Enalapril maleate; felodipine - Generic Drug Details
What are the generic sources for enalapril maleate; felodipine and what is the scope of freedom to operate?
Enalapril maleate; felodipine
is the generic ingredient in one branded drug marketed by Astrazeneca and is included in one NDA. Additional information is available in the individual branded drug profile pages.Summary for enalapril maleate; felodipine
| US Patents: | 0 |
| Tradenames: | 1 |
| Applicants: | 1 |
| NDAs: | 1 |
| Raw Ingredient (Bulk) Api Vendors: | 1 |
| DailyMed Link: | enalapril maleate; felodipine at DailyMed |
Anatomical Therapeutic Chemical (ATC) Classes for enalapril maleate; felodipine
US Patents and Regulatory Information for enalapril maleate; felodipine
| Applicant | Tradename | Generic Name | Dosage | NDA | Approval Date | TE | Type | RLD | RS | Patent No. | Patent Expiration | Product | Substance | Delist Req. | Exclusivity Expiration |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Astrazeneca | LEXXEL | enalapril maleate; felodipine | TABLET, EXTENDED RELEASE;ORAL | 020668-002 | Oct 28, 1998 | DISCN | No | No | ⤷ Start Trial | ⤷ Start Trial | ⤷ Start Trial | ||||
| Astrazeneca | LEXXEL | enalapril maleate; felodipine | TABLET, EXTENDED RELEASE;ORAL | 020668-001 | Dec 27, 1996 | DISCN | No | No | ⤷ Start Trial | ⤷ Start Trial | ⤷ Start Trial | ||||
| >Applicant | >Tradename | >Generic Name | >Dosage | >NDA | >Approval Date | >TE | >Type | >RLD | >RS | >Patent No. | >Patent Expiration | >Product | >Substance | >Delist Req. | >Exclusivity Expiration |
Expired US Patents for enalapril maleate; felodipine
| Applicant | Tradename | Generic Name | Dosage | NDA | Approval Date | Patent No. | Patent Expiration |
|---|---|---|---|---|---|---|---|
| Astrazeneca | LEXXEL | enalapril maleate; felodipine | TABLET, EXTENDED RELEASE;ORAL | 020668-002 | Oct 28, 1998 | 4,374,829 | ⤷ Start Trial |
| Astrazeneca | LEXXEL | enalapril maleate; felodipine | TABLET, EXTENDED RELEASE;ORAL | 020668-001 | Dec 27, 1996 | 4,374,829 | ⤷ Start Trial |
| Astrazeneca | LEXXEL | enalapril maleate; felodipine | TABLET, EXTENDED RELEASE;ORAL | 020668-001 | Dec 27, 1996 | 4,703,038 | ⤷ Start Trial |
| Astrazeneca | LEXXEL | enalapril maleate; felodipine | TABLET, EXTENDED RELEASE;ORAL | 020668-002 | Oct 28, 1998 | 4,703,038 | ⤷ Start Trial |
| >Applicant | >Tradename | >Generic Name | >Dosage | >NDA | >Approval Date | >Patent No. | >Patent Expiration |
Enalapril Maleate and Felodipine Market Dynamics, Patent Status, and Financial Trajectory
The enalapril maleate/felodipine extended-release combination was commercialized in the United States as Lexxel for hypertension. Its commercial value has largely disappeared because the underlying antihypertensive ingredients became generic, the branded combination was discontinued, and treatment shifted toward cheaper generic ACE inhibitors, calcium-channel blockers, and widely available fixed-dose combinations. No meaningful current product-level revenue is publicly reported for Lexxel.
What is enalapril maleate/felodipine?
Enalapril maleate/felodipine combines two antihypertensive mechanisms:
| Component | Drug class | Primary action |
|---|---|---|
| Enalapril maleate | ACE inhibitor | Reduces angiotensin II formation and aldosterone activity |
| Felodipine extended release | Dihydropyridine calcium-channel blocker | Relaxes arterial smooth muscle and lowers peripheral vascular resistance |
The product was marketed as Lexxel extended-release tablets. It was indicated for hypertension when combination therapy was appropriate or when monotherapy did not provide sufficient blood-pressure control. Felodipine was supplied in an extended-release formulation to support once-daily dosing.
The combination had a clinically rational mechanism, but its commercial differentiation was limited. Physicians could prescribe the two ingredients separately, often at lower generic cost, and could select other ACE inhibitor/calcium-channel blocker combinations.
