List of Excipients in Branded Drug RENFLEXIS

RENFLEXIS Excipient Strategy and Commercial Opportunities

Last updated: August 20, 2026

Renflexis (infliximab-abda) is a lyophilized intravenous biosimilar containing infliximab, sucrose, polysorbate 80, and phosphate buffers. Its excipient profile is commercially conservative: sucrose stabilizes the protein during freeze-drying, polysorbate 80 limits interfacial aggregation, and phosphate salts control pH. The main commercial opportunities are not new excipient claims around the existing vial, but differentiated presentations, improved reconstitution, reduced dosing waste, cold-chain robustness, and device-enabled administration.

Renflexis is marketed in the United States by Organon and was developed by Samsung Bioepis. It is biosimilar to Johnson & Johnson’s Remicade (infliximab), with FDA approval covering rheumatoid arthritis, Crohn’s disease, ulcerative colitis, ankylosing spondylitis, psoriatic arthritis, and plaque psoriasis in the relevant approved populations.[1]

What excipients are in Renflexis?

Renflexis is supplied as a sterile, white to slightly yellow lyophilized powder in a single-dose 100 mg vial. The labeled excipients are:

Excipient	Primary function	Commercial relevance
Sucrose	Cryoprotectant and lyoprotectant	Supports protein stability during freezing and drying
Polysorbate 80	Surfactant	Reduces adsorption and aggregation at air-liquid and container interfaces
Sodium phosphate monobasic monohydrate	Buffer component	Supports pH control
Sodium phosphate dibasic anhydrous	Buffer component	Completes phosphate buffering system

The product is reconstituted and diluted before intravenous infusion. The label instructs healthcare professionals to use sterile water for injection for reconstitution and to further dilute the resulting solution in 0.9% sodium chloride injection.[1]

Why does Renflexis use sucrose?

Sucrose is a standard stabilizer for monoclonal antibodies in lyophilized formulations. During freezing and drying, it can help preserve the native protein structure by replacing some water-protein interactions and limiting damage caused by ice formation and dehydration.

Sucrose also supports the commercial choice of a lyophilized vial. A freeze-dried biologic can have improved storage stability relative to an aqueous formulation, although it still requires controlled refrigerated storage and careful reconstitution. For Renflexis, sucrose is part of a conventional formulation architecture rather than a publicly identified differentiated technology.

Why is polysorbate 80 included?

Polysorbate 80 reduces protein adsorption to vial surfaces, infusion containers, and tubing. It also helps limit agitation-induced aggregation. These functions matter during shipping, reconstitution, dilution, and intravenous administration.

Polysorbate 80 can degrade through oxidation and hydrolysis, generating species that may affect protein quality or create subvisible particles. That creates potential development opportunities around surfactant grade, impurity control, analytical release testing, and alternative surfactants. Any substitution would require a comparability package covering aggregation, particles, potency, immunogenicity-related attributes, and stability.

What role do the phosphate buffers play?

Phosphate salts maintain the formulation pH during storage and reconstitution. The buffer system must balance protein stability with compatibility during dilution and infusion.

Phosphate concentration and pH can affect antibody aggregation, charge variants, viscosity, and adsorption. A reformulation using histidine, citrate, or another buffer could create a distinct product profile, but it would also introduce comparability and regulatory risk. For a biosimilar, an excipient change cannot be evaluated only by chemical similarity. The sponsor would need to demonstrate that the change does not alter clinical performance or immunogenicity risk.

What is the FDA regulatory status of Renflexis?

Renflexis is approved under the FDA’s abbreviated 351(k) biosimilar pathway. The FDA approved infliximab-abda in April 2017 as a biosimilar to Remicade.[2]

Regulatory item	Renflexis status
Active ingredient	Infliximab-abda
Reference product	Remicade, infliximab
FDA pathway	Biologics Price Competition and Innovation Act, section 351(k)
Dosage form	Lyophilized powder for intravenous infusion
Strength	100 mg per vial
Interchangeable designation	No FDA interchangeable designation identified in the cited labeling
Primary U.S. commercial entities	Samsung Bioepis and Organon
Reference-product exclusivity	Remicade’s 12-year U.S. reference-product exclusivity has expired
Orange Book listing	Not the principal biologic patent reference; biologic-related patent and exclusivity information is handled through the Purple Book and related patent procedures

The FDA label states that Renflexis has the same route of administration and dosage form as Remicade and that its approved indications are based on the biosimilarity determination and the reference product’s labeling.[1]

What patents protect Renflexis and its excipient formulation?

