Last updated: September 8, 2026
Benralizumab, marketed by AstraZeneca as Fasenra, is an anti-interleukin-5 receptor alpha biologic for severe eosinophilic asthma. Its commercial profile is supported by a differentiated mechanism, eight-week maintenance dosing, and AstraZeneca’s global respiratory infrastructure. Reported sales increased from about $660 million in 2019 to approximately $1.4 billion in 2023, although growth is moderating as the severe-asthma biologic market matures and competition intensifies. The main long-term value drivers are COPD expansion, geographic penetration, and the timing of biosimilar or follow-on competition after the U.S. biologic exclusivity period.
What is benralizumab and how does Fasenra work?
Benralizumab is a humanized afucosylated monoclonal antibody that binds interleukin-5 receptor alpha, or IL-5Rα, on eosinophils and basophils. The antibody recruits natural killer cells through antibody-dependent cell-mediated cytotoxicity, producing rapid and near-complete depletion of circulating eosinophils.
Fasenra is approved for add-on maintenance treatment of patients aged 6 years and older with severe asthma and an eosinophilic phenotype. The approved adult and adolescent regimen is:
| Treatment phase |
Dose |
| First three doses |
30 mg subcutaneously every four weeks |
| Subsequent doses |
30 mg subcutaneously every eight weeks |
The every-eight-week maintenance schedule is a commercial differentiator versus several competing biologics requiring administration every two or four weeks. The FDA approved Fasenra in November 2017, with later approvals for pediatric patients and a prefilled autoinjector presentation. (U.S. Food and Drug Administration, 2017, 2024a)
How large is the benralizumab market?
The global severe-asthma biologics market is estimated to be worth several billion dollars annually and is growing through increased diagnosis of type 2 inflammation, wider biologic eligibility, and treatment escalation among uncontrolled asthma patients.
Benralizumab competes within the eosinophilic or type 2 asthma segment against:
| Drug |
Company |
Principal target |
Typical maintenance interval |
| Fasenra, benralizumab |
AstraZeneca |
IL-5Rα |
Every eight weeks after loading |
| Nucala, mepolizumab |
GSK |
IL-5 |
Every four weeks |
| Dupixent, dupilumab |
Sanofi and Regeneron |
IL-4Rα |
Every two or four weeks, depending on indication |
| Tezspire, tezepelumab |
Amgen and AstraZeneca |
TSLP |
Every four weeks |
| Xolair, omalizumab |
Genentech and Novartis |
IgE |
Every two or four weeks |
| Cinqair, reslizumab |
Teva |
IL-5 |
Intravenous every four weeks |
Fasenra’s positioning is strongest in patients with high blood eosinophil counts, recurrent exacerbations, oral corticosteroid exposure, and a preference for infrequent self-administration. Dupilumab and tezepelumab have broader biomarker positioning, which can limit benralizumab’s share among patients without clearly elevated eosinophils.
What are AstraZeneca’s benralizumab sales and financial trajectory?
AstraZeneca has reported sustained double-digit or near-double-digit growth for Fasenra during much of its commercial life. Public company reporting indicates the following approximate trajectory:
| Fiscal year |
Fasenra revenue, approximate |
Commercial development |
| 2018 |
$300 million |
First full commercial year after U.S. approval |
| 2019 |
$660 million |
Rapid uptake in severe eosinophilic asthma |
| 2020 |
$1.1 billion |
Expansion in major respiratory markets |
| 2021 |
$1.2 billion |
Continued penetration despite pandemic-related diagnosis disruption |
| 2022 |
$1.3 billion |
Growth from international markets and self-administration |
| 2023 |
$1.4 billion |
Mature blockbuster growth with continued volume expansion |
| 2024 outlook |
Continued growth expected |
Expansion depends on asthma share and new indications |
The reported figures are rounded because AstraZeneca’s annual reports and results releases may present currency-adjusted growth, product revenue, and regional performance using different reporting conventions. AstraZeneca classifies Fasenra within its Respiratory and Immunology portfolio. (AstraZeneca, 2020, 2022, 2024)
The revenue trajectory has several characteristics:
- Initial growth was driven by rapid adoption in the United States and Japan.
- The product benefited from less frequent maintenance dosing than many competing biologics.
- Growth has shifted from new class adoption toward competitive switching and geographic expansion.
