US Patent 10,612,027: Scope, Claims, Expiration Risk, and siRNA Patent Landscape
US Patent No. 10,612,027 protects a chemically defined class of double-stranded RNA agents, including GalNAc-conjugated siRNA products. Its strongest limitation is the antisense strand’s exact fluorine-modification pattern: four or six, and only four or six, 2′-fluoro nucleotides. The patent also claims specific nucleotide positions, terminal chemistry, phosphorothioate or methylphosphonate linkages, 5′-vinyl phosphonate groups, PS2-linked deoxythymidine, ASGPR ligands, pharmaceutical compositions, and administration methods.
The patent is a platform patent rather than a patent limited to one target gene or one therapeutic indication. A competing siRNA product can avoid infringement by failing any required structural limitation, including the antisense length, formula-Ia architecture, modification count, modification positions, or ligand configuration. [1]
What does US Patent 10,612,027 claim?
The patent has three principal claim groups:
| Claim group |
Claims |
Protected subject matter |
| Modified dsRNA agents |
1-15, 22-25 |
Chemically modified antisense and sense strands |
| Pharmaceutical composition |
16 |
dsRNA agent with carrier or excipient |
| Therapeutic and delivery methods |
17-21 |
Gene-expression inhibition and tissue delivery |
Claim 1 is the principal composition claim. It requires a dsRNA agent with:
- An antisense strand of 19-25 nucleotides.
- Complementarity to at least part of a target-gene mRNA.
- The structural arrangement represented by formula (Ia).
- Defined B and T nucleotide blocks.
- A prescribed range for q1 through q7.
- Exactly four or exactly six antisense-strand 2′-fluoro modifications.
The target gene is not limited in the claim. The same claim can therefore reach siRNAs directed to multiple genes if the claimed chemical architecture is present.
How narrow is claim 1?
Claim 1 is broad in sequence and target-gene scope but narrow in chemistry. It is not a general claim to every modified siRNA. The accused product must satisfy the full combination of structural requirements.
The most commercially important limitation is the following:
- Four, and only four, antisense 2′-F modifications; or
- Six, and only six, antisense 2′-F modifications.
A product with five antisense 2′-F nucleotides would fall outside the literal wording of claim 1. A product with seven would also fall outside the claim. Products using four or six fluorines in different positions may still implicate claim 1, but claims 23 and 25 impose more specific positional requirements.
What do claims 22 through 25 add?
Claims 22-25 divide the fluorine limitation into two defined embodiments.
| Claim |
Required antisense 2′-F pattern |
| 22 |
Exactly four 2′-F modifications |
| 23 |
Four 2′-F modifications at positions 2, 6, 14 and 16 |
| 24 |
Exactly six 2′-F modifications |
| 25 |
Six 2′-F modifications at positions 2, 6, 8-9, 14 and 16 |
Positions are measured from the 5′ end of the antisense strand. Claim 23 is materially narrower than claim 22 because it fixes all four positions. Claim 25 is similarly narrower than claim 24.
These dependent claims create prosecution and litigation value. If a court invalidates or narrows the broader “four or six” limitation, the specified positional patterns may remain enforceable if they satisfy written-description, enablement, novelty, and obviousness requirements.
What nucleotide modifications are protected?
The patent combines several modification classes.
B-region modifications
Claims 1 and 6 require or permit B1′, B2′, B3′ and B4′ modifications. Claim 6 specifies 2′-O-methyl modifications for each of those positions.
The formula is material because the B positions are not merely optional modifications scattered throughout the strand. They occupy defined locations within the claimed sequence architecture. The exact nucleotide positions should be mapped against the patent’s formula and specification before making a freedom-to-operate conclusion.
T-region modifications
The T1′, T2′ and T3′ positions may contain DNA, RNA, LNA, 2′-F, or 2′-F-5′-methyl nucleotides. The dependent claims impose positional requirements:
- Claim 2 requires T1′ and T3′ to be separated by 11 nucleotides.
- Claim 3 places T1′ at position 14 from the antisense 5′ end and sets q2 at one nucleotide.
- Claim 4 places T3′ at position 2 and sets q6 at one nucleotide.
- Claim 5 places T2′ at positions 6-10 and sets q4 at one nucleotide.
These restrictions create a sequence-position claim chart that can be tested against an accused oligonucleotide’s full analytical sequence.
Backbone modifications
Claim 7 requires two blocks of two phosphorothioate or methylphosphonate internucleotide linkages, separated by 16-18 phosphate linkages.
Claim 15 adds an alternative terminal modification: a 2′-deoxythymidine linked through a phosphorodithioate, or PS2, linkage at the 5′ end of either strand.
