BICILLIN L-A Drug Patent Profile

When do Bicillin L-a patents expire, and when can generic versions of Bicillin L-a launch?

Bicillin L-a is a drug marketed by King Pharms Llc and Wyeth Ayerst and is included in two NDAs.

The generic ingredient in BICILLIN L-A is penicillin g benzathine. There is one drug master file entry for this compound. Two suppliers are listed for this compound. Additional details are available on the penicillin g benzathine profile page.

Summary for BICILLIN L-A

US Patents:	0
Applicants:	2
NDAs:	2
Finished Product Suppliers / Packagers:	2
Raw Ingredient (Bulk) Api Vendors:	2
Clinical Trials:	3
Patent Applications:	693
Drug Prices:	Drug price information for BICILLIN L-A
What excipients (inactive ingredients) are in BICILLIN L-A?	BICILLIN L-A excipients list
DailyMed Link:	BICILLIN L-A at DailyMed

See drug prices for BICILLIN L-A

Recent Clinical Trials for BICILLIN L-A

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

Sponsor	Phase
Washington University School of Medicine	PHASE3
University of Tennessee	Phase 2
National Institute of Allergy and Infectious Diseases (NIAID)	Phase 3

See all BICILLIN L-A clinical trials

Pharmacology for BICILLIN L-A

Drug Class

Penicillin-class Antibacterial

US Patents and Regulatory Information for BICILLIN L-A

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
King Pharms Llc	BICILLIN L-A	penicillin g benzathine	INJECTABLE;INJECTION	050141-003	Approved Prior to Jan 1, 1982		DISCN	Yes	No
King Pharms Llc	BICILLIN L-A	penicillin g benzathine	INJECTABLE;INJECTION	050141-001	Approved Prior to Jan 1, 1982	BC	RX	Yes	Yes
Wyeth Ayerst	BICILLIN L-A	penicillin g benzathine	INJECTABLE;INJECTION	050131-001	Approved Prior to Jan 1, 1982		DISCN	No	No

BICILLIN L-A Market Dynamics, Financial Trajectory, Patent Position and Generic Entry Risk

Last updated: August 2, 2026

Bicillin L-A is Pfizer’s long-acting intramuscular benzathine penicillin G product. Its market is small relative to major pharmaceutical brands but strategically important because it is a first-line or preferred treatment for several syphilis indications and an important option for rheumatic fever prophylaxis. The product has no meaningful new-molecule exclusivity, and Pfizer does not disclose standalone Bicillin L-A revenue. Its commercial position is supported primarily by manufacturing complexity, limited alternative suppliers, regulatory barriers for sterile suspensions, and periods of supply shortage.

What is Bicillin L-A and who manufactures it?

Bicillin L-A contains penicillin G benzathine, a long-acting beta-lactam antibiotic administered by deep intramuscular injection. Pfizer markets the product in the United States under the Bicillin L-A brand.

The FDA-approved label identifies Bicillin L-A for treatment of infections caused by penicillin-susceptible organisms, including selected streptococcal infections, syphilis, and yaws. It is also used for prevention of recurrent rheumatic fever and rheumatic heart disease in appropriate patients (FDA, 2023a).

Attribute	Bicillin L-A
Active ingredient	Penicillin G benzathine
Drug class	Long-acting penicillin antibiotic
Route	Deep intramuscular injection
Dosage form	Injectable aqueous suspension
U.S. sponsor/manufacturer	Pfizer
Regulatory category	Prescription drug
Primary institutional uses	Syphilis treatment, rheumatic fever prophylaxis
Main substitutes	Other penicillin formulations, alternative antibiotics where clinically appropriate
Main market constraint	Manufacturing and supply capacity

Bicillin L-A is not interchangeable with Bicillin C-R. Bicillin C-R contains both penicillin G benzathine and penicillin G procaine and has different clinical and regulatory characteristics. Confusion between the products has generated FDA safety communications and clinical warnings because Bicillin L-A is the preferred product for many syphilis treatment regimens (FDA, 2017).

How large is the Bicillin L-A market?

The U.S. market is commercially important but not large by branded pharmaceutical standards. Pfizer does not report Bicillin L-A revenue as a separate line item in its annual reports. Revenue is included within broader product or business-category reporting, preventing a reliable public calculation of annual sales, volume, gross margin, or market share (Pfizer, 2024).

The most reliable market indicators are:

1. Persistent public-health demand for syphilis treatment.
2. Limited availability of equivalent long-acting injectable penicillin products.
3. FDA shortage listings and allocation constraints.
4. Procurement by public-health departments, hospitals, clinics, and correctional systems.
5. Increased clinical demand during periods of rising syphilis incidence.