- The commercial ceiling is constrained by the narrower eosinophilic-asthma population compared with broader type 2 or severe-asthma products.
- COPD development could materially extend the product’s revenue life if clinical and regulatory outcomes support approval.
At approximately $1.4 billion in annual sales, Fasenra is a meaningful AstraZeneca growth asset but is smaller than the company’s largest oncology and cardiometabolic products. Its profitability is likely supported by biologic pricing, specialty distribution, and manufacturing scale, although net revenue is affected by rebates, payer restrictions, patient support programs, and government pricing.
What are the main growth drivers for benralizumab?
COPD expansion
AstraZeneca has evaluated benralizumab in chronic obstructive pulmonary disease, particularly patients with elevated blood eosinophils and frequent exacerbations. Earlier Phase III trials, including GALATHEA and TERRANOVA, did not establish a broad COPD approval. AstraZeneca later pursued a more targeted COPD development strategy using enriched patient populations and treatment-response characteristics.
The COPD opportunity is commercially important because the eligible population is substantially larger than the severe eosinophilic-asthma population. A successful label expansion could support:
- Higher patient volume.
- Increased use in older patients with multiple respiratory conditions.
- New payer contracts across asthma and COPD populations.
- Greater utilization of home administration.
- Longer product durability before biosimilar competition.
The risk is material. COPD is biologically heterogeneous, and prior failures in the class indicate that eosinophil count alone may not identify a consistently responsive population. As of mid-2024, COPD remained a development opportunity rather than an established approved indication in the United States.
Home administration
Fasenra’s prefilled syringe and autoinjector options support administration outside infusion centers. Home dosing can lower administration burden and improve retention in chronic therapy. It also strengthens the product’s positioning against intravenous or more frequent alternatives.
Pediatric and adolescent use
Expansion into patients aged 6 years and older increases the addressable population and can support earlier treatment continuity. Pediatric use also creates potential persistence benefits because patients who respond well may remain on therapy for multiple years.
International growth
AstraZeneca has established commercial operations in Europe, Japan, China, and other markets. International growth can offset U.S. payer pressure, but price levels are generally lower and reimbursement decisions vary by country. Japan is strategically important because respiratory biologics have substantial specialist use and AstraZeneca has a strong local commercial presence.
What patents and exclusivity protect benralizumab?
Benralizumab is a biologic, so its regulatory and patent framework differs from that of a conventional small-molecule drug.
FDA exclusivity
The FDA approved Fasenra on November 14, 2017. Reference biologics receive 12 years of reference-product exclusivity under the Biologics Price Competition and Innovation Act. On that basis, the statutory U.S. exclusivity floor runs to November 14, 2029, subject to the specific regulatory treatment of any supplements or pediatric exclusivity. A biosimilar application may be submitted after four years, but approval cannot occur before the 12-year reference-product exclusivity period expires. (FDA, 2024b)
The exclusivity date does not necessarily equal the earliest commercial biosimilar launch date. Patent litigation, settlement agreements, manufacturing patents, formulation patents, and regulatory injunctions can extend practical market protection.
Patent estate
The benralizumab patent estate is expected to include claims covering:
- The anti-IL-5Rα antibody molecule.
- Specific antibody sequences and binding regions.
- Antibody production in engineered cell lines.
- Pharmaceutical compositions.
- Subcutaneous administration.
- Dosing methods for eosinophilic asthma.
- Use in patients with specified eosinophil counts or exacerbation histories.
The principal composition-of-matter protection is generally the most commercially important asset. Secondary patents may have later expiration dates but are more vulnerable to invalidity or non-infringement challenges.
Because biologics are not listed in the FDA Orange Book in the same manner as small-molecule drugs, Fasenra does not have an Orange Book patent listing structure comparable to products such as inhaled corticosteroids or oral kinase inhibitors. Biosimilar sponsors instead address patent issues through the BPCIA “patent dance,” litigation, declaratory actions, and negotiated launch agreements. The FDA Purple Book identifies licensed biological products and biosimilar relationships but does not provide an Orange Book-style complete patent certification framework. (FDA, 2024c)
When does benralizumab lose exclusivity?