What was the FDA regulatory status of Lexxel?
Lexxel was approved through a U.S. new drug application for the fixed-dose combination of enalapril maleate and felodipine extended release. FDA records identify the product as discontinued rather than as a currently marketed branded antihypertensive.[1]
| Regulatory item | Status |
|---|---|
| Product | Lexxel |
| Active ingredients | Enalapril maleate and felodipine |
| Dosage form | Extended-release oral tablet |
| Therapeutic area | Hypertension |
| U.S. application | NDA 020636 |
| Current U.S. commercial status | Discontinued |
| Biosimilar pathway | Not applicable |
| Current branded revenue disclosure | None identified in public company reporting |
Discontinuation does not establish that the product was removed for safety or efficacy reasons. The likely commercial drivers were generic competition, limited differentiation, and the declining value of a branded fixed-dose combination in a mature hypertension market.
What patents protected enalapril maleate and felodipine?
The original patent estate covered the individual active ingredients, pharmaceutical compositions, and, in some jurisdictions, specific formulations or therapeutic uses. Those core rights have expired.
Enalapril patent position
Enalapril was developed and commercialized by Merck as Vasotec. The principal U.S. compound patent expired around 2000, subject to applicable patent-term rules and any regulatory extension.[2] Generic enalapril maleate has been available for many years.
The historical enalapril estate included:
- Compound and ACE-inhibitor patents
- Enalapril maleate salt claims
- Pharmaceutical composition claims
- Treatment-of-hypertension claims
- Formulation and manufacturing claims
These rights no longer create a meaningful U.S. exclusivity barrier.
Felodipine patent position
Felodipine was developed as a long-acting dihydropyridine calcium-channel blocker and commercialized in the United States as Plendil. Its original compound and product patents also expired years ago. Generic felodipine extended-release tablets are available in the U.S. market.
The historical felodipine estate included:
- Felodipine compound claims
- Extended-release tablet formulations
- Controlled-release manufacturing processes
- Hypertension treatment methods
- Tablet composition and dissolution-profile claims
The most commercially relevant formulation rights have expired or no longer support an active branded franchise.
Combination-product patent position
A fixed-dose combination can receive separate patent protection even when its ingredients are old. Potential claim categories include:
- The combination of enalapril and felodipine
- Specific dose ratios
- Extended-release felodipine with immediate-release or modified-release enalapril
- Tablet-layering or multiparticulate delivery systems
- Treatment of patients inadequately controlled on monotherapy
No currently material U.S. patent barrier is publicly associated with Lexxel. The product’s original U.S. exclusivity period has ended, and the branded product is no longer an active commercial platform.
When did enalapril/felodipine lose exclusivity?
The product lost practical exclusivity in stages rather than on a single date.
| Period | Event | Commercial effect |
|---|---|---|
| 1980s | Enalapril and felodipine developed and patented | Strong ingredient-level protection |
| Early-to-mid 1990s | Individual branded products commercialized | High-value branded hypertension market |
| 1990s | Lexxel introduced in the United States | Combination positioned around convenience and blood-pressure control |
| Around 2000 | Core enalapril patent protection expired | Generic ACE-inhibitor competition expanded |
| Early 2000s | Felodipine patent protection expired or weakened | Generic calcium-channel blocker competition expanded |
| 2000s onward | Generic substitution and therapeutic alternatives increased | Lexxel’s pricing power declined |
| Current period | Lexxel listed as discontinued | No active branded franchise |
The combination’s practical loss of exclusivity was driven by the expiration of ingredient patents and the availability of separate generic components. Even where a fixed-dose combination itself did not have an immediately substitutable generic, prescribers and payers could replicate its clinical effect with two low-cost tablets.
Are there Paragraph IV challenges to enalapril maleate/felodipine?
No commercially significant current Paragraph IV litigation is associated with Lexxel in the public record.
Paragraph IV risk was more relevant when a branded fixed-dose product had active Orange Book patents. Lexxel’s commercial discontinuation and the age of its patent estate reduce the economic incentive for a new abbreviated new drug application challenger to litigate.
A generic manufacturer could pursue several routes:
- File an ANDA for the combination product if an approved reference product and regulatory pathway remain viable.
- Market enalapril maleate and felodipine separately.
- Rely on prescribing substitution rather than reproduce the discontinued combination.
- Develop a different fixed-dose ACE inhibitor/calcium-channel blocker product.
