United States Patent 8,592,362: What Is Claimed and How the Fabry Landscape Closes In
What does US 8,592,362 claim in scope terms?
US 8,592,362 is directed to a method of treating Fabry disease by administering 1-deoxygalactonojirimycin (DGJ) to a patient identified as having a mutant α-galactosidase A (α-Gal A) relative to a defined human reference α-Gal A sequence (nucleic acid SEQ ID NO:2). The claim scope is defined through a patient-selection requirement (mutant genotype) and a drug-selection requirement (DGJ), then narrowed through dependent claims for patient sex and salt form.
Independent claim 1 (core scope)
- Preamble / condition: treating a patient diagnosed with Fabry disease
- Drug: administer a therapeutically effective dose of 1-deoxygalactonojirimycin (DGJ)
- Patient-selection marker: patient is identified as having a mutant α-galactosidase A
- Reference: mutation is defined “relative to a human α-galactosidase A encoded by nucleic acid sequence set forth in SEQ ID NO:2”
- Permitted mutant variants: the mutation is selected from a closed list of specific α-Gal A mutations:
Mutation list recited in claim 1 (verbatim scope driver)
- A121T
- A288D
- A288P
- A292P
- A348P
- A73V
- C52R
- C94Y
- D234E
- D244H
- D264Y
- E338K
- E341D
- E398K
- E48K
- G271S
- G35R
- H225R
- I219N
- I242N
- I270T
- I303N
- I317T
- I354K
- L14P
- L243F
- L300F
- L310F
- L45R
- M267I
- M76R
- N224S
- N298K
- N298S
- N320I
- N34K
- P205R
- P259L
- P265L
- P265R
- P293A
- P293S
- P409S
- P40L
- P40S
- Q279R
- Q280H
- Q280K
- Q321E
- Q321R
- Q327E
- R301P
- R49G
- R49L
- R49S
- S201Y
- S276N
- S297C
- S345P
- V269M
- W340R
- W47L
- W95S
Dependent claims
- Claim 2: method of claim 1 where the patient is female.
- Claim 3: method of claim 1 where DGJ is in a pharmaceutically acceptable salt form.
- Claim 4: method of claim 3 where salt form is 1-deoxygalactonojirimycin hydrochloride.
What is the legal “shape” of the claims: where does infringement attach?
US 8,592,362 is a method claim that turns on two gating elements:
-
Administration element
- infringement is tied to providing DGJ at a therapeutically effective dose to treat Fabry disease patients.
-
Diagnosis plus genotype element
- infringement also requires that the treated patient is identified as having a mutant α-Gal A, and that the mutation is among the enumerated list and is defined relative to the SEQ ID NO:2 encoded reference.
Practically, this means the claim is structured to reduce overbreadth. Even if a treated patient has Fabry disease, the method claim is not universally applicable unless the patient’s α-Gal A mutation matches one of the specified variants.
How broad is the claim set versus standard Fabry care pathways?
The claim does not restrict:
- route of administration,
- dosing frequency,
- therapeutic endpoints (e.g., lyso-Gb3 reduction, pain, organ outcomes),
- concomitant therapy.
Instead, it narrows mostly by patient genotype and drug identity (DGJ), with further narrowing in dependent claims to female sex and HCl salt form.
That yields a scope profile typical of Fabry-era genotype/phenotype claim strategies:
- Broad pharmacology footprint: DGJ administration for Fabry broadly in principle, but
- Narrow clinical population footprint: only enumerated α-Gal A mutations.
Which claim components are most vulnerable on validity or design-around?
Most design-around sensitive
- Mutation list limitation (claim 1 enumerates specific α-Gal A mutations). If a competitor targets patient populations whose mutations are outside the list, it can avoid claim 1 entirely, assuming genotype targeting is done in a way that prevents the “patient is identified” element from being met.
Most product/form sensitive
- Claims 3 and 4 narrow to salt forms, with claim 4 specifically locking to DGJ hydrochloride. A competitor using a different pharmaceutically acceptable salt (if they remain within claim 1’s mutation scope) could fall outside claim 4, and likely outside claim 3 if not using any salt form covered by claim 3’s phrasing is interpreted as broad enough to cover all pharmaceutically acceptable salts. Here, claim 3 is broad (any pharmaceutically acceptable salt), so avoiding claim 3 would require avoiding salts entirely and using free base, which may be impractical depending on formulation.
Sex limitation in dependent claim
- Claim 2 is a narrow dependent limitation: female patients only. It can be avoided by treating male patients if the strategic aim is to avoid claim 2, but that does not avoid claim 1.
What does “mutant α-galactosidase A relative to SEQ ID NO:2” operationally mean?
The claim ties “mutation selection” to the defined baseline genetic reference encoded by SEQ ID NO:2. That matters because:
- it defines what counts as “the mutation” in relation to the specified reference sequence,
- it can affect whether a given patient variant is considered the same mutation as enumerated, especially for variants that might be described differently across reports (e.g., equivalent substitutions, numbering differences).
What is the competitive and patent landscape pressure around DGJ for Fabry?
DGJ is a well-known pharmacologic approach in Fabry: it is used to inhibit glycosphingolipid processing and to promote lysosomal trafficking of α-Gal A in certain settings. Patent strategy in this space often concentrates on:
- specific patient genotype subgroups most responsive to DGJ (or to pharmacological chaperones),
- specific drug forms (salts, formulations),
- and specific treatment methods (dosing regimens or combinations).
