US Patent 8,110,560: SMN2 Exon 7 Splicing Claims, Nusinersen Coverage, and Patent Landscape

US Patent 8,110,560 is a foundational patent for antisense treatment of spinal muscular atrophy through modulation of SMN2 pre-mRNA splicing. Its claims cover methods using oligonucleotides directed to the ISS-N1 intronic splicing silencer in intron 7 of SMN2. The patent is especially relevant to nusinersen, marketed as Spinraza, because nusinersen targets the ISS-N1 region and increases inclusion of exon 7 in SMN2 mRNA.

The patent claims methods rather than a particular commercial drug composition. The principal risk is therefore method-of-use infringement when an accused product is administered to increase exon 7-containing SMN2 mRNA or treat SMA. The patent’s core term is expected to run from the 2005 priority date into 2026, subject to the official patent-term calculation, disclaimers, and any applicable adjustments.

What does US Patent 8,110,560 cover?

US 8,110,560 covers antisense oligonucleotide methods that alter SMN2 splicing by binding sequences in intron 7, particularly the ISS-N1 silencer region.

The central limitations are:

Claim element	Scope
Biological target	SMN2 pre-mRNA, specifically intron 7
Functional result	Increased exon 7-containing SMN2 mRNA
Sequence relationship	At least 80% complementary to intron 7 over the full oligonucleotide length
ISS-N1 relationship	At least 85% complementary to SEQ ID NO:1 or SEQ ID NO:3
Principal exact-sequence claim	Claim 25 requires 100% complementarity to the ISS-N1 sequence in SEQ ID NO:1
Length	Dependent claims cover 10-15, 15-20, and 15-40 nucleotides
Chemistry	Modified nucleotides, modified sugars, 2'-substitutions, morpholino groups, bicyclic or LNA nucleotides, and phosphorothioate linkages
Therapeutic use	SMA treatment in a patient
Biological setting	In vitro, in vivo, cells, organisms, mammals, and humans
Additional indication	Claim 28 recites ALS, while claim 41 narrows that subject back to SMA

The independent method claims are claims 1, 20, 24, 25, 26, and 27. Claims 1 and 20 focus on increasing exon 7-containing SMN2 mRNA. Claim 24 expressly covers treating SMA. Claims 25 and 26 focus on inhibiting the ISS-N1 splicing silencer. Claim 27 covers administration to a subject without limiting the claim to SMA, although dependent claim 28 recites ALS.

How do the independent claims differ?

Claim 1: cellular SMN2 splicing modulation

Claim 1 requires contacting a cell with an oligonucleotide satisfying two sequence tests:

At least 80% complementarity to intron 7 of SMN2 across the entire oligonucleotide.
At least 85% complementarity to SEQ ID NO:1 or SEQ ID NO:3.

The oligonucleotide must increase exon 7-containing SMN2 mRNA. This is a functional limitation. Sequence similarity alone is not sufficient if the treatment does not produce the claimed increase.

Claim 20: organism-level administration

Claim 20 extends the cellular concept to administration to an organism. Claim 22 narrows the organism to a human, and claim 23 narrows the human to a person with SMA.

This claim structure creates a direct path from molecular targeting to clinical treatment:

Claim	Required context
1	Cell
20	Organism
22	Human
23	Human with SMA
24	Patient with SMA and therapeutic treatment
27	Subject receiving an effective dose
28	Subject with ALS
41	Claim 28 subject further specified as having SMA

Claim 25: exact ISS-N1 inhibition

Claim 25 is narrower in sequence identity but potentially stronger in factual application. It requires an oligonucleotide that is 100% complementary to the ISS-N1 sequence in SEQ ID NO:1 and that inhibits the SMN2 intronic splicing silencer site.

An antisense oligonucleotide directed precisely to ISS-N1 is the clearest infringement candidate under this claim if the accused product also produces the claimed silencer inhibition.

Claim 24: SMA treatment

Claim 24 is the most commercially important claim. It requires:

Administration to a patient.
An oligonucleotide meeting the sequence-complementarity limitations.
An effective dose.
Increased exon 7-containing SMN2 mRNA in patient cells.
Treatment of SMA.

This claim is directed to clinical use rather than research use. It is the claim most closely aligned with nusinersen’s approved indication.

What oligonucleotide chemistries are protected?

The patent uses broad dependent claims to cover multiple antisense chemistries. The claims are not limited to one backbone or sugar modification.

