Last updated: August 1, 2026
AMPHADASE is a prescription hyaluronidase human injection manufactured by Amphastar Pharmaceuticals. The product contains 150 USP units/mL of purified human hyaluronidase and is approved as an absorption and dispersion aid for subcutaneous fluids, injectable drugs, and subcutaneous urography.[1] Public evidence does not show an active late-stage clinical development program, material patent exclusivity, or a disclosed licensing transaction tied specifically to AMPHADASE. Its commercial outlook depends primarily on hospital and specialty-use demand, product availability, reimbursement, and competition from recombinant hyaluronidase products.
What is AMPHADASE and what is it approved to treat?
AMPHADASE is an injectable preparation of human hyaluronidase. Hyaluronidase temporarily hydrolyzes hyaluronic acid in the extracellular matrix, increasing tissue permeability and facilitating the absorption and dispersion of co-administered substances.
| Product attribute |
AMPHADASE status |
| Active ingredient |
Hyaluronidase, human |
| Strength |
150 USP units/mL |
| Dosage form |
Injection |
| Route |
Subcutaneous use; route varies by indication and co-administered product |
| Sponsor/manufacturer |
Amphastar Pharmaceuticals, Inc. |
| FDA application |
NDA 021664 |
| FDA regulatory category |
Prescription drug |
| Primary uses |
Subcutaneous fluid administration, dispersion and absorption of injected drugs, subcutaneous urography |
| Storage |
Refrigerated storage under the FDA prescribing information |
| Key contraindication |
Hypersensitivity to hyaluronidase or formulation components |
The FDA label does not position AMPHADASE as a systemic therapeutic for a standalone disease. Its value is procedural: it improves the movement and absorption of fluids or medicines administered into subcutaneous tissue.[1]
What clinical trials support AMPHADASE?
AMPHADASE does not appear to have a current clinical-trial program comparable to a new therapeutic drug. Its FDA-approved uses rely on the established pharmacology of hyaluronidase, clinical literature, and historical use rather than a modern pivotal development package.
Clinical evidence for human hyaluronidase has historically covered:
- Facilitation of subcutaneous hydration.
- Improved dispersion of injected medicines.
- Use in subcutaneous urography.
- Reduction of local tissue resistance to fluid administration.
- Management of selected extravasation events, depending on the medicine involved and institutional protocol.
ClinicalTrials.gov does not identify a substantial active interventional program specifically evaluating AMPHADASE as a branded product. Studies involving hyaluronidase may use another brand, a compounded preparation, recombinant hyaluronidase, or the ingredient without specifying AMPHADASE.
Are there active AMPHADASE clinical trials?
No publicly visible late-stage or registration-enabling trial program has been associated with AMPHADASE. The product is an established FDA-approved formulation, so future clinical activity would more likely involve:
- New administration settings.
- Combination use with specialty drugs.
- Pediatric or geriatric protocols.
- Drug-extravasation management.
- Home or outpatient subcutaneous hydration.
- Comparative studies against recombinant hyaluronidase.
These uses would require careful distinction between evidence for the hyaluronidase class and evidence for the AMPHADASE formulation.
What is the FDA regulatory status of AMPHADASE?
AMPHADASE is FDA-approved under NDA 021664. The approved label covers use as an absorption and dispersion aid rather than as a disease-modifying treatment.[1]
The principal safety risks include hypersensitivity reactions, local injection-site reactions, edema, and potential enhancement of systemic absorption of co-administered drugs. The label warns against intravenous administration because hyaluronidase is intended to facilitate absorption from subcutaneous tissue rather than to be administered directly into the bloodstream.[1]
The FDA label also identifies limitations involving formulation compatibility, dose selection, and the need to follow the prescribing instructions for the co-administered drug or fluid.
What is the Orange Book status of AMPHADASE?
AMPHADASE is listed in FDA drug databases as an approved prescription product. Public Orange Book information does not indicate a commercially significant current patent barrier associated with the product.
For generic competition, the practical questions are:
- Whether the product has current Orange Book-listed patents or exclusivity.
- Whether an applicant would pursue an ANDA or a suitability-related pathway.
