United States Drug Patent US 8,906,938: Scope, Claim Coverage, and Patent Landscape
US 8,906,938 is a US drug patent structured around broad compound and composition claims. The claim set, as provided, is generic in scope: it recites a “compound having the formula” (formula not fully reproduced in the prompt), permits pharmaceutically acceptable salts, hydrates, and rotamers, and then claims pharmaceutical compositions that include the compound with a pharmaceutically acceptable carrier. The operative claim boundaries therefore hinge on the exact chemical structure that appears in the “formula” positions of claims 1 and 4, and on what the specification defines as salts, hydrates, and rotamers.
What is the claim scope of US 8,906,938 based on the provided claim text?
What do Claims 1 and 4 cover?
From the text provided, the patent’s primary protection is claim-formula centered:
- Claim 1: “A compound having the formula … or a pharmaceutically acceptable salt or rotamer thereof.”
- Claim 4: “A compound having the formula: …” (a second formula-bearing claim; the full formula is not shown in the prompt, so the scope depends on what that formula is).
Practical implication for enforcement:
If the “formula” in Claim 1 defines a specific core chemical structure, Claim 1 is a direct-structure claim. It will read on:
- the free base (or the chemically defined form) as encompassed by the patent’s formula definition, and
- pharmaceutically acceptable salts of that structure, and
- rotamers (conformational isomers) of that structure.
If Claim 4 defines a different structure (or a specific stereochemical subset), it can broaden coverage or carve out an alternative scaffold, depending on the specification’s definitions and how the formulas differ.
How broad are Claims 2 and 5?
- Claim 2: “The compound of claim 1, in a pharmaceutically acceptable salt form.”
- Claim 5: “A pharmaceutical composition comprising a compound having the formula and a pharmaceutically acceptable carrier.”
Practical implication:
- Claim 2 is narrower than Claim 1 by restricting the compound to a salt form, but it still inherits whatever structure Claim 1 defines.
- Claim 5 is a second composition claim that again uses the formula structure as the key element, tying composition coverage to compound inclusion, not to method-of-use or administration.
How broad are Claims 3?
- Claim 3: “A composition comprising a pharmaceutically acceptable carrier and a compound having the formula: or a pharmaceutically acceptable salt, hydrate or rotamer thereof.”
Practical implication:
Claim 3 extends composition protection to:
- salt forms,
- hydrates,
- rotamers.
This is the most “form-dependent” composition claim in the set as provided, because it expressly adds hydrate to the set of tolerated solid forms. If competitors market solid-state variants (hydrates vs anhydrates), Claim 3 is the claim most likely to read onto those variants, assuming the underlying chemical structure matches the formula.
How the claim language translates into enforceable coverage
Structure coverage: formula as the gatekeeper
Because the prompt-provided claims are formula-based, enforceability and infringement analysis will track two things:
- Whether the accused compound’s structure matches the claimed formula (including stereochemistry as defined by the formula and specification).
- Whether the accused product’s form maps to “pharmaceutically acceptable salt,” “hydrate,” or “rotamer” as those terms are interpreted in the patent.
No claims in the provided set are method-of-treatment, dosing, or route-specific. The claims instead focus on:
- the compound (Claim 1 and Claim 4),
- the salt form (Claim 2),
- the composition with a carrier (Claim 3 and Claim 5).
Form coverage: salts, rotamers, hydrates
The scope visibly includes multiple “forms,” which typically expand claim reach beyond the exact crystalline form that first entered the market:
- Salts: explicitly permitted in Claims 1, 2, and 3.
- Rotamers: explicitly permitted in Claims 1 and 3.
- Hydrates: explicitly permitted only in Claim 3 (as provided).
Business impact:
A competitor attempting to design around by switching to a salt or solid-state hydrate form is still within the claim set if the underlying active structure matches the formula definitions. Rotamer-driven design-around is also unlikely to escape if the claimed structure includes rotamers as a tolerated variant.
What is missing from the prompt that determines the true breadth?
The claim text provided includes placeholders (“formula” and “formula:”) without the actual chemical structures. That means the actual scope (what specific compound is covered, whether stereochemistry is limited, and whether Claim 4 is an alternative structure or a subset) cannot be fully mapped from the prompt alone.
Under patent-analytic practice, for formula claims, the structure text is the decisive element for:
- literal infringement,
- equivalents analysis boundaries,
- and cross-family landscape comparisons (whether this patent overlaps with other filings on the same scaffold).
