ASPIRIN AND DIPYRIDAMOLE Drug Patent Profile

Which patents cover Aspirin And Dipyridamole, and what generic alternatives are available?

Aspirin And Dipyridamole is a drug marketed by Amneal Pharms, Ani Pharms, Barr, Chartwell Molecular, Dr Reddys, Glenmark Speclt, Micro Labs, Ph Health, Sandoz, Sun Pharm, and Zydus Pharms. and is included in eleven NDAs.

The generic ingredient in ASPIRIN AND DIPYRIDAMOLE is aspirin; dipyridamole. There is one drug master file entry for this compound. Nine suppliers are listed for this compound. Additional details are available on the aspirin; dipyridamole profile page.

DrugPatentWatch^® Litigation and Generic Entry Outlook for Aspirin And Dipyridamole

A generic version of ASPIRIN AND DIPYRIDAMOLE was approved as aspirin; dipyridamole by BARR on August 14^th, 2009.

Summary for ASPIRIN AND DIPYRIDAMOLE

US Patents:	0
Applicants:	11
NDAs:	11
Finished Product Suppliers / Packagers:	9
Clinical Trials:	25
What excipients (inactive ingredients) are in ASPIRIN AND DIPYRIDAMOLE?	ASPIRIN AND DIPYRIDAMOLE excipients list
DailyMed Link:	ASPIRIN AND DIPYRIDAMOLE at DailyMed

Recent Clinical Trials for ASPIRIN AND DIPYRIDAMOLE

Identify potential brand extensions & 505(b)(2) entrants

Sponsor	Phase
Rutgers, The State University of New Jersey	Phase 3
Région Hauts de France, France	Phase 3
Ministry of Health, France	Phase 3

See all ASPIRIN AND DIPYRIDAMOLE clinical trials

Pharmacology for ASPIRIN AND DIPYRIDAMOLE

Drug Class	Nonsteroidal Anti-inflammatory Drug Platelet Aggregation Inhibitor
Mechanism of Action	Cyclooxygenase Inhibitors
Physiological Effect	Decreased Platelet Aggregation Decreased Prostaglandin Production

US Patents and Regulatory Information for ASPIRIN AND DIPYRIDAMOLE

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Amneal Pharms	ASPIRIN AND DIPYRIDAMOLE	aspirin; dipyridamole	CAPSULE, EXTENDED RELEASE;ORAL	206392-001	Mar 8, 2016	AB	RX	No	No
Micro Labs	ASPIRIN AND DIPYRIDAMOLE	aspirin; dipyridamole	CAPSULE, EXTENDED RELEASE;ORAL	209929-001	Aug 11, 2021	AB	RX	No	No
Chartwell Molecular	ASPIRIN AND DIPYRIDAMOLE	aspirin; dipyridamole	CAPSULE, EXTENDED RELEASE;ORAL	204552-001	Mar 20, 2019		DISCN	No	No

Aspirin and Dipyridamole Market Dynamics, Patent Expiry, Generic Entry, and Financial Trajectory

Last updated: September 27, 2026

Aspirin and extended-release dipyridamole is an established antiplatelet combination sold in the United States under the brand Aggrenox. The product contains aspirin 25 mg and extended-release dipyridamole 200 mg per capsule and is administered twice daily to reduce the risk of stroke in patients with prior transient ischemic attack or ischemic stroke.

The commercial profile has shifted from branded growth to mature generic competition. Core U.S. patent protection has expired, FDA-approved generic products are available, and the combination faces price erosion from low-cost alternatives. The market remains clinically relevant because the product has a defined secondary stroke-prevention indication, but its financial trajectory is constrained by generic substitution, low-cost aspirin alternatives, and competition from clopidogrel and other antiplatelet regimens.

What is aspirin and dipyridamole used for?

Aspirin and extended-release dipyridamole is used for secondary prevention of ischemic stroke and transient ischemic attack. Aspirin inhibits platelet cyclooxygenase and thromboxane-mediated platelet activation. Dipyridamole inhibits platelet aggregation through phosphodiesterase inhibition and increases platelet cyclic AMP.

The U.S. prescribing information recommends one capsule twice daily, approximately 12 hours apart. The product is not indicated for acute treatment of stroke, myocardial infarction, or unstable coronary disease. The primary commercial product is:

Product	Active ingredients	Strength	Dosage form	Original U.S. sponsor
Aggrenox	Aspirin and extended-release dipyridamole	25 mg/200 mg	Extended-release capsule	Boehringer Ingelheim
Generic equivalents	Aspirin and extended-release dipyridamole	25 mg/200 mg	Extended-release capsule	Multiple ANDA sponsors

The combination was supported by the European Stroke Prevention Study 2, which evaluated dipyridamole, aspirin, and the combination in patients with prior stroke or transient ischemic attack. The FDA approved Aggrenox in 1999 for secondary stroke prevention.[1][2]

How large is the aspirin and dipyridamole market?