- Whether formulation, manufacturing, or reference-product requirements create a meaningful barrier.
- Whether the product is commercially attractive enough to justify development.
No material active patent exclusivity is apparent from the public regulatory record available for AMPHADASE. The absence of a listed patent does not guarantee immediate generic entry. It reduces one legal barrier but does not eliminate manufacturing, quality, supply, or commercial barriers.
What patents protect AMPHADASE?
The available public record does not identify a current Orange Book patent estate that protects AMPHADASE through a later expiry date. The product’s commercial protection is therefore more dependent on regulatory approval, manufacturing know-how, supply reliability, and market relationships than on an active composition-of-matter patent.
| IP category |
AMPHADASE position |
| Composition-of-matter patent |
No current commercially relevant listed patent identified |
| Formulation patent |
No current listed formulation patent identified |
| Method-of-use patent |
No current listed method-of-use patent identified |
| Device patent |
Not a primary AMPHADASE protection mechanism |
| Manufacturing know-how |
Potential practical barrier |
| Trade secrets |
Potentially relevant to purification, fill-finish, and quality control |
| Regulatory exclusivity |
No major current exclusivity period identified |
| Geographic protection |
Primarily jurisdiction-specific regulatory and manufacturing rights |
Hyaluronidase itself is an old biological enzyme. Patent protection for the basic active ingredient is therefore not expected to provide meaningful long-term exclusivity. Any defensible IP position would be more likely to involve a specific formulation, production process, delivery system, or combination use.
When does AMPHADASE lose exclusivity?
AMPHADASE does not appear to have a meaningful remaining period of new-drug exclusivity. Its market protection is best analyzed as substantially post-exclusivity.
The key dates are:
| Event |
Approximate status |
| FDA approval |
Historical approval under NDA 021664 |
| New-chemical-entity exclusivity |
Not a current commercial factor |
| Current Orange Book patent expiry |
No material listed patent identified |
| Current regulatory exclusivity |
No material active exclusivity identified |
| Generic or alternative-product risk |
Ongoing, subject to FDA pathway and commercial economics |
The lack of exclusivity increases the theoretical risk of generic or alternative hyaluronidase entry. In practice, the market is constrained by the need to demonstrate pharmaceutical equivalence, maintain enzyme potency, meet sterility requirements, and secure reliable production.
Which companies compete with AMPHADASE?
The closest branded competitor is HYLENEX recombinant, marketed by Halozyme Therapeutics. HYLENEX contains recombinant human hyaluronidase PH20 and is used for similar facilitation of subcutaneous fluid and drug absorption.[2]
| Product |
Active ingredient |
Manufacturer or sponsor |
Competitive position |
| AMPHADASE |
Human hyaluronidase |
Amphastar Pharmaceuticals |
Established human-derived hyaluronidase injection |
| HYLENEX recombinant |
Recombinant human hyaluronidase PH20 |
Halozyme Therapeutics |
Branded recombinant competitor |
| Compounded hyaluronidase |
Variable |
Compounding pharmacies and institutions |
Potential price and availability substitute |
| Hospital-use alternatives |
Variable |
Institutional protocols |
May reduce demand in selected procedures |
AMPHADASE can compete on established use, availability, and physician familiarity. HYLENEX may compete on recombinant production, commercial partnerships, and adoption in specialty drug delivery.
How does AMPHADASE compare with HYLENEX?
The products share the same functional purpose but are not identical in production origin or regulatory presentation. AMPHADASE uses human hyaluronidase, while HYLENEX uses recombinant human hyaluronidase PH20.[1][2]
The competitive decision may depend on:
- Product availability.
- Hospital formulary status.
- Contract pricing.
- Supply continuity.
- Institutional preference for human-derived or recombinant products.
- Compatibility with a specialty drug or fluid.
- Procurement requirements for biologically derived materials.
No public evidence establishes a universal clinical superiority advantage for AMPHADASE over HYLENEX. Product selection is generally operational and formulary-driven.
What generic entry risks exist for AMPHADASE?
Generic entry risk is moderate from a legal perspective but more limited from a manufacturing and commercial perspective.
