United States Drug Patent 9,133,461: Claim Scope, Givosiran Coverage, and Patent Landscape

U.S. Patent No. 9,133,461 is a core Alnylam patent covering GalNAc-conjugated double-stranded RNA molecules that silence the hepatic ALAS1 gene. Its claims combine a defined ALAS1 target sequence, specific sense and antisense strands, 2'-O-methyl and 2'-fluoro nucleotide chemistry, phosphorothioate linkages, strand-end architecture, GalNAc targeting, pharmaceutical compositions, and treatment of hepatic porphyrias.

The patent is directly relevant to Givlaari (givosiran), Alnylam's FDA-approved siRNA therapy for acute hepatic porphyria. The patent is listed in the FDA Orange Book with an expiration date reported as December 19, 2030. FDA orphan-drug exclusivity for Givlaari runs for seven years from approval, through November 20, 2026. Patent protection therefore extends beyond regulatory orphan exclusivity by approximately four years.[1,2]

What does U.S. Patent 9,133,461 cover?

The patent covers a defined class of ALAS1-directed siRNA products and their therapeutic use. The claims are not limited to a single commercial formulation. They reach across molecular composition, conjugation chemistry, pharmaceutical compositions, cells, and methods for treating porphyria.

Claim category	Claims	Principal subject matter
ALAS1 dsRNA composition	1-40	Defined sense and antisense sequences, GalNAc ligands, nucleotide modifications and duplex architecture
Pharmaceutical compositions	41-45	Compositions containing the claimed dsRNA, including intravenous or subcutaneous formulations
Cells	46-47	Isolated cells, including liver cells, containing the dsRNA
Treatment methods	48-58	Treatment of ALAS1-related disorders, elevated ALA or PBG, and hepatic porphyrias

The claims use a layered structure. Claims 1, 2, 29 and 40 are the principal composition claims. The remaining composition claims add narrower structural limitations.

What ALAS1 sequence is claimed?

The claimed antisense strand is directed to nucleotides 871-889 of SEQ ID NO:1. Claims 3, 4 and 29 identify the specific antisense sequence as SEQ ID NO:1296 and the sense sequence as SEQ ID NO:1295 or a qualifying contiguous portion of that sequence.

This sequence limitation is commercially significant. A competing siRNA directed to a different ALAS1 region would not fall within the literal sequence limitation merely because it silences the same gene. It could, however, face separate patent claims in the broader Alnylam ALAS1 patent family or infringement arguments under the doctrine of equivalents, depending on its sequence and chemical design.

How broad are the GalNAc limitations?

Claim 2 covers an ALAS1 dsRNA having one or more GalNAc derivatives and the specified nucleotide modifications. Claim 21 places the GalNAc derivative at the 3' end of the sense strand. Claims 22-26 narrow the ligand to biantennary or triantennary GalNAc structures and specified linker arrangements.

The GalNAc limitations are directed to hepatocyte delivery. GalNAc ligands bind the asialoglycoprotein receptor on hepatocytes, enabling selective uptake after subcutaneous administration. This is the same delivery strategy used by givosiran and several other Alnylam siRNA products.

The supplied claim text omits the chemical drawings referenced in claims 1, 23, 26, 36, 39 and 40. Those drawings are legally material. The claims cannot be assessed for exact ligand or linker identity from the text alone. The sequence, modification, and architecture limitations can still be analyzed, but the precise scope of the depicted chemical structures requires the issued patent figures.

Which claims are most relevant to givosiran?

Givosiran is a GalNAc-conjugated siRNA targeting ALAS1 mRNA. Its commercial product is administered subcutaneously and uses chemically modified RNA strands designed for nuclease stability and reduced immune activation.[2]

The strongest apparent product-overlap claims are claims 29-40 because they combine the core elements of an optimized commercial siRNA:

SEQ ID NO:1296 antisense sequence;
SEQ ID NO:1295-derived sense sequence;
a 15-30 base-pair duplex;
a biantennary or triantennary GalNAc ligand;
at least 20 2'-O-methyl or 2'-fluoro modified nucleotides;
a 3' overhang;
a blunt-ended sense strand;
phosphorothioate linkages; and
modified nucleotides across both strands.

Claim 40 is particularly narrow but commercially focused. It requires:

the specified ALAS1 antisense target;
19-24 nucleotide strands;
a specified ligand structure;
chemical modifications across both strands;
a two-nucleotide antisense 3' overhang; and
a blunt-ended sense strand.