The third option has been commercially more attractive because separate generic products already satisfy most of the same treatment demand.
What is the Orange Book status of enalapril/felodipine?
The Orange Book is relevant because it records approved drug products, patent listings, and market status. Lexxel is not a current growth product in the Orange Book ecosystem. FDA records identify the product as discontinued, and there is no active branded revenue stream comparable to products with current listed patents and pending generic litigation.[1]
The key regulatory distinction is between:
- A product that is approved but discontinued;
- A product withdrawn for safety or efficacy reasons; and
- A product that remains actively marketed.
Lexxel falls into the discontinued-product category. That status limits its value as a reference product and weakens the commercial case for developing a dedicated generic combination.
How strong is the patent estate for enalapril maleate/felodipine?
The current patent estate is weak from a U.S. commercial-exclusivity perspective.
| Patent category | Historical strength | Current value |
|---|---|---|
| Enalapril compound patents | High | Expired |
| Felodipine compound patents | High | Expired |
| Salt-form patents | Moderate | Expired or commercially obsolete |
| Extended-release formulation patents | Moderate to high | Largely expired |
| Combination-product patents | Moderate | No material current barrier identified |
| Manufacturing-process patents | Variable | Limited blocking value |
| Method-of-use patents | Moderate historically | Low current value for hypertension |
| Orphan or biologic exclusivity | Not applicable | None |
The remaining commercial barriers are operational rather than patent-based. They include regulatory development costs, reference-product availability, bioequivalence requirements for modified-release felodipine, manufacturing complexity, and limited market size.
What formulations are protected by the historical product?
The commercially relevant formulation was an oral extended-release tablet containing felodipine. The formulation strategy was designed to release felodipine over an extended period while combining it with enalapril maleate.
Potential formulation-control points included:
- Release rate and dissolution profile
- Tablet excipient composition
- Drug-layer or matrix technology
- Stability of the enalapril salt
- Dose uniformity
- Bioequivalence to the reference product
- Packaging controls for moisture and degradation
These features could have supported formulation patents or regulatory differentiation during the product’s commercial life. They do not create a current high-value barrier where the patents have expired and the reference product is discontinued.
How does enalapril/felodipine compare with competing antihypertensive combinations?
The product competed in a crowded market that included ACE inhibitor/thiazide combinations, angiotensin-receptor blocker/calcium-channel blocker combinations, and separate generic therapy.
| Therapy | Commercial position | Competitive assessment |
|---|---|---|
| Enalapril plus felodipine | Legacy combination | Low current commercial relevance |
| Enalapril plus hydrochlorothiazide | Established generic combination | Lower cost and broader familiarity |
| Lisinopril plus amlodipine | Common generic combination | Stronger prescribing and formulary position |
| Benazepril plus amlodipine | Former branded combination, now generic | Established fixed-dose alternative |
| ARB plus calcium-channel blocker | Widely used modern combination | Strong payer and physician acceptance |
| Separate enalapril and felodipine | Generic component therapy | Most practical substitute for Lexxel |
Amlodipine has a broader prescribing base than felodipine and is available through multiple low-cost generic suppliers. ARB-based combinations also gained share because of tolerability and guideline use in patients who do not receive ACE inhibitors.
What financial trajectory did the product have?
Lexxel’s financial trajectory followed the standard pattern for an older combination antihypertensive:
- Initial branded pricing supported by ingredient patents and combination convenience.
- Slower growth as physicians used separate products and competing combinations.
- Price erosion after generic entry for enalapril and felodipine.
- Reduced formulary support as payers favored generic alternatives.
- Commercial discontinuation and loss of standalone revenue visibility.
Public financial statements from the relevant originator companies generally reported cardiovascular portfolios in aggregate rather than disclosing Lexxel revenue separately. No reliable current product-level revenue figure is available.
The product’s economic value was also constrained by its dosage architecture. Fixed-dose combinations improve convenience, but they reduce titration flexibility. Physicians may prefer separate tablets when adjusting ACE-inhibitor and calcium-channel blocker doses independently. That limitation reduces the willingness of payers to pay a premium for the combination.
Revenue exposure
Current revenue exposure is effectively zero for an active branded franchise. Residual value could exist in limited international markets where generic penetration is lower or where legacy registrations remain, but no material global revenue base is publicly documented.
For a potential acquirer, the asset would offer little strategic value unless bundled with:
- An established generic portfolio;
- A regional registration network;
- A low-cost modified-release manufacturing platform; or
- A broader cardiovascular product package.
