United States Patent 9,469,847: Sacrosidase Formulation Claims, Claim Scope, and US Patent Landscape

What does US 9,469,847 claim, in plain technical terms?

US 9,469,847 claims a specific sacrosidase (sucrase) enzyme solution derived from Saccharomyces with tightly controlled formulation, potency, and residual papain. The core claim is directed to a patient-use formulation intended to address allergic reaction risk tied to residual protease (papain).

Independent Claim 1 (core scope)

Claim 1 requires all of the following elements:

Substance: “a solution of sacrosidase derived from Saccharomyces”
Solvent system: ~1:1 glycerol/water
Potency: enzymatic activity ≥ 7,500 IU/mL
Residual papain limit: < 10 ng/mL papain
Clinical safety assertion: a daily dose of ~2 to 10 mL/day “does not induce an allergic reaction” in a human with congenital sucrase-isomaltase deficiency
Protein primary structure: sacrosidase is a 513 amino acid polypeptide that is glycosylated

Dependent claims (tightening residual papain detectability)

Claim 2: residual papain < 3.0 ng/mL
Claim 3: “no detectable papain” by ELISA with LLOQ 3 ng/mL
Claim 4: “no detectable papain” by SDS-PAGE on a sample size of up to 15 µg of solution
Claim 5: enzymatic activity ~7,500 to 10,000 IU/mL

Immediate claim-architecture implications

The patent is not directed to sacrosidase in general. It is directed to a composition defined by:
- a source and protein structure (513 aa glycosylated),
- a vehicle (1:1 glycerol/water),
- a potency window (≥7,500 IU/mL; dependent 7,500 to 10,000 IU/mL),
- residual papain control with multiple measurement methods (ELISA and SDS-PAGE),
- and a dose-and-allergy outcome for a defined patient population.

From a freedom-to-operate standpoint, any competitor design that changes the vehicle ratio, enzymatic activity range, residual papain control approach, or protein identity/structure could avoid literal infringement, but the “principal structure 513 amino acid glycosylated” element is particularly constraining for alternative enzyme preparations.

How strong are the claims against common design-around levers?

The claim-set concentrates on three hard technical choke points: residual papain, formulation vehicle, and protein identity/structure.

Residual papain limits create the most exploitable boundary?

Yes, because the claims tie papain to numerical thresholds and analytical method detectability.

Claim thresholds and assays

Claim	Residual papain requirement	Measurement constraint
1	< 10 ng/mL	Not tied to a specific assay in the text, but “residual papain” is quantified
2	< 3.0 ng/mL	Numeric threshold
3	No detectable papain	ELISA, LLOQ = 3 ng/mL
4	No detectable papain	SDS-PAGE using up to ~15 µg sample

Practical effect: a competitor that cannot meet <3 ng/mL (or cannot show “no detectable” in the stated contexts) faces high infringement risk.

Design-around leverage: the most realistic route is to eliminate papain as an impurity by changing upstream processing (or using different starting reagents) so the residual impurity level stays below the patent’s detectability thresholds.

Vehicle requirement (1:1 glycerol/water) is a hard literal constraint

Claim 1 requires about 1:1 glycerol/water. Even small deviations can matter depending on claim construction, but “about” provides some tolerance.

Design-around leverage: shift to a different stabilizing system (different glycerol fraction, different polyol, or different excipient system) while still meeting potency and allergen controls. However, the claim’s potency and protein-identity requirements still constrain alternatives.

Protein identity (513 aa glycosylated) is restrictive

Claim 1 specifies that sacrosidase’s primary structure is a 513 amino acid polypeptide that is glycosylated.

Design-around leverage:

Produce sacrosidase using a materially different polypeptide length/sequence or non-glycosylated form could avoid this element.
Real-world risk: sacrosidase as a therapeutic is typically a glycosylated enzyme; deviating from that may undermine function or regulatory comparability.

Where do these claims sit relative to established sacrosidase products and purification impurity control?

US 9,469,847 aligns with a formulation-and-purity strategy that targets papain as a specific residual protease impurity. The claim language indicates papain is a known impurity from manufacturing steps and that it can drive allergic reactions at the dose range used in sucrase-isomaltase deficiency therapy.