Renflexis is a biosimilar, not the originator product. Its commercial protection is therefore based primarily on regulatory approval, manufacturing know-how, process controls, and market access rather than on a publicly prominent composition-of-matter patent covering a new active molecule.

The core Remicade molecule was developed and commercialized before modern biologic patent landscapes became standardized. Many early infliximab patents have expired or are no longer the principal barriers to U.S. entry. The material patent issues for Renflexis relate more closely to:

• Cell-line development and expression systems
• Upstream and downstream manufacturing processes
• Purification methods
• Formulation and stability
• Device or delivery systems
• Manufacturing controls and analytical methods
• Potential product-specific patents covering biosimilar presentations

Publicly available product labeling identifies Renflexis excipients but does not establish that sucrose, polysorbate 80, and phosphate salts are protected by a current, Renflexis-specific composition patent. Standard excipients generally provide limited exclusionary value because they are widely used across biologics and are difficult to protect as broad standalone inventions.

Are Renflexis excipients listed in the Orange Book?

No conventional Orange Book strategy should be assumed for Renflexis. The Orange Book primarily lists approved small-molecule drug products and associated patents. Biological products approved under the Public Health Service Act are tracked through the FDA Purple Book framework, while patent disputes may arise under the biologics patent-exchange process established by the Biologics Price Competition and Innovation Act.[3][4]

For commercial diligence, the relevant questions are whether a patent covers the product, formulation, manufacturing process, delivery system, or use, and whether that patent is enforceable against a competing biologic. An excipient appearing in the FDA label does not itself establish patent protection.

When does Renflexis lose exclusivity?

Renflexis did not receive a new 12-year reference-product exclusivity period because it was approved as a biosimilar. Its market position depends on the expiration of Remicade-related barriers and on any patents or settlement restrictions affecting individual competitors.

The practical exclusivity timeline is:

Event	Date or status
Remicade FDA approval	1998
Renflexis FDA approval	April 2017
U.S. reference-product exclusivity for Remicade	Expired before Renflexis approval
Renflexis product-specific biologic exclusivity	Not a separate 12-year period
Generic-style substitution	Not applicable in the same manner as small-molecule generics
Interchangeability	Requires a separate FDA designation; biosimilar approval alone does not establish automatic pharmacy substitution

Renflexis can face competition from other infliximab biosimilars without waiting for a new Renflexis exclusivity period to expire. Competition is driven by biosimilar approvals, payer contracting, hospital formulary decisions, provider familiarity, and net pricing.

Which companies compete with Renflexis?

The U.S. infliximab market includes the originator Remicade and multiple biosimilar products. Key competitors include:

Product	Active ingredient	Sponsor or commercial entity	Competitive position
Remicade	Infliximab	Janssen Biotech and related entities	Originator brand
Renflexis	Infliximab-abda	Organon; Samsung Bioepis	Early U.S. biosimilar entrant
Inflectra	Infliximab-dyyb	Pfizer; Celltrion development partner	Early U.S. biosimilar competitor
Avsola	Infliximab-axxq	Amgen	Later U.S. biosimilar competitor

The competitive differentiation is not primarily excipient-driven. All products must satisfy demanding biologic comparability requirements, but providers and payers typically focus on acquisition cost, contracting, supply reliability, infusion-center economics, reimbursement, interchangeability status, and manufacturer support.

How does Renflexis compare with Remicade?

Renflexis uses a similar lyophilized intravenous presentation and the same general therapeutic mechanism as Remicade. The products are not identical in every manufacturing attribute because biologics are made in living systems, but the FDA determined that Renflexis is highly similar to Remicade and has no clinically meaningful differences in safety, purity, and potency for the approved uses.[1][2]

Issue	Renflexis	Remicade
Regulatory status	Biosimilar	Reference biologic
Administration	Intravenous infusion	Intravenous infusion
Common vial strength	100 mg	100 mg
Formulation type	Lyophilized powder	Lyophilized powder
Excipient strategy	Sucrose, polysorbate 80, phosphate salts	Comparable conventional biologic excipient approach
Automatic substitution	Not established solely by biosimilarity	Originator product
Main commercial lever	Net price and contracting	Brand loyalty, clinical history, contracting

What commercial opportunities exist for Renflexis excipient strategy?

