Last updated: September 8, 2026
Kineret, the anakinra biologic marketed by Swedish Orphan Biovitrum AB (Sobi), is a mature interleukin-1 pathway product with durable orphan-disease demand and limited direct competition. Its core composition patent protection has expired, and U.S. regulatory exclusivity ended years ago. The commercial franchise remains resilient because of rare-disease indications, physician familiarity, reimbursement support, manufacturing complexity, and the absence of an FDA-approved anakinra biosimilar as of the latest publicly available regulatory information.
Kineret’s long-term risk is commercial erosion rather than abrupt patent-driven loss of exclusivity. The main threats are biosimilar development, payer pressure, substitution by newer interleukin-1 therapies, and declining COVID-19-related demand.
What is Kineret and how does anakinra work?
Kineret is a recombinant form of the human interleukin-1 receptor antagonist, or IL-1Ra. It blocks the biological activity of interleukin-1 alpha and interleukin-1 beta, cytokines involved in inflammation, fever, tissue injury, and immune activation.
| Attribute |
Kineret |
| Active ingredient |
Anakinra |
| Drug class |
Recombinant interleukin-1 receptor antagonist |
| Route |
Subcutaneous injection |
| U.S. sponsor |
Swedish Orphan Biovitrum AB |
| Original U.S. approval |
November 14, 2001 |
| U.S. reference product |
Kineret |
| Biologic license |
BLA 103950 |
| Primary commercial markets |
United States and Europe |
| Principal indications |
Rheumatoid arthritis, CAPS, DIRA, and certain COVID-19 patients |
| Main commercial segment |
Rare inflammatory and autoinflammatory disease |
The initial U.S. approval covered moderately to severely active rheumatoid arthritis in adults who had failed one or more disease-modifying antirheumatic drugs. Later approvals expanded the product’s value in rare diseases, where patient populations are smaller and treatment alternatives are limited.
What diseases and indications does Kineret treat?
Kineret has a broader clinical and commercial role in Europe than in the United States, although the precise labels differ by jurisdiction.
Rheumatoid arthritis
Kineret was initially developed as an anti-inflammatory treatment for rheumatoid arthritis. Its role in this market declined as tumor necrosis factor inhibitors, interleukin-6 inhibitors, Janus kinase inhibitors, and other targeted therapies became standard options.
Rheumatoid arthritis remains relevant for established prescribing and certain patients who cannot tolerate or do not respond to other agents. It is not the principal growth engine for Kineret.
Cryopyrin-associated periodic syndromes
The FDA approved Kineret for cryopyrin-associated periodic syndromes, or CAPS, in 2007. CAPS includes rare autoinflammatory diseases driven by excessive interleukin-1 activity.
CAPS demand is commercially important because treatment is often chronic, diagnosis is specialist-led, and discontinuation rates can be low when patients respond well. The segment also supports premium pricing relative to broad rheumatology indications.
Deficiency of interleukin-1 receptor antagonist
The FDA approved Kineret for deficiency of interleukin-1 receptor antagonist, or DIRA, in 2013. DIRA is an ultra-rare genetic autoinflammatory disease that usually presents in infancy.
DIRA is a small-volume indication but has high strategic value. Treatment can be lifelong, and the absence of practical alternatives creates substantial retention and switching barriers.
COVID-19
The FDA expanded Kineret’s approval in 2022 for certain hospitalized adults with COVID-19 pneumonia who are at risk of progressing to severe respiratory failure and have elevated soluble urokinase plasminogen activator receptor, or suPAR, levels. The approval was based on the SAVE-MORE study and related evidence reviewed by the FDA.[1]
COVID-19 created a temporary demand opportunity. It did not change the structural profile of the Kineret franchise because pandemic-related use is episodic and dependent on hospital protocols, patient selection, and disease waves.
When does Kineret lose exclusivity?
Kineret’s principal U.S. exclusivity periods have already expired.
| Protection type |
Key date or status |
| U.S. approval |
November 14, 2001 |
| U.S. biologic data exclusivity |
Expired by approximately 2013 under the 12-year reference-product framework |
| Orphan exclusivity for CAPS |
Expired in 2014 |
| Core composition patent protection |
Expired before the modern biosimilar era |
| Current protection profile |
Primarily regulatory, manufacturing, clinical, and commercial rather than foundational patent protection |
The original anakinra patent estate included patents covering recombinant interleukin-1 receptor antagonist technology. U.S. Patent No. 5,075,222, assigned to Synergen and related parties, is commonly associated with the foundational IL-1 receptor antagonist platform. Its effective U.S. term ended before Kineret’s current commercial period.
Kineret therefore does not depend on an unexpired composition-of-matter patent to block competition. The key question is whether a competitor can obtain approval and reliably manufacture a sufficiently similar anakinra product.