A potential entrant could face the following barriers:
- Demonstrating equivalent strength and enzyme activity.
- Matching the reference product’s formulation and container closure.
- Establishing sterility and stability.
- Proving pharmaceutical equivalence.
- Managing the biological variability associated with enzyme production.
- Securing a reliable source or manufacturing process.
- Reaching sufficient hospital and specialty-pharmacy volume.
Because AMPHADASE is an enzyme product, regulatory comparability may be more complex than for a simple small-molecule injection. A competitor might pursue an ANDA if FDA requirements permit, or a 505(b)(2) application if reliance on published literature or differences in formulation and manufacturing is necessary. The precise pathway would depend on FDA determinations and the applicant’s formulation.
What patent litigation or Paragraph IV challenges affect AMPHADASE?
No material publicly reported patent litigation or Paragraph IV campaign targeting AMPHADASE has been identified in the available record.
The absence of litigation is consistent with the product’s age and the lack of an apparent high-value active patent estate. A future Paragraph IV filing would likely challenge any newly listed formulation, process, or use patent rather than a basic hyaluronidase composition patent.
The commercial impact of a challenge would depend on:
- The existence of a listed patent.
- The timing of FDA approval.
- Any 30-month stay.
- Whether the reference product has sufficient sales to support launch.
- The entrant’s ability to manufacture a stable sterile enzyme injection.
Are there biosimilar risks for AMPHADASE?
AMPHADASE faces alternative-biologic and recombinant-product risk, but conventional biosimilar analysis is not straightforward.
AMPHADASE is approved as an NDA product rather than as a reference biologic licensed under a BLA. A competitor therefore may not necessarily use the Public Health Service Act biosimilar pathway. Depending on FDA classification and product characteristics, competition could arise through an ANDA, 505(b)(2), or another application route.
HYLENEX is a competitive recombinant hyaluronidase product, but it is not automatically a biosimilar to AMPHADASE. The products differ in manufacturing origin and may differ in regulatory status, formulation, and product-specific labeling.[2]
What licensing deals involve AMPHADASE?
No major publicly disclosed licensing transaction tied specifically to AMPHADASE has been identified. Amphastar has entered broader commercial and development arrangements across its portfolio, but those transactions should not be attributed to AMPHADASE without product-specific disclosure.
The principal strategic value of AMPHADASE is as a commercial product in Amphastar’s injectable portfolio. Potential transaction structures could include:
- Product acquisition.
- Regional distribution rights.
- Hospital-contracting arrangements.
- Co-promotion.
- Supply agreements.
- Combination-use partnerships with specialty-drug developers.
No such transaction is treated here as confirmed for AMPHADASE.
What is the AMPHADASE market size and revenue outlook?
Amphastar does not generally disclose a detailed standalone revenue line for AMPHADASE in its public financial reporting. As a result, a precise product-level market share or revenue forecast cannot be derived from company filings alone.
The product operates in a niche market rather than a high-volume chronic-care category. Demand is linked to:
- Subcutaneous hydration.
- Hospital and outpatient procedures.
- Specialty injectable therapies.
- Drug-extravasation protocols.
- Institutional purchasing contracts.
- Availability of competing hyaluronidase products.
AMPHADASE 2025-2030 projection
The following is a scenario-based commercial projection, not reported company guidance.
| Scenario |
2025-2030 annual demand trend |
Main drivers |
| Low case |
Decline of 3%-6% annually |
Recombinant substitution, generic entry, supply disruption |
| Base case |
Flat to 3% annual growth |
Stable institutional demand and modest specialty-drug use |
| High case |
Growth of 4%-7% annually |
Expansion of subcutaneous delivery and outpatient hydration |
The base case implies a mature, relatively stable product with limited pricing power. A higher-growth outcome would require wider use of subcutaneous administration or inclusion in protocols for specialty medicines. A lower-growth outcome would follow from formulary substitution, lower-cost competitors, or recurring supply constraints.
The largest commercial variable is not patent expiry. It is whether AMPHADASE retains reliable access to hospital and specialty-provider purchasing channels.
How strong is the AMPHADASE patent estate?
