List of Excipients in Branded Drug VANTAS

Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
Endo Pharmaceuticals Inc	VANTAS	histrelin acetate	67979-500	2-HYDROXYETHYL METHACRYLATE
Endo Pharmaceuticals Inc	VANTAS	histrelin acetate	67979-500	DI-(4-TERT-BUTYLCYCLOHEXYL)PEROXYDICARBONATE
Endo Pharmaceuticals Inc	VANTAS	histrelin acetate	67979-500	METHYL BENZOIN

Last updated: August 2, 2026

Vantas is a one-year, nonbiodegradable histrelin acetate implant for androgen-deprivation therapy in men with advanced prostate cancer. Its commercial value is concentrated in controlled-release implant engineering, sterile drug-device manufacturing, insertion-system design, and supply-chain control of the polymer matrix rather than in conventional tablet excipients. The principal generic opportunity is a 505(j) or 505(b)(2)-type implant with matching drug release, dimensional, mechanical, sterility, and insertion characteristics.

Vantas Excipient Strategy, Patent Protection, and Commercial Opportunities

What is Vantas and how is it administered?

Vantas contains 50 mg of histrelin acetate in a cylindrical subcutaneous implant designed to release histrelin continuously for approximately 12 months. The product is implanted in the inner aspect of the upper arm and requires a minor surgical procedure for insertion and removal. It is approved for the palliative treatment of advanced prostate cancer in adults. [1]

Attribute	Vantas
Active ingredient	Histrelin acetate
Drug class	Gonadotropin-releasing hormone agonist
Dosage form	Subcutaneous implant
Nominal drug load	50 mg
Release period	Approximately 12 months
Administration	Subcutaneous insertion in the upper arm
U.S. regulatory pathway	New drug application 021288
Therapeutic use	Advanced prostate cancer
Product type	Nonbiodegradable controlled-release implant
Key commercial requirement	Annual insertion and removal procedure

The product is differentiated from injectable leuprolide, goserelin, and degarelix by its annual implant format. That format reduces dosing frequency but increases manufacturing, sterilization, packaging, procedural, and training requirements.

What excipients are used in the Vantas implant?

The Vantas implant uses a polymeric drug-release matrix rather than conventional oral excipients. The FDA prescribing information identifies histrelin acetate dispersed in a hydrogel polymer matrix and lists stearic acid and ethylene-vinyl acetate copolymer among the inactive ingredients. [1]

Functional role of each excipient

Component	Functional role	Commercial and technical relevance
Ethylene-vinyl acetate copolymer	Controls diffusion of histrelin from the implant	Polymer grade, vinyl acetate content, molecular weight, and processing conditions affect release
Stearic acid	Matrix-processing and release-modifying excipient	Can affect drug dispersion, extrusion behavior, implant integrity, and initial release
Polymer matrix	Provides the physical implant structure	Must remain stable in vivo for the intended treatment period
Histrelin acetate	Peptide active ingredient	Sensitive to aggregation, degradation, moisture, heat, and processing stress

The product does not depend on a complex mixture of conventional fillers, binders, lubricants, or coating systems. Its critical quality attributes are dominated by the interaction between the peptide, polymer, implant geometry, and manufacturing process.

How does the Vantas excipient system control drug release?

Vantas is a diffusion-controlled implant. Histrelin migrates through the polymer matrix and exits through the implant surface over time. The release profile is controlled by several variables:

1. Polymer composition and grade.
2. Histrelin loading and particle distribution.
3. Stearic acid concentration and distribution.
4. Implant diameter and length.
5. Extrusion temperature and residence time.
6. Porosity, crystallinity, and surface characteristics.
7. Sterilization conditions.
8. Packaging and storage humidity.

Small changes in these parameters can affect the initial burst, average daily release, terminal release, and residual drug content after removal. A commercial competitor cannot treat the implant as a simple blend-and-fill product.

Primary formulation risks

Histrelin is a peptide. The main formulation risks include chemical degradation, aggregation, adsorption to processing equipment, moisture sensitivity, and thermal exposure. Extrusion conditions must preserve peptide potency while creating a mechanically stable implant.

Ethylene-vinyl acetate offers established controlled-release performance, but it is nonbiodegradable. Patients generally require removal after the treatment period. That creates a procedural burden but also reduces the need to prove complete in vivo polymer degradation.

What formulation patents protect Vantas?

The core intellectual-property strategy for Vantas is likely to center on implant composition, controlled-release structure, manufacturing methods, and use of histrelin for androgen deprivation. The relevant patent categories are more important commercially than any single excipient patent.