Therapeutic dose mapping and potential exposure

Claim 1 ties “no allergic reaction” to a daily dose of 2 to 10 mL/day. Because the claim also specifies potency (≥7,500 IU/mL), the patient exposure window for activity is broadly:

At 2 mL/day: ≥15,000 IU/day
At 10 mL/day: ≥75,000 IU/day

The patent uses the outcome (no allergic reaction) as a functional limitation tied to that dosing regimen.

What is the patent landscape likely covering around this claim space in the US?

The landscape relevant to US 9,469,847 can be divided into four practical clusters:

Sacrosidase enzyme production and identity (protein sequence, glycosylation, sourcing)
Formulation and stabilization (glycerol/water systems; potency retention)
Residual impurity control (specific enzymes like papain; analytical methods like ELISA and SDS-PAGE)
Clinical use and immunogenicity/allergy mitigation (dose regimens and allergen risk)

Most likely “crowding” areas

Residual papain: A narrow impurity target often leads to serial continuation patents and method-of-control patents, plus formulation claims in later generations.
Vehicle: Polyol-water stabilizers are common; patents often compete through “about” ranges and impurity specs.
Analytical thresholds: When claims tie to an assay LLOQ, competitors may attempt alternate validation approaches, but the claim uses detectability standards that are difficult to sidestep while still demonstrating “no detectable” under those constraints.

How competitors typically respond

Competitors can:

change processing to reduce papain,
change purification steps to avoid protease impurities,
change formulation vehicle while keeping enzyme stable,
and/or demonstrate that papain is below detection under method-specific conditions.

The key question for infringement is whether the competitor’s product meets the specific vehicle ratio and residual papain thresholds plus the 513-aa glycosylated identity requirement.

What legal and technical issues could govern claim validity or enforceability in practice?

This section focuses on predictable litigation and prosecution arguments that map tightly onto the claim text.

1) Enablement and characterization risk for the “no allergic reaction” limitation

Claim 1 includes a clinical outcome: a daily dose of 2 to 10 mL/day “does not induce an allergic reaction” in a defined patient population.

Patent enforcement often hinges on whether:

the patent provides adequate support for the allergy outcome across the claimed dosing range, and
the limitation is a true property of the claimed formulation, not a generic clinical expectation.

From a technical standpoint, “no allergic reaction” depends on patient variability and study design, but the claim locks it to dosing volume and a composition defined by residual papain control.

2) Distinguishability of residual papain across methods

Claims 3 and 4 define “no detectable papain” with:

ELISA LLOQ 3 ng/mL, and
SDS-PAGE detectability for up to 15 µg of sample.

Competitors can argue measurement variability and assay sensitivity differences, but the dependent claim text ties to an explicit threshold (ELISA LLOQ).

3) Constructing “about 1:1” and activity ranges

The claim uses “about” for glycerol/water and dosing, and “about” for activity in claim 5. That can broaden scope for minor deviations, but it also increases interpretive dependence on prosecution history and claim construction standards.

4) Protein identity constraint

The “513 amino acid polypeptide that is glycosylated” element is a strong anchor for novelty and non-obviousness arguments. It can also become a vulnerability if prior art sacrosidase equivalents already have the same structural characteristics.

Is US 9,469,847 likely to overlap with other sacrosidase formulation patents?

Yes, overlap is likely in three areas:

Purity specifications in sacrosidase products
Stabilizer system choices (glycerol/water)
Assay-based impurity detectability claims (ELISA/specific protein assays and SDS-PAGE)

The unique feature in this patent is the explicit focus on residual papain with layered numeric and detectability controls, plus a dose-linked allergy outcome.

Claim-by-claim infringement sensitivity

The following table ranks infringement sensitivity by how directly each claim element maps to product attributes that competitors can control.

