United States Patent 11,857,603: Scope, Claim Scope Boundaries, and US Patent Landscape for Subcutaneous Controlled-Release PTH With Low Peak-to-Trough Exposure
What is the claimed invention in US 11,857,603?
US 11,857,603 claims a method of treating hypoparathyroidism in a human patient using a subcutaneous controlled-release PTH (parathyroid hormone) compound defined by a specific PTH conjugate structure and a specific pharmacokinetic exposure profile at steady state.
The core claim (claim 1) has four technical pillars:
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Indication and route
- Treat hypoparathyroidism
- Subcutaneous administration of a PTH compound
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Exposures over an administration interval
- At steady state, the PTH compound has a peak-to-trough ratio < 4 within one administration interval
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Molecular identity
- The PTH compound is a water-soluble controlled-release PTH compound of formula (Ia) (or a pharmaceutically acceptable salt)
- The PTH moiety is a PTH moiety having the sequence of SEQ ID NO: 51
- The conjugation scaffold includes -D, -L2-L1, and a variable segment containing m and p ranges
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Release kinetics
- The PTH moiety has a release half-life ≥ 12 hours
Claim-1 scaffolding (as provided)
- PTH moiety identity
- Linker architecture
- “-L2-L1-” with attachment by an amide bond to a nitrogen of “-D”
- Attachment to “-Z” indicated by asterisk in the formula description
- Variable polymer/chain segment
- x = 1
- “-Z comprises a moiety of formula (b)”
- The dashed line indicates attachment to “-L2”
- m and p independently are integers in the claimed range for sub-claims (see below)
- Release half-life
- Exposure
- peak-to-trough ratio < 4 (steady state; within one dosing interval)
How broad is claim 1, and what are the enforceable boundaries?
Claim 1 is broad in use (method of treatment for hypoparathyroidism) but narrow in what counts as an infringing product because it requires all of the following simultaneously:
A. Mandatory pharmacokinetic requirement (exposure definition)
- Peak-to-trough ratio < 4 at steady state, measured “within one administration interval”
This is a performance limitation that typically functions as a gating criterion. In litigation terms, it restricts claim coverage to PTH compounds that actually produce the required exposure flattening under the claimed dosing interval and steady-state regimen.
B. Mandatory formulation/type requirement (chemical class)
- “water-soluble controlled-release PTH compound”
- compound is formula (Ia) (or salt)
So the claim is not merely “controlled-release PTH.” It is controlled-release PTH having this conjugate structure.
C. Mandatory release kinetics
- PTH moiety released with release half-life ≥ 12 hours
This further constrains the release mechanism. A product that delivers PTH too quickly (release half-life below the threshold) does not meet claim 1 even if it has a low peak-to-trough ratio.
D. Mandatory molecular identity
- PTH moiety has sequence SEQ ID NO: 51
This prevents substituting other PTH sequences unless they fall within the same sequence definition.
Which dependent claims narrow dosing interval, formulation pH, and variable segments?
Dependent claims add specific numerical and operational constraints that create a layered infringement map.
Dosing interval narrowing (claims 2 to 4)
- Claim 2: administration interval ≥ 24 hours
- Claim 3: administration interval = 24 hours
- Claim 4: administration interval = one week
These dependent claims are structured to cover common real-world regimens:
- daily (24 hours)
- weekly (one week)
Route and device implementation (claims 5 to 6)
- Claim 5: subcutaneous administration via subcutaneous injection
- Claim 6: subcutaneous administration occurs with a pen device
These are narrower implementation elements. A product delivered by another subcutaneous modality not using an injection/pen may avoid those dependent claims while still potentially implicating claim 1 if the core requirements are met.
Exposure tightening (claim 7)
- Claim 7: peak-to-trough ratio < 3 (instead of < 4)
This increases coverage for “flatter” profiles. A product meeting <4 but not <3 would satisfy claim 1 but not claim 7.
Formulation pH (claims 8 to 9)
- Claim 8: composition pH 3 to 8 (inclusive)
- Claim 9: composition pH 4 to 5 (inclusive)
This creates formulation coverage for a wide pH band and a tighter commercial sweet spot (4 to 5). If a competitor’s formulation falls outside these ranges, it can avoid at least claims 8 and 9 while still possibly meeting claim 1 if formulation pH is not treated as limiting in claim 1 (claim 1 does not expressly recite pH).
Variable segment tightening (claims 10 to 12)
- Claim 10: m and p independently are integers 400 to 500
- Claim 11: “-L2-L1 is attached to the N-terminal amine functional group of -D”
- Claim 12: repeats claim 11 (duplicate as presented)
These claims tighten the conjugate definition around a specific m/p window and a specific attachment point to the N-terminus.
What is the practical infringement landscape for competitors?
US 11,857,603 is a method-of-treatment claim driven by (i) product identity and (ii) measured PK performance.
A competitor’s risk splits into three distinct technical gates:
Gate 1: Does the PTH compound match the formula (Ia) with SEQ ID NO: 51?
- If the competitor’s PTH moiety sequence is not SEQ ID NO: 51, or the conjugation pattern does not align to formula (Ia) requirements, they fall outside claim 1.
Gate 2: Does the compound deliver with release half-life ≥ 12 hours?
- If the release kinetics produce a faster release, they miss claim 1.
Gate 3: Does the compound achieve steady-state peak-to-trough ratio < 4?