The commercial profile differs from a conventional branded medicine. Bicillin L-A has low relative pricing power from patent protection, but Pfizer can retain substantial market leverage because few suppliers manufacture the product at scale.

What is driving Bicillin L-A demand?

Rising syphilis incidence

Syphilis is the primary demand driver. The Centers for Disease Control and Prevention has reported substantial increases in U.S. syphilis cases, including congenital syphilis. Benzathine penicillin G remains the recommended treatment for many pregnant patients and for several stages of syphilis, limiting substitution options (CDC, 2021; CDC, 2024).

Demand is less discretionary than demand for many branded medicines. When clinicians require benzathine penicillin G, alternative antibiotics may be clinically unsuitable, particularly in pregnancy or for prevention of congenital syphilis.

Rheumatic fever prophylaxis

Patients with prior rheumatic fever or rheumatic heart disease may require recurring intramuscular prophylaxis. This creates a base of repeat demand that is less sensitive to short-term changes in infection incidence.

Public-health stockpiling and allocation

Health departments and hospitals may increase orders when shortages are anticipated. That behavior can amplify short-term demand and make commercial sales appear stronger even when underlying patient volumes have changed less sharply.

Limited therapeutic substitution

Oral penicillin, other injectable penicillins, and non-penicillin antibiotics cannot always replace Bicillin L-A on a clinically equivalent basis. The product’s long duration of action and established treatment protocols create switching friction.

What caused Bicillin L-A supply shortages?

FDA shortage records have identified increased demand and manufacturing-related constraints as drivers of Bicillin L-A supply pressure. The shortage environment became especially visible as syphilis cases rose and public-health agencies sought more product (FDA, 2023b).

The supply chain has several structural vulnerabilities:

• Sterile injectable manufacturing requires validated aseptic processing.
• The formulation is a suspension rather than a simple solution.
• Production requires specialized equipment and quality-control testing.
• Penicillin manufacturing facilities often require segregation from other products because of severe beta-lactam allergy risks.
• Requalification of a manufacturing line or expansion of capacity can take substantial time.
• A limited supplier base increases the impact of any plant disruption.

FDA authorized temporary importation of an alternative benzathine penicillin G product during the shortage period. Such action helped expand availability but did not immediately create a large, permanent U.S. competitive market (FDA, 2023c).

What is the financial trajectory for Bicillin L-A?

Pfizer has not publicly disclosed standalone Bicillin L-A revenue. The product’s financial trajectory therefore must be assessed through market conditions rather than a reported product-level income statement.

Period	Financial and market direction
Pre-shortage mature period	Stable, low-growth branded antibiotic with limited patent leverage
Rising syphilis period	Higher demand and stronger utilization
Shortage period	Demand exceeded supply; revenue was constrained by available units
Capacity recovery period	Potential volume normalization, with pricing and mix dependent on supply conditions
Long term	Durable demand but limited ability to produce blockbuster-level revenue without broader public-health expansion

The shortage likely increased the product’s strategic value more than its disclosed financial importance. A supply-constrained product can generate high utilization and favorable pricing while still producing modest absolute revenue because total annual treatment volume remains limited.

Pfizer’s public reporting does not permit a defensible estimate of Bicillin L-A sales, operating profit, or year-over-year growth. Any precise revenue figure published without a company disclosure or verified prescription and procurement dataset should be treated as an estimate rather than reported financial data.

What is the FDA regulatory status of Bicillin L-A?

Bicillin L-A is an FDA-approved prescription product. The product is regulated as a conventional small-molecule injectable, not as a biologic. It does not qualify for biosimilar competition because biosimilar pathways apply to biologic products, while penicillin G benzathine is a conventional pharmaceutical active ingredient.

The regulatory value of the product rests on its approved labeling, established clinical use, and manufacturing history. Pfizer must maintain compliance with current good manufacturing practice requirements for sterile injectable products. Changes to manufacturing sites, formulation controls, sterilization processes, or container systems may require FDA review.

What is the Orange Book status of Bicillin L-A?

Bicillin L-A is associated with an FDA-approved prescription drug application and appears in the FDA’s approved drug-product framework. The Orange Book is the relevant source for determining listed patents, exclusivity, therapeutic-equivalence evaluations, and approved product information (FDA, 2024).

The product does not have new chemical entity exclusivity. Penicillin G benzathine has been used for decades, and any original composition-of-matter patent protection has expired.

The public commercial record does not establish a current patent estate that creates a durable, molecule-level barrier to generic entry. The principal barriers are more likely to be:

• sterile injectable manufacturing capability;
• formulation and suspension-control know-how;
• validated production capacity;
• regulatory investment;
• supply-chain economics;
• limited market size relative to development costs.

What patents protect Bicillin L-A?