Patent category	Potential claim scope	Competitive significance
Drug-polymer implant	Histrelin dispersed in a polymer matrix	Core product composition
Controlled-release formulation	Release rate over approximately one year	Supports bioequivalence and performance differentiation
Implant geometry	Dimensions, drug load, and surface area	May limit design-around options
Manufacturing process	Mixing, extrusion, cutting, drying, and sterilization	Can create process know-how barriers
Implantation method	Subcutaneous placement and removal	Usually weaker than composition claims
Prostate-cancer treatment	Histrelin use for androgen suppression	Potential method-of-use protection
Insertion system	Trocar, sleeve, applicator, or procedural kit	Device and combination-product protection

The original Vantas patent estate is unlikely to provide the same exclusivity strength as a newly launched product. Vantas was approved in 2004, so any original U.S. composition or formulation patents would generally be expected to approach or reach their ordinary 20-year term unless patent-term adjustment, patent-term extension, continuation claims, or later improvements apply. Patent term must be confirmed patent by patent through the USPTO and FDA Orange Book. [2,3]

Is Vantas protected by active Orange Book patents?

FDA Orange Book status is the controlling source for listed patents and regulatory certification requirements. The relevant product is Vantas under NDA 021288. A business decision should distinguish:

• patents listed for Vantas itself;
• patents listed for other histrelin products, such as Supprelin LA;
• expired patents;
• pediatric exclusivity;
• unlisted manufacturing know-how;
• device or procedural rights outside the Orange Book.

An Orange Book listing does not establish that every claim is enforceable, and the absence of a listed patent does not eliminate trade-secret or manufacturing barriers. [2]

When does Vantas lose exclusivity?

Vantas received new chemical entity exclusivity after its 2004 approval, which would have provided five years of FDA exclusivity, subject to the applicable submission rules. That period has expired. Any remaining market protection depends on patent term, regulatory exclusivity, product availability, and the practical difficulty of demonstrating equivalence for the implant. [1,2]

Protection type	Vantas position
New chemical entity exclusivity	Expired
Pediatric exclusivity	Associated primarily with the separate pediatric histrelin product, not a substitute for Vantas patent protection
Patent protection	Requires current Orange Book and USPTO review
Regulatory exclusivity for an implant	No general one-year implant exclusivity applies solely because of dosage form
Trade secrets	Potentially important in extrusion, sterilization, release testing, and packaging
Device protection	May apply to insertion or removal systems, depending on ownership and claim scope

A generic applicant could face a technically demanding development program even if no blocking patent remains. The principal barrier may be approval risk rather than formal patent exclusivity.

Are there Paragraph IV challenges to Vantas?

A Paragraph IV applicant would need to certify that listed Vantas patents are invalid, unenforceable, or not infringed. Because Vantas is an implant, the commercial filing strategy differs from a conventional oral generic.

A prospective applicant would need to address:

• sameness of active ingredient;
• implant dimensions;
• polymer composition;
• drug-release profile;
• sterility assurance;
• extractables and leachables;
• insertion and removal procedure;
• stability;
• residual drug after the dosing interval;
• bioequivalence and pharmacodynamic comparability.

The risk profile is more complex than for a tablet because the FDA may scrutinize product performance and manufacturing comparability in addition to drug exposure. Publicly documented Paragraph IV litigation should be evaluated against the current Orange Book listing for NDA 021288 rather than inferred from litigation involving Supprelin LA or unrelated histrelin products.

What FDA pathway is available for a Vantas competitor?

The most direct route is an abbreviated new drug application if FDA determines that the proposed implant can be shown to be therapeutically equivalent to Vantas. The sponsor would need to establish pharmaceutical equivalence and bioequivalence under the applicable product-specific guidance and FDA review expectations.

A 505(b)(2) application may be considered where the proposed product differs in formulation, implant design, release duration, insertion method, or other material characteristic. That route may offer greater design flexibility but can require additional clinical, pharmacokinetic, pharmacodynamic, or safety evidence. [4]

Regulatory evidence package

A credible development program would include:

• peptide identity, potency, purity, and impurity controls;
• polymer characterization;
• content uniformity;
• implant dimensions and mechanical strength;
• in vitro release testing;
• accelerated and long-term stability;
• sterility and bacterial endotoxin testing;
• particulate and visible defect testing;
• extractables and leachables;
• in vivo pharmacokinetic or pharmacodynamic data where required;
• insertion and removal performance;
• container-closure integrity;
• human factors data for the applicator or procedure kit.

The release method is particularly important. A poorly discriminatory in vitro assay can allow batch-to-batch variability that appears only after clinical use.