The existing excipients provide a stable platform, but they offer limited differentiation by themselves. The strongest opportunities are product-development programs that use excipient changes to reduce operational friction.

1. Improve reconstitution time

A 100 mg lyophilized vial requires reconstitution before dilution and infusion. Faster dissolution could reduce nursing time and improve infusion-center throughput.

Potential approaches include:

• Optimizing cake structure and pore size
• Adjusting sucrose concentration
• Reducing residual moisture
• Improving vial geometry
• Developing controlled swirling instructions
• Using more efficient diluents or transfer devices

The commercial value is highest in high-volume infusion centers where preparation labor and chair utilization directly affect margins.

2. Develop a ready-to-dilute or liquid presentation

An aqueous, ready-to-dilute formulation could remove reconstitution steps. The principal technical barriers are protein aggregation, oxidation, particle formation, viscosity, surfactant degradation, and long-term refrigerated stability.

A liquid product could use:

• Alternative buffer systems
• Different sugar or polyol stabilizers
• Optimized polysorbate levels
• Histidine or citrate buffering
• Improved container-closure systems
• Low-binding infusion components

A liquid presentation would likely require a substantial comparability program. It could also create a new product configuration with separate intellectual-property opportunities around formulation, container closure, and manufacturing.

3. Reduce polysorbate-related degradation

Polysorbate 80 is useful but can produce degradation products that affect biologic quality. A targeted excipient strategy could focus on:

• Higher-purity polysorbate 80
• Tighter control of peroxide and fatty-acid impurities
• Stabilized surfactant grades
• Poloxamer or other surfactant alternatives
• Packaging systems that reduce oxidation exposure

A successful program could improve shelf life or reduce subvisible particles. The challenge is proving that the modified excipient system maintains clinical comparability.

4. Improve cold-chain tolerance

Renflexis is refrigerated. Excipient and lyophilization optimization could expand allowable excursion limits or increase stability during short shipping disruptions.

Commercial benefits include:

• Lower product loss
• Greater distributor flexibility
• Improved supply to smaller hospitals
• Reduced temperature-monitoring costs
• Better access in markets with weaker cold-chain infrastructure

The opportunity is more likely to produce manufacturing or formulation know-how than broad composition claims.

5. Reduce dose and vial waste

Infliximab dosing is weight-based, and the 100 mg vial may not match a patient’s calculated dose. Unused drug can be discarded after preparation, depending on handling conditions and institutional policy.

Potential commercial strategies include:

• Additional vial strengths
• More concentrated formulations
• Smaller-dose presentations
• Pharmacy compounding and transfer systems
• Contracting models tied to vial utilization
• Dose-rounding support tools

Additional strengths could reduce waste but would increase manufacturing complexity, inventory requirements, validation costs, and regulatory filings.

6. Enable subcutaneous or device-based delivery

The current Renflexis label covers intravenous infusion. A subcutaneous formulation would require a materially different concentration and delivery profile because monoclonal antibodies can be highly viscous at the concentrations required for injection.

Potential technologies include:

• High-concentration formulations
• Autoinjectors
• Prefilled syringes
• On-body delivery systems
• Hyaluronidase-enabled subcutaneous administration
• Dual-chamber devices

This is a major commercial opportunity but also a high-risk development path. It would compete with other subcutaneous anti-TNF products and could require new clinical, device, immunogenicity, and human-factors evidence.

What formulation patents could protect a Renflexis follow-on product?

A differentiated formulation patent would need more than the presence of a conventional excipient. Stronger claim strategies could focus on a defined combination of:

• Infliximab concentration
• Buffer identity and pH range
• Sucrose or alternative stabilizer concentration
• Surfactant concentration and impurity profile
• Low aggregate content after defined stress conditions
• Freeze-drying cycle parameters
• Residual moisture limits
• Container-closure configuration
• Reconstitution time
• Stability under defined temperature excursions

Manufacturing claims could cover cell culture conditions, purification sequences, viral clearance, aggregate removal, or process controls. These claims may have greater practical value than broad excipient claims because they can be difficult for competitors to design around without affecting product quality.