The market is a mature, low-growth prescription segment dominated by generic products. Public companies do not consistently report revenue for aspirin and extended-release dipyridamole as a distinct product category. Aggrenox sales were historically material for Boehringer Ingelheim’s cardiovascular portfolio, but the product is no longer a significant growth asset after U.S. patent expiry and generic entry.

Market size is difficult to measure because:

• Aspirin and dipyridamole are reported as separate molecules in some commercial datasets.
• Generic suppliers may report the product within broader cardiovascular portfolios.
• Retail prices vary sharply by payer, channel, manufacturer, and generic availability.
• Many patients receive aspirin monotherapy or clopidogrel rather than the fixed-dose combination.
• Boehringer Ingelheim is privately held and does not publish comprehensive brand-level revenue for Aggrenox.

The commercial market therefore has two different measures: prescription volume and branded revenue. Prescription demand remains relatively stable because secondary stroke prevention is a continuing clinical need. Revenue has declined because generic products capture volume at substantially lower prices.

When did Aggrenox lose market exclusivity?

Aggrenox lost practical U.S. market exclusivity after expiration of the principal patent estate and subsequent approval of generic products. The original product’s commercial protection was based on formulation and combination claims rather than composition-of-matter protection for the active ingredients, which had been known for decades.

U.S. exclusivity timeline

Milestone	Approximate date	Commercial effect
FDA approval of Aggrenox	1999	Launch of branded fixed-dose combination
Brand formulation patent litigation and Orange Book protection	2000s-early 2010s	Delayed or contested generic entry
Core U.S. patent expiry	Mid-2010s	Removal of major patent barrier
First generic approvals	2015 onward	Entry of ANDA products
Mature generic market	Late 2010s-present	Price compression and multi-source competition

The exact commercial loss-of-exclusivity date depends on the specific patent, pediatric exclusivity, and generic approval sequence. The practical conclusion is that Aggrenox no longer has meaningful U.S. market exclusivity.

What patents protect aspirin and dipyridamole?

The relevant patent estate primarily protected the combination’s extended-release delivery design and dosage form. Aspirin and dipyridamole themselves are established active ingredients with no remaining basic composition-of-matter exclusivity.

The key patent issues historically involved:

1. The combination of immediate-release aspirin with extended-release dipyridamole.
2. Controlled or sustained release of dipyridamole.
3. Capsule composition and release characteristics.
4. Methods for preventing recurrent ischemic events.
5. Manufacturing processes capable of producing the required release profile.

The principal U.S. patent commonly associated with Aggrenox was U.S. Patent No. 5,616,793, covering aspects of the aspirin and extended-release dipyridamole combination. The patent was assigned to Boehringer Ingelheim entities and was listed in FDA’s Orange Book during the product’s protected period.[3]

Because the formulation patents have expired, current competitive differentiation depends more on regulatory approval, manufacturing consistency, supply reliability, and payer contracting than on enforceable exclusivity.

What is the Orange Book status of aspirin and dipyridamole?

The FDA Orange Book historically listed Aggrenox patents covering the product’s formulation and method of use. Those listings supported patent certifications in abbreviated new drug applications, including Paragraph IV certifications where applicants asserted that listed patents were invalid, unenforceable, or would not be infringed.

For current commercial purposes, the Orange Book is more important as a historical record than as an active barrier. The branded product does not have a durable patent position capable of preventing generic competition.

The most relevant regulatory characteristics are:

Regulatory issue	Status
FDA-approved reference product	Aggrenox
Approval pathway for generics	ANDA under section 505(j)
Therapeutic equivalence	Demonstrated through FDA generic approval standards
Biosimilar pathway	Not applicable
Active composition patent	None of practical commercial significance
Formulation patent barrier	Expired
Current exclusivity	No meaningful branded exclusivity

Which companies challenged the Aggrenox patent estate?

Generic competition emerged through ANDA filings by multiple manufacturers. Dr. Reddy’s Laboratories was among the companies associated with early U.S. generic entry. Other generic suppliers have included major manufacturers and labelers active in cardiovascular medicines, although product availability has varied over time.

Paragraph IV litigation was relevant before generic entry because an ANDA applicant could trigger patent litigation by certifying that a listed patent was invalid, unenforceable, or not infringed. A patent infringement action could impose a statutory 30-month stay on FDA approval, subject to the governing provisions and litigation outcome.[4]

The commercial importance of the litigation declined after the relevant patents expired. Current market access depends primarily on FDA approval, supply capacity, wholesaler distribution, and reimbursement.

What formulations are protected by aspirin and dipyridamole patents?

