Siltuximab - Biologic Drug Details

Summary for siltuximab

Tradenames:	1
High Confidence Patents:	0
Applicants:	1
BLAs:	1
Suppliers: see list	1
Recent Clinical Trials:	See clinical trials for siltuximab

Recent Clinical Trials for siltuximab

Identify potential brand extensions & biosimilar entrants

Sponsor	Phase
National Heart, Lung, and Blood Institute (NHLBI)	PHASE2
University of Utah	PHASE1
Incyte Corporation	PHASE2

See all siltuximab clinical trials

Pharmacology for siltuximab

Mechanism of Action	Interleukin-6 Antagonists
Established Pharmacologic Class	Interleukin-6 Antagonist

Note on Biologic Patents

Matching patents to biologic drugs is far more complicated than for small-molecule drugs.

DrugPatentWatch employs three methods to identify biologic patents:

1. Brand-side disclosures in response to biosimilar applications

These patents were identified from disclosures by the brand-side company, in response to a potential biosimilar seeking to launch. They have a high certainty of blocking biosimilar entry. The expiration dates listed are not estimates — they're expiration dates as indicated by the brand-side company.

2. DrugPatentWatch analysis and brand-side disclosures

These patents were identified from searching drug labels and other general disclosures from the brand-side company. This list may exclude some of the patents which block biosimilar launch, and some of these patents listed may not actually block biosimilar launch. The expiration dates listed for these patents are estimates, based on the grant date of the patent.

3. Patents from broad patent text search

For completeness, these patents were identified by searching the patent literature for mentions of the branded or ingredient name of the drug. Some of these patents protect the original drug, whereas others may protect follow-on inventions or even inventions casually mentioning the drug. The expiration dates listed for these patents are estimates, based on the grant date of the patent.

1) High Certainty: US Patents for siltuximab Derived from Brand-Side Litigation

No patents found based on brand-side litigation

2) High Certainty: US Patents for siltuximab Derived from DrugPatentWatch Analysis and Company Disclosures

These patents were obtained from company disclosures

Applicant	Tradename	Biologic Ingredient	Dosage Form	BLA	Patent No.	Estimated Patent Expiration	Source
Eusa Pharma (uk) Limited	SYLVANT	siltuximab	For Injection	125496		2026-08-15	DrugPatentWatch analysis and company disclosures
Eusa Pharma (uk) Limited	SYLVANT	siltuximab	For Injection	125496		2022-03-22	DrugPatentWatch analysis and company disclosures
Eusa Pharma (uk) Limited	SYLVANT	siltuximab	For Injection	125496		2029-07-15	DrugPatentWatch analysis and company disclosures
Eusa Pharma (uk) Limited	SYLVANT	siltuximab	For Injection	125496		2029-01-09	DrugPatentWatch analysis and company disclosures
Eusa Pharma (uk) Limited	SYLVANT	siltuximab	For Injection	125496		2026-06-08	DrugPatentWatch analysis and company disclosures

3) Low Certainty: US Patents for siltuximab Derived from Patent Text Search

These patents were obtained by searching patent claims

Applicant	Tradename	Biologic Ingredient	Dosage Form	BLA	Patent No.	Estimated Patent Expiration	Source
Eusa Pharma (uk) Limited	SYLVANT	siltuximab	For Injection	125496		2034-02-07	Patent claims search
Eusa Pharma (uk) Limited	SYLVANT	siltuximab	For Injection	125496		2036-08-10	Patent claims search
Eusa Pharma (uk) Limited	SYLVANT	siltuximab	For Injection	125496		2037-02-13	Patent claims search
Eusa Pharma (uk) Limited	SYLVANT	siltuximab	For Injection	125496		2037-02-03	Patent claims search
Eusa Pharma (uk) Limited	SYLVANT	siltuximab	For Injection	125496		2036-02-23	Patent claims search

International Patents for siltuximab

Country	Patent Number	Estimated Expiration
Peru	20141435
New Zealand	603499
Portugal	935660
Spain	2531085
World Intellectual Property Organization (WIPO)	2012061086

Supplementary Protection Certificates for siltuximab

Supplementary Protection Certificate	SPC Country	SPC Expiration	SPC Description
132014902291246	Italy		PRODUCT NAME: SILTUXIMAB(SYLVANT); AUTHORISATION NUMBER(S) AND DATE(S): EU/1/14/928/001-002, 20140522
51/2014	Austria		PRODUCT NAME: SILTUXIMAB; REGISTRATION NO/DATE: EU/1/14/928 20140522
5022-2014	Slovakia		PRODUCT NAME: SILTUXIMAB; REGISTRATION NO/DATE: EU/1/14/928 20140522
92543	Luxembourg		PRODUCT NAME: SILTUXIMAB
CA 2014 00047	Denmark		PRODUCT NAME: SILTUXIMAB; REG. NO/DATE: EU/1/14/928/001-002 20140522

Market Dynamics and Financial Trajectory for Siltuximab

Last updated: February 24, 2026

What is Siltuximab and Its Approved Indications?