Patent strength should be assessed using five factors:

Factor	Stronger position	Weaker position
Claim scope	Specific formulation-performance relationship	Generic listing of known excipients
Technical effect	Demonstrated stability or reduced aggregation	No unexpected result
Enablement	Broad data across concentrations and conditions	Narrow example support
Design-around risk	Multiple interdependent limitations	One easily substituted excipient
Enforcement evidence	Product testing can identify infringement	Process steps hidden from public view

What patent litigation and Paragraph IV risks affect Renflexis?

Paragraph IV litigation is principally associated with abbreviated new drug applications for small-molecule products. Renflexis and competing infliximab biosimilars proceed through the biologics framework, not the standard ANDA Paragraph IV pathway.

For infliximab biosimilars, legal risk can involve:

• Patent infringement allegations
• Biosimilar patent-exchange negotiations
• Declaratory-judgment actions
• Manufacturing-process patents
• Formulation patents
• Delivery-device patents
• Method-of-use patents
• Settlement agreements governing launch dates

A biosimilar sponsor may launch after patent expiration, under a license, after settlement, or at litigation risk. Settlement terms can materially affect market entry and discount depth.

The absence of a conventional Paragraph IV certification does not mean that Renflexis has no patent risk. It means that the legal pathway and dispute mechanics differ from those used for small-molecule generics.

What method-of-use patents affect infliximab products?

Method-of-use patents may cover treatment of inflammatory conditions, dosing schedules, patient subgroups, combination therapy, or administration protocols. Their commercial value depends on claim scope and whether the relevant indication is carved out from a biosimilar label.

Infliximab products have broad use across autoimmune and inflammatory diseases. A sponsor seeking to preserve a protected indication may use a label strategy that omits a patented use, subject to FDA requirements and applicable patent law. Prescribers, payers, and pharmacies may still create practical substitution issues, especially where products share most indications.

Method-of-use patents are generally less relevant to excipient strategy than formulation and manufacturing patents. They can still affect launch sequencing and contracting.

What licensing deals support Renflexis commercialization?

Renflexis was developed by Samsung Bioepis and commercialized in the United States through a collaboration with Merck, later associated with Organon after the separation of Merck’s established brands business. Organon became the U.S. commercial partner for Renflexis.[5]

The partnership model illustrates a common biosimilar structure:

• One company funds or conducts development and manufacturing.
• A commercial partner manages market access, distribution, and contracting.
• The parties share development, supply, and commercial economics under private agreements.
• Patent settlements may determine launch timing for individual markets.

Commercial diligence should distinguish between product ownership, marketing authorization, manufacturing responsibility, and distribution rights. Those roles can be split among multiple affiliates and can vary by country.

What geographic opportunities exist for Renflexis excipients and manufacturing?

Renflexis-related commercial opportunities differ by jurisdiction. The United States emphasizes FDA biosimilar approval, payer substitution, and biologic patent disputes. Europe relies on centralized authorization and national reimbursement decisions. Emerging markets may place greater value on shelf-life, temperature tolerance, manufacturing cost, and supply continuity.

Geographic expansion opportunities include:

• Regional fill-finish partnerships
• Local secondary packaging
• Technology-transfer agreements
• Additional manufacturing sites
• Reduced cold-chain requirements
• Country-specific vial configurations
• Hospital tender strategies
• Ex-U.S. formulation or device licenses

Manufacturing know-how can be more valuable than a narrow excipient patent where regulatory authorities require extensive process validation and product-specific comparability data.

How strong is the Renflexis patent and excipient estate?

The Renflexis excipient estate is best characterized as moderate for operational know-how and limited for broad, publicly visible excipient exclusivity.

Asset category	Strategic strength
Conventional excipient composition	Low to moderate
Lyophilization cycle and cake structure	Moderate
Polysorbate impurity control	Moderate
Manufacturing process	Moderate to strong if difficult to reproduce
Formulation with unexpected stability result	Moderate to strong
Device-enabled delivery	Potentially strong
Method-of-use patents	Indication-dependent
Regulatory and commercial execution	High practical importance

The strongest defensibility would likely come from an integrated package combining formulation, process, analytical controls, supply reliability, and payer contracting. A competitor may be able to copy the listed excipients, but reproducing the entire quality profile and commercial supply system can be more difficult.