A product meeting all of those limitations would present a high literal-infringement risk if the specified sequence and ligand structure are also present.

How do the independent composition claims differ?

Claim	Scope	Relative breadth
1	Defined ALAS1 sequence, SEQ ID NO:1296 antisense, SEQ ID NO:1295-derived sense, depicted ligand/linker and 2'-O-methyl or 2'-fluoro modifications	Narrow because of the specified structure
2	ALAS1 sequence region, GalNAc derivative and 2'-O-methyl or 2'-fluoro chemistry	Broadest principal composition claim
29	Specific antisense sequence, GalNAc ligand, 20 or more modified nucleotides and 3' overhang	Intermediate, commercially focused
40	Specific target, strand lengths, depicted ligand, full-strand modification, antisense overhang and blunt sense end	Narrowest principal composition claim

Claim 2 has the greatest theoretical reach because it does not require the exact SEQ ID NO:1296 antisense sequence until dependent claim 3. It still requires the antisense strand to be complementary to the specified ALAS1 region and requires GalNAc and defined nucleotide chemistry.

Claims 29 and 40 are more vulnerable to design-around strategies because they require exact sequence and structural combinations. They are also more likely to map directly onto the marketed product.

What formulation and chemical features are protected?

The patent protects several design elements used in modern siRNA medicines.

Nucleotide modifications

Claims 5-8 and 29-40 cover combinations of:

2'-O-methyl nucleotides;
2'-fluoro nucleotides;
at least five of each modification in certain embodiments;
at least 20 modified nucleotides;
modifications across the entire sense and antisense strands; and
phosphorothioate linkages.

These modifications can improve nuclease resistance, pharmacokinetics and tolerability. The claims do not require a particular pattern of modification unless the relevant dependent claim imposes that requirement.

Strand architecture

Claims 9-20 and 29-40 cover:

blunt-ended duplexes;
one or two 3' overhangs;
a one- or two-nucleotide overhang;
an antisense-strand overhang;
a blunt-ended sense strand;
15-30 base-pair duplexes;
preferred 19-23 base-pair duplexes; and
19-24 nucleotide individual strands.

These limitations distinguish the claimed molecules from longer RNA constructs, asymmetric duplexes and products with different end configurations.

GalNAc attachment

Claims 21-26, 36-40 require or permit attachment of the GalNAc ligand to the 3' end of the sense strand, with or without a linker. The placement is relevant because the sense strand can tolerate conjugation while preserving the antisense strand's interaction with the RNA-induced silencing complex.

What methods of use are protected?

Claims 48-58 protect treatment of ALAS1-related disorders, with the main focus on porphyria.

The method claims cover administration of the claimed dsRNA to patients who:

have or are at risk of porphyria;
have elevated ALA, PBG or both;
require treatment before, during or after an acute porphyria attack;
are in a prodromal phase; or
need reduction in porphyrin or porphyrin precursor levels.

Claim 53 identifies hepatic porphyrias including:

acute intermittent porphyria;
hereditary coproporphyria;
variegate porphyria;
ALA dehydratase deficiency porphyria; and
hepatoerythropoietic porphyria.

The claims reach prophylactic and attack-related treatment scenarios. They also cover reducing the frequency or incidence of acute attacks when a patient is exposed to a precipitating factor.

When does U.S. Patent 9,133,461 lose exclusivity?

The FDA Orange Book reports December 19, 2030, as the patent expiration date for U.S. Patent 9,133,461 in connection with Givlaari.[1] The applicable date reflects the patent term recorded for the listed patent and can differ from a simple twenty-year calculation based on an individual application date.

Exclusivity event	Date
Givlaari FDA approval	November 20, 2019
New chemical entity exclusivity	November 20, 2024
Orphan-drug exclusivity	November 20, 2026
U.S. Patent No. 9,133,461 Orange Book expiration	December 19, 2030

Orphan-drug exclusivity blocks FDA approval of the same drug for the same orphan indication, subject to statutory exceptions. It is separate from patent rights. The expiration of NCE exclusivity in 2024 did not remove the patent barrier.

Givlaari may also be protected by later-issued or related Alnylam patents. A complete launch analysis must assess the full Orange Book listing and any continuation or divisional patents, not Patent 9,133,461 in isolation.