Claim element	Competitor control	Infringement sensitivity
Sacrosidase derived from Saccharomyces	Manufacturing choice	High
Primary structure 513 aa glycosylated	Biologic identity	High
~1:1 glycerol/water	Formulation	High
Activity ≥ 7,500 IU/mL (or 7,500 to 10,000 IU/mL)	Potency spec	Medium-High
Residual papain < 10 ng/mL	Purification/processing	Very High
Residual papain < 3 ng/mL	Purification/processing	Very High
No detectable papain by ELISA LLOQ 3 ng/mL	Analytical confirmation	Very High
No detectable papain by SDS-PAGE (≤15 µg sample)	Both manufacturing and analytics	High
No allergic reaction at 2-10 mL/day	Requires evidence and outcome linkage	Litigation-sensitive

Where is the highest competitive risk for a generic or biosimilar-style product?

If a competitor attempts to match sacrosidase function while differing only in formulation excipients or purification steps, the residual papain constraints dominate the risk profile.

A practical risk ladder:

If residual papain is measurable above 10 ng/mL, claim 1 is missed but claim 1 may still be challenged if enforcement focuses on equivalents (depends on jurisdiction and construction).
If residual papain is below 10 ng/mL but above 3 ng/mL, claims 1 and not 2-4 may be relevant.
If residual papain is below 3 ng/mL but not provably “no detectable” under the stated ELISA/SDS-PAGE settings, claims 3 and 4 become contested.

What to watch in the US patent landscape around this exact claim set

Because the patent uses:

a defined stabilizer ratio,
numeric impurity thresholds,
assay-anchored detectability,
and a clinical dose-linked safety limitation,

the most active landscape will likely show:

follow-on claims narrowing residual impurity specs further (e.g., lower ng/mL),
assay methodology improvements (ELISA platforms with defined LLOQs),
alternate vehicle systems, and
added process control patents that indirectly ensure papain removal.

The most relevant US filings for competitive monitoring are those that claim:

sacrosidase compositions with glycerol/water and potency windows,
impurity specifications for protease-related contaminants,
and sacrosidase protein identity with the 513-aa glycosylated structure.

Key Takeaways

US 9,469,847 claims a sacrosidase solution defined by vehicle (~1:1 glycerol/water), potency (≥7,500 IU/mL; dependent 7,500-10,000 IU/mL), and residual papain controls (tiered thresholds and assay-based “no detectable” requirements).
The patent’s strongest enforceable choke points are the residual papain numeric limits and assay-specific detectability standards, reinforced by a dose-linked “no allergic reaction” limitation in congenital sucrase-isomaltase deficiency.
The protein identity requirement (513 aa glycosylated) and the vehicle ratio create additional non-trivial constraints on design-around strategies.
In the US landscape, the most likely competitive overlap and follow-on activity clusters around purity specifications, stabilizer systems, and assay-anchored impurity control rather than around sacrosidase use alone.

FAQs

1) What is the residual papain limit in the broadest claim?
Claim 1 requires < 10 ng/mL papain.

2) How do claims 3 and 4 define “no detectable papain”?
Claim 3 uses ELISA with lower limit of quantification of 3 ng/mL. Claim 4 uses SDS-PAGE with up to ~15 µg of sample.

3) Does the patent claim a specific daily dose range?
Yes. Claim 1 states about 2 to 10 mL per day does not induce an allergic reaction in the defined patient population.

4) Is glycerol/water the only vehicle?
The claim requires about 1:1 glycerol/water, making the vehicle a literal claim element.

5) What is the potency range in the dependent claim?
Claim 5 specifies an enzymatic activity of about 7,500 to 10,000 IU/mL.

References (APA)

[1] United States Patent 9,469,847. (n.d.). Sacrosidase composition with controlled residual papain and reduced allergy risk. United States Patent and Trademark Office.

Applicant	Tradename	Biologic Ingredient	Dosage Form	BLA	Approval Date	Patent No.	Expiredate
Qol Medical, Llc	SUCRAID	sacrosidase	Solution For Oral	020772	April 09, 1998	9,469,847	2035-08-17
Qol Medical, Llc	SUCRAID	sacrosidase	Solution For Oral	020772	May 25, 2022	9,469,847	2035-08-17
>Applicant	>Tradename	>Biologic Ingredient	>Dosage Form	>BLA	>Approval Date	>Patent No.	>Expiredate

Patent: 9,469,847

Summary for Patent: 9,469,847