The commercial formulation is technically more difficult than a simple co-packaged aspirin and dipyridamole product. Aggrenox combines:

• Immediate-release aspirin.
• Extended-release dipyridamole.
• A capsule designed to deliver the two components in a specified release pattern.
• Manufacturing controls intended to preserve dissolution and dose uniformity.

The formulation created a regulatory barrier because generic applicants had to demonstrate pharmaceutical equivalence and bioequivalence to the reference product. That barrier delayed simple substitution compared with unformulated aspirin, but it did not produce permanent protection.

Generic manufacturers must reproduce the relevant quality attributes, including:

• Active-ingredient identity and strength.
• Dissolution profile.
• Release characteristics for dipyridamole.
• Impurity limits.
• Stability.
• Capsule performance.
• Bioequivalence under FDA requirements.

These requirements create manufacturing complexity but not a durable legal moat.

How does aspirin and dipyridamole compare with clopidogrel?

Clopidogrel is the main commercial comparator in secondary stroke prevention. Aspirin monotherapy is less expensive and remains widely used. The choice among therapies depends on prior stroke characteristics, bleeding risk, tolerance, clinical guidelines, and physician preference.

Attribute	Aspirin/dipyridamole ER	Clopidogrel	Aspirin alone
Primary use	Secondary stroke prevention	Secondary prevention across atherosclerotic disease	Broad antiplatelet prevention
Dosing	Twice daily	Once daily	Usually once daily
Formulation	Fixed-dose combination	Single active ingredient	Single active ingredient
Generic availability	Yes	Yes	Yes
Cost profile	Low after generic entry, but higher than aspirin alone	Low generic cost	Lowest cost
Key tolerability issue	Headache, gastrointestinal effects	Bleeding, drug interaction considerations	Gastrointestinal bleeding
Commercial differentiation	Limited	Broader cardiovascular use	Price and familiarity

The combination’s twice-daily regimen and dipyridamole-associated headache can reduce adherence relative to once-daily clopidogrel. Its main competitive support is the evidence base for recurrent stroke prevention rather than pricing power.

What is the FDA regulatory status?

Aggrenox is FDA-approved for reduction of the risk of stroke in patients who have experienced a previous stroke or transient ischemic attack. Generic versions are approved through the ANDA pathway and must demonstrate equivalence to the reference listed drug.

The combination is not a biologic and has no biosimilar exposure. The regulatory risks are conventional generic-drug risks:

• Manufacturing deviations.
• Dissolution or release-profile failures.
• Drug shortages.
• Labeling differences.
• Product recalls.
• Changes in supplier qualification.
• FDA inspection findings.

Because both active ingredients are well established, regulatory risk is lower than for a new chemical entity. Manufacturing quality remains important because the product relies on differentiated release characteristics.

What generic entry risks affect the market?

Generic entry has produced the main commercial change: lower net pricing and reduced branded share. The risk to the originator is effectively complete in the U.S. unless the brand retains a contractual, supply, or distribution advantage.

The principal generic-entry effects are:

1. Rapid substitution after multiple ANDA approvals.
2. Pharmacy purchasing based on lowest available acquisition cost.
3. Reduced physician influence over product selection.
4. Lower reimbursement ceilings.
5. Greater vulnerability to supply interruptions.
6. Limited ability to sustain premium pricing through formulation differentiation.

A generic launch can produce a temporary price premium if only one or two suppliers are available. That premium usually erodes as additional manufacturers enter. The market can also experience intermittent price increases when suppliers withdraw or face manufacturing problems, but those increases are supply-driven rather than evidence of durable market power.

What is the financial trajectory for aspirin and dipyridamole?

The financial trajectory has four stages:

Branded growth

Aggrenox benefited from a differentiated fixed-dose combination and a defined stroke-prevention indication. Revenue expanded while the product had patent protection and limited direct generic competition.

Patent litigation and delayed generic entry

Patent certifications and infringement litigation protected the brand’s commercial position during the late life-cycle period. Revenue remained supported by prescription demand and branded reimbursement.

Generic launch and rapid price erosion

After FDA-approved generic products entered, the brand lost negotiating leverage. Gross-to-net pressure increased, pharmacy substitution accelerated, and revenue declined.

Mature generic stabilization

The product now has recurring prescription demand but limited pricing power. Financial value is concentrated in manufacturing efficiency, supply reliability, and portfolio fit rather than patent exclusivity.

The expected long-term market pattern is stable or modestly declining volume, falling average selling prices, and low single-digit or negative revenue growth for suppliers that lack a cost or supply advantage. The product can remain profitable for efficient generic manufacturers because the active ingredients are inexpensive and clinical demand persists.

What patent litigation and settlement agreements affect the product?

Historical litigation centered on Orange Book-listed formulation patents and ANDA Paragraph IV certifications. These disputes were commercially important before generic approval but have limited current impact because the principal patent barriers have expired.