US 8,592,362 is firmly in the genotype-gated method category. That positioning typically creates two kinds of landscape outcomes:
- Overlap risk with other chaperone-method patents that treat Fabry by DGJ but use different genotype definitions.
- Hole creation where genotype lists differ: a competitor can sometimes route around by targeting enumerated mutations not covered, or by using different active agents entirely.
Where do other claims commonly sit in the Fabry chaperone portfolio (and how does this one fit)?
Even without reproducing every adjacent patent here, the claim mechanics of US 8,592,362 place it into a common Fabry “stack”:
- Core drug identity layer: DGJ is used for Fabry treatment.
- Population stratification layer: only patients with certain α-Gal A mutations are treated.
- Variant definition layer: mutations are defined against a particular reference sequence.
- Dependent narrowing layer: sex (female) and salt form (DGJ HCl).
For business planning, this matters because licensing and freedom-to-operate (FTO) analyses in this area generally hinge on:
- whether the commercial indication is “Fabry broadly” or “Fabry patients with X mutations,”
- whether the product is DGJ (and if yes, which salt),
- and whether clinical protocols require genotyping that brings treated patients into the enumerated list.
Claim-by-Claim Scope Table
| Claim |
Activity type |
Therapeutic agent |
Key limiting element(s) |
What must be true for infringement |
| 1 |
Treating method |
1-deoxygalactonojirimycin (DGJ) |
Fabry diagnosis + identified mutant α-Gal A relative to SEQ ID NO:2 + mutation is one of the enumerated list |
The treated patient has one of the listed α-Gal A mutations and DGJ is administered at a therapeutically effective dose |
| 2 |
Treating method |
DGJ |
All of claim 1 + patient is female |
Patient sex is female and all claim 1 conditions are met |
| 3 |
Treating method |
DGJ in pharmaceutically acceptable salt form |
All of claim 1 + DGJ is formulated as a salt |
Salt formulation is used (scope depends on interpretation of “pharmaceutically acceptable salt form”) |
| 4 |
Treating method |
DGJ hydrochloride |
All of claim 3 + salt is hydrochloride |
Product is DGJ HCl and all claim 1 conditions are met |
Patent landscape implications for R&D, clinical programming, and product strategy
If a development program targets DGJ for Fabry with genotype screening
US 8,592,362 is directly implicated where:
- DGJ is used, and
- protocols screen for α-Gal A mutations and treat only those in the enumerated list,
- genotyping documentation is used to identify eligible patients.
For internal planning, the risk profile is highest when a commercial plan is intentionally “DGJ for Fabry with specific mutant α-Gal A variants,” because that matches the claim’s patient-selection engine.
If a development program uses DGJ but broadens beyond the enumerated mutations
Expanding indication to include patients whose α-Gal A variants are not on the list can reduce the chance that treated patients meet the claim’s mutation limitation. The key is that the method claim requires identification as having a mutant α-Gal A selected from the specific list. If patients are treated without confirming those mutations (or if the mutation is outside the list), claim 1 is not satisfied.
If a development program changes the salt or avoids HCl
- Claim 4 (DGJ hydrochloride) can be avoided by using a different DGJ salt, but only if that still stays outside claim 3’s “pharmaceutically acceptable salt form.”
- Claim 3 is broad, so avoiding it may require using DGJ as a free base rather than a salt form, depending on the literal interpretation of “salt form.”
If a development program changes sex targeting
Claim 2 can be avoided by treating male patients, but that does not avoid claim 1. If a commercial plan includes females and DGJ use for covered mutations, claim 2 becomes relevant.
Key Takeaways
- US 8,592,362 is a DGJ-for-Fabry method patent gated by enumerated α-Gal A mutations.
- Infringement requires both DGJ administration and patient genotype identification within the explicit mutation list relative to SEQ ID NO:2.
- Dependent claims add narrow constraints: female patients (claim 2) and DGJ salt form, specifically hydrochloride (claims 3 and 4).
- Design-around is most feasible by changing the treated genotype set (outside the enumerated mutations) and, secondarily, by changing salt form (claim 4) or formulation strategy (claim 3).
- For landscape planning, the patent’s commercial risk is highest in genotype-screened DGJ programs aligned to the enumerated α-Gal A variants.
FAQs
-
Does US 8,592,362 cover Fabry patients broadly?
No. Claim 1 requires Fabry diagnosis plus identification of a mutant α-Gal A from the specific mutation list relative to SEQ ID NO:2.
-
Is 1-deoxygalactonojirimycin (DGJ) the only active drug covered?
Yes for these claims. The asserted scope in the provided text is limited to administering DGJ.
-
How does the SEQ ID NO:2 reference affect the mutation list?
It anchors what is considered the “mutant α-galactosidase A relative to” the defined nucleic acid reference, which can matter for how variants are classified against the enumerated list.
-
Can the claim be avoided by treating males instead of females?
It avoids claim 2 only. Claim 1 still applies to male patients if the mutation is in the enumerated list and DGJ is administered.
-
Is DGJ hydrochloride the only formulation covered?
Claim 4 is specifically DGJ hydrochloride, while claim 3 covers DGJ in any pharmaceutically acceptable salt form (per the provided claim language).
References (APA)
[1] United States Patent 8,592,362 (provided claim text: claims 1-4).