No commercially significant active ingredient patent is expected to protect Bicillin L-A. The relevant intellectual-property analysis is more likely to involve formulation, manufacturing, device, packaging, or process claims than the penicillin molecule itself.

Potentially relevant claim categories include:

Patent category	Commercial relevance
Composition-of-matter patents	Little or no relevance because the active ingredient is old
Injectable suspension formulation	Could affect particle size, stability, excipients, or syringe performance
Manufacturing-process patents	Could cover crystallization, particle control, filling, or sterilization
Container or delivery patents	Could cover prefilled syringes, vial systems, or packaging
Method-of-use patents	Limited value for long-established penicillin indications
Trade secrets	Potentially important for scale-up, suspension uniformity, and yield

Patent protection does not appear to be the main reason generic or alternative supply has remained limited. For an old injectable antibiotic, intellectual property can be less important than the economics and technical risk of building a compliant manufacturing operation.

When does Bicillin L-A lose exclusivity?

Bicillin L-A lost any original small-molecule exclusivity decades ago. There is no meaningful upcoming new chemical entity exclusivity expiration date comparable to a modern branded drug.

The more relevant timing question is when a competing manufacturer can obtain FDA approval and consistently supply a therapeutically substitutable product. That timeline depends on:

1. Development of a stable injectable suspension.
2. Demonstration of quality and manufacturing control.
3. FDA review of the abbreviated or full application.
4. Facility inspection and approval.
5. Commercial-scale production.
6. Inclusion in the FDA’s therapeutic-equivalence framework where applicable.

The absence of patent exclusivity does not guarantee immediate generic launch. Injectable products can remain effectively single-source for years after underlying patents expire.

Are there Paragraph IV challenges against Bicillin L-A?

No widely reported Paragraph IV litigation has established a major current challenge to Pfizer’s Bicillin L-A franchise. A Paragraph IV certification would be relevant only if an ANDA applicant were required to address an unexpired listed patent. Because the active ingredient is longstanding and no clearly dominant patent barrier is publicly established, future competition would more likely depend on regulatory and manufacturing execution than on patent litigation.

A generic applicant could pursue an abbreviated pathway if the reference-product and regulatory requirements permit it. The practical risk to Pfizer would come from approval of a reliable competing injectable rather than from a conventional patent-cliff event.

Which companies are challenging Pfizer’s Bicillin L-A position?

The competitive threat is fragmented. Potential participants include:

• manufacturers of generic benzathine penicillin G;
• international suppliers seeking U.S. authorization;
• contract manufacturers with sterile injectable capacity;
• public-health procurement suppliers;
• companies using temporary importation mechanisms during shortages.

The arrival of imported alternatives during the shortage demonstrated that the market can support non-Pfizer supply under regulatory pressure. It did not establish that a permanent competitor had achieved the same scale, commercial reliability, or U.S. distribution coverage as Pfizer.

How strong is the Bicillin L-A patent estate?

The patent estate appears weak as a long-term exclusivity platform and stronger as a manufacturing and regulatory position.

Dimension	Assessment
Active-ingredient patents	Weak or expired
Method-of-use patents	Limited value because indications are established
Formulation patents	Possible but not clearly decisive
Manufacturing know-how	Potentially meaningful
Regulatory history	Strong incumbent advantage
Supply capacity	Strong during constrained periods
Generic vulnerability	Moderate to high if a reliable rival is approved
Near-term substitution risk	Constrained by manufacturing scarcity

Pfizer’s strongest asset is not patent exclusivity. It is the combination of an approved product, established demand, clinical familiarity, and scarce sterile manufacturing capacity.

What generic launch scenarios exist for Bicillin L-A?

Scenario 1: No durable competitor

Pfizer remains the principal U.S. supplier, while occasional imported product addresses shortages. Revenue remains stable but supply interruptions continue to influence sales.

Scenario 2: One approved generic

A single generic could pressure price and institutional contracts. Pfizer would retain an advantage if it maintains better availability and physician confidence.

Scenario 3: Multiple generic suppliers

Several approved manufacturers could reduce price, improve supply resilience, and shift procurement toward lowest-cost tenders. Pfizer’s revenue and margins would face greater pressure.

Scenario 4: Public-health procurement expansion

Higher syphilis incidence, congenital syphilis prevention programs, and government purchasing could expand total market volume enough to offset some price erosion.

The most likely competitive sequence is gradual rather than a single patent-cliff launch. Approval, inspection, validation, and commercial supply reliability are the critical milestones.

What litigation or settlement agreements affect Bicillin L-A?

No major publicly reported patent litigation or settlement agreement appears to define the current Bicillin L-A market. The key legal exposure is more likely to arise from product liability, shortage-related procurement disputes, manufacturing compliance, or competition involving generic approval rather than from an established patent settlement.

How does Bicillin L-A compare with other penicillin products?