The key U.S. regulatory date is November 2029, based on Fasenra’s 2017 approval and the 12-year reference-product exclusivity period. Commercial biosimilar entry could occur after that date unless AstraZeneca reaches a settlement or obtains enforceable patent protection that delays launch.
| Protection type |
Relevant timing |
| U.S. FDA approval |
November 14, 2017 |
| Four-year biosimilar submission barrier |
Expired in November 2021 |
| Twelve-year reference-product exclusivity |
Runs to November 2029 |
| Patent-based protection |
Depends on individual patent terms and litigation |
| Practical biosimilar entry |
Potentially from late 2029 onward, subject to patents and settlements |
European Union and other international markets apply different biologic data and market-exclusivity rules. The EU generally provides eight years of data exclusivity and two years of market protection, with a possible additional year for a new indication meeting specified conditions. National patent terms, supplementary protection certificates, and reimbursement rules can change the practical launch date. (European Medicines Agency, 2024)
Are biosimilars and Paragraph IV challenges a risk for benralizumab?
Yes, but the pathway differs from small-molecule generic competition.
A traditional Paragraph IV certification applies to an abbreviated new drug application referencing an Orange Book-listed small molecule. Benralizumab is licensed as a biologic, so a competing product would generally use the 351(k) biosimilar pathway rather than an ANDA Paragraph IV filing.
Potential competitive actions include:
- A biosimilar application under Section 351(k).
- Patent litigation under the BPCIA.
- Declaratory judgment litigation.
- Challenges to composition, formulation, manufacturing, or use patents.
- A settlement allowing launch before the latest asserted patent expiry.
- An interchangeable designation, if the sponsor meets FDA requirements.
No major publicly disclosed benralizumab biosimilar litigation or commercial biosimilar launch had materially altered the U.S. market as of mid-2024. The more immediate competitive threat is branded biologic substitution among Fasenra, Dupixent, Nucala, and Tezspire.
How strong is the benralizumab patent estate?
The estate is commercially meaningful because the core biologic is protected by a combination of regulatory exclusivity and antibody-related patents. Its strength depends on four factors.
First, composition claims covering the antibody sequence are generally stronger than narrow method-of-use claims. Second, manufacturing patents can be difficult for a biosimilar sponsor to avoid but may be harder to detect and enforce. Third, formulation and dosing claims can support settlements but may be vulnerable if the competing product uses a different formulation or administration schedule. Fourth, the absence of Orange Book listing reduces the visibility of the full patent landscape compared with small-molecule products.
The estate should be viewed as moderately strong through the late 2020s, with a larger uncertainty window after 2029. Regulatory exclusivity provides the clearest U.S. barrier. Patent litigation could extend practical protection, but public information does not establish a guaranteed post-2029 launch delay.
What litigation and settlement risks affect Fasenra?
As of mid-2024, no widely reported major U.S. biosimilar litigation had created a defined benralizumab launch date. The principal litigation risks are prospective:
- Invalidity challenges to antibody composition claims.
- Non-infringement arguments based on different cell lines or manufacturing processes.
- Challenges to dosing and patient-selection claims.
- Antitrust scrutiny if AstraZeneca uses bundled contracting or settlement arrangements.
- Patent-term disputes across Europe and Japan.
- Disputes over interchangeability and substitution.
A settlement with a future biosimilar entrant could preserve revenue beyond the statutory exclusivity date while establishing a controlled entry date. The commercial value of such a settlement would depend on Fasenra’s remaining sales, the number of biosimilar competitors, and the extent of payer-driven substitution.
How does benralizumab compare financially with competing asthma biologics?
Fasenra’s economic profile is strongest when dosing convenience and eosinophil depletion drive treatment selection. Dupixent has broader use across asthma, atopic dermatitis, chronic rhinosinusitis with nasal polyps, and other conditions, giving Sanofi and Regeneron a larger cross-indication commercial platform. Tezspire has broad severe-asthma positioning and does not require the same degree of eosinophilic biomarker selection. Nucala remains a direct anti-eosinophil competitor with an established respiratory franchise.
| Commercial factor |
Fasenra position |
| Biomarker focus |
Strong in eosinophilic disease |
| Dosing convenience |
Strong after loading, with eight-week maintenance |
| Label breadth |
Narrower than Dupixent and potentially Tezspire |
| Administration |
Subcutaneous, including home-use options |
| COPD upside |
Material but dependent on clinical success |
| Biosimilar timing |
Regulatory floor in the U.S. in 2029 |
| Pricing pressure |
Increasing as biologic competition expands |
What generic launch scenarios exist for benralizumab?
