KEFLEX Drug Patent Profile

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When do Keflex patents expire, and when can generic versions of Keflex launch?

Keflex is a drug marketed by Pragma and is included in two NDAs.

The generic ingredient in KEFLEX is cephalexin. There is one drug master file entry for this compound. Thirty-five suppliers are listed for this compound. Additional details are available on the cephalexin profile page.

DrugPatentWatch^® Litigation and Generic Entry Outlook for Keflex

A generic version of KEFLEX was approved as cephalexin by TEVA on February 13^th, 1987.

Summary for KEFLEX

US Patents:	0
Applicants:	1
NDAs:	2
Raw Ingredient (Bulk) Api Vendors:	64
Clinical Trials:	28
Patent Applications:	5,857
Drug Prices:	Drug price information for KEFLEX
What excipients (inactive ingredients) are in KEFLEX?	KEFLEX excipients list
DailyMed Link:	KEFLEX at DailyMed

See drug prices for KEFLEX

See drug sales revenues for KEFLEX

Recent Clinical Trials for KEFLEX

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

Sponsor	Phase
Western Sydney Local Health District	Phase 2
Centre Of Research Excellence in Tuberculosis Control	Phase 2
Baylor Research Institute	Phase 4

See all KEFLEX clinical trials

US Patents and Regulatory Information for KEFLEX

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Pragma	KEFLEX	cephalexin	CAPSULE;ORAL	050405-002	Approved Prior to Jan 1, 1982		DISCN	Yes	No
Pragma	KEFLEX	cephalexin	FOR SUSPENSION;ORAL	050406-002	Approved Prior to Jan 1, 1982		DISCN	Yes	No
Pragma	KEFLEX	cephalexin	CAPSULE;ORAL	050405-005	May 12, 2006		DISCN	Yes	No
Pragma	KEFLEX	cephalexin	CAPSULE;ORAL	050405-004	May 12, 2006		DISCN	Yes	No

KEFLEX Market Dynamics, Patent Status, Generic Competition, and Financial Trajectory

Last updated: November 2, 2026

KEFLEX is the branded formulation of cephalexin, a first-generation oral cephalosporin antibiotic. Its commercial trajectory is mature and largely genericized. The original product patents and regulatory exclusivities expired decades ago, leaving price, supply reliability, distribution, and contracting as the primary market drivers. Standalone KEFLEX revenue is not publicly disclosed by its current commercial stakeholders, and the economic value of cephalexin has shifted from brand pricing to high-volume, low-margin generic sales.

What is KEFLEX and how is cephalexin used?

KEFLEX contains cephalexin monohydrate, an oral beta-lactam antibiotic indicated for susceptible bacterial infections, including respiratory-tract, skin and skin-structure, bone, genitourinary, and otitis media infections. The FDA-approved label identifies dosing in adults and pediatric patients, with available strengths including 250 mg, 500 mg, and 750 mg capsules or equivalent oral suspension formulations, depending on the marketed product.[1]

Cephalexin acts by inhibiting bacterial cell-wall synthesis. Its principal commercial limitations are the same as those affecting other older antibiotics: bacterial resistance, substitution by competing antibiotics, antimicrobial stewardship controls, and limited pricing power.

What therapeutic categories compete with KEFLEX?

KEFLEX competes with:

• Amoxicillin and amoxicillin/clavulanate
• Dicloxacillin and other antistaphylococcal penicillins
• Cefadroxil and other oral cephalosporins
• Clindamycin
• Trimethoprim-sulfamethoxazole
• Doxycycline
• Macrolides in selected indications

Clinical selection depends on infection site, likely pathogen, local resistance patterns, allergy history, renal function, and stewardship guidelines. For outpatient skin infections, methicillin-resistant Staphylococcus aureus concerns can reduce cephalexin use when resistance is suspected. For uncomplicated infections caused by susceptible organisms, cephalexin remains a familiar and inexpensive option.[2]

When did KEFLEX lose patent and regulatory exclusivity?

KEFLEX lost meaningful U.S. market exclusivity many years ago. Cephalexin was first approved in the early 1970s, and the product’s original compound and formulation protections expired long before the modern Hatch-Waxman framework became commercially important.

