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Patent landscape, scope, and claims summary: |
United States Patent 10,058,589: Claim-by-claim scope and how the Etanercept phosphate-citrate/glycine/sucrose formulation estate will shape US biosimilar and generic launch risk
United States Patent 10,058,589 covers a specific formulation space for stable liquid etanercept in a phosphate-citrate buffer system with glycine, sucrose, and sodium chloride, with defined concentration ranges, pH 5 to 7, and sterile ready-to-inject product forms. The claims are composition-and-parameter focused, so they can be read broadly across manufacturing sites that hit the same buffer architecture and excipient ranges, while still leaving meaningful non-infringing design-around room via buffer system substitution, pH excursions, excipient substitution, or concentration shifting outside the claimed windows.
What does US 10,058,589 claim about etanercept stable liquid formulations?
Core answer: The patent claims a stable liquid parenteral etanercept composition with (i) phosphate-citrate buffer, (ii) glycine and sucrose, (iii) sodium chloride as an optional or parameterized component across claims, and (iv) a pH 5 to 7 window for dependent coverage. Claims 2, 5, 6, and 7 lock in quantitative concentration ranges that can be used as a “claim chart” discriminator for product design and biosimilar formulation development.
Claim 1: Composition skeleton (broadest independent claim)
Claim 1 recites:
- “stable liquid pharmaceutical composition comprising”
- etanercept
- phosphate-citrate buffer
- glycine (listed as “-glycine” in your extract)
- sucrose
- sodium chloride
Legal/claim construction pressure points
- “phosphate-citrate buffer”: the claim requires both phosphate and citrate components in the buffer. A formulation using phosphate-only or citrate-only buffer is outside literal scope if citrate or phosphate is absent.
- “stable”: stability is a functional limitation. In practice this often invites expert disputes about what stability metric is required (aggregation, potency loss, oxidation, sub-visible particles, freeze-thaw recovery, etc.). That can narrow or expand practical infringement depending on the claim’s prosecution history and how the specification defines “stable.”
- “stable liquid”: implies storage/handling stability and excludes lyophilized formats unless reconstituted liquids are treated as “liquid pharmaceutical composition” under the claim (fact dependent).
Claim 2: Quantitative range claim (medium strength because it constrains key variables)
Claim 2 depends from Claim 1 and specifies ranges:
- etanercept: 10 mg/mL to 100 mg/mL
- phosphate-citrate buffer: about 10 mM to 100 mM
- glycine: about 10 mM to 300 mM
- sodium chloride: about 50 mM to 120 mM
- sucrose: about 0.5 wt% to 10 wt%
Scope effect
- This claim is a classic “formulation parameter gate.” A product that preserves the excipient set but shifts any one excipient outside the numeric window can avoid literal infringement.
- “about” introduces uncertainty, but numeric-driven windows still give clear engineering targets. For infringement analysis, the most leverage usually comes from the “tightest” range.
Claim 3: pH-dependent coverage (often used for design-around)
Claim 3 depends from Claim 1 and adds:
Scope effect
- If a competitor shifts pH to an allowed formulation stability regime outside 5 to 7, it may avoid Claim 3 while still potentially infringing Claims 1/2/5/6/7 depending on their dependence structure.
Claim 4: Sterile ready-for-parenteral administration (format dependent)
Claim 4 depends from Claim 1 and requires:
- sterile
- ready for parenteral administration
Scope effect
- This is generally satisfied by most commercial prefilled or vial-ready etanercept liquid products. Design-around via sterilization method is unlikely to be practical, but the claim may still matter for intermediate products or non-sterile concentrates.
How do Claims 5, 6, and 7 change the risk profile?
Claim 5: Same structure but allows low/zero sodium chloride
Claim 5 depends from Claim 1 (per your extract) and covers:
- etanercept: 10 mg/mL to 100 mg/mL
- phosphate-citrate buffer: about 10 mM to 100 mM
- glycine: about 10 mM to 300 mM
- sodium chloride: about 0 mM to 150 mM
- sucrose: about 0.5 wt% to 10 wt%
Key distinction vs Claim 2
- Claim 2 locks sodium chloride to 50 to 120 mM.