- Even if chemical identity and release half-life align, failure of PK flattening misses claim 1.
Dependent claims further add:
- dosing interval (24 hours or one week)
- exposure tightness (<3)
- pH range (3-8; or 4-5)
- specific m/p ranges and N-terminal attachment
How does claim scope compare across the “PK profile” and “chemical formula” dimensions?
Claim 1 uses both structure and function. This hybrid approach matters for design-around strategy.
Structural constraints in claim 1 (hard boundaries)
- formula (Ia) (or salt)
- PTH moiety sequence = SEQ ID NO: 51
- linker and scaffold definition includes variable segment “-Z” with m and p (the exact range appears in dependent claim 10, but the structure category is present in claim 1)
Functional constraints in claim 1 (hard boundaries)
- release half-life ≥ 12 hours
- steady-state peak-to-trough ratio < 4 within one dosing interval
This combination makes the claim harder to design around purely through small dose changes; it also reduces the chance that an unrelated controlled-release PTH with different conjugation chemistry could still infringe.
What dosing patterns are explicitly within claim coverage?
The dependent claim set implies explicit covered regimens for hypoparathyroidism treatment:
| Claim |
Administration interval |
Covered schedule |
| 2 |
≥ 24 hours |
daily-or-slower intervals |
| 3 |
24 hours |
once-daily |
| 4 |
one week |
once-weekly |
Independent claim 1 does not specify the interval length, but it defines “within one administration interval at steady state.” Dependent claims make the interval explicit.
Where are the strongest “narrow” claim hooks for litigation leverage?
If US 11,857,603 is asserted, the most leverage typically comes from the narrowest dependent claims that define:
- peak-to-trough < 3 (claim 7)
- pH 4 to 5 (claim 9)
- m and p = 400 to 500 (claim 10)
- N-terminal amine attachment (claims 11-12)
- one-week dosing (claim 4)
- pen device delivery (claim 6)
These constraints can act as “must-mean” proof points when comparing competitor dossiers and clinical PK curves.
Patent landscape: what matters around US 11,857,603 from a scope/claims standpoint
You provided only the claim text for US 11,857,603 and not the rest of the patent document (specification, definitions of formula elements beyond the snippet, prosecution history, or cited references). Without those, the landscape can only be mapped at the level of claim-driven design space and where close alternatives tend to sit.
Likely competitive clusters (claim-driven)
Based on the technical elements recited in claim 1, nearby US patent activity in this field typically clusters around:
- PTH conjugates with controlled-release linkers or scaffolds
- Designed to achieve low peak-to-trough and sustained exposure
- Different conjugate attachment points to PTH
- The claim explicitly limits to “N-terminal amine functional group” in dependent claims
- Release kinetics
- Engineering to achieve release half-life ≥ 12 hours
- Formulation pH and solubility
- Claim 8-9 covers pH 3-8 and specifically pH 4-5
- Dosing interval engineering
- daily versus weekly delivery strategies
- Delivery device implementation
- pen device subcutaneous delivery is explicitly captured in claim 6
Design-around patterns that reduce infringement risk (claim-driven)
A competitor can reduce risk by deviating on at least one hard boundary:
- Use a PTH moiety that is not the claimed SEQ ID NO: 51
- Alter conjugation chemistry so it is not “water-soluble controlled-release PTH compound of formula (Ia)”
- Engineer release kinetics to fall below release half-life ≥ 12 hours
- Use a regimen that yields steady-state peak-to-trough ≥ 4
- Use formulation outside pH 3-8 or specifically avoid pH 4-5 (if targeting dependent claim 9)
- Avoid dosing intervals explicitly tied to dependent claims (24 hours or one week)
- Avoid pen-device delivery to reduce exposure under claim 6 (depending on infringement theory)
Key Takeaways
- US 11,857,603 claim 1 requires all of:
- hypoparathyroidism treatment in humans
- subcutaneous administration of a water-soluble controlled-release PTH conjugate of formula (Ia) with PTH moiety sequence SEQ ID NO: 51
- release half-life ≥ 12 hours
- steady-state peak-to-trough ratio < 4 within one administration interval
- Dependent claims tighten the net around:
- dosing intervals (≥24 hours, 24 hours, one week)
- exposure (<3)
- formulation pH (3-8, 4-5)
- conjugate parameter window (m and p 400-500)
- attachment point (N-terminal amine)
- delivery modality (pen device)
- Enforceability is anchored in PK performance plus structural identity. Competitors face design-around pressure on measured exposure (peak-to-trough), not only on chemical class.
FAQs
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Is the patent claim restricted to a specific dosing interval in claim 1?
Claim 1 defines peak-to-trough “within one administration interval at steady state,” while dependent claims expressly cover ≥24 hours, 24 hours, and one week.
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What is the main pharmacokinetic threshold in claim 1?
The PTH compound must have a peak-to-trough ratio < 4 at steady state within one administration interval.
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How do claims 7 and 1 differ on exposure?
Claim 1 requires <4, while claim 7 tightens to <3.
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Do the claims require a specific formulation pH?
Claim 1 does not state a pH range. Claims 8-9 do: pH 3-8 and pH 4-5, respectively.
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What additional constraints appear in claims 10-12?
Claim 10 limits m and p to 400-500; claims 11-12 specify attachment of -L2-L1 to the N-terminal amine functional group of -D.
References
- User-provided claims text for US Drug Patent 11,857,603 (claims 1-12).
