List of Excipients in Branded Drug HEPLISAV-B

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Last updated: September 24, 2026

ecutive summary. HEPLISAV-B is a two-dose adult hepatitis B vaccine built around recombinant hepatitis B surface antigen and Dynavax’s CpG 1018 adjuvant. Its excipient strategy is commercially important because the product’s differentiation depends less on conventional formulation ingredients than on the stability, manufacturability, and supply security of the CpG 1018 adjuvant system. The main opportunities are long-term oligonucleotide supply, analytical control, vial and syringe presentations, refrigerated distribution, and potential use of CpG 1018 in additional vaccine products.

HEPLISAV-B Excipient Strategy, Patent Position, and Commercial Opportunities

What is the formulation and excipient composition of HEPLISAV-B?

HEPLISAV-B is a recombinant hepatitis B vaccine for adults aged 18 years and older. It uses a 2-dose schedule administered one month apart, unlike many conventional hepatitis B vaccines that require three doses over six months.[1]

Each 0.5 mL dose contains:

Component	Function
Recombinant hepatitis B surface antigen, HBsAg	Vaccine antigen
CpG 1018 adjuvant	Toll-like receptor 9 agonist that enhances immune response
Sodium chloride	Tonicity and formulation control
Polysorbate 80	Surfactant and protein-stabilizing excipient
Water for injection	Vehicle

The formulation is supplied as a sterile injectable suspension in a single-dose vial. The principal formulation differentiator is CpG 1018, not the conventional excipient package. The U.S. prescribing information identifies 20 mcg of HBsAg and 3,000 mcg of CpG 1018 per 0.5 mL dose.[1]

Why is CpG 1018 the critical formulation component?

CpG 1018 is a synthetic oligodeoxynucleotide containing unmethylated CpG motifs. It activates TLR9 in immune cells and promotes a stronger and faster adaptive immune response than antigen-only vaccination. Its commercial value derives from several properties:

• It supports a two-dose adult schedule.
• It can improve seroprotection in populations with weaker vaccine responses.
• It creates a proprietary adjuvant platform separate from the HBsAg antigen.
• It may be applicable to other recombinant protein and subunit vaccines.

CpG 1018 is therefore both an excipient-like adjuvant and a core product-defining active component. Conventional excipients such as sodium chloride and polysorbate 80 are unlikely to create meaningful market exclusivity on their own.

How does HEPLISAV-B compare with competing hepatitis B vaccines?

HEPLISAV-B competes mainly with Engerix-B and Recombivax HB in the adult U.S. market. The commercial comparison centers on dose burden, speed of protection, response rates in certain adult populations, and procurement economics.

Product	Manufacturer	Adjuvant or formulation approach	Adult schedule	Key commercial characteristic
HEPLISAV-B	Dynavax Technologies	CpG 1018 adjuvant	2 doses over 1 month	Faster completion and differentiated immune response
Engerix-B	GSK	Aluminum-based adjuvant system	Typically 3 doses over 6 months	Established market presence and broad institutional use
Recombivax HB	Merck	Aluminum-based adjuvant system	Typically 3 doses over 6 months	Established hepatitis B vaccine franchise
PreHevbrio	VBI Vaccines	Three-antigen hepatitis B formulation	3 doses	Additional adult competitor, subject to evolving commercial availability

HEPLISAV-B’s strongest commercial advantage is schedule completion. A shorter schedule can reduce missed appointments, occupational-health administration costs, and patient drop-off. That advantage is particularly relevant for healthcare workers, dialysis patients, correctional populations, homeless populations, and adults with limited healthcare access.

What excipient and adjuvant supply risks affect HEPLISAV-B?

The highest supply risk is CpG 1018, not sodium chloride or polysorbate 80.

CpG 1018 supply chain

CpG 1018 is a synthetic oligonucleotide that requires:

• Controlled phosphoramidite or equivalent nucleotide chemistry
• Sequence-specific synthesis
• Purification and removal of truncated species
• Endotoxin and bioburden control
• Residual solvent and impurity testing
• Identity, purity, and potency assays
• Scale-up capability consistent with vaccine demand

At 3,000 mcg per dose, CpG 1018 is used at a materially higher mass than many conventional small-molecule vaccine adjuvants. A commercial producer must therefore manage synthetic capacity, purification throughput, raw-material qualification, and lot-to-lot consistency.