Settlement agreements in the generic pharmaceutical sector can include:

• A licensed entry date before patent expiry.
• Restrictions on launch timing.
• Agreements covering authorized generic supply.
• Resolution of patent infringement claims without a final invalidity decision.

The economic effect of any historical settlement was to determine the timing of generic launch. It does not restore current exclusivity for the combination.

What geographic coverage does the patent estate have?

The former commercial patent position was strongest in the United States, where Orange Book listing and Hatch-Waxman litigation can delay ANDA approval. European and other jurisdictions applied separate national patent and regulatory rules.

Current geographic conditions are:

Region	Current commercial position
United States	Mature generic market
European Union	Generic or multisource market, subject to national authorization and reimbursement
Japan	Separate regulatory and reimbursement environment
Emerging markets	Price-sensitive market with variable generic penetration
Global	Limited opportunity for premium branded pricing

The absence of active U.S. patent protection does not eliminate country-specific manufacturing, registration, or supply barriers. It does mean that geographic expansion is principally a regulatory and commercial exercise rather than a patent-led strategy.

How strong is the patent estate for aspirin and dipyridamole?

The current patent estate is weak as a commercial defense. The product retains technical differentiation through its modified-release formulation, but the legal exclusivity that once protected that formulation has expired.

Patent-strength factor	Assessment
Active-ingredient protection	Exhausted
Core formulation patents	Expired
Method-of-use protection	No material current barrier
Manufacturing know-how	Moderate operational value
Regulatory complexity	Moderate
Generic substitution risk	High
Long-term pricing power	Low
Biosimilar risk	Not applicable

The residual competitive advantage lies in cost, quality, dependable supply, and distribution. New patent value would require a genuinely differentiated formulation, indication, or delivery system rather than a repackaging of the existing combination.

What generic launch scenarios exist?

The market has three practical scenarios:

Multi-source generic competition

This is the base case. Multiple suppliers compete, prices remain low, and the brand retains limited share.

Supply-constrained pricing

If one or more manufacturers exit, prices can rise temporarily. The increase is vulnerable to new entry and does not represent durable exclusivity.

Reformulated or improved delivery product

A new product with once-daily dosing, improved tolerability, or a clinically meaningful adherence benefit could pursue separate intellectual-property protection. Commercial success would require evidence that the improvement justifies a premium over low-cost generic therapy.

Key Takeaways

• Aspirin and extended-release dipyridamole is an established secondary stroke-prevention combination marketed originally as Aggrenox.
• The FDA-approved strength is aspirin 25 mg plus extended-release dipyridamole 200 mg, taken twice daily.
• Aggrenox’s U.S. formulation and method-of-use patent protection has expired.
• Generic entry began in the mid-2010s and materially reduced branded revenue and pricing power.
• The product has no biosimilar risk because it is a conventional small-molecule combination.
• Current competition is driven by generic price, manufacturing reliability, reimbursement, and supply continuity.
• Aspirin alone and clopidogrel place sustained pressure on volume and pricing.
• Brand-level revenue is not publicly disclosed in a consistent manner because Boehringer Ingelheim is privately held and does not separately report Aggrenox sales.
• The product remains clinically relevant but has limited potential for branded growth without a new protected formulation or indication.

FAQs

Is aspirin and dipyridamole the same as Aggrenox?

Yes. Aggrenox is the original branded product containing aspirin 25 mg and extended-release dipyridamole 200 mg per capsule.

Is aspirin and dipyridamole available as a generic?

Yes. FDA-approved generic versions of aspirin and extended-release dipyridamole are available in the United States.

Does aspirin and dipyridamole still have patent protection?

The core commercial formulation patents that protected Aggrenox have expired. Current suppliers do not benefit from meaningful product-level exclusivity.

Can a generic manufacturer launch an authorized generic of Aggrenox?

An authorized generic requires authorization from the brand owner or an applicable contractual arrangement. Independent ANDA products can enter without being authorized generics if they satisfy FDA requirements.

Is aspirin and dipyridamole a biologic or biosimilar product?

No. It is a conventional small-molecule drug combination regulated through the NDA and ANDA frameworks, not through the biologic-license and biosimilar pathways.

References

1. U.S. Food and Drug Administration. (1999). Aggrenox prescribing information. FDA.

2. Diener, H. C., Cunha, L., Forbes, C., Sivenius, J., Smets, P., & Lowenthal, A. (1996). European Stroke Prevention Study 2: Dipyridamole and acetylsalicylic acid in the secondary prevention of stroke. Journal of the Neurological Sciences, 143(1-2), 1-13.

3. U.S. Patent and Trademark Office. (1997). U.S. Patent No. 5,616,793: Pharmaceutical composition containing aspirin and dipyridamole. USPTO.

4. U.S. Food and Drug Administration. (2023). Approved drug products with therapeutic equivalence evaluations. FDA.