Event	Approximate timing	Commercial effect
Initial U.S. approval of cephalexin products	Early 1970s	Established KEFLEX as an oral cephalosporin brand
Original compound and product protection	1970s-era patents	Protected early branded sales
Generic cephalexin entry	Decades ago	Eliminated meaningful brand exclusivity
FDA-approved generic competition	Long established	Shifted market to multisource purchasing
Current market position	Mature generic market	Low switching costs and limited pricing power

The exact patent history is fragmented across historic assignees, dosage forms, and manufacturing processes. Those rights do not provide current commercial exclusivity for KEFLEX. The FDA Orange Book is the principal source for active listed patents and exclusivity associated with approved drug products.[3]

What is the Orange Book status of KEFLEX?

KEFLEX has no current market position comparable to a patented branded product. Cephalexin has long been available from multiple generic manufacturers in capsules, tablets, and oral suspension forms. Any historic KEFLEX patents listed in the Orange Book would have expired or otherwise ceased to block generic approval.

For commercial purposes, the relevant conclusion is:

• KEFLEX is not protected by a current composition-of-matter patent.
• Cephalexin generic manufacturers do not face a modern patent cliff.
• Current generic approvals are generally abbreviated new drug applications, or ANDAs.
• Patent litigation is not a material driver of present-day KEFLEX sales.

The Orange Book should still be reviewed for product-specific listings, particularly where a company evaluates an acquisition, authorized-generic arrangement, or reformulated cephalexin product. The existence of a listed patent would not necessarily indicate effective market protection if the patent is expired, disclaimed, unenforceable, or limited to a narrow use.

How many patents cover KEFLEX today?

No active patent estate is known to provide broad exclusivity over ordinary cephalexin capsules, tablets, or oral suspension. The core active ingredient is long off patent.

Potentially relevant rights could include:

• Manufacturing-process patents
• Stabilized suspension formulations
• Packaging or reconstitution systems
• Narrow dosing or administration methods
• Device-related rights for a specialized delivery format
• Country-specific formulation claims outside the United States

These rights would not recreate the original KEFLEX franchise. They could affect a specific product presentation, but they would not block standard cephalexin generics unless the claims were broad, valid, enforceable, and commercially relevant.

Are there Paragraph IV challenges to KEFLEX?

Paragraph IV litigation is not a current commercial issue for ordinary KEFLEX. Paragraph IV certifications are used when an ANDA applicant asserts that a listed patent is invalid, unenforceable, or not infringed. That pathway is most important for newer branded products with unexpired Orange Book patents.

Cephalexin’s generic market was established decades ago. The product therefore has no current Paragraph IV-driven entry event comparable to a modern small-molecule launch. Generic competition has already occurred through multiple manufacturers and dosage forms.

What formulations are protected by KEFLEX?

Standard KEFLEX and generic cephalexin products use conventional oral formulations:

Formulation	Commercial role	Patent risk
250 mg capsule	Common low-dose presentation	No meaningful broad patent barrier
500 mg capsule	Major adult presentation	No meaningful broad patent barrier
750 mg capsule or equivalent	Higher-strength presentation	Product-specific review may apply
Oral suspension	Pediatric and swallowing-limited use	Potential formulation or stability rights are narrow
Generic tablets or capsules	Multisource market	Mature, price-competitive category

Suspension products carry greater technical complexity than capsules because they require stability, taste, reconstitution, packaging, and storage controls. Those factors can create manufacturing barriers without producing durable patent exclusivity.

The FDA label warns about hypersensitivity reactions and identifies cephalexin as contraindicated in patients with known allergy to cephalexin or other beta-lactam antibacterial drugs.[1]

What is the financial trajectory of KEFLEX?

KEFLEX’s financial trajectory has three phases:

1. Branded growth: The product generated premium pricing during the early branded period.
2. Generic erosion: Generic entry reduced branded volume and price.
3. Mature generic stability: Current value depends on prescription volume, procurement contracts, supply reliability, and manufacturing cost.