Conventional excipients

Sodium chloride and polysorbate 80 are widely available pharmaceutical excipients. Their commercial risk is lower, but they remain relevant to:

• Protein aggregation control
• Container compatibility
• Particulate formation
• Extractables and leachables
• Freeze-thaw and temperature excursion performance
• Long-term refrigerated stability

A change in polysorbate grade, supplier, peroxide level, or manufacturing process can require comparability work because surfactant degradation may affect protein stability and visible or subvisible particles.

What formulation patents protect HEPLISAV-B and CpG 1018?

HEPLISAV-B protection is expected to rely on several overlapping IP categories rather than a single conventional excipient patent:

1. CpG 1018 composition and sequence claims.
2. Oligonucleotide synthesis and purification claims.
3. Adjuvant-antigen combination claims.
4. Vaccine composition claims.
5. Methods of inducing an immune response.
6. Hepatitis B vaccination schedules.
7. Manufacturing and analytical-control methods.
8. Platform claims covering CpG adjuvants in additional vaccines.

Dynavax has developed a broader CpG 1018 platform around synthetic immunostimulatory oligonucleotides. The relevant patent estate may include U.S. and foreign applications directed to sequences, motifs, backbone chemistry, formulations, therapeutic combinations, and vaccine uses. The commercial significance depends on claim scope, continuation practice, terminal disclaimers, prosecution history, and whether claims cover the marketed dose and schedule.

The conventional excipients do not appear to be the primary source of exclusivity. A competitor could generally use sodium chloride, polysorbate 80, and water for injection if it did not practice protected claims directed to the specific antigen-adjuvant combination, CpG sequence, formulation, or method of use.

When does HEPLISAV-B lose regulatory exclusivity?

HEPLISAV-B was approved by the FDA on November 9, 2017, under the Public Health Service Act as a biologic vaccine.[2] The Biologics Price Competition and Innovation Act provides 12 years of reference-product exclusivity for a licensed biologic, subject to statutory rules and FDA interpretation. On that basis, the reference-product exclusivity period is generally expected to run until approximately November 2029.[3]

Regulatory exclusivity and patent expiry are separate.

Protection type	Approximate timing	Commercial effect
FDA approval	November 2017	Commercial launch authorization
Biologic reference-product exclusivity	Approximately November 2029	Limits approval of a biosimilar relying on the reference product before the exclusivity period ends
Patent protection	Patent-specific	May extend beyond or expire before regulatory exclusivity
Pediatric exclusivity	Product-specific	No general assumption should be made without an FDA-recognized grant
Orphan exclusivity	Not the principal HEPLISAV-B protection	Hepatitis B vaccination is not generally treated as an orphan indication

The practical entry date depends on the full patent estate, FDA Purple Book status, litigation, regulatory exclusivity, and the challenger’s development strategy.

What is the Orange Book status of HEPLISAV-B?

HEPLISAV-B is a biologic vaccine and is not treated like a conventional small-molecule drug listed in the Orange Book. The principal reference source for biologic reference products and biosimilar activity is the FDA Purple Book.[4]

This distinction affects the challenge pathway:

• Orange Book Paragraph IV certifications are associated with small-molecule abbreviated new drug applications.
• A biosimilar applicant generally relies on the 351(k) pathway.
• A vaccine competitor may also pursue an independent biologics license application rather than a biosimilar application.
• Patent disputes can arise through the BPCIA patent-exchange process, ordinary patent litigation, or independent infringement actions.

A generic-drug strategy based on an ANDA is therefore not the normal path for a competing HEPLISAV-B product.

Are there Paragraph IV challenges to HEPLISAV-B?

No conventional Paragraph IV pathway applies to HEPLISAV-B because it is licensed as a biologic rather than approved through an NDA subject to ANDA substitution.

The relevant competitive scenarios are:

1. A biosimilar or interchangeable biosimilar application under section 351(k).
2. A separately developed hepatitis B vaccine under section 351(a).
3. A patent challenge involving CpG 1018, vaccine composition, formulation, or method-of-use claims.
4. A licensing or supply arrangement involving CpG 1018 and a competing antigen platform.

The absence of an Orange Book Paragraph IV challenge does not mean the product has no patent risk. It means the legal and regulatory pathway is different.

What manufacturing and IP barriers protect the product?

The highest barriers are process and know-how barriers surrounding CpG 1018 and the combination product.

