CTLA4-Ig Fusion Protein Formulation for Aggregation Control

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Solution Overview

Problem

Fusion proteins, particularly CTLA4-Ig, are prone to instability due to aggregation, fragmentation, and oxidation, which affects their bioactivity and stability under various environmental conditions, necessitating the development of a suitable formulation that maintains stability and activity.

Innovation Solution

A stable pharmaceutical formulation of CTLA4-Ig fusion protein comprising phosphate buffer, sucrose or mannitol, histidine, and poloxamer, with histidine and sugar added during the tangential flow filtration process, enhancing colloidal stability and reducing aggregation and fragmentation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If fusion protein is formulated in solution, then it can be administered and used therapeutically, but it undergoes aggregation, deamidation, and oxidation leading to instability

Engineering Contradiction:
Improveroute of administrationVSAvoidprotein stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent modifies formulation parameters including pH (maintained at 6.0-8.0 using phosphate buffer), temperature (storage at controlled conditions), and excipient concentrations to stabilize the fusion protein in solution, preventing aggregation and degradation while maintaining therapeutic usability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces intermediary substances (excipients) such as sugars, amino acids, and surfactants that mediate between the fusion protein and the aqueous environment, protecting the protein from harmful interactions with water and stabilizing its structure during storage and administration

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If fusion protein concentration is increased to improve therapeutic dosage, then treatment effectiveness increases, but aggregation rate increases rapidly

Engineering Contradiction:
Improveprotein concentrationVSAvoidcolloidal stability
Core Design Contradiction:
Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent employs excipients as intermediary agents that interfere with protein-protein interactions, preventing aggregation even at high concentrations. These intermediaries create a protective environment that allows high protein concentration without loss of colloidal stability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent optimizes multiple formulation parameters simultaneously including pH, ionic strength, and excipient concentrations to expand the stable concentration range of the fusion protein, enabling high-dose formulations without aggregation

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If multiple excipients are added to stabilize the fusion protein, then protein stability improves, but formulation complexity increases

Engineering Contradiction:
Improveprotein stabilityVSAvoidformulation complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent combines multiple stabilizing functions into a coordinated excipient system where sugars provide structural stabilization, amino acids maintain pH and prevent deamidation, and surfactants prevent surface aggregation, achieving comprehensive protection through synergistic interaction rather than isolated components

Inventive Principle:
Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The formulation maintains the CTLA4-Ig fusion protein's stability for at least two weeks at 30°C with less than 10% in aggregate form, ensuring effective bioactivity and colloidal stability.

Implementation Method 1

comprising phosphate buffer at a pH ranging from pH 6.0 to pH 8.0

Methodology Applied
Scientific EffectBuffer system:

Implementation Method 2

sucrose or mannitol, histidine, and surfactant (poloxamer), wherein the fusion protein is a CTLA4-Ig molecule

Methodology Applied
Scientific EffectColloidal stability: Colloid

Implementation Method 3

Deamidation can occur at aspargine or glutamine residues, resulting in a charge variant/s of the protein

Methodology Applied
Scientific EffectDeamidation prevention:

Implementation Method 4

Oxidation of fusion proteins involves mainly methionine residues, and are generally influenced by external factors such as exposure to light and transition metal ions

Methodology Applied
Scientific EffectOxidation prevention: Oxidation

Implementation Method 5

surfactant (poloxamer)

Methodology Applied
Scientific EffectSurfactant action: Surfactant

Data Source

PatentEP3801605B1Stable fusion protein formulation
Publication Date: 2025.09.10 DR REDDYS LAB LTD

AI summary

The present invention discloses a stable pharmaceutical formulation of a fusion protein, wherein the formulation contains buffer, sugar, amino acid and surfactant, and optionally includes salts. The disclosed fusion protein formulations are liquid formulations that are also suitable for lyophilization.