Product	Active ingredient	Duration/use profile	Competitive position
Bicillin L-A	Penicillin G benzathine	Long-acting IM	Strong clinical relevance for syphilis and prophylaxis
Bicillin C-R	Benzathine plus procaine penicillin G	Different formulation	Not interchangeable with Bicillin L-A
Penicillin G potassium or sodium	Aqueous penicillin G	Shorter-acting, often intravenous	Not a direct substitute for long-acting outpatient use
Oral penicillin V	Phenoxymethylpenicillin	Oral therapy	Not equivalent for all Bicillin L-A indications
Alternative syphilis antibiotics	Various agents	Depends on drug	Restricted in pregnancy and selected clinical settings

Bicillin L-A’s differentiation is duration of action and guideline-supported use, not molecular novelty.

What is the investment outlook for Bicillin L-A?

Bicillin L-A is unlikely to become a blockbuster product based solely on price or market expansion. Its investment relevance is defensive and strategic:

• demand is supported by public-health need;
• clinical substitution is limited in important patient groups;
• the market can experience supply-driven pricing power;
• manufacturing capacity is difficult to replicate quickly;
• patent expiry does not automatically produce generic competition.

The principal downside is that a successful generic or imported competitor could compress pricing once supply stabilizes. A second risk is reputational and regulatory exposure from shortages, allocation decisions, or manufacturing disruptions. Pfizer’s broader financial results will not provide a clean read-through because Bicillin L-A is not separately reported.

Key Takeaways

• Bicillin L-A is Pfizer’s long-acting benzathine penicillin G injection.
• Its primary demand drivers are syphilis treatment and rheumatic fever prophylaxis.
• Rising syphilis incidence has increased utilization and intensified shortages.
• Pfizer does not disclose standalone Bicillin L-A revenue or profit.
• The product has no meaningful new-molecule exclusivity remaining.
• Patent protection is less important than sterile manufacturing, formulation know-how, and supply capacity.
• Biosimilar competition is not applicable because Bicillin L-A is a conventional small-molecule drug.
• No major publicly reported Paragraph IV litigation or patent settlement currently defines the market.
• Generic entry risk is real but depends on reliable FDA-approved injectable supply.
• The product’s commercial value is based on clinical necessity and limited competition, not a modern patent cliff.

FAQs About Bicillin L-A Market Competition and Financial Risk

Is Bicillin L-A a biologic drug?

No. Bicillin L-A is a conventional small-molecule antibiotic containing penicillin G benzathine. Biosimilar approval is therefore not the applicable competitive pathway.

Can oral penicillin replace Bicillin L-A?

Not in every indication. Oral therapy may be clinically appropriate in some infections, but it does not provide the same long-acting intramuscular exposure and is not an equivalent replacement for all syphilis or prophylaxis regimens.

Why can an old antibiotic remain difficult to genericize?

The drug substance may be old, but the product requires controlled sterile manufacturing, suspension uniformity, validated filling, quality testing, and reliable commercial-scale supply. Those requirements can deter competitors even without strong patents.

Does a Bicillin L-A shortage increase Pfizer’s revenue?

Not necessarily. A shortage can increase demand and pricing pressure while reducing the number of units Pfizer can sell. Reported company filings do not provide enough product-level data to quantify the net effect.

What would most threaten Pfizer’s Bicillin L-A franchise?

The greatest threat would be a U.S.-approved competitor that can produce and distribute a therapeutically substitutable benzathine penicillin G injection consistently. A patent challenge alone would have limited effect without manufacturing capacity.

References

1. Centers for Disease Control and Prevention. (2021). Sexually transmitted infections treatment guidelines, 2021. https://www.cdc.gov/std/treatment-guidelines/default.htm

2. Centers for Disease Control and Prevention. (2024). Sexually transmitted infections surveillance 2022. https://www.cdc.gov/std/statistics/2022/default.htm

3. U.S. Food and Drug Administration. (2017). FDA warns about medication errors with Bicillin C-R and Bicillin L-A. https://www.fda.gov

4. U.S. Food and Drug Administration. (2023a). Bicillin L-A prescribing information. Pfizer Laboratories. https://labeling.pfizer.com

5. U.S. Food and Drug Administration. (2023b). Drug shortages: Bicillin L-A. https://www.accessdata.fda.gov/scripts/drugshortages/

6. U.S. Food and Drug Administration. (2023c). FDA allows temporary importation of benzathine penicillin G during shortage. https://www.fda.gov

7. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. https://www.fda.gov/drugs/drug-approvals-and-databases/approved-drug-products-therapeutic-equivalence-evaluations-orange-book

8. Pfizer Inc. (2024). Annual report 2023. https://www.pfizer.com/investors/financial-reports-annual-reports