Oligonucleotide manufacturing

A competing manufacturer would need to reproduce or design around:

• Sequence composition
• Backbone chemistry
• Purification specifications
• Residual impurity limits
• Analytical potency methods
• Stability-indicating assays
• Conjugation or mixing conditions, if applicable
• Sterile manufacturing controls

Even where a competitor avoids literal infringement, it may face substantial development costs to establish equivalent immunostimulatory activity and acceptable vaccine stability.

Antigen-adjuvant compatibility

The HBsAg and CpG 1018 components must remain compatible during storage and administration. Formulation development must control:

• Adsorption or interaction between antigen and oligonucleotide
• Particle formation
• Potency loss
• pH and ionic strength
• Surfactant degradation
• Container closure integrity
• Sterility over the labeled shelf life

These technical requirements can provide practical protection that is broader than the listed excipient composition.

What commercial opportunities exist for excipients and formulation suppliers?

CpG 1018 manufacturing partnerships

The largest opportunity is contract or strategic manufacturing capacity for synthetic oligonucleotides. A qualified supplier could provide:

• GMP-grade CpG 1018
• Custom oligonucleotide synthesis
• Purification and analytical release
• Scale-up and redundancy
• Long-term supply agreements
• Process validation support

Supplier qualification is likely to be stringent because a change in CpG 1018 source could affect potency, impurity profile, and regulatory comparability.

High-purity polysorbate 80

Polysorbate 80 suppliers can compete on:

• Low-peroxide grades
• Low-particulate material
• Pharmaceutical documentation
• Lot consistency
• Container compatibility
• Supply continuity

For recombinant protein vaccines, surfactant quality can influence stability and manufacturing yield. A supplier with validated low-degradation material may obtain a stronger position than a commodity excipient producer.

Primary packaging

HEPLISAV-B is distributed in single-dose vials. Commercial opportunities include:

• Low-adsorption glass vials
• Elastomeric closures compatible with oligonucleotides and surfactants
• Prefilled syringe development
• Integrated delivery systems
• Reduced-overfill presentations
• Container-closure integrity testing

A prefilled syringe could reduce preparation time and administration errors, but it would require device development, extractables and leachables assessment, and regulatory bridging.

Cold-chain and stability services

HEPLISAV-B is stored refrigerated at 2°C to 8°C and should not be frozen.[1] Opportunities include:

• Temperature-monitoring systems
• Vaccine logistics
• Stability modeling
• Excursion qualification
• Secondary packaging
• Distribution to occupational-health and retail-pharmacy channels

A formulation that permitted controlled room-temperature storage would have significant commercial value, but such a change would require extensive stability and regulatory support.

How strong is the HEPLISAV-B patent estate?

The estate is strongest where claims cover the specific CpG 1018 sequence, its use as a vaccine adjuvant, and the combination with HBsAg. It is weaker where protection depends only on standard excipients.

IP category	Relative strategic strength	Reason
CpG 1018 sequence and composition	High	Directly tied to the product-defining adjuvant
CpG 1018 manufacturing process	Potentially high	Can protect know-how and commercial-scale production
HBsAg-CpG vaccine combination	High	Closely aligned with marketed product
Two-dose hepatitis B method	Medium to high	Commercially relevant but subject to claim scope and validity
Sodium chloride formulation	Low	Common excipient
Polysorbate 80 formulation	Low to medium	Common ingredient, but grade and stability claims may matter
Container and delivery system	Medium	Can protect a differentiated presentation
General TLR9 vaccine use	Variable	Broad claims may face validity and prior-art challenges

Patent strength should be assessed claim by claim. The commercial risk is likely to remain meaningful even after selected patent expirations if CpG 1018 supply, manufacturing know-how, and regulatory comparability create a high barrier to entry.

What generic, biosimilar, and independent-launch scenarios exist?

Scenario 1: No near-term biosimilar

A competitor may avoid the product because the market is specialized, the CpG 1018 platform is difficult to reproduce, and a 351(k) filing would require extensive analytical and clinical justification.

Scenario 2: Independent hepatitis B vaccine

A company could develop a separate 351(a) vaccine with a different adjuvant or antigen design. This would avoid direct biosimilar reliance but require a full development program and commercial differentiation.

Scenario 3: CpG 1018 licensing

A vaccine developer could license CpG 1018 from Dynavax or obtain access through a strategic collaboration. This would reduce technical risk but create royalty, supply, and field-of-use constraints.