What is the Orange Book status of Patent 9,133,461?

The patent is listed in the FDA Orange Book for Givlaari. The listing identifies a patent believed by the NDA holder to cover the drug, its composition, or an approved method of use.[1]

The relevant regulatory consequences are:

an ANDA applicant must address the listed patent;
a Paragraph IV certification can trigger patent litigation;
a timely infringement action can impose a 30-month stay on FDA approval under the Hatch-Waxman framework;
a Paragraph III certification would defer approval until patent expiration; and
a non-infringement or invalidity position would normally proceed through Paragraph IV.

Because givosiran is a chemically synthesized siRNA rather than a protein biologic, a future competitor would generally pursue an ANDA or possibly a 505(b)(2) pathway, not a biosimilar application under section 351(k).

Which companies are challenging givosiran patents?

No publicly reported Paragraph IV litigation or settlement involving U.S. Patent 9,133,461 and a generic givosiran applicant is identified in the public FDA and federal patent-litigation records reviewed through 2025.

The competitive threat is therefore more likely to arise from:

a future ANDA applicant challenging sequence or formulation patents;
an alternative ALAS1 siRNA using a different target sequence;
a different ligand or linker architecture;
a non-GalNAc hepatic delivery system; or
competing therapies that reduce porphyria attacks without directly infringing the claimed dsRNA.

A competitor using the same ALAS1 sequence, GalNAc conjugation and strand architecture would face a substantially higher Paragraph IV and infringement risk than a competitor using a different target sequence or delivery chemistry.

How strong is the patent estate?

Patent strength is highest against close copies of the givosiran molecular design. It is weaker against products that change multiple independent variables.

Design-around variable	Risk relative to Patent 9,133,461
Same antisense and sense sequences	High
Same ALAS1 region but different guide sequence	Lower under literal sequence claims
Same sequence with non-GalNAc ligand	Lower under claims requiring GalNAc
Same GalNAc platform but different ALAS1 target	Lower under sequence claims
Different strand lengths or end structure	Potentially lower, depending on claim element
Different sugar modifications	Potentially lower, but may implicate other Alnylam patents
Same product with different formulation excipients	Little effect if the dsRNA itself remains within the claims
Alternative mechanism of action	Outside the direct composition claims

The patent's main strength is cumulative claim coverage. A competitor must avoid the sequence, GalNAc, modification and duplex-architecture limitations that appear in different combinations across the claims. Its main weakness is that many claims are highly specific. A technically distinct ALAS1 siRNA could avoid literal infringement if it does not use the claimed sequences or structures.

What patent litigation and settlement risks affect launch timing?

A Paragraph IV filing against an Orange Book-listed patent could produce litigation shortly after notice to Alnylam. The commercial consequences would depend on:

whether Alnylam files suit within the statutory period;
whether the patent is held valid and infringed;
whether other listed patents remain in force;
whether the applicant receives 180-day first-filer exclusivity;
whether a settlement permits a licensed or delayed launch; and
whether the proposed product uses the same givosiran sequence and conjugate.

No public settlement agreement concerning Patent 9,133,461 has been identified. The absence of a reported settlement does not eliminate the possibility of later litigation involving other patents in the Givlaari portfolio.

What manufacturing and IP barriers exist?

The patent covers the final dsRNA architecture rather than every manufacturing step. A competitor may still face separate barriers involving:

solid-phase oligonucleotide synthesis;
site-specific GalNAc conjugation;
linker chemistry;
purification of double-stranded RNA;
control of single-stranded impurities;
analytical characterization;
sterile subcutaneous formulation; and
manufacturing know-how protected as trade secrets.

The chemical synthesis route is more accessible than biologic manufacturing, but high-purity conjugated siRNA production remains technically demanding. Patent freedom to operate does not by itself establish FDA pharmaceutical equivalence or manufacturing readiness.

How does givosiran compare with competing porphyria treatments?

Givosiran directly suppresses ALAS1 expression and reduces production of toxic porphyrin precursors upstream in the heme pathway. Heme arginate and intravenous hemin act through different mechanisms and are primarily associated with management of acute attacks. RNA-based ALAS1 suppression is therefore differentiated by its preventive treatment model and subcutaneous administration.

