Last updated: September 11, 2026
Soliris, AstraZeneca’s eculizumab, remains one of the highest-value complement inhibitors in rare disease. Its commercial trajectory is defined by three forces: migration to the longer-acting successor Ultomiris, durable demand across paroxysmal nocturnal hemoglobinuria (PNH), atypical hemolytic uremic syndrome (aHUS), and generalized myasthenia gravis (gMG), and increasing competition from next-generation complement drugs.
Soliris revenue declined from its peak as AstraZeneca moved patients to Ultomiris. The product retains substantial cash generation because of its established clinical record, broad regulatory labeling, specialist prescriber base, and high treatment prices. Its principal strategic risk is commercial substitution rather than immediate generic erosion.
What is Soliris and how does it work?
Soliris is a monoclonal antibody containing eculizumab, a humanized antibody that binds complement protein C5. The drug blocks terminal complement activation and prevents formation of the membrane attack complex.
The U.S. Food and Drug Administration approved Soliris in 2007 for PNH. Subsequent approvals expanded the label to include:
| Indication |
Initial FDA approval |
| Paroxysmal nocturnal hemoglobinuria |
2007 |
| Atypical hemolytic uremic syndrome |
2011 |
| Generalized myasthenia gravis |
2017 |
| Neuromyelitis optica spectrum disorder |
2019 |
Soliris is administered intravenously. The standard maintenance schedule for most adult indications is 1,200 mg every two weeks after an induction phase. The treatment requires meningococcal vaccination and infection-risk management because terminal complement inhibition increases susceptibility to invasive meningococcal disease (FDA, 2023).
How large is the Soliris market?
Soliris built a multibillion-dollar franchise before the launch of Ultomiris. AstraZeneca reported the following product sales:
| Year |
Soliris sales |
Year-over-year trend |
| 2021 |
Approximately $4.1 billion |
Decline began |
| 2022 |
Approximately $3.9 billion |
Down versus 2021 |
| 2023 |
Approximately $3.4 billion |
Continued decline |
The figures reflect AstraZeneca’s reported product sales for Soliris following its acquisition of Alexion Pharmaceuticals. Exact regional reporting can vary by annual-report presentation and foreign-exchange effects (AstraZeneca, 2022, 2023, 2024).
Ultomiris has become the growth engine of the franchise. Its longer dosing interval, including once-every-eight-weeks maintenance administration for many adult patients, supports switching from Soliris and reduces infusion frequency. AstraZeneca has reported rising Ultomiris sales as Soliris revenue falls.
Why is Soliris still commercially important?
Soliris retains value for four reasons:
- It has long-term real-world evidence across rare complement-mediated disorders.
- Physicians and treatment centers have extensive experience with its safety monitoring.
- Some patients remain on Soliris because of clinical stability, physician preference, or access conditions.
- Soliris continues to support pediatric and specialized treatment settings where switching decisions can be slower.
The product is also an established platform for complement inhibition. Its safety, pharmacology, and validated biomarker effects reduce prescriber uncertainty compared with newer agents.
What is the financial trajectory for Soliris?
Soliris is in a late-life-cycle decline, but the decline is controlled rather than abrupt. The principal source of erosion is internal cannibalization by Ultomiris.
Revenue trajectory
Soliris revenue peaked before the full commercial adoption of Ultomiris. Following Ultomiris’ launch, AstraZeneca prioritized conversion of eligible Soliris patients, particularly in PNH and aHUS. The resulting revenue pattern is:
- Peak sales above $4 billion annually.
- Progressive decline after Ultomiris adoption increased.
- Continued multibillion-dollar revenue through 2023.
- Long-term erosion from switching, new competitor launches, and potential biosimilar entry.
The economic value of the franchise has not disappeared. It has shifted from a single-product model toward a complement portfolio in which Soliris supplies mature revenue and Ultomiris captures new starts and switches.
Product mix and margin implications
Soliris has the economics of a specialty biologic: high price per patient, low patient volume, substantial medical-need differentiation, and specialist distribution. Its gross-margin contribution is likely strong, but net revenue is affected by:
- Government pricing programs.
- Rebates and payer contracting.
- International reference pricing.
- Patient assistance.
- Hospital and specialty-pharmacy purchasing terms.
- Foreign-exchange movements.
- Treatment discontinuation and migration to Ultomiris.
As the product ages, sales and marketing costs can decline. That can partially offset revenue erosion and preserve operating profit.