US 8,906,938 claim set: structured view
| Claim |
Type |
Core limitation in provided text |
Included variants (from prompt) |
What it protects |
| 1 |
Compound |
“compound having the formula …” |
pharmaceutically acceptable salt; rotamer |
Active compound (and certain conformers/salts) |
| 2 |
Compound |
“compound of claim 1 in a pharmaceutically acceptable salt form” |
salt only |
Salt form of Claim 1 compound |
| 3 |
Composition |
carrier + compound having the formula … |
salt; hydrate; rotamer |
Form-variant pharmaceutical composition |
| 4 |
Compound |
“compound having the formula: …” |
not specified in provided text beyond what the formula implies |
Second formula-scoped compound coverage |
| 5 |
Composition |
pharmaceutical composition with compound having the formula |
not specified beyond what is inherent in the “compound” limitation |
Composition including the formula-scoped compound |
Where US 8,906,938 sits in the broader US drug patent landscape
How this patent style typically maps to other IP layers
The claim structure (compound + salt/rotamer + composition with carrier) is consistent with patents that cover:
- the active ingredient and its acceptable solid forms,
- and basic pharmaceutical formulations without specific excipient recipes or use instructions.
In landscapes, that typically means this patent:
- pairs with other patents covering specific polymorphs/solvates,
- pairs with process patents (manufacturing routes, intermediates),
- and often pairs with method-of-use or dosing patents, if present in the family.
Without family-document identifiers in the prompt, the exact adjacency cannot be enumerated here. What can be stated from the claims provided is that the protection in US 8,906,938 is not limited to a particular formulation recipe, unit dose, or treatment regimen.
What competitors can and cannot typically do
Given the claim set’s breadth:
- Switching to a salt form is unlikely to avoid Claims 1-3 if the salt is “pharmaceutically acceptable.”
- Switching to a hydrate is still captured by Claim 3 if the hydrate relates to the same formula-scoped compound.
- Rotamer changes do not avoid the compound claim if rotamers of the same structure fall within the claimed term.
The primary remaining design-around strategy, in practical terms, is usually to depart from the claimed chemical structure rather than from the solid form.
Freedom-to-operate (FTO) implications based on claim structure
What products are most likely to fall within the claims
Based solely on the provided claim text, the highest-risk product categories are:
- Drug products whose active ingredient matches the claimed formula and is marketed as a free base or “pharmaceutically acceptable salt.”
- Drug products formulated with a carrier containing the active compound, including solid-state variants (hydrates and rotamers) where applicable under Claim 3.
- Generic or follow-on products that are structurally the same API and use conventional pharmaceutical carriers (because the claims do not require a unique formulation component list).
What reduces overlap risk
Lower-risk scenarios typically involve:
- APIs that do not match the claimed formula(s),
- or formulations where the accused active ingredient differs in structure and is not within the “compound having the formula” boundaries.
This assessment is structural and does not depend on dosing, unless additional claims (not provided) exist in the full patent.
Key Takeaways
- US 8,906,938 has formula-centric compound claims (Claims 1 and 4) that include pharmaceutically acceptable salts and rotamers.
- The patent’s composition claims (Claims 3 and 5) protect pharmaceutical formulations using a pharmaceutically acceptable carrier, including salts, hydrates, and rotamers in Claim 3.
- The provided claim set is not method-of-treatment limited and is not tied to a specific formulation recipe, which makes the primary design-around lever the chemical structure, not the solid form.
- For landscape and FTO purposes, the patent’s enforceable reach will track the exact chemical structures embedded in the “formula” placeholders and the patent’s definitions of salt/hydrate/rotamer.
FAQs
1) Does US 8,906,938 protect only one crystalline form of the drug?
No. The provided claims cover multiple “forms” including salts and rotamers, and Claim 3 expressly includes hydrates.
2) Are method-of-use or dosing limitations part of Claims 1-5 as provided?
No. The provided claims are compound and composition claims, not treatment or dosing regimen claims.
3) If a competitor sells the same molecule as a different salt, is it likely still covered?
Yes, based on Claim 1 and Claim 2 (salt forms) and Claim 3 (salt forms in compositions), assuming the molecule matches the claimed formula.
4) Do the claims cover pharmaceutical compositions, not just the active ingredient?
Yes. Claim 3 and Claim 5 claim pharmaceutical compositions comprising a pharmaceutically acceptable carrier plus the formula-scoped compound (and additional tolerated forms in Claim 3).
5) Which claim most directly covers hydrate-based variants?
Claim 3, because it expressly includes hydrate alongside salts and rotamers.
References
[1] United States Patent and Trademark Office. “US 8,906,938.” Patent document (claim text as provided in the prompt).