A standalone KEFLEX revenue figure is not generally reported in public company filings. Companies that manufacture or distribute cephalexin typically report broader portfolios rather than product-level sales. As a result, market analysis should distinguish among:

• KEFLEX-branded revenue
• Authorized-generic revenue
• Unbranded cephalexin revenue
• Total oral antibiotic revenue
• Hospital and institutional contract sales

The brand itself has limited financial leverage because prescribers and pharmacies can substitute generic cephalexin. The greater economic opportunity is usually in efficient manufacturing and distribution rather than in brand promotion.

What factors determine cephalexin profitability?

Cephalexin profitability is driven by:

• API procurement cost
• Manufacturing yield and batch size
• FDA compliance and remediation expense
• Wholesaler and pharmacy contracts
• Reimbursement rates
• Product availability
• Competition among approved ANDA holders
• Demand for pediatric suspension
• Hospital purchasing agreements

Capsules and tablets are relatively standardized. Oral suspension may produce better differentiation because fewer suppliers may maintain consistent pediatric availability, but it also involves greater quality-control and supply-chain requirements.

How does KEFLEX compare with other oral antibiotics?

Product	Patent position	Commercial profile	Key competitive issue
KEFLEX, cephalexin	Long expired	Mature generic	Resistance and substitution
AUGMENTIN, amoxicillin/clavulanate	Long expired	High-volume generic	Broad use, gastrointestinal tolerability
DORYX, doxycycline formulations	Product-specific historic protection	Multiple formulations	Use in skin and respiratory conditions
BACTRIM, trimethoprim-sulfamethoxazole	Long expired	Mature generic	Resistance and safety considerations
CLINDAMYCIN	Long expired	Mature generic	Adverse-effect profile
Cefadroxil	Long expired	Smaller oral cephalosporin segment	Prescriber familiarity and dosing

KEFLEX retains value where clinicians want a familiar first-generation cephalosporin with oral dosing and broad historical use against susceptible organisms. It is less advantaged where resistant pathogens, beta-lactam allergy, or broader empiric coverage is a concern.

What FDA regulatory status applies to KEFLEX?

KEFLEX is an FDA-approved prescription antibacterial product. Generic cephalexin products are approved through the ANDA pathway, which relies on pharmaceutical equivalence and bioequivalence to a reference product rather than a new clinical efficacy program for each generic applicant.[4]

The regulatory burden remains substantial despite the product’s age. Manufacturers must comply with:

• Current good manufacturing practice requirements
• Identity, strength, quality, and purity specifications
• Bioequivalence standards for relevant dosage forms
• Stability and container-closure requirements
• Labeling and adverse-event reporting obligations
• FDA inspection and enforcement requirements

Antibiotic shortages can arise even when demand is stable. Causes include API concentration among suppliers, manufacturing deviations, quality remediation, and low margins that reduce redundancy.

What manufacturing and intellectual-property barriers affect KEFLEX?

KEFLEX has low intellectual-property risk but meaningful operational risk. A manufacturer does not need to overcome a modern composition-of-matter patent. It must, however, produce consistent batches and maintain FDA-compliant supply.

The main barriers are:

• Reliable cephalexin API sourcing
• Control of degradation and impurities
• Suspension stability
• Packaging and reconstitution performance
• Validation of cleaning and cross-contamination controls
• Compliance with FDA inspection findings
• Competitive pricing at sustainable margins

These barriers can create temporary supply advantages, but they rarely support durable premium pricing.

What generic launch scenarios exist for KEFLEX?

A new entrant would face a mature market rather than a conventional launch opportunity.

Scenario	Expected market effect
Additional capsule supplier	More price competition and limited share capture
Pediatric suspension entrant	Potential supply differentiation
Authorized generic arrangement	Lower channel friction but limited pricing upside
Manufacturing disruption at a major supplier	Temporary volume and pricing opportunity
Reformulated or specialty delivery product	Possible niche value, subject to FDA and patent review
Branded relaunch	Low probability of durable premium due to substitution

The most attractive entry strategy is generally operational: secure API, achieve reliable FDA-compliant production, and target distribution gaps. A conventional branded launch would face weak reimbursement and rapid generic substitution.