Claim 14 adds a 5′-vinyl phosphonate. This is a separate chemical feature and can materially affect the scope of a product claim when combined with the base architecture of claim 1.
What formulations and delivery systems are protected?
ASGPR and GalNAc conjugates
Claims 10-13 cover an ASGPR ligand, with claim 11 placing the ligand at the 3′ end of the sense strand. Claim 12 identifies one or more GalNAc derivatives attached through a bivalent or trivalent branched linker.
This is the most commercially relevant portion of the patent because GalNAc conjugation supports hepatocyte delivery after subcutaneous administration. Products using a different ligand, a different attachment site, or a materially different linker may avoid the dependent claims, but could still fall within claim 1 if the underlying dsRNA agent satisfies the independent claim.
The structural depiction associated with claim 13 is essential to determine the full reach of that claim. The text supplied does not include the chemical structure after “wherein the ASGPR ligand is.” Claim 13 therefore cannot be fully charted from the provided claim text alone.
Pharmaceutical compositions
Claim 16 covers the claimed dsRNA agent with a pharmaceutically acceptable carrier or excipient. This claim can reach a formulated product even when the commercial product is sold as a drug substance and drug product with different manufacturing specifications.
The claim does not require a specific dosage, concentration, buffer, vial, prefilled syringe, or excipient. Its scope is therefore broader than a conventional formulation claim but remains dependent on the underlying dsRNA structure.
Administration methods
Claims 17-21 cover:
- Inhibition of target-gene expression.
- Subcutaneous or intravenous administration.
- Delivery to a specified target in a subject.
- Intramuscular, intrabronchial, intrapleural, intraperitoneal, intraarterial, lymphatic, intravenous, subcutaneous, or cerebrospinal administration.
Method claims require proof that the accused product was administered in the claimed manner and that the claimed gene-expression or delivery result occurred. Claims 19-21 may be more difficult to enforce against upstream manufacturers than composition claims because they require an act of administration or delivery.
When does US Patent 10,612,027 lose exclusivity?
A US patent generally expires 20 years from the effective US nonprovisional filing date, subject to patent-term adjustment, patent-term extension, terminal disclaimers, and other statutory adjustments. The issue date, April 7, 2020, does not determine the expiration date. [2]
The enforceable term should be confirmed in the USPTO Patent Center record and the face of the issued patent. Relevant checks include:
| Term issue |
Why it matters |
| Earliest effective nonprovisional or PCT filing |
Establishes the baseline 20-year term |
| Patent-term adjustment |
May extend the baseline term |
| Patent-term extension |
May apply only in qualifying regulatory circumstances |
| Terminal disclaimer |
May shorten the term to that of an earlier patent |
| Continuation or divisional status |
May affect priority and expiration analysis |
The patent’s term cannot be reliably calculated from the claim text alone. Any commercial launch analysis should use the USPTO term data rather than an issue-date calculation.
What is the Orange Book status of US Patent 10,612,027?
US Patent 10,612,027 is not, by itself, an Orange Book listing. The FDA Orange Book lists patents submitted by an NDA holder for an approved small-molecule drug product, subject to FDA listing requirements. A platform patent is not automatically listed merely because it may cover an approved product. [3]
For an approved siRNA product, Orange Book relevance depends on:
- Whether the product was approved under an NDA.
- Whether the NDA holder submitted the patent to FDA.
- Whether the patent claims the drug substance, drug product, or an approved method of use.
- Whether FDA accepted the listing under applicable Orange Book criteria.
A patent claiming a broad siRNA platform may not qualify for listing if it does not claim the specific approved drug or an approved method of use. The absence of an Orange Book listing would materially change the generic-challenge pathway.
What Paragraph IV and generic-entry risks exist?
A Paragraph IV certification applies to an ANDA applicant challenging a patent listed in the Orange Book for the reference listed drug. It does not apply automatically to every patent that may cover an siRNA product.
Potential entry routes include:
| Entry route |
Relevance to this patent |
| ANDA with Paragraph IV |
Relevant only if the patent is properly listed for the reference product |
| 505(b)(2) NDA |
May be used for a product relying partly on existing FDA findings |
| Full NDA |
More likely where the product has a different sequence, conjugate, or delivery profile |
| Biosimilar application |
Generally not the expected route for chemically synthesized siRNA products |
A competing product could challenge validity on anticipation, obviousness, written description, enablement, indefiniteness, or lack of patentable subject matter. The exact 2′-F count and positional limitations may strengthen novelty but also create potential written-description and obviousness issues if the specification does not adequately support the full claimed genus.
Does biosimilar risk apply?
Classic biosimilar risk is limited. Chemically synthesized siRNA products are generally regulated as drugs rather than protein biologics. A follow-on product would more commonly raise generic, hybrid NDA, or independent NDA issues than a biosimilar application under the Public Health Service Act.