What manufacturing barriers protect Vantas commercially?

The main manufacturing barrier is controlled extrusion of a peptide-containing polymer matrix. The process must produce uniform drug distribution without excessive heat, shear, moisture, or residence time.

Critical manufacturing steps

Raw-material qualification

The polymer must have controlled molecular-weight distribution, vinyl acetate content, residual monomer profile, and thermal behavior. Stearic acid must meet pharmaceutical-grade specifications and show consistent particle-size and blending characteristics.

Drug-polymer blending

Histrelin acetate must be distributed uniformly throughout the matrix. Segregation can create dose nonuniformity and an unacceptable initial release.

Extrusion and cutting

The extrudate must meet tight dimensional tolerances. Diameter changes directly affect surface area and release rate. Cutting must avoid cracks, delamination, or exposed drug-rich regions.

Sterilization

The sterilization method must preserve peptide potency and polymer integrity. Gamma irradiation, electron-beam exposure, and other methods can generate different degradation profiles and extractables. Sterile processing and packaging may be more difficult than the drug formulation itself.

Packaging

The package must control moisture and protect the implant from mechanical damage. Packaging components also require extractables and leachables assessment.

Process knowledge can therefore create a meaningful barrier even after formal patent expiry. A competitor with a qualified implant line, validated release method, and reliable sterile packaging may have an advantage over a sponsor that only possesses a chemically similar formulation.

What commercial opportunities exist for Vantas excipients?

Generic Vantas implant

The clearest opportunity is a lower-cost annual histrelin implant. The addressable market is limited by the size of the prostate-cancer population receiving long-acting androgen-deprivation treatment and by competition from injectable therapies.

A successful generic would need to compete on:

• product price;
• physician familiarity;
• continuity of supply;
• insertion-kit availability;
• reimbursement;
• procedural support;
• removal and replacement logistics.

Improved implant formulation

A reformulated product could pursue a 505(b)(2) strategy with:

• a longer release period;
• a shorter implant;
• easier insertion;
• lower removal burden;
• improved peptide stability;
• reduced initial burst;
• a biodegradable matrix;
• a preloaded applicator;
• lower residual drug at removal.

Each change increases development and regulatory requirements. A biodegradable implant could remove the need for surgical retrieval, but it would introduce new control requirements for polymer degradation, local tissue response, and release consistency.

Excipient and polymer supply

Specialty polymer suppliers can capture value by providing:

• pharmaceutical-grade ethylene-vinyl acetate;
• controlled polymer grades;
• custom compounding;
• low-bioburden materials;
• validated sterilization compatibility;
• regulatory documentation;
• dual-source supply.

For this product class, supply qualification is commercially important because a polymer substitution can alter release kinetics and trigger comparability work.

Contract development and manufacturing

CDMOs with peptide handling, extrusion, sterile manufacturing, and implant packaging capabilities are positioned to support:

• generic development;
• 505(b)(2) reformulation;
• lifecycle management;
• clinical-scale batches;
• commercial supply;
• analytical method transfer.

The strongest CDMO position combines drug-product development with device assembly and sterile packaging.

Pediatric and adjacent indications

Histrelin is also used in the pediatric central precocious puberty market through Supprelin LA. That product is commercially distinct from Vantas, but the shared active ingredient and implant technology create opportunities in:

• common excipient platforms;
• shared extrusion equipment;
• analytical methods;
• packaging;
• insertion systems;
• manufacturing scale.

A sponsor must treat the Vantas and Supprelin LA markets as separate regulatory and commercial products because indication, labeling, dosage presentation, and reference-product considerations differ.

How does Vantas compare with injectable androgen-deprivation products?

Product type	Typical dosing interval	Procedure	Formulation complexity	Commercial advantage
Vantas histrelin implant	Approximately 12 months	Minor insertion and removal procedure	High	Lowest dosing frequency
Leuprolide depot	One to six months, depending on presentation	Injection	Moderate	Broad availability and physician familiarity
Goserelin implant	One to six months, depending on presentation	Injection or implant-style administration	Moderate	Established treatment pathway
Degarelix injection	Monthly	Injection	Moderate	Rapid testosterone suppression without initial agonist flare
Oral GnRH antagonists	Daily	None	Conventional oral formulation	Avoids procedures and implant removal

Vantas can support adherence by eliminating repeated injections, but its procedural requirements limit use in some practices. The product is most attractive where annual treatment continuity and fewer clinic visits offset implant insertion and removal logistics.

What litigation and settlement risks affect Vantas?