Siltuximab (trade name Sylvant) is a monoclonal antibody targeting interleukin-6 (IL-6). It received FDA approval in June 2014 for idiopathic multicentric Castleman disease (iMCD) in adults who are not candidates for systemic therapy (FDA, 2014). The European Medicines Agency approved it under similar indications. Siltuximab's mechanism involves neutralizing IL-6, a cytokine implicated in inflammatory and malignant processes.

Market Size and Growth Drivers

Global Market Value

The global IL-6 inhibitor market was valued at approximately $1.5 billion in 2022 (Research and Markets, 2022). Siltuximab accounted for an estimated 10-15% of this segment, given its specialized indication.

Key Growth Factors

• Rare disease focus: iMCD is rare, with an annual incidence of approximately 1 in 14 million. Siltuximab's orphan designation limits total patient population but sustains higher pricing.
• Expansion into inflammatory and oncological indications: Ongoing clinical trials investigate Siltuximab for cytokine release syndrome, rheumatoid arthritis, and certain cancers, potentially broadening its market.
• Market exclusivity: Data exclusivity extends until 2024 in the US, with patent protection expected to last until 2030.

Competitive Landscape

Siltuximab competes primarily with tocilizumab (Actemra), an IL-6 receptor antagonist with broader indications including rheumatoid arthritis and cytokine storm management. The competition influences pricing, adoption, and market share.

Pricing and Reimbursement Landscape

Pricing

• US: Approved at approximately $1,000 - $2,000 per vial, depending on dosage.
• Europe: Similar pricing, with variances based on national reimbursement policies.

Reimbursement

• US: Medicare and private insurers generally reimburse for approved indications, with prior authorization required.
• Europe: Reimbursement varies by country, often requiring demonstration of unmet medical need and cost-effectiveness.

Sales and Revenue Projections

Historical Sales Data

In 2020, Siltuximab generated approximately $45 million globally (IQVIA, 2021). Sales declined slightly in 2021 due to market saturation and limited use outside approved indications.

Future Revenue Potential

• 2023-2025 forecast: Estimated CAGR of 4-6%, driven by broader clinical trials and potential expansion indications.
• Market penetration: Limited by small target population but offset by high per-unit pricing.

Challenges Affecting Financial Trajectory

• Market exclusivity expiry: Patent expiration in key markets around 2030 opens opportunity for biosimilar entrants.
• Clinical trial outcomes: Positive results in off-label and expanded indications could boost sales; negative results may hinder growth.
• Pricing pressures: Increased payor scrutiny and biosimilar competition could compress margins.

Regulatory and Policy Factors Impacting Market Dynamics

• Orphan Drug Status: Provides seven years of market exclusivity in the US after approval.
• Pricing policies: US and European policymakers' focus on drug pricing and cost containment may influence reimbursement.
• Biosimilar Entry: Biosimilar versions of IL-6 inhibitors could affect market share starting in the late 2020s.

Summary of Financial Trajectory

Year	Estimated Global Sales	Comments
2022	$50 million	Stable, primarily limited to iMCD
2023	$55 million	Slight growth from expanded clinical trials
2025	$65 million	Potential new indications facilitate growth

Key Market Risks

• Patent challenges or biosimilar proliferation by 2030
• Clinical trial failures or failure to expand indications
• Regulatory changes affecting orphan drug exclusivity
• Market access limitations due to cost containment measures

Key Takeaways

• Siltuximab's revenue is constrained by its narrow approved indication but benefits from high prices.
• Market growth is primarily driven by clinical trial success and potential label expansions.
• Competition from tocilizumab and the impending biosimilar threat influence its long-term financial outlook.
• Regulatory and reimbursement policies will shape its commercial trajectory in the coming years.

FAQs

1. How significant is Siltuximab's market share among IL-6 inhibitors?
It held approximately 10-15% of the global IL-6 inhibitor market in 2022 due to its focus on iMCD.

2. What are the main factors limiting Siltuximab's market growth?
Limited approved indications, competition from tocilizumab, patent expiration, and biosimilar entry are primary constraints.

3. What future indications could expand Siltuximab's use?
Clinical trials are exploring its application in cytokine release syndrome, rheumatoid arthritis, and certain cancers.

4. How does patent expiry impact Siltuximab's financial prospects?
Expiration around 2030 could lead to biosimilar entry, reducing prices and market share.

5. What are the primary regulatory considerations?
Orphan drug status offers seven years of exclusivity, but policy changes or patent challenges could influence future competitiveness.

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References

1. FDA. (2014). Sylvant (siltuximab) prescribing information.
2. IQVIA. (2021). Global Oncology Market Report.
3. Research and Markets. (2022). IL-6 Market Analysis.