What generic launch risks exist?
A new generic combination would face regulatory and commercial risks despite the absence of meaningful patent barriers.
Regulatory risks
The primary regulatory issue would be demonstrating bioequivalence for the extended-release felodipine component. Modified-release products can require more complex comparative pharmacokinetic testing than immediate-release tablets.
Other risks include:
- Identifying an acceptable reference product;
- Establishing equivalent strength and release characteristics;
- Demonstrating product stability;
- Managing enalapril degradation and impurity controls;
- Meeting manufacturing scale and content-uniformity requirements.
Commercial risks
The product would compete against two inexpensive generic tablets. A dedicated combination product could therefore have limited pricing power. Pharmacy benefit managers may prefer separate products because they are already available from multiple suppliers.
The strongest launch case would be a low-cost product targeted at markets where fixed-dose adherence products receive reimbursement preference. The weakest case would be a U.S.-only launch requiring new development work for a discontinued reference product.
What licensing deals and litigation affect the product?
No major current licensing transaction, settlement agreement, or active patent litigation involving Lexxel has a material effect on the U.S. market.
Historical commercialization was associated with large pharmaceutical companies that controlled the individual branded assets, including Merck for enalapril and Astra for felodipine. The product’s strategic rationale depended on combining established cardiovascular brands rather than creating a new protected mechanism.
There is no active biosimilar risk because enalapril and felodipine are small molecules. The relevant competitive threat is generic substitution, not biosimilar entry.
What is the outlook for enalapril/felodipine?
The product has no credible path to renewed branded growth in the United States. Its active ingredients remain clinically useful, but the commercial opportunity belongs to generic manufacturers and alternative fixed-dose combinations.
The most likely market outcomes are:
- Continued use of separate generic enalapril and felodipine where clinically appropriate;
- Replacement by lisinopril/amlodipine or ARB/calcium-channel blocker combinations;
- Limited regional sales of legacy combination products;
- No meaningful patent-driven price protection;
- Low probability of new U.S. branded investment.
Key Takeaways
- Lexxel was a fixed-dose extended-release combination of enalapril maleate and felodipine for hypertension.
- FDA records identify the U.S. product as discontinued.
- Core patents for both active ingredients expired years ago.
- No material current U.S. patent barrier or Paragraph IV litigation is associated with the product.
- The product has no biosimilar exposure because both ingredients are small molecules.
- Generic separate-tablet therapy is the main substitute.
- Public filings do not disclose material standalone revenue for Lexxel.
- A new generic combination would face modified-release bioequivalence and weak pricing economics.
- The product’s current value is primarily historical, regulatory, or regional rather than growth-oriented.
FAQs
Is enalapril maleate/felodipine still available in the United States?
The branded Lexxel product is listed as discontinued. Enalapril and felodipine may be available separately as generic medicines.
Is felodipine the same as amlodipine?
No. Both are dihydropyridine calcium-channel blockers, but they are different active ingredients with different pharmacokinetic profiles, labeling histories, and commercial markets.
Can a generic company launch enalapril/felodipine without a Paragraph IV lawsuit?
Potentially, if no unexpired Orange Book patent blocks the product. The larger challenges are reference-product status, modified-release bioequivalence, manufacturing cost, and limited demand.
Does enalapril/felodipine have biosimilar competition?
No. Biosimilars apply to biological products. Enalapril and felodipine are chemically synthesized small molecules and compete through generic pathways.
Is there investment value in the enalapril/felodipine patent estate?
The U.S. patent estate has little current investment value because the core composition and formulation protections have expired or lost practical commercial relevance. Any residual value would depend on specific non-U.S. rights, registrations, or manufacturing assets.
References
- U.S. Food and Drug Administration. (n.d.). Drugs@FDA: FDA-approved drugs, Lexxel (enalapril maleate and felodipine) extended-release tablets, NDA 020636.
- U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations: Orange Book.
- U.S. Food and Drug Administration. (n.d.). FDA’s list of discontinued drug products.
- Merck & Co., Inc. (n.d.). Vasotec (enalapril maleate) prescribing information.
- AstraZeneca. (n.d.). Plendil (felodipine) extended-release tablets prescribing information.
- Joint National Committee. (2003). The seventh report of the Joint National Committee on prevention, detection, evaluation, and treatment of high blood pressure. National Heart, Lung, and Blood Institute.
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