What is the Orange Book status of Kineret?
Kineret is a biologic, so its core U.S. regulatory reference is the Purple Book rather than the Orange Book.
The Orange Book principally lists patents and exclusivity for small-molecule drugs approved through abbreviated new drug applications. The Purple Book identifies licensed biological products and reference products relevant to the biosimilar pathway under the Biologics Price Competition and Innovation Act.
Kineret’s U.S. competitive position is therefore not based on an Orange Book patent listing. A prospective competitor would generally pursue a biosimilar or interchangeable biosimilar pathway under section 351(k) of the Public Health Service Act, rather than an ANDA Paragraph IV challenge.
Are there Paragraph IV challenges against Kineret?
No conventional Paragraph IV litigation framework applies to Kineret in the same way it applies to an FDA-approved small-molecule drug.
A Paragraph IV certification challenges an Orange Book-listed patent through an ANDA. Kineret’s relevant competition would arise through a 351(k) biosimilar application. That pathway can generate patent disputes under the so-called patent dance and related federal litigation, but it does not require a traditional Paragraph IV certification against an Orange Book listing.
As of the latest available public information, there is no widely reported U.S. Kineret biosimilar litigation comparable to the major patent disputes involving insulin, adalimumab, trastuzumab, or ranibizumab.
How strong is the Kineret patent estate?
The Kineret patent estate is weak on core molecule protection and stronger on practical market barriers.
Patent strength assessment
| Protection category |
Assessment |
Commercial relevance |
| Core anakinra composition |
Weak or expired |
Does not materially block biosimilar entry |
| Original recombinant production claims |
Largely expired or vulnerable to design-around |
Limited current exclusivity value |
| Formulation claims |
Potentially relevant, but not the principal barrier |
May require alternative formulation development |
| Device or delivery claims |
Limited public evidence of a blocking estate |
Secondary importance |
| Method-of-use claims |
Indication-specific value |
Can affect labeling and promotion, not necessarily approval |
| Manufacturing know-how |
Stronger practical barrier |
Important for product consistency and scale |
| Clinical and regulatory history |
High commercial value |
Reduces development and launch risk for Sobi |
| Orphan-disease physician relationships |
High commercial value |
Supports retention in rare indications |
A biosimilar developer would not need to copy every aspect of Sobi’s manufacturing process. It would need to demonstrate high similarity, resolve analytical and immunogenicity questions, and satisfy FDA requirements for the selected indications. Manufacturing process controls, reference-standard access, assay development, and comparability work can still require substantial investment.
What formulations are protected by Kineret-related intellectual property?
Kineret is supplied as a sterile prefilled-syringe formulation for subcutaneous administration. The product’s commercial differentiation has historically depended more on the established product, dose flexibility, supply reliability, and clinical familiarity than on a clearly dominant formulation patent.
Potential formulation and product-quality issues include:
- Protein aggregation and degradation.
- Container-closure compatibility.
- Subcutaneous injection tolerability.
- Stability under refrigerated storage.
- Delivered-dose consistency.
- Immunogenicity and impurity profiles.
- Prefilled-syringe manufacturing and device usability.
A biosimilar may use a different formulation or device if it demonstrates comparability and meets regulatory requirements. Formulation differences can slow development but are unlikely to create a permanent barrier equivalent to an unexpired composition patent.
What is Kineret’s FDA regulatory status?
Kineret is an FDA-approved biologic with a long post-market record. Its regulatory profile benefits from extensive exposure data, established pharmacology, and broad clinical experience.
The U.S. label includes warnings and precautions relating to serious infections, neutropenia, hypersensitivity, and immunosuppression-related risks. These risks are familiar to specialists and are incorporated into treatment selection and monitoring.
The product’s long regulatory history has two opposing effects:
- It lowers the clinical uncertainty associated with treatment.
- It makes the product more exposed to biosimilar competition because the reference product has accumulated extensive analytical and clinical data.
Kineret’s rare-disease approvals are commercially more defensible than its rheumatoid arthritis indication because orphan populations are difficult to recruit for new trials and have fewer high-volume competitors.
How has Kineret’s financial trajectory developed?
Sobi’s acquisition and commercialization strategy transformed Kineret from a mature inflammatory product into a core specialty and rare-disease asset. Sobi obtained rights to Kineret in stages through transactions with Amgen, including expanded commercial rights in North America.[2]
Kineret’s financial trajectory has had four phases:
| Period |
Financial and market driver |
| 2001-2007 |
Initial rheumatoid arthritis commercialization |
| 2007-2013 |
Expansion into CAPS and DIRA, improving specialty value |
| 2018-2021 |
Sobi integration and greater focus on rare diseases |
| 2022 onward |
COVID-19 demand contribution followed by normalization and broader portfolio pressure |
Public Sobi reporting has consistently identified Kineret as a material product within the company’s specialty-care portfolio. Revenue performance has benefited from chronic rare-disease treatment, geographic expansion, and COVID-19 use, while rheumatoid arthritis demand has faced mature-market competition.