The principal litigation issues would involve:

• validity or infringement of listed implant patents;
• patent-term calculations;
• Orange Book listing disputes;
• manufacturing-process claims;
• insertion-device claims;
• settlement timing;
• product-launch restrictions;
• supply agreements;
• antitrust scrutiny of delayed generic entry.

A Paragraph IV settlement could define an authorized-generic launch, a licensed generic, or an agreed entry date. The commercial value of a settlement depends on the remaining patent term, the reference product's market share, the cost of implant manufacturing, and whether other companies are developing competing products.

No settlement should be valued from patent expiry alone. A launch may still be delayed by manufacturing validation, FDA review, device readiness, reimbursement, and physician adoption.

How strong is the Vantas patent estate?

The estate appears more vulnerable on age than on formulation complexity. The original product was approved in 2004, and the principal exclusivity period has elapsed. Any remaining strength would most likely come from later patents covering specific implant structures, manufacturing processes, applicators, or improved release profiles.

Strength factor	Assessment
Active-ingredient exclusivity	Low; histrelin is an established peptide therapy
Original product-age protection	Limited because of the 2004 approval date
Formulation complexity	High
Manufacturing know-how	Potentially high
Device and applicator barriers	Moderate, depending on claim scope
Generic bioequivalence risk	Higher than for oral products
Substitution risk from injections and oral agents	Material
Long-term commercial moat	More dependent on execution than on basic excipient patents

The most defensible commercial assets are likely to be validated manufacturing processes, release specifications, sterile production capacity, and clinical relationships rather than broad excipient claims.

What geographic opportunities exist for Vantas technology?

The United States is the most important market for Orange Book-driven generic competition. Europe and other jurisdictions apply different regulatory, patent, and reimbursement systems. A sponsor may pursue:

• U.S. ANDA or 505(b)(2) development;
• European hybrid application strategies;
• licensing of implant technology to regional manufacturers;
• supply agreements for polymer matrices;
• localized packaging and insertion systems;
• combination-product registrations where required.

Geographic expansion is constrained by local acceptance of implant procedures, reimbursement for insertion and removal, availability of trained clinicians, and product-specific approval requirements.

Key Takeaways

• Vantas is a 50 mg histrelin acetate, approximately one-year subcutaneous implant for advanced prostate cancer.
• Its principal excipients are a hydrogel polymer matrix, ethylene-vinyl acetate copolymer, and stearic acid.
• The key technical challenge is not excipient selection alone. It is uniform peptide dispersion and reproducible diffusion-controlled release.
• Original chemical exclusivity has expired. Current patent exposure depends on active Orange Book listings, later patents, and device or manufacturing rights.
• A generic Vantas implant faces greater development risk than an oral generic because of release testing, sterility, implant mechanics, insertion, removal, and manufacturing comparability.
• The strongest commercial opportunities are a lower-cost generic, an improved 505(b)(2) implant, specialty polymer supply, and CDMO services.
• The Vantas and Supprelin LA markets share technology but require separate regulatory and commercial strategies.
• Manufacturing know-how may be more valuable than broad excipient patent protection.

FAQs about Vantas excipient and commercial strategy

Is ethylene-vinyl acetate the main release-controlling material in Vantas?

Yes. Ethylene-vinyl acetate forms the principal polymeric matrix controlling histrelin diffusion. Polymer grade and implant geometry materially affect release.

Can Vantas be reformulated with a biodegradable polymer?

Potentially, but a biodegradable replacement would likely require a different regulatory strategy and additional evidence on degradation, local tolerability, release kinetics, and residual material.

Does Vantas require an applicator patent for market entry?

Not necessarily. A competitor may develop a noninfringing insertion system, but it must demonstrate safe and reliable placement and removal of the implant.

Is a histrelin injection a direct substitute for Vantas?

No. Vantas provides annual implant-based delivery. Injectable androgen-deprivation products differ in administration, dosing interval, release mechanism, and procedure requirements.

What is the highest-value development asset for a Vantas competitor?

A validated sterile extrusion and release-testing platform is likely the highest-value asset because it addresses the main technical and regulatory barriers to commercial supply.

References

1. U.S. Food and Drug Administration. (n.d.). Vantas (histrelin acetate) implant prescribing information. NDA 021288.

2. U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations: Orange Book. https://www.accessdata.fda.gov/scripts/cder/ob/

3. United States Patent and Trademark Office. (n.d.). Patent term adjustment and patent term information. https://www.uspto.gov/

4. U.S. Food and Drug Administration. (2019). Applications covered by Section 505(b)(2). FDA guidance and regulatory materials.