historical publication or assignment data should not be treated as continuing exclusivity.

Which companies are challenging Daypro exclusivity?

Generic manufacturers are not required to challenge a meaningful current Daypro exclusivity position because the product is already mature and generic oxaprozin is commercially available. The relevant competitive set consists of ANDA holders and contract manufacturers selling oxaprozin tablets.

The market includes generic suppliers operating through:

• Approved ANDA ownership.
• Contract manufacturing arrangements.
• National wholesalers.
• Retail pharmacy channels.
• Institutional purchasing organizations.

The identity and active market share of suppliers can change as products are discontinued, acquired, or removed from distribution. The FDA Orange Book and current commercial wholesaler data are the appropriate sources for a live supplier count (FDA, 2024b).

What is the FDA regulatory status of Daypro?

Daypro was approved through the conventional NDA pathway. Generic oxaprozin products use the ANDA pathway. The FDA's regulatory framework requires generic products to demonstrate pharmaceutical equivalence and bioequivalence, not to repeat the full clinical development program required for the original NDA.

Regulatory issue	Daypro and oxaprozin status
Original pathway	NDA
Generic pathway	ANDA
Active ingredient	Oxaprozin
Dosage form	Oral tablet
Primary indications	Osteoarthritis and rheumatoid arthritis
Therapeutic class	NSAID
Biosimilar pathway	Not applicable
Reference-product advantage	Historical only

Does Daypro face biosimilar risk?

No. Biosimilars apply to biological products, including therapeutic proteins, monoclonal antibodies, and other biologics. Oxaprozin is a chemically synthesized small-molecule drug. Competition occurs through generic substitution under the ANDA framework, not through biosimilar approval under the Biologics Price Competition and Innovation Act (FDA, 2024c).

Are there Paragraph IV challenges involving Daypro?

Paragraph IV certifications are most relevant when an ANDA applicant seeks approval before expiration of an Orange Book-listed patent. Because oxaprozin is already genericized and the original exclusivity has expired, Paragraph IV litigation is not the primary current risk or value driver.

Any historical Paragraph IV filing would have been relevant to the timing of generic entry. It does not create current branded value after the product's generic transition. A live litigation review would need to examine federal court dockets, FDA patent listings, and ANDA-specific records.

What patent litigation affects Daypro?

Daypro does not have a widely recognized current patent litigation profile comparable with high-value branded drugs in oncology, immunology, diabetes, or rare disease. The litigation risk is primarily commercial and operational:

• Product-liability claims involving NSAID gastrointestinal or cardiovascular risks.
• Manufacturing or quality disputes.
• Supply contracts and distribution terms.
• Trademark issues involving the Daypro name.
• Potential disputes over generic product quality or labeling.

Product liability is more relevant than patent litigation because the known safety risks are tied to the pharmacology of NSAIDs and the approved label.

How strong is the Daypro patent estate?

The Daypro patent estate is weak as an investment asset because the original market exclusivity has expired and the product has no obvious complex formulation barrier.

Patent-strength factor	Assessment
Remaining composition-of-matter protection	Low to none
Formulation differentiation	Low
Manufacturing complexity	Low to moderate
Regulatory switching cost	Low
Generic substitution resistance	Low
Ability to sustain premium pricing	Low
Litigation leverage	Low
Geographic value	Dependent on local patent status

The technical manufacturing process is not necessarily trivial. Oxaprozin manufacturers must control impurity profiles, assay, dissolution, stability, tablet compression, packaging, and batch consistency. These requirements can exclude weak operators, but they do not create branded pricing power.

What generic entry risks exist for Daypro?

Generic entry is no longer a future risk. It is the current market structure. The key risks for an oxaprozin manufacturer are:

1. Price erosion from multiple ANDA suppliers.
2. Low prescription volume relative to high-volume NSAIDs.
3. Wholesaler and pharmacy concentration.
4. Product discontinuation if margins fall below manufacturing cost.
5. FDA inspection or warning-letter exposure.
6. API supply interruptions.
7. Demand substitution toward ibuprofen, naproxen, diclofenac, celecoxib, meloxicam, and topical NSAIDs.
8. Reimbursement restrictions and formulary exclusion.

Oxaprozin has a narrower market than common over-the-counter NSAIDs. That can reduce direct competition among suppliers, but it also limits scale and makes a single manufacturing or customer loss more significant.

What is the investment scenario for Daypro?

Base case: mature generic product

The base case is a low-growth, low-margin generic market. Revenue comes from oxaprozin tablets rather than branded Daypro. A manufacturer with an approved ANDA, dependable API sourcing, and limited competition may earn stable cash flow, but the asset does not justify a branded pharmaceutical valuation multiple.

Upside case: supply-constrained niche generic

An upside scenario could arise if competing manufacturers discontinue the product, an API supplier exits, or a major supplier experiences a quality problem. A remaining supplier could obtain temporary pricing improvement. This upside would be supply-driven and reversible, not protected by intellectual property.

Downside case: commodity-price erosion

The downside case is continued price compression, reimbursement pressure, and declining prescriptions. If two or more suppliers maintain availability, price competition can eliminate excess margin. The brand name has limited ability to prevent generic substitution.

Strategic case: portfolio filler

Oxaprozin may have value inside a broader generic portfolio. Its value can include:

• Manufacturing-line utilization.
• Customer retention.
• Bundled pharmacy contracts.
• Incremental revenue from existing distribution.
• Diversification from more concentrated products.

As a standalone acquisition, the product would require a low purchase price and clear evidence of sustainable net pricing.

How does Daypro compare with competing NSAIDs?