The most important financial characteristic is not peak growth. It is cash-flow durability. Kineret has an established production base, a recognized brand, and a concentrated specialist prescriber market. Even without meaningful unit growth, these factors can support substantial revenue for an extended period.
COVID-19-related sales introduced volatility. Hospital use increased during periods when treatment protocols included Kineret for selected patients, but that demand was less predictable than chronic CAPS or DIRA treatment. Investors should separate pandemic-related revenue from recurring rare-disease revenue when valuing the franchise.[3]
What revenue exposure does Kineret create for Sobi?
Kineret is strategically important but no longer represents Sobi’s entire growth profile. Sobi’s broader portfolio includes Doptelet, Empaveli, Doptelet-related hematology products, and other specialty medicines. This diversification reduces the impact of a sudden Kineret decline.
Kineret remains exposed to several revenue risks:
- Biosimilar price competition.
- Lower utilization in rheumatoid arthritis.
- Hospital protocol changes for COVID-19.
- Reimbursement restrictions.
- Supply interruptions.
- Physician movement toward alternative IL-1 therapies.
- Concentration of rare-disease prescribing in specialist centers.
Its revenue quality is higher in DIRA and CAPS than in rheumatoid arthritis because rare-disease patients often require persistent treatment and have limited substitutes. Its revenue quality is lower for pandemic-related use because COVID-19 demand depends on epidemiology and treatment policy.
Which companies are challenging Kineret?
No FDA-approved anakinra biosimilar has established broad U.S. commercial competition as of the latest available information. The competitive field is divided into direct IL-1 competitors and potential biosimilar entrants.
Direct pharmacologic competitors
The principal branded IL-1 alternatives include:
- Ilaris, or canakinumab, marketed by Novartis.
- Arcalyst, or rilonacept, marketed by Regeneron.
- Other off-label or specialist-directed anti-inflammatory treatments.
Canakinumab has a long-acting dosing profile and strong positioning in certain autoinflammatory diseases. Rilonacept is relevant to recurrent inflammatory syndromes and selected pericarditis uses. These products compete clinically, but they do not automatically displace Kineret across all indications.
Biosimilar competitors
Potential anakinra biosimilar developers face a smaller addressable market than developers of adalimumab or ustekinumab biosimilars. The opportunity is concentrated in specialist indications, which can reduce the commercial return from development.
Competition could emerge through:
- A U.S. 351(k) biosimilar application.
- European Union biosimilar authorization.
- Regional products in markets with less developed biologic substitution rules.
- Compounded or non-reference products in jurisdictions with different regulatory standards.
The absence of an approved biosimilar does not mean the franchise is insulated. It indicates that the expected return, development complexity, and commercial opportunity have so far limited direct entry.
What generic or biosimilar launch scenarios exist for Kineret?
Scenario 1: No direct biosimilar entry
Kineret retains specialist demand, with erosion driven mainly by payer pressure and alternative branded therapies. This is the most favorable scenario for Sobi.
Scenario 2: One biosimilar entrant
A first entrant could target price-sensitive rheumatoid arthritis use while initially avoiding aggressive competition in DIRA and CAPS. Sobi would likely defend share through contracting, supply reliability, and patient-support programs.
Scenario 3: Multiple biosimilar entrants
Several entrants could trigger rapid price compression in rheumatology. Rare-disease erosion would likely be slower because physicians may prioritize continuity, manufacturing confidence, and established clinical experience.
Scenario 4: Indication-focused competition
A competitor could seek approval or commercial focus in a narrow inflammatory indication. This would reduce the immediate impact on Kineret’s entire label but could pressure high-value segments over time.
The most plausible launch pattern is gradual erosion rather than a sudden generic cliff.
What patent litigation and settlement agreements affect Kineret?
There is no prominent public U.S. patent-litigation or Paragraph IV settlement history comparable to the major small-molecule blockbusters. The absence of a major settlement is consistent with Kineret’s expired core patent protection and biologic regulatory pathway.
If a biosimilar sponsor enters the market, disputes would more likely concern:
- Biosimilar patent dance disclosures.
- Manufacturing and process patents.
- Formulation or device claims.
- Labeling and method-of-use issues.
- Interchangeability or substitution strategy.
- Trade-secret and confidential-information allegations.
The commercial outcome would depend more on FDA approval timing, payer coverage, and contracting than on a single Orange Book patent expiry date.