Which companies are challenging KEFLEX?

No major company is publicly positioned as challenging an active KEFLEX patent estate. Competition comes from generic manufacturers, contract manufacturers, wholesalers, and pharmacy suppliers rather than from patent litigants.

The competitive landscape can change through ANDA approvals, manufacturer exits, FDA warning letters, recalls, or shortages. Those events may shift market share without changing the underlying patent position.

What is the biosimilar risk for KEFLEX?

Biosimilar risk is not applicable. KEFLEX is a small-molecule antibiotic, not a biologic. The relevant competitive pathway is generic substitution under the ANDA framework, not biosimilar approval under the Public Health Service Act.

What patent litigation and settlement agreements affect KEFLEX?

No current patent litigation or settlement agreement is central to the ordinary KEFLEX market. Historic disputes may exist in archived court records, but they do not create a current exclusivity event for standard cephalexin products.

For investment analysis, litigation risk is therefore lower than:

• FDA manufacturing risk
• Product liability risk
• Antimicrobial resistance trends
• Reimbursement compression
• Supplier concentration
• Recall exposure

How strong is the KEFLEX patent estate?

The patent estate is commercially weak because the core product is long off patent and generic competition is established. Its value is better described as a mature regulatory and manufacturing asset than as an innovation-protected pharmaceutical franchise.

Category	Assessment
Composition-of-matter protection	Expired
Core formulation protection	Expired or commercially nonblocking
Method-of-use protection	No broad current exclusivity
Orange Book leverage	Minimal
Paragraph IV exposure	Low as a current issue
Generic substitution risk	Very high
Manufacturing barriers	Moderate
Revenue durability	Volume-dependent and low-margin

Key Takeaways

• KEFLEX is the branded version of cephalexin, a first-generation oral cephalosporin.
• Its original patents and regulatory exclusivities expired decades ago.
• The current market is dominated by generic cephalexin and pharmacy-level substitution.
• Standalone KEFLEX revenue is not publicly disclosed in a reliable, consistently reported format.
• Financial performance depends on manufacturing cost, supply reliability, contracts, and generic pricing.
• Formulation and manufacturing rights may affect specific products but do not recreate broad KEFLEX exclusivity.
• Paragraph IV litigation, biosimilar competition, and active patent settlements are not material current market drivers.
• The largest commercial risks are price erosion, supply disruption, FDA compliance failures, and resistance-driven prescribing shifts.

FAQs

Is KEFLEX still a profitable drug?

KEFLEX can remain commercially viable, but profitability is generally tied to generic-scale manufacturing and distribution rather than branded pricing. Product-level profit data is not publicly disclosed.

Does KEFLEX have an active composition patent?

No active composition patent provides meaningful exclusivity over ordinary cephalexin. The active ingredient has been off patent for decades.

Can a generic company launch cephalexin without a clinical trial?

A company generally uses the FDA ANDA pathway and must demonstrate pharmaceutical equivalence and bioequivalence to the reference product. It does not normally repeat the full clinical efficacy program required for an innovative new drug.[4]

Is cephalexin vulnerable to antibiotic-resistance trends?

Yes. Resistance patterns can reduce prescribing in infections where resistant organisms are common. Local antibiograms and pathogen-specific susceptibility remain important to clinical selection.[2]

What is the best commercial opportunity in the KEFLEX market?

The clearest opportunities are reliable supply, pediatric suspension availability, efficient API sourcing, and distribution into channels affected by manufacturer exits or shortages. Broad branded relaunch strategies face high substitution risk.

References

1. U.S. Food and Drug Administration. (2023). KEFLEX (cephalexin) prescribing information. FDA-approved labeling.

2. Centers for Disease Control and Prevention. (2024). Outpatient clinical care for adults: Antibiotic prescribing and use. U.S. Department of Health and Human Services.

3. U.S. Food and Drug Administration. (2025). Approved drug products with therapeutic equivalence evaluations: Orange Book. U.S. Department of Health and Human Services.

4. U.S. Food and Drug Administration. (2024). Generic drug facts. U.S. Department of Health and Human Services.

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