Product or approach	Mechanism	Delivery	Direct overlap with Patent 9,133,461
Givlaari/givosiran	GalNAc-siRNA suppression of ALAS1	Subcutaneous	Direct
Hemin	Replenishes heme and suppresses ALAS1 indirectly	Intravenous	None
ALA or PBG monitoring and supportive care	Disease management	Varies	None
Future ALAS1 siRNA	Direct gene silencing	Likely subcutaneous or hepatic delivery	Depends on sequence and chemistry
Non-RNA ALAS1 inhibitor	Small-molecule or alternative mechanism	Varies	Generally outside composition claims

Key Takeaways

U.S. Patent 9,133,461 is a core composition and method patent for GalNAc-conjugated ALAS1 siRNA.
Claims 1-40 focus on the molecular product; claims 41-47 cover compositions and cells; claims 48-58 cover porphyria treatment.
The most commercially relevant limitations are the ALAS1 target sequence, GalNAc conjugation, 2'-O-methyl and 2'-fluoro chemistry, phosphorothioate linkages, and duplex-end architecture.
The FDA Orange Book lists the patent with an expiration date of December 19, 2030.
Givlaari's seven-year orphan exclusivity ends November 20, 2026, before patent expiry.
No publicly reported Paragraph IV challenge or settlement involving Patent 9,133,461 was identified through 2025.
The patent is strongest against a product that copies givosiran's sequence, GalNAc ligand and strand architecture.
A competing ALAS1 siRNA using a different target sequence or delivery ligand has a stronger design-around position, although other Alnylam patents may remain relevant.
Givosiran is a chemically synthesized siRNA and is generally subject to generic-drug pathways rather than the biosimilar pathway.

Frequently Asked Questions

Is givosiran a biologic subject to biosimilar competition?

No. Givosiran is a chemically synthesized oligonucleotide drug. A competing product would generally be evaluated under the ANDA or 505(b)(2) framework rather than the section 351(k) biosimilar pathway.

Does Patent 9,133,461 cover every ALAS1 siRNA?

No. The claims require defined ALAS1 sequence relationships and, in many claims, specific strand sequences. An ALAS1 siRNA using a materially different target sequence may avoid literal infringement of this patent.

Can a generic launch after orphan exclusivity ends in 2026?

Not necessarily. Patent 9,133,461 remains listed through December 19, 2030, and other Givlaari patents may also remain enforceable. A generic applicant must address all relevant listed patents.

Does changing the GalNAc ligand avoid infringement?

It may avoid claims requiring a particular GalNAc structure, but broader claims covering GalNAc derivatives could remain relevant. The omitted chemical drawings in the supplied claim text are decisive for a final structure-by-structure analysis.

Are the porphyria treatment claims limited to acute attacks?

No. The claims cover treatment before, during or after an acute attack, during prodrome, and prophylactic reduction of attack frequency or incidence. They also cover patients with elevated ALA or PBG.

References

U.S. Food and Drug Administration. (2025). Approved drug products with therapeutic equivalence evaluations: The Orange Book. FDA.
U.S. Food and Drug Administration. (2019). Givlaari (givosiran) prescribing information. FDA.
U.S. Patent and Trademark Office. (2015). U.S. Patent No. 9,133,461, double-stranded ribonucleic acids for inhibiting ALAS1 gene expression. U.S. Department of Commerce.
Alnylam Pharmaceuticals, Inc. (2024). Annual report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934. U.S. Securities and Exchange Commission.
U.S. Food and Drug Administration. (2024). Approved drug product list and patent information resources. FDA.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Alnylam Pharms Inc	GIVLAARI	givosiran sodium	SOLUTION;SUBCUTANEOUS	212194-001	Nov 20, 2019		RX	Yes	Yes	9,133,461	⤷ Start Trial	Y	Y		TREATMENT OF ACUTE HEPATIC PORPHYRIA	⤷ Start Trial
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>TE	>Type	>RLD	>RS	>Patent No.	>Patent Expiration	>Product	>Substance	>Delist Req.	>Patented / Exclusive Use	>Submissiondate

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	090641	⤷ Start Trial
Argentina	129562	⤷ Start Trial
Australia	2013245949	⤷ Start Trial
Australia	2018203098	⤷ Start Trial
Australia	2020202970	⤷ Start Trial
Australia	2024200975	⤷ Start Trial
Brazil	112014025020	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 9,133,461

Which drugs does patent 9,133,461 protect, and when does it expire?

Summary for Patent: 9,133,461