When does Soliris lose exclusivity?
Soliris has already lost portions of its regulatory exclusivity and core patent protection in the United States, but the practical timing of competition depends on patent litigation, biosimilar development, approval timing, and commercial launch agreements.
Regulatory exclusivity
Soliris received orphan-drug exclusivity for its individual rare-disease indications. Orphan exclusivity generally lasts seven years from approval of the relevant indication in the United States. The earliest PNH exclusivity period expired years ago. Later indications received separate periods, but orphan exclusivity does not prevent all competing products across every disease or mechanism.
Soliris also received the 12-year U.S. reference-product exclusivity available to biologics under the Biologics Price Competition and Innovation Act. That period expired in 2019, based on the 2007 U.S. approval date.
Patent protection
Soliris patent protection is distributed across composition, production, formulation, dosing, and use claims. The core antibody and related patent families have different filing and expiration dates. Some important U.S. patent terms reached expiration around or after 2021, while later patents and litigation positions have been used to delay or manage biosimilar competition.
The relevant commercial question is not whether one patent has expired. It is whether a biosimilar applicant can launch without infringing enforceable claims or whether the applicant agrees to a later entry date.
What patents protect Soliris?
Soliris protection has historically included the following categories:
| Patent category |
Protected subject matter |
Commercial role |
| Antibody composition |
Eculizumab antibody sequences and binding characteristics |
Core molecule protection |
| Complement inhibition |
Use of anti-C5 antibodies to treat complement-mediated disease |
Method-of-use protection |
| PNH treatment |
Dosing and treatment of hemolysis in PNH |
Indication-specific protection |
| aHUS treatment |
Use in complement-mediated renal disease |
Label and reimbursement protection |
| Formulation |
Stable liquid antibody formulations |
Manufacturing and product protection |
| Manufacturing |
Cell culture, purification, and antibody production |
Process and supply-chain protection |
| Dosing regimen |
Maintenance schedules and patient-selection approaches |
Lifecycle-management protection |
A complete freedom-to-operate analysis requires a current patent-family review in each jurisdiction. U.S. Orange Book listings do not provide the same coverage for biologics that they provide for small-molecule drugs. Soliris is regulated under the Public Health Service Act, and its patent transparency is handled principally through the biologics patent-exchange process rather than a conventional Orange Book listing.
What is the Orange Book status of Soliris?
Soliris is not treated like a conventional small-molecule product in the Orange Book. The FDA’s biologics framework uses the Purple Book to identify reference biological products, biosimilars, and interchangeable biosimilars.
The relevant U.S. regulatory pathway is:
- Soliris is the reference biological product.
- A biosimilar applicant may submit a 351(k) application.
- Patent disputes proceed under the biologics patent-exchange framework.
- FDA approval does not automatically determine the date of commercial launch.
- Interchangeability requires a separate regulatory finding and is not necessary for a biosimilar to compete.
The absence of a standard Orange Book listing does not mean Soliris lacks patent protection. It means the applicable regulatory and patent architecture differs from that used for chemical drugs.
Which companies are challenging Soliris?
The main competitive threat comes from companies developing eculizumab biosimilars and from manufacturers selling alternative complement inhibitors.
Eculizumab biosimilar developers
Known industry participants have included:
- Amgen, with ABP 959.
- Samsung Bioepis.
- Celltrion.
- Other regional biosimilar developers and contract manufacturers.
As of mid-2024, the FDA had not approved an eculizumab biosimilar. Development and launch timing remained dependent on clinical comparability, manufacturing validation, patent resolution, and commercial strategy.
Eculizumab is technically difficult to copy because it is a complex monoclonal antibody requiring comparability across structure, binding, potency, impurities, and immunogenicity. Manufacturing scale and supply reliability are material barriers.
Competing complement inhibitors
| Product |
Company |
Mechanism or profile |
Competitive effect |
| Ultomiris |
AstraZeneca |
Long-acting C5 antibody |
Directly replaces Soliris |
| Empaveli |
Apellis |
C3 inhibitor |
Competes in PNH |
| Fabhalta |
Novartis |
Oral factor B inhibitor |
Oral alternative in PNH |
| Piasky |
Roche |
Long-acting C5 antibody |
Competes in PNH |
| Voydeya |
Novartis |
Factor D inhibitor |
Add-on treatment in PNH |
| Iptacopan |
Novartis |
Oral complement-pathway inhibitor |
Expands non-infusion competition |
Ravulizumab, marketed as Ultomiris, is the most important competitor because it is also AstraZeneca’s product. It reduces treatment burden and protects the broader franchise from external erosion.