The principal competitive risks are therefore:
- A chemically distinct siRNA that avoids the claimed fluorine pattern.
- A GalNAc conjugate using a different linker or attachment position.
- A non-GalNAc delivery system.
- A product with five or more than six antisense 2′-F modifications.
- A product using a different backbone pattern.
- A product directed to a different gene and marketed through an independent regulatory pathway.
How does this patent compare with competing siRNA estates?
The patent sits within the broader chemical-modification and targeted-delivery landscape.
| Technology area |
Commercial participants |
Relationship to US 10,612,027 |
| GalNAc-conjugated siRNA |
Alnylam, Novartis, Roche, Silence Therapeutics, Dicerna/Merck |
Highest potential overlap |
| Lipid nanoparticle siRNA |
Alnylam and other RNA companies |
Lower overlap with the ASGPR claims |
| Dicer-substrate RNA |
Dicerna, Arrowhead and others |
May avoid 19-25 nucleotide antisense architecture depending on product |
| Antisense oligonucleotides |
Ionis and partners |
Usually outside the dsRNA requirement |
| LNP mRNA and other RNA platforms |
Moderna, BioNTech and others |
Generally outside the claimed dsRNA and ASGPR structure |
Alnylam-related licensing and collaboration arrangements are commercially relevant because GalNAc delivery, siRNA chemistry, and product-specific rights may be distributed across separate agreements. A license to a GalNAc platform does not necessarily grant rights to every patent covering a particular antisense modification pattern. Agreement-by-agreement analysis is required.
How strong is the patent estate?
Based on the supplied claims, US 10,612,027 has moderate-to-strong blocking potential against products that reproduce the claimed architecture, especially products with:
- 19-25 nucleotide antisense strands;
- exactly four or six antisense 2′-F modifications;
- the specified positions 2, 6, 14 and 16, or 2, 6, 8-9, 14 and 16;
- 2′-OMe B-region modifications;
- GalNAc attached to the sense-strand 3′ end;
- the claimed backbone and terminal modifications.
Its scope is weaker against products that change the core architecture. A competing developer can potentially design around the patent by changing the number or location of 2′-F groups, using a different antisense length, modifying the q-region arrangement, selecting another ligand or linker, or replacing the claimed backbone chemistry.
The patent is unlikely to block the entire siRNA market. Its practical value depends on whether commercially important products fall within every limitation of claim 1 or a surviving dependent claim.
Key Takeaways
- US Patent 10,612,027 is a chemistry and delivery platform patent for modified dsRNA agents.
- Claim 1 requires exactly four or six antisense 2′-F modifications.
- Claims 23 and 25 define particularly important four- and six-fluorine positional patterns.
- Claims 10-13 target ASGPR and GalNAc delivery, including 3′ sense-strand attachment.
- Claims 14 and 15 cover 5′-vinyl phosphonate and PS2-linked terminal chemistry.
- The patent is not automatically an Orange Book patent.
- Paragraph IV exposure depends on whether the patent is listed for a specific approved product.
- Biosimilar risk is generally less relevant than generic, 505(b)(2), or independent-NDA competition.
- Exact product-level infringement requires a full sequence, modification map, linker structure, backbone map, and administration facts.
- Claim 13 cannot be fully assessed without the omitted ASGPR-ligand structure.
FAQs
Can an siRNA with five antisense 2′-fluoro modifications infringe claim 1?
Literal infringement of the expressly recited “four, and only four” or “six, and only six” limitation would be unlikely. Claims 22-25 also would not cover five fluorines as written.
Does a GalNAc-siRNA automatically infringe US 10,612,027?
No. GalNAc attachment is recited in dependent claims 10-13, but the product must also satisfy the independent dsRNA architecture and fluorine limitations.
Is US Patent 10,612,027 a patent on a specific drug?
No. The claims are target-gene agnostic and cover a class of modified dsRNA agents, compositions, and delivery methods.
Can a non-GalNAc siRNA avoid the patent?
It may avoid claims 10-13, but it can still infringe claim 1 or other claims if its dsRNA sequence and chemical architecture satisfy the independent limitations.
What is the main freedom-to-operate test for this patent?
The decisive analysis is a limitation-by-limitation map covering antisense length, formula-Ia positions, q-region lengths, total 2′-F count, fluorine positions, backbone linkages, terminal groups, ligand structure, and administration route.
References
- United States Patent No. 10,612,027, claims 1-25 (issued Apr. 7, 2020).
- 35 U.S.C. § 154; United States Patent and Trademark Office, Manual of Patent Examining Procedure § 2710.
- U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations, commonly known as the Orange Book.