Sugar and nucleotide modifications

Claims 8 through 16 cover modified nucleotides and modified sugar moieties. Claim 13 covers modification at the 2'-position. Claim 14 lists broad substituent categories, including hydrogen, alkoxy, alkyl, halo, thiol, amino, and related groups.

Claim 31 expressly identifies a 2'-O-methyl modification. Claims 34 through 40 extend coverage to oligonucleotides in which every nucleotide is modified, including oligonucleotides in which each nucleotide carries the same modification.

Morpholino and bicyclic nucleotides

Claim 10 covers morpholino moieties. Claims 33 and 37 cover bicyclic nucleotides. Claim 19 covers LNA nucleotides.

These claims could reach different antisense platforms if the sequence and functional limitations are satisfied. They do not mean that every LNA, morpholino, or bicyclic oligonucleotide directed to SMN2 infringes. The target sequence and demonstrated biological effect remain required.

Phosphorothioate linkages

Claims 17 and 18 cover modified linkages and phosphorothioate linkages. Claim 32 requires every linkage to be phosphorothioate.

This limitation is important for nusinersen analysis because nusinersen is a chemically modified antisense oligonucleotide with phosphorothioate linkages and 2'-O-(2-methoxyethyl) sugar modifications. A nusinersen-like product would likely satisfy the chemistry limitations in claims 13, 17, 18, 31, and 32 if the remaining claim elements are met.

Does US 8,110,560 cover nusinersen?

US 8,110,560 is technically relevant to nusinersen because both are directed to the ISS-N1 region of intron 7 in SMN2 pre-mRNA. Nusinersen increases production of full-length SMN protein by promoting inclusion of exon 7.

A product-use comparison is as follows:

Feature	US 8,110,560 claims	Nusinersen
Target	ISS-N1/intron 7 of SMN2	ISS-N1/intron 7 of SMN2
Mechanism	Blocks an intronic splicing silencer	Promotes exon 7 inclusion
Modality	Antisense oligonucleotide	Antisense oligonucleotide
Chemistry	Broadly covers modified sugars and linkages	2'-MOE, phosphorothioate antisense chemistry
Clinical result	Increased exon 7-containing SMN2 mRNA	Increased full-length SMN protein
Indication in patent	SMA and other subject claims	SMA
Administration	Organism, human, patient	Intrathecal administration

The patent does not claim the commercial name Spinraza or a single fixed formulation. It claims use of qualifying oligonucleotides for the stated molecular and therapeutic purposes. Infringement would depend on the asserted claim, the sequence and chemistry of the accused product, the administered indication, and proof of the claimed molecular result.

When does US Patent 8,110,560 lose exclusivity?

The patent was filed against a priority date of June 27, 2005, and issued on February 7, 2012. The ordinary United States patent term for a nonprovisional application filed after June 8, 1995, is generally 20 years from the earliest effective nonprovisional filing date, subject to patent-term adjustment, terminal disclaimers, and related statutory rules.[1]

On that basis, the apparent base expiration date is June 27, 2026. The official expiration date should be determined from the USPTO patent record because patent-term adjustment or a terminal disclaimer can change the operative date.

Event	Date
Earliest stated priority date	June 27, 2005
Patent issued	February 7, 2012
Apparent 20-year term endpoint	June 27, 2026
Expected post-expiration status	Claims generally unavailable for prospective infringement after expiration

Expiration does not eliminate potential liability for conduct occurring while the patent was in force. It also does not terminate separate patent rights covering nusinersen composition, manufacturing, formulation, dosing, or other uses.

What is the Orange Book status of US 8,110,560?

Orange Book treatment must be distinguished from patent validity and enforceability. FDA Orange Book listing depends on whether a patent is submitted for an approved drug application and whether it claims the drug substance, drug product, or an approved method of use.[2]

US 8,110,560 is a method-of-use patent directed to SMN2 splicing and SMA treatment. If listed for Spinraza, it would be relevant primarily to a generic applicant’s Paragraph IV certification and to the scope of any use code submitted by the NDA holder. The presence or absence of an Orange Book listing does not determine whether the patent is otherwise enforceable.

A generic applicant seeking approval for a product that can be used for the patented SMA indication could face:

A Paragraph IV certification alleging invalidity, unenforceability, or non-infringement.
A 30-month FDA approval stay if the NDA holder timely files suit.
A carve-out or section viii statement for a patented method of use, depending on the FDA-listed use code.
Litigation over whether the proposed label induces infringement.