What generic and biosimilar launch risks exist for Renflexis?

Renflexis faces biosimilar competition rather than conventional generic substitution. Key risks include:

1. Price erosion from multiple infliximab biosimilars.
2. Hospital tenders favoring the lowest net-cost product.
3. Payer formularies that move patients between infliximab products.
4. Reduced differentiation from the Remicade brand.
5. Manufacturing interruptions or limited vial supply.
6. Provider resistance to switching stable patients.
7. Lack of automatic substitution where no interchangeable designation exists.
8. Margin pressure from rebates and contracting.
9. Formulation changes that trigger regulatory comparability work.
10. Competitive migration to subcutaneous anti-TNF products.

The main commercial defense is a lower total cost of treatment, supported by reliable supply and efficient infusion-center operations. Excipient improvements matter when they reduce preparation time, waste, product loss, or temperature excursions.

What revenue exposure is linked to Renflexis?

Renflexis revenue is exposed to the broader erosion of the Remicade market. The relevant metrics are not only unit sales but also:

• Net price per 100 mg vial
• Average discount to Remicade
• Hospital and clinic share
• Payer-covered lives
• Infusion-center purchasing volume
• Vial waste rate
• Average dose per patient
• Supply fill rate
• Contract renewal rate
• Share of new starts versus switching patients

A formulation that reduces waste by even one vial fraction per treatment can have economic value in high-volume centers. A ready-to-use product could command a premium if it reduces labor and chair time, but that premium must be weighed against the cost of new manufacturing, validation, regulatory filings, and inventory.

Key Takeaways

• Renflexis uses sucrose, polysorbate 80, sodium phosphate monobasic monohydrate, and sodium phosphate dibasic anhydrous.
• The current excipient system is conventional for a lyophilized monoclonal antibody.
• Broad excipient patent protection is likely weaker than protection based on formulation performance, manufacturing, or device integration.
• The most credible commercial opportunities are faster reconstitution, lower vial waste, better excursion stability, liquid presentation, and subcutaneous delivery.
• Renflexis is regulated as a biosimilar under section 351(k), not as a small-molecule generic.
• Paragraph IV analysis does not directly apply; biologic patent disputes use a different statutory framework.
• Competition is driven by infliximab biosimilars, payer contracting, hospital tenders, supply reliability, and infusion economics.
• Manufacturing know-how and commercial execution may provide more durable value than the listed excipients alone.

FAQs About Renflexis Excipient Strategy

Does Renflexis contain polysorbate 80?

Yes. Polysorbate 80 is included as a surfactant to limit protein adsorption and aggregation during storage, reconstitution, dilution, and infusion.[1]

Is Renflexis available as a prefilled syringe?

The cited U.S. labeling describes Renflexis as a 100 mg lyophilized powder in a vial for intravenous infusion. It does not describe a prefilled syringe or autoinjector presentation.[1]

Can Renflexis be reformulated without new clinical trials?

Not automatically. A reformulation would require a regulatory comparability assessment. The need for additional clinical evidence would depend on the magnitude and nature of the formulation change, analytical comparability, stability data, and FDA review.

Are Renflexis excipients interchangeable with biosimilar excipients?

No. Biosimilar products may use different excipients, but each formulation must support comparable quality, stability, safety, and immunogenicity outcomes. Excipients cannot be treated as interchangeable solely because they are common in monoclonal-antibody products.

Does Renflexis have a 12-year biologic exclusivity period?

No. Renflexis was approved as a biosimilar to Remicade and did not receive a new 12-year reference-product exclusivity period. Its commercial protection depends on biosimilar approval, patents, settlements, manufacturing capability, and contracting.

References

1. U.S. Food and Drug Administration. (2023). Renflexis (infliximab-abda) prescribing information. Organon LLC.

2. U.S. Food and Drug Administration. (2017). FDA approves Inflectra and Renflexis biosimilars to Remicade. https://www.fda.gov

3. U.S. Food and Drug Administration. (2024). Purple Book: Database of licensed biological products. https://purplebooksearch.fda.gov

4. Biologics Price Competition and Innovation Act, 42 U.S.C. § 262.

5. Organon. (2022). Annual report and product information for Renflexis. Organon & Co.