How strong is the Soliris patent estate?
The Soliris patent estate is commercially meaningful but no longer comparable to a new biologic with unexpired core exclusivity.
Strengths
- Multiple patent families across composition, formulation, use, and manufacturing.
- Long clinical history that supports regulatory confidence.
- Several approved indications with separate clinical and reimbursement positions.
- High technical barriers to antibody manufacturing.
- A strong incumbent supplier relationship with specialist treatment centers.
Weaknesses
- The 12-year U.S. biologic exclusivity period has expired.
- The earliest core patent rights have expired or approached expiration.
- New competitors can rely on the established mechanism and disease biology.
- Ultomiris creates an internal substitute for Soliris.
- Biosimilar applicants can target the same molecule after regulatory exclusivity expiration.
Patent strength is therefore best characterized as moderate for Soliris itself and strong for the broader AstraZeneca complement franchise. The franchise has greater defensive value than the legacy product alone because Ultomiris absorbs many patients who might otherwise be exposed to an external biosimilar.
What litigation and settlement issues affect Soliris?
Soliris-related litigation risk centers on four areas:
- Patent infringement claims against eculizumab biosimilar applicants.
- Patent validity challenges involving antibody, formulation, or method-of-use claims.
- Declaratory-judgment actions concerning launch rights.
- Commercial settlements that establish negotiated biosimilar entry dates.
The most important litigation variable is the difference between FDA approval and market entry. A biosimilar may receive approval while remaining subject to a settlement-defined launch date or ongoing patent dispute.
Settlements can include:
- A fixed launch date.
- Geographic restrictions.
- License rights for specified indications.
- Supply or manufacturing terms.
- Covenant-not-to-sue provisions.
- Confidential commercial provisions.
Publicly available data should be reviewed at the patent-family and district-court docket level because biologic disputes often involve multiple patents and jurisdictions.
What is the biosimilar risk for Soliris?
Biosimilar risk is increasing, but the commercial impact is likely to be gradual.
Near-term risk
The immediate risk is limited by:
- Complex manufacturing.
- Small patient populations.
- Specialist prescribing.
- Vaccination and monitoring requirements.
- Payer controls.
- AstraZeneca’s ability to move patients to Ultomiris.
- The absence, as of mid-2024, of an FDA-approved U.S. eculizumab biosimilar.
Medium-term risk
Once an eculizumab biosimilar launches, price erosion could be substantial in procurement-sensitive channels. The first entrants may compete on discount, contracting, and supply reliability rather than clinical differentiation.
Soliris may retain patients who are stable on treatment, while new starts move toward Ultomiris or newer oral and subcutaneous options. Payers could use step edits, preferred-product strategies, or site-of-care restrictions to increase biosimilar uptake.
How does Soliris compare with Ultomiris?
| Factor |
Soliris |
Ultomiris |
| Active ingredient |
Eculizumab |
Ravulizumab |
| Target |
C5 |
C5 |
| Administration |
Frequent intravenous dosing |
Longer-interval intravenous dosing |
| Lifecycle position |
Mature |
Growth and defense product |
| Main commercial risk |
Biosimilar and internal switching |
New mechanism competition |
| Strategic role |
Legacy revenue and clinical anchor |
Franchise replacement |
| Patient burden |
Higher infusion frequency |
Lower infusion frequency |
Ultomiris has a more durable commercial position because it combines the validated C5 mechanism with reduced dosing frequency. Its main risk is that competitors such as Fabhalta, Empaveli, and Piasky offer alternative administration routes or pathway targets.
What are the generic launch scenarios for Soliris?
Scenario 1: Delayed biosimilar entry
A biosimilar receives approval but launches after patent litigation or settlement. Soliris revenue declines mainly through Ultomiris switching and competitor penetration.
Scenario 2: One biosimilar entrant
A single biosimilar gains preferred payer access. Price erosion is meaningful but limited by Soliris brand loyalty, clinical inertia, and AstraZeneca’s internal switching strategy.
Scenario 3: Multiple biosimilar entrants
Several eculizumab biosimilars compete on price. Soliris could face rapid erosion in mature PNH and aHUS accounts, particularly where payers control product selection.