The key commercial issue is the label. A generic label that includes SMA treatment language creates a clearer method-of-use exposure than a label that omits the patented use, although physicians may still prescribe an approved product for the patented indication.

How strong is the patent estate for nusinersen?

US 8,110,560 is best viewed as an early, foundational patent rather than the entire nusinersen estate. A commercial product can be protected by several patent categories:

Patent category	Typical subject matter
Target and mechanism	ISS-N1 binding and SMN2 exon 7 inclusion
Composition	Specific antisense sequences and chemical structures
Backbone chemistry	Phosphorothioate or other modified linkages
Sugar chemistry	2'-MOE, 2'-O-methyl, LNA, or related modifications
Formulation	Concentration, pH, excipients, container, and stability
Dosing	Loading and maintenance regimens
Administration	Intrathecal delivery
Manufacturing	Oligonucleotide synthesis, purification, and quality controls
Method of treatment	SMA subtypes, age groups, and patient populations

The patent at issue is strong at the mechanism and treatment-method level because the claims connect the sequence target to the biological result. Its limitations also create potential vulnerabilities:

Sequence identity: An accused oligonucleotide may argue that it does not meet the 80% or 85% complementarity thresholds.
Functional result: The accused party may dispute whether the product increases exon 7-containing SMN2 mRNA as required.
Claim construction: The meaning of “complementary,” “over the entire length,” and the reference sequences may be contested.
Induced infringement: Liability may depend on the approved label, promotional activity, and physician use.
Enablement and written description: Broad sequence and chemistry claims could face scrutiny under current Supreme Court and Federal Circuit standards.
Obviousness: Earlier work on antisense splicing modulation may be asserted against broad claims.
Expiration: The apparent 2026 endpoint reduces its remaining standalone blocking value.

The estate can remain commercially significant after this patent expires if later patents cover nusinersen’s exact sequence, chemistry, formulation, administration, or dosing regimen.

Which companies are challenging or competing with nusinersen?

The competitive landscape includes approved and investigational products that use different mechanisms or delivery technologies.

Product	Sponsor	Modality	SMN-related mechanism
Spinraza	Biogen and Ionis Pharmaceuticals	Antisense oligonucleotide	Promotes SMN2 exon 7 inclusion
Evrysdi	Roche and PTC Therapeutics	Oral small molecule	SMN2 splicing modifier
Zolgensma	Novartis	AAV gene replacement	Delivers an SMN1 transgene
Investigational antisense programs	Multiple developers	Antisense or RNA-based	May target SMN2 splicing or SMN expression

Evrysdi and Zolgensma generally present a lower direct infringement risk under claims limited to an oligonucleotide complementary to ISS-N1. They remain commercial competitors because they address the same SMA treatment market through different modalities.

Biosimilar risk is not the principal issue for nusinersen. Nusinersen is a chemically synthesized oligonucleotide, not a biologic protein. The relevant regulatory pathway is an abbreviated generic or hybrid application, depending on product characteristics and FDA requirements, rather than a conventional biosimilar application under the Public Health Service Act.

What generic launch risks exist after patent expiration?

A post-expiration launch would still require regulatory approval and commercial manufacturing capability. The main barriers are:

Demonstrating pharmaceutical equivalence and suitable quality attributes.
Establishing the required pharmacokinetic, pharmacodynamic, or clinical bridge.
Manufacturing a highly pure, sequence-specific oligonucleotide.
Matching the approved concentration and route of administration.
Managing intrathecal delivery and sterile manufacturing requirements.
Addressing patents that expire later than US 8,110,560.
Avoiding inducement liability under listed method-of-use claims.
Resolving any pediatric-exclusivity or regulatory exclusivity period that remains operative.

The most plausible launch scenarios are:

Scenario	Commercial effect
Core patent expires with no enforceable later patent	Generic entry becomes legally more feasible
Later composition or formulation patents remain in force	Entry may require Paragraph IV litigation or a delayed launch
Label carve-out is accepted	Limited approval may be possible without the patented indication
Courts uphold method claims before expiration	Launch may be delayed by litigation or settlement
Product-specific manufacturing barriers persist	Legal freedom to operate may not translate into rapid supply

What litigation and settlement issues matter?