- Claim 5 expands sodium chloride to 0 to 150 mM.
Practical implications
- Claim 5 is broader on salt. If a competitor tries to design around by reducing or increasing NaCl, Claim 5 can still capture the product if it stays within the other ranges.
Claims 6 and 7: Two specific parameter sets (narrow but high-evidence value)
These are “worked examples” style numeric recitations that can be easier to map to accused product labels, ANDAs/BLA submission data, or internal formulation documents.
Claim 6 recites (example-like values):
- etanercept: 50 mg/mL
- phosphate buffer: ~16.6 mM
- citrate buffer: ~15.3 mM
- glycine: ~75 mM
- sodium chloride: ~65 mM
- sucrose: ~1 wt%
Claim 7 recites alternative values:
- etanercept: 50 mg/mL
- phosphate-citrate buffer: ~31.9 mM total (as recited)
- glycine: ~75 mM
- sodium chloride: ~65 mM
- sucrose: ~1 wt%
Scope effect
- Claims 6 and 7 are narrower than Claims 1, 2, and 5.
- But they can be strategically decisive in litigation because they create a “snapshot” mapping. If an accused product matches one of these example sets (or lands within “about” tolerance), it can become a straightforward infringement case.
How strong are the infringement levers: what exactly must an accused product contain?
For a composition patent like this, infringement analysis typically turns on whether the accused liquid product:
- contains etanercept, and
- uses a phosphate-citrate buffer system (not phosphate-only or citrate-only),
- includes glycine and sucrose, and
- lands in the claimed concentration and pH windows depending on which dependent claims are asserted.
“At-issue” limitations that are most likely to be litigated
- Presence of phosphate-citrate: whether the buffer is truly phosphate-citrate or a different system (even if it has phosphate and citrate in different ratios or as non-buffer additives).
- “about” around concentration numbers: whether lab variance, formulation drift across lots, or analytical method differences affect the infringement threshold.
- Stability definition: whether stability is substantiated by aggregation/ potency retention criteria in the patent specification and prosecution history.
- pH compliance (Claim 3): whether accused product pH is measured under conditions matching the claim and whether pH drift over shelf life matters.
Where is the design-around space if you are developing an etanercept biosimilar or follow-on?
Design-around categories most relevant to this claim set:
1) Buffer architecture substitution
- Use a buffer system not meeting “phosphate-citrate buffer” (e.g., histidine, acetate, phosphate-only, citrate-only).
- Even with overlap in excipient family, the claim’s requirement that phosphate and citrate are present in the buffer system is a structural blocker for literal infringement.
2) Excipient removal or substitution
- Claim 1 requires glycine and sucrose and sodium chloride. If a competitor uses a different stabilizer (e.g., trehalose, mannitol, polysorbates without sucrose) and removes sucrose or glycine, it can avoid at least Claim 1 literal scope.
- Claim 4 requires sterile, ready-to-parenteral format. That’s hard to avoid for finished drug products, but it is relevant for non-final forms.
3) Salt and concentration window engineering
- Targeting Claim 2: sodium chloride outside 50 to 120 mM may avoid Claim 2, but not necessarily Claim 5.
- Targeting Claim 5: sodium chloride outside 0 to 150 mM would be a counter target if the rest matches.
- Concentrations outside:
- etanercept 10–100 mg/mL
- phosphate-citrate buffer 10–100 mM
- glycine 10–300 mM
- sucrose 0.5–10 wt%
are the most direct literal escape routes.
4) pH shift outside Claim 3
- Move pH outside 5 to 7 while preserving stability and compatibility.
- This avoids Claim 3 but may still trigger Claims 1, 2, 5, 6, and 7 depending on asserted counts.
5) Avoid exact “example” compositions
- Claims 6 and 7 have fixed numeric recitations. A product that does not match these parameter sets even within “about” tolerance reduces the risk that the claims are satisfied by “label match” evidence.
What patents usually cluster around this type of etanercept formulation estate?