AMPHADASE has a weak apparent patent estate but a potentially durable operational position.
| Strength factor |
Assessment |
| Active composition patent |
Weak or absent |
| Listed formulation protection |
No material current listing identified |
| Regulatory exclusivity |
Limited |
| Manufacturing complexity |
Moderate |
| Product familiarity |
Positive |
| Switching costs |
Low to moderate |
| Hospital procurement relationships |
Potentially important |
| Competitive differentiation |
Limited at the active-ingredient level |
The product’s defensibility is therefore operational rather than primarily legal. Manufacturing consistency, sterile fill-finish capability, inventory continuity, and contracting can matter more than patent ownership.
What generic launch scenarios are plausible?
A first generic or alternative entrant could follow three broad scenarios.
Early competitive entry
An entrant obtains FDA approval and launches with a price discount. The likely impact would be concentrated in hospitals and large buyers with competitive tendering systems.
Delayed entry
Regulatory development proceeds, but manufacturing validation, enzyme comparability, or commercial scale delays launch. AMPHADASE retains share despite limited formal exclusivity.
No meaningful entry
The market remains too small to support development costs. HYLENEX and compounded or institutional alternatives remain the principal competitive pressures.
For investors and licensing teams, the third scenario may be more commercially relevant than a patent-litigation scenario. A weak patent estate does not necessarily produce multiple generic entrants when annual market opportunity is limited.
Key Takeaways
- AMPHADASE is a 150 USP units/mL human hyaluronidase injection marketed by Amphastar Pharmaceuticals.
- FDA-approved uses involve subcutaneous fluid administration, drug dispersion and absorption, and subcutaneous urography.
- No substantial active clinical-trial program specific to AMPHADASE is publicly evident.
- The product has no apparent high-value current Orange Book patent barrier.
- No material Paragraph IV litigation or AMPHADASE-specific patent settlement is publicly identified.
- HYLENEX recombinant is the principal branded competitive reference.
- Biosimilar terminology does not directly resolve competition because AMPHADASE is an NDA product, not a conventional BLA reference product.
- Standalone AMPHADASE revenue is not separately disclosed in a way that supports a precise market-size calculation.
- The base commercial outlook is mature and broadly stable, with annual growth more likely to remain in the low single digits than reach specialty-drug growth rates.
- Manufacturing, supply reliability, and hospital contracting are more important defenses than patent exclusivity.
FAQs About AMPHADASE
Is AMPHADASE a biologic drug?
AMPHADASE contains a biologically derived enzyme, human hyaluronidase, but it is approved under an NDA rather than as a conventional BLA product. Its competitive pathway must therefore be assessed under FDA product-specific requirements.
Is AMPHADASE interchangeable with HYLENEX?
The products have similar clinical purposes but are not automatically interchangeable. Substitution depends on FDA labeling, institutional policy, prescriber direction, formulation considerations, and product availability.
Can AMPHADASE be used for cancer-drug extravasation?
Hyaluronidase may be included in institutional extravasation protocols for selected agents, but use depends on the specific drug, timing, route, and applicable clinical guidance. The AMPHADASE label should be reviewed before use.
Does AMPHADASE have orphan-drug exclusivity?
No material current orphan-drug exclusivity is associated with AMPHADASE in the public regulatory record.
What is the main investment risk for AMPHADASE?
The main risks are competitive substitution, limited market scale, supply disruption, hospital price pressure, and entry by a lower-cost hyaluronidase product. Patent expiry is not the primary risk because the product does not appear to rely on a significant current patent barrier.
References
- U.S. Food and Drug Administration. (n.d.). Amphadase: Hyaluronidase injection, human prescribing information. Drugs@FDA, NDA 021664.
- U.S. Food and Drug Administration. (n.d.). Hylenex recombinant: Hyaluronidase human injection prescribing information. Drugs@FDA.
- U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. Center for Drug Evaluation and Research.
- ClinicalTrials.gov. (2024). Search results for AMPHADASE and hyaluronidase clinical studies. National Library of Medicine.
- Amphastar Pharmaceuticals, Inc. (2024). Annual report and filings. U.S. Securities and Exchange Commission.