The principal litigation questions would concern:

Whether the accused sequence is complementary to SEQ ID NO:1 or SEQ ID NO:3.
Whether the asserted product is administered for SMA.
Whether the product increases exon 7-containing SMN2 mRNA.
Whether the patent claims are enabled across the claimed sequence and chemistry breadth.
Whether prior art discloses the ISS-N1 target and the claimed splicing effect.
Whether a generic label induces infringement.
Whether the patent is listed in the Orange Book with a sufficiently specific use code.

A settlement could include a delayed generic launch date, a license, a manufacturing agreement, a covenant not to sue, or a label restriction. Settlement terms should not be inferred from the existence of patent litigation alone. The operative agreement and court docket control.

What geographic coverage does the patent provide?

US 8,110,560 provides rights only in the United States. Parallel protection may exist in foreign jurisdictions through related applications, national-stage filings, or continuations. Foreign scope can differ materially because:

European claims may be narrower or directed to medical use.
Patent-term calculations vary by jurisdiction.
Supplementary protection certificates may apply to approved products.
Claim validity standards differ.
National courts may construe sequence identity and functional limitations differently.

A global freedom-to-operate analysis therefore requires a family-level review across the United States, Europe, Japan, China, Canada, and other key SMA markets.

Key Takeaways

US 8,110,560 covers antisense modulation of SMN2 splicing through intron 7, especially the ISS-N1 silencer.
Claims 1, 20, 24, 25, 26, and 27 are the principal independent method claims.
Claim 24 is the most commercially relevant claim because it expressly covers treating SMA.
The patent broadly covers modified antisense chemistries, including 2'-modified sugars, phosphorothioate linkages, morpholino groups, LNA nucleotides, and bicyclic nucleotides.
Nusinersen is technically aligned with the patent’s target and mechanism, but infringement depends on claim construction and proof of every limitation.
The apparent base expiration date is June 27, 2026, subject to the official USPTO term calculation.
The patent is one component of the broader nusinersen estate. Later composition, formulation, dosing, administration, and manufacturing patents may control actual generic-entry timing.
Generic and biosimilar analysis should not be conflated. Nusinersen is a synthetic oligonucleotide, so biosimilar rules are generally not the primary pathway.
The highest-value legal issues are sequence identity, functional activity, label-induced infringement, patent-term status, and later Orange Book-listed patents.

FAQs

Does US 8,110,560 claim nusinersen by name?

No. The patent claims methods using qualifying oligonucleotides directed to SMN2 intron 7 and ISS-N1. Nusinersen may fall within those method claims because of its target, chemistry, and SMA use.

Does the patent cover oral SMN2 splicing modifiers?

Generally no, unless the accused product is an oligonucleotide meeting the claimed complementarity and functional limitations. Oral small-molecule splicing modifiers are materially different from the claimed antisense modality.

Is an antisense sequence with one or more mismatches automatically outside the patent?

No. Claims 1, 20, 24, and 27 use percentage-complementarity thresholds, while claim 25 requires 100% complementarity to SEQ ID NO:1. The result depends on oligonucleotide length, mismatch position, sequence interpretation, and the asserted claim.

Can a generic launch occur immediately after June 27, 2026?

Not necessarily. Other patents, regulatory exclusivity, Orange Book listings, manufacturing patents, formulation rights, or litigation settlements may delay or constrain launch.

Is a patent directed to SMA treatment automatically an Orange Book patent?

No. Orange Book listing is governed by FDA rules for patents submitted for an approved drug application and depends on whether the patent claims the drug, its formulation, or an approved method of use.

References

United States Patent and Trademark Office. (2024). Patent term adjustment and patent term calculation resources. https://www.uspto.gov/patents/laws/patent-term-adjustment
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. https://www.accessdata.fda.gov/scripts/cder/ob/
United States Patent and Trademark Office. (2012). U.S. Patent No. 8,110,560: Methods and compositions for treating spinal muscular atrophy.
U.S. Food and Drug Administration. (2016). Spinraza (nusinersen) prescribing information. Biogen Inc.
Hua, Y., Vickers, T. A., Okunola, H. L., Bennett, C. F., & Krainer, A. R. (2008). Antisense masking of an hnRNP A1/A2 intronic splicing silencer corrects SMN2 splicing in transgenic mice. American Journal of Human Genetics, 82(4), 834-848.
U.S. Food and Drug Administration. (2021). Drug competition action plan and generic drug approval resources. https://www.fda.gov/drugs/generic-drugs-settlement-agreements/generic-drug-user-fee-amendmentsJapgolly

Details for Patent: 8,110,560

Summary for Patent: 8,110,560