Scenario 4: Formulation or presentation improvement

A competitor could pursue a prefilled syringe, improved stability, or alternate packaging. The product would still face the need to demonstrate acceptable quality, safety, and immunogenicity.

What licensing and partnership opportunities surround CpG 1018?

Dynavax has positioned CpG 1018 as a vaccine adjuvant platform. The primary commercial opportunities include:

• Licensing to vaccine developers
• Co-development of non-hepatitis B vaccines
• Regional commercialization agreements
• Contract manufacturing of CpG 1018
• Supply agreements tied to clinical and commercial volumes
• Platform access for pandemic or adult immunization programs

The most attractive counterparties are companies with validated recombinant-antigen platforms but without a differentiated adjuvant. CpG 1018 can improve product positioning where a faster schedule, stronger response, or improved response in older adults is commercially valuable.

What is the revenue exposure and competitive outlook?

HEPLISAV-B’s revenue exposure is concentrated in the U.S. adult hepatitis B vaccine market. The principal value drivers are:

• Two-dose completion
• Occupational-health contracts
• Pharmacy administration
• Dialysis and immunocompromised populations
• Public-sector procurement
• Health-system preference for shorter schedules
• Supply availability relative to competing vaccines

Revenue risk comes from pricing pressure, procurement substitution, new adult hepatitis B vaccines, supply interruptions, and eventual biosimilar or independent biologic competition.

The product’s commercial position is stronger when providers value schedule completion and weaker when procurement decisions prioritize established low-cost vaccines. The excipient strategy supports product quality and supply continuity, but CpG 1018 remains the central strategic asset.

Key Takeaways

• HEPLISAV-B’s key formulation differentiator is CpG 1018, not its conventional excipients.
• Sodium chloride, polysorbate 80, and water for injection are commercially important for stability but are unlikely to provide material standalone exclusivity.
• CpG 1018 manufacturing, purification, analytical control, and supply redundancy are the main excipient-related barriers.
• HEPLISAV-B does not follow the conventional Orange Book Paragraph IV pathway.
• FDA biologic reference-product exclusivity is generally expected to extend to approximately November 2029.
• The main competitive risks are a biosimilar, an independently developed hepatitis B vaccine, or a licensed competing product using the CpG 1018 platform.
• The strongest commercial opportunities are oligonucleotide manufacturing, low-peroxide polysorbate 80, primary packaging, prefilled delivery systems, and cold-chain services.
• Patent analysis should focus on CpG 1018 composition, vaccine combinations, dosing methods, manufacturing processes, and continuation patents rather than standard excipient claims.

FAQs

Does HEPLISAV-B contain aluminum?

No. HEPLISAV-B uses CpG 1018 as its adjuvant and does not use the conventional aluminum-based adjuvant approach associated with many hepatitis B vaccines.[1]

Is CpG 1018 an excipient or an active ingredient?

CpG 1018 functions as an adjuvant. In regulatory and formulation analysis, it is an excipient-like immunostimulatory component, but it is central to the product’s biological activity and product differentiation.

Can a competitor copy the polysorbate 80 and sodium chloride formulation?

A competitor could generally use common excipients, subject to applicable patent claims and regulatory requirements. Copying the conventional excipients would not by itself reproduce the CpG 1018 platform or establish equivalence to HEPLISAV-B.

Could HEPLISAV-B be substituted automatically like a generic drug?

No. HEPLISAV-B is a biologic vaccine, so substitution and approval follow biologic and vaccine-specific regulatory rules rather than the standard small-molecule ANDA framework.

What is the most valuable commercial component of the HEPLISAV-B formulation?

CpG 1018 is the most valuable component because it drives the product’s two-dose schedule, immune-response differentiation, platform potential, and manufacturing-related IP barriers.

References

1. Dynavax Technologies Corporation. (2023). HEPLISAV-B prescribing information. U.S. Food and Drug Administration. https://www.accessdata.fda.gov
2. U.S. Food and Drug Administration. (2017). FDA approves new vaccine for prevention of hepatitis B virus infection in adults. https://www.fda.gov
3. U.S. Food and Drug Administration. (2024). Reference product exclusivity and biosimilar biological products. https://www.fda.gov
4. U.S. Food and Drug Administration. (2024). Purple Book: Database of licensed biological products. https://purplebooksearch.fda.gov