For biologics formulation, patent families often split into:
- buffer composition and pH windows
- stabilizers and cryo-/freeze-thaw protectants
- container-closure and leachables (glass vials, stoppers)
- manufacturing process steps affecting degradation pathways
- analytical stability methods
US 10,058,589’s claim set is tightly focused on excipient composition and numeric ranges. In competitive landscapes, that usually coexists with other patents that may be broader on:
- formulation stability methods
- container-closure compatibility
- alternate pH/buffer systems
- alternate stabilizers or surfactants
- manufacturing and purification steps tied to product CQAs
Without the rest of the relevant asserted list and Orange Book/BLA listing data, the actionable conclusion is limited to the claim math of this patent itself: infringement will likely be decided on the buffer system and excipient range compliance.
What is the practical litigation posture likely for US 10,058,589?
Composition-range patents like this tend to be litigated through:
- comparison of accused product formulation specs vs claimed numeric ranges
- testing of stability and pH, with expert testimony tethered to “stable” as used in the patent
- evidence requests for formulation development records and/or regulatory submissions
Timing and pathway relevance
- If this patent is listed in the US for an etanercept reference product, it can materially affect:
- biosimilar development timelines
- settlement leverage in patent exchange
- the design-around decisions on final formulation
How to read “strong vs weak” relative to other patent types
- Compared with method-of-manufacture or use patents, a formulation composition patent often has:
- clearer literal elements (what excipients, what buffers, what concentrations)
- but factual complexity around “about” and “stable”
So its enforceability usually depends on:
- how closely accused product composition matches the parameter ranges
- whether buffer meets the phosphate-citrate definition
- whether stability is contested
How does US 10,058,589 compare with typical etanercept formulation competitors?
Against a competitor formulation that uses:
- phosphate-only buffer: likely non-infringing on the “phosphate-citrate buffer” element.
- citrate-only buffer: likewise likely outside.
- different stabilizer package (no glycine and/or no sucrose): likely outside Claim 1.
- same excipients but different NaCl range: may avoid Claim 2 yet still potentially fall under Claim 5 if NaCl remains within 0–150 mM.
- same excipients but different pH: may avoid Claim 3 only.
Against an accused product that matches:
- the excipient set (etag + phosphate-citrate + glycine + sucrose + NaCl)
- and the numeric ranges
- and pH 5–7
then Claim 1, Claim 2 or Claim 5, and potentially Claim 6/7 depending on exact parameters are all in play.
Key Takeaways
- US 10,058,589 is an excipient-and-parameter formulation patent for stable liquid etanercept, anchored on phosphate-citrate buffer + glycine + sucrose + sodium chloride (Claim 1).
- Claim 2 and Claim 5 control NaCl range differently: 50–120 mM (Claim 2) versus 0–150 mM (Claim 5). A NaCl design-around that escapes Claim 2 may still fall within Claim 5.
- Claim 3 adds pH 5–7, a common formulation variable that can be engineered, but only protects against the dependent claim, not the independent claim.
- Claims 6 and 7 are narrow numeric compositions that function as high-evidence infringement targets if an accused product matches the example values (within “about” tolerance).
- The most reliable design-around routes are buffer system substitution (avoiding phosphate-citrate), stabilizer set changes (removing glycine or sucrose), or concentration/pH shifts outside the numeric windows.
FAQs
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Can a biosimilar avoid US 10,058,589 by changing sodium chloride alone?
Changing NaCl can avoid Claim 2 (50–120 mM) but may still infringe Claim 5 if NaCl remains within 0–150 mM.
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Does US 10,058,589 require etanercept to be at a specific concentration?
The independent Claim 1 does not recite concentration, but dependent Claims 2 and 5 limit etanercept to 10–100 mg/mL.
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What is the main design-around lever in US 10,058,589?
Avoiding a phosphate-citrate buffer system or removing/changing required excipients (glycine and sucrose) is the cleanest structural escape.
-
How does “about” affect infringement risk for Claims 6 and 7?
“About” creates tolerance around the recited numeric values, so infringement turns on measured formulation parameters and the patent’s interpretation of acceptable deviation.
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Does pH outside 5–7 eliminate all infringement risk?
It eliminates coverage under Claim 3, but infringement under Claim 1, Claim 2, Claim 5, and potentially Claims 6/7 can remain if the other limitations are satisfied.
References
No external sources were provided or used in the prompt; therefore, no citations can be listed.
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