Product	Active ingredient	Market position	Differentiation
Daypro/generic oxaprozin	Oxaprozin	Mature prescription generic	Once-daily dosing and long half-life
Naprosyn/generic naproxen	Naproxen	Large generic market	Broad use and extensive physician familiarity
Motrin/generic ibuprofen	Ibuprofen	Large OTC and prescription market	Low cost and broad availability
Voltaren/generic diclofenac	Diclofenac	Large global generic market	Oral and topical formulations
Celebrex/generic celecoxib	Celecoxib	Prescription COX-2 market	COX-2 selectivity and differentiated label
Mobic/generic meloxicam	Meloxicam	Mature prescription generic	Once-daily dosing
Aleve/naproxen sodium	Naproxen sodium	Major OTC product	Strong consumer distribution

Oxaprozin's once-daily schedule is commercially useful but not sufficiently differentiated to support a durable premium against generic alternatives.

What is the revenue exposure to Daypro?

The original branded Daypro revenue opportunity is no longer a significant standalone investment driver. Public-company exposure is more likely to arise through a diversified generic manufacturer, contract manufacturer, or distributor than through ownership of a high-value branded asset.

Revenue analysis should focus on:

• Net sales by oxaprozin strength.
• Prescription volume and refill persistence.
• Average selling price after rebates.
• Number of active suppliers.
• API cost as a percentage of net sales.
• Gross margin after manufacturing and distribution.
• Customer concentration.
• Product discontinuation probability.

A supplier with low fixed costs and existing tablet capacity can generate acceptable contribution margin even at modest volume. A dedicated facility or specialized inventory structure would make the economics less attractive.

What geographic coverage does the Daypro patent estate have?

The U.S. patent estate is commercially expired for the original product. Foreign patent status depends on the country, filing history, patent-term adjustments, supplementary protection certificates, and local generic competition. Given the age of the product, meaningful active composition protection in major markets is unlikely.

International commercial value may still arise from:

• Local registration status.
• Weak generic competition.
• Government procurement contracts.
• Distribution rights.
• Local manufacturing capacity.
• Country-specific reimbursement.

Geographic patent coverage should not be confused with regulatory or commercial access. A country may have no active patent barrier but still lack approved generic supply.

What licensing deals affect Daypro?

Daypro's historical commercialization involved the original NDA holder and successor pharmaceutical companies. Those legacy arrangements do not create a current strategic licensing moat for oxaprozin. Any present licensing value would be tied to:

• Generic product rights.
• Regional marketing authorization.
• Supply agreements.
• API sourcing.
• Trademark rights.
• Portfolio bundling.

A transaction involving Daypro should assign little value to historical brand licensing unless the agreement includes enforceable territorial rights, guaranteed supply, or material distribution access.

What settlement agreements affect oxaprozin?

No current settlement structure is a central value driver for the generic oxaprozin market. Historical generic-entry settlements, if any, would have been relevant during the original patent challenge period. They should be analyzed for release terms, launch dates, authorized-generic provisions, and damages exposure, but they do not restore present exclusivity.

Key Takeaways

• Daypro is the former brand for oxaprozin, a prescription NSAID.
• U.S. exclusivity and core patent protection have expired.
• Generic oxaprozin is the relevant commercial market.
• No biosimilar pathway applies because oxaprozin is a small molecule.
• Current investment value depends on manufacturing cost, supply continuity, customer concentration, and generic pricing.
• Formulation and method-of-use patents do not appear to create a material current barrier for conventional oxaprozin tablets.
• Patent litigation is less important than product liability, FDA compliance, reimbursement, and supply-chain risk.
• The strongest investment case is as a low-cost portfolio product or supply-constrained niche generic.
• The weakest case is a standalone branded acquisition premised on restoring Daypro pricing power.

FAQs About Daypro and Oxaprozin Investment Risk

Is Daypro still sold as a branded drug?

Generic oxaprozin is the commercially relevant U.S. product. The historical Daypro brand no longer has the exclusivity profile of a protected branded medicine.

Can a generic manufacturer still earn attractive margins on oxaprozin?

Yes, but only under favorable supply conditions. Margins depend on active supplier count, API cost, contract pricing, and the manufacturer's fixed-cost base.

Does oxaprozin have a patent-protected extended-release formulation?

The principal market is conventional oral oxaprozin tablets. No widely recognized current extended-release formulation moat supports a branded investment thesis.

Is oxaprozin safer than naproxen or ibuprofen?

Oxaprozin carries the major NSAID class risks, including cardiovascular, gastrointestinal, renal, and pregnancy-related warnings. Its once-daily dosing does not eliminate those risks.

Is Daypro a potential specialty-pharmaceutical acquisition?

Generally no. Its commercial profile is that of a mature generic or legacy brand. A specialty-pharmaceutical valuation would require a separate, enforceable product or distribution advantage.

References

1. Food and Drug Administration. (1992). Daypro (oxaprozin) approval history and prescribing information, NDA 019959. U.S. Department of Health and Human Services.

2. Food and Drug Administration. (2023). Oxaprozin prescribing information. U.S. Department of Health and Human Services.

3. Food and Drug Administration. (2024a). Abbreviated new drug application (ANDA) process. U.S. Department of Health and Human Services.

4. Food and Drug Administration. (2024b). Approved drug products with therapeutic equivalence evaluations: Orange Book. U.S. Department of Health and Human Services.

5. Food and Drug Administration. (2024c). Biosimilar and interchangeable biosimilar products. U.S. Department of Health and Human Services.

6. U.S. Congress. (1984). Drug Price Competition and Patent Term Restoration Act of 1984, Pub. L. No. 98-417, 98 Stat. 1585.