How does Kineret compare with other IL-1 inhibitors?
| Product |
Active ingredient |
Main advantage |
Main competitive limitation |
| Kineret |
Anakinra |
Extensive experience, daily dose flexibility, broad IL-1 pathway use |
Daily injection and mature patent position |
| Ilaris |
Canakinumab |
Long dosing interval and strong specialty positioning |
Higher cost and narrower practical use in some settings |
| Arcalyst |
Rilonacept |
Long-acting IL-1 blockade |
Indication and access constraints |
| Potential anakinra biosimilar |
Anakinra |
Lower price potential |
Development, substitution, and manufacturing hurdles |
Kineret’s daily administration is a disadvantage in adherence-sensitive markets. Its dosing flexibility is useful in acute or rapidly changing inflammatory conditions, where clinicians may prefer control over exposure rather than a long-acting product.
What is the geographic coverage of Kineret?
Sobi commercializes Kineret across major European markets and other international territories, subject to local approvals, reimbursement, and distribution arrangements. Geographic performance depends on:
- National reimbursement decisions.
- Orphan-drug pricing systems.
- Hospital versus outpatient procurement.
- Local biologic substitution rules.
- Distribution reliability.
- Availability of competing IL-1 products.
The European market is particularly important because rare-disease reimbursement and centralized specialist care can support persistent use. The United States remains important because of pricing, specialty prescribing, and the value of orphan indications.
What manufacturing and intellectual-property barriers protect Kineret?
The most credible barriers are operational rather than patent-based. These include:
- Maintaining a consistent recombinant protein process.
- Demonstrating batch comparability.
- Controlling impurities and aggregates.
- Preserving refrigerated supply-chain performance.
- Producing prefilled syringes at commercial scale.
- Meeting biologic pharmacopoeial and quality requirements.
- Supporting post-market pharmacovigilance.
These barriers can delay entry but generally do not prevent it indefinitely. A well-funded biosimilar company with biologic manufacturing capacity could overcome them.
Key Takeaways
- Kineret is an established anakinra biologic marketed by Sobi.
- Its core composition and primary U.S. exclusivity protections have expired.
- The product is regulated as a biologic and is relevant to the Purple Book, not a conventional Orange Book Paragraph IV strategy.
- CAPS and DIRA provide the strongest long-term commercial support.
- Rheumatoid arthritis is a mature and more competitive indication.
- COVID-19 created temporary revenue upside but should not be treated as recurring demand.
- No FDA-approved anakinra biosimilar has established broad U.S. market competition as of the latest available information.
- Kineret’s strongest defenses are manufacturing quality, rare-disease experience, physician familiarity, and patient continuity.
- A future biosimilar launch would probably cause gradual price and volume erosion rather than an immediate revenue collapse.
- Sobi’s broader portfolio reduces its dependence on Kineret, but the product remains a material specialty-care asset.
FAQs
Is Kineret still under patent protection?
Kineret’s foundational anakinra patent protection has expired. Current commercial durability depends on biologic manufacturing, regulatory history, rare-disease use, and market access rather than a blocking composition patent.
Is there a generic version of Kineret?
There is no conventional generic equivalent because Kineret is a biologic. A competitor would generally pursue a biosimilar pathway. No broadly commercialized FDA-approved anakinra biosimilar has established U.S. competition as of the latest available information.
Can Kineret be substituted automatically at the pharmacy?
Automatic substitution depends on FDA interchangeability status, state law, payer policy, and the product’s approved designation. The existence of a biosimilar would not by itself guarantee pharmacy-level substitution.
What would most reduce Kineret sales?
The largest risks are an FDA-approved anakinra biosimilar, aggressive payer contracting, declining COVID-19 use, and migration from Kineret to longer-acting IL-1 inhibitors.
Is Kineret a growth drug for Sobi?
Kineret is better characterized as a durable specialty and rare-disease revenue asset than as a high-growth product. Its financial value comes from recurring chronic use and market longevity, while Sobi’s newer products provide more of the company’s future growth potential.
References
- U.S. Food and Drug Administration. (2022). FDA approves Kineret to treat COVID-19. https://www.fda.gov
- Swedish Orphan Biovitrum AB. (2018). Sobi acquires U.S. rights to Kineret from Amgen. https://www.sobi.com
- Swedish Orphan Biovitrum AB. (2023). Annual report 2023. https://www.sobi.com
- U.S. Food and Drug Administration. (2024). Purple Book: Database of licensed biological products. https://purplebooksearch.fda.gov
- U.S. Food and Drug Administration. (2024). Kineret prescribing information. https://www.accessdata.fda.gov
- U.S. Food and Drug Administration. (2024). Biosimilar and interchangeable biosimilar products. https://www.fda.gov
- World Intellectual Property Organization. (1989). U.S. Patent No. 5,075,222: Interleukin-1 receptor antagonist. https://patents.google.com