Scenario 4: Franchise substitution
AstraZeneca moves most commercially attractive patients to Ultomiris before biosimilar competition reaches scale. Soliris becomes a smaller maintenance product, while the company preserves complement revenue through ravulizumab.
The fourth scenario is the most strategically coherent for AstraZeneca.
What is the geographic outlook for Soliris?
The United States remains the largest value market because of high treatment prices and concentrated specialist care. Europe offers substantial demand but faces stronger health-technology assessment controls, reference pricing, and country-specific reimbursement negotiations.
Emerging markets can expand patient access but generate lower net prices. Soliris demand in these markets depends on:
- National reimbursement.
- Rare-disease diagnosis rates.
- Local vaccination infrastructure.
- Import and cold-chain requirements.
- Availability of specialist infusion centers.
- Local biosimilar competition.
The geographic risk is uneven. U.S. erosion is more likely to occur through product switching and biosimilar contracting. European erosion is more likely to involve tendering, reference pricing, and mandated substitution policies.
What is the revenue exposure for AstraZeneca?
Soliris remains material to AstraZeneca’s Alexion business but is no longer the primary growth driver. The company’s financial exposure is increasingly concentrated in the broader complement portfolio rather than Soliris alone.
Key variables include:
- Speed of Soliris-to-Ultomiris conversion.
- Uptake of Ultomiris in new indications.
- Biosimilar approval and launch timing.
- Net price reductions.
- Expansion of oral complement inhibitors.
- PNH patient growth and diagnosis.
- Treatment duration and persistence.
- Regulatory expansion into additional complement-mediated diseases.
A declining Soliris line can coexist with stable or growing Alexion revenue if Ultomiris and newer rare-disease products capture the displaced demand.
Key Takeaways
- Soliris is a mature multibillion-dollar biologic with declining revenue.
- AstraZeneca’s main defense is migration to Ultomiris, not continued reliance on Soliris exclusivity.
- U.S. biologic exclusivity expired in 2019, and the earliest core patent rights have expired or weakened.
- Soliris is not governed by a conventional Orange Book listing; the Purple Book and biologics patent framework are more relevant.
- As of mid-2024, no FDA-approved eculizumab biosimilar had launched in the United States.
- Biosimilar risk is real but technically and commercially complex.
- The strongest external competitors are Empaveli, Fabhalta, Piasky, and other complement-pathway drugs.
- The most likely financial outcome is continued Soliris erosion accompanied by franchise-level protection through Ultomiris.
FAQs About Soliris Market and Patent Risk
What is the main reason Soliris sales are declining?
The primary reason is patient conversion from Soliris to Ultomiris, which provides longer dosing intervals and lower infusion burden.
Is Soliris still protected by orphan-drug exclusivity?
The original PNH orphan exclusivity has expired. Later indications received separate orphan exclusivity periods, but those periods do not create broad protection against all complement inhibitors.
Can a biosimilar replace Soliris automatically?
No. Biosimilar approval does not guarantee automatic substitution. Interchangeability, payer policy, physician prescribing, state law, and contracting determine the practical level of substitution.
Which drug is most likely to replace Soliris?
Ultomiris is the leading replacement because it is AstraZeneca’s longer-acting C5 inhibitor and shares the Soliris treatment platform. Fabhalta and Empaveli are important alternatives in PNH.
Does Soliris have manufacturing barriers?
Yes. Eculizumab is a complex monoclonal antibody requiring controlled cell culture, purification, analytical characterization, and potency testing. These requirements make biosimilar development more difficult than generic small-molecule production.
References
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AstraZeneca. (2022). Annual report and Form 20-F 2021. AstraZeneca PLC.
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AstraZeneca. (2023). Annual report and Form 20-F 2022. AstraZeneca PLC.
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AstraZeneca. (2024). Annual report and Form 20-F 2023. AstraZeneca PLC.
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U.S. Food and Drug Administration. (2023). Soliris (eculizumab) prescribing information. U.S. Department of Health and Human Services.
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U.S. Food and Drug Administration. (2024). Purple Book: Database of licensed biological products. U.S. Department of Health and Human Services.
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U.S. Food and Drug Administration. (2024). Biosimilar and interchangeable biosimilar products. U.S. Department of Health and Human Services.
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U.S. Food and Drug Administration. (2007). FDA approves Soliris for rare blood disorder. U.S. Department of Health and Human Services.