The relevant entry scenarios are biosimilar rather than conventional generic.
Early controlled entry
AstraZeneca reaches a settlement with one or more biosimilar developers, allowing entry before or around 2029. This could reduce abrupt erosion while preserving a period of branded sales.
First-wave biosimilar entry after exclusivity
One or more biosimilars launch near late 2029 or 2030. Payers may initially favor the lower-cost products, but physician switching could be slower than in small-molecule markets because of administration systems, clinical familiarity, and specialty pharmacy contracts.
Delayed entry
Patent litigation or manufacturing claims delay launch beyond 2029. This scenario requires enforceable patents that survive or avoid invalidity challenges.
Indication-led protection
AstraZeneca obtains additional approved indications, such as COPD, and secures method-of-use or dosing patents. This would not necessarily block all biosimilar competition, but it could preserve branded use in protected subpopulations.
What is the commercial outlook for benralizumab?
Fasenra should remain a substantial respiratory product through the late 2020s. The base business has a durable severe-asthma market, strong dosing convenience, and a recognized safety and efficacy profile. Revenue growth is likely to slow as the market becomes more competitive and biologic penetration rises.
The upside case depends on COPD approval and broad reimbursement. The downside case includes loss of share to Dupixent and Tezspire, payer preference for competing products, lower net pricing, and biosimilar entry after 2029. A reasonable strategic view is that Fasenra remains a billion-dollar-plus product before exclusivity erosion, but its long-term trajectory depends more on indication expansion than on additional penetration of the established severe-asthma segment.
Key Takeaways
- Benralizumab is AstraZeneca’s Fasenra, an anti-IL-5Rα biologic for severe eosinophilic asthma.
- Reported sales grew from approximately $660 million in 2019 to about $1.4 billion in 2023.
- Eight-week maintenance dosing is a major commercial advantage.
- Dupixent, Tezspire, Nucala, Xolair, and Cinqair are the principal competitive products.
- The U.S. 12-year biologic reference-product exclusivity period is expected to run to November 2029.
- Biosimilar, rather than conventional Paragraph IV generic, competition is the relevant post-exclusivity risk.
- COPD is the largest potential revenue expansion opportunity, but approval depends on positive late-stage evidence and FDA review.
- The patent estate is likely strongest around antibody composition and manufacturing, while secondary formulation and method-of-use claims face greater challenge risk.
- Fasenra’s revenue durability will depend on COPD expansion, international growth, payer access, and the timing of biosimilar entry.
FAQs
What is the annual revenue of Fasenra?
AstraZeneca reported approximately $1.4 billion in Fasenra revenue in 2023, based on rounded public company disclosures.
Is benralizumab approved for COPD?
No broad U.S. COPD approval had been established as of mid-2024. AstraZeneca has pursued clinical development in selected COPD populations.
Does benralizumab have an Orange Book listing?
No. As a biologic, benralizumab is not listed through the conventional Orange Book framework used for small-molecule drugs.
Can a biosimilar launch before November 2029?
A biosimilar may be submitted before November 2029, but FDA approval of the reference product generally cannot occur before the 12-year biologic exclusivity period ends.
Which competitor poses the greatest commercial threat to Fasenra?
Dupixent poses the broadest commercial threat because of its larger type 2 inflammatory disease platform and wider indication base. Tezspire is also a significant threat because of its broader severe-asthma positioning.
References
-
AstraZeneca. (2020). Annual report and Form 20-F 2019. AstraZeneca PLC.
-
AstraZeneca. (2022). Annual report and Form 20-F 2021. AstraZeneca PLC.
-
AstraZeneca. (2024). Annual report and Form 20-F 2023. AstraZeneca PLC.
-
European Medicines Agency. (2024). Biosimilar medicines: Overview and regulatory framework. European Union.
-
U.S. Food and Drug Administration. (2017). FDA approves new treatment for patients with severe asthma. U.S. Department of Health and Human Services.
-
U.S. Food and Drug Administration. (2024a). Fasenra prescribing information. U.S. Department of Health and Human Services.
-
U.S. Food and Drug Administration. (2024b). Implementation of the Biologics Price Competition and Innovation Act. U.S. Department of Health and Human Services.
-
U.S. Food and Drug Administration. (2024c). Purple Book: Database of licensed biological products. U.S. Department of Health and Human Services.
