PEG-Modified Exendin-4 Half-Life Extension via Branched PEG Linkage

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Solution Overview

Problem

Current exendin and exendin analogs face challenges such as short half-life in the blood, poor stability, and immunogenicity, leading to frequent injections and reduced bioactivity due to PEG modification, which complicates their application in treating diabetes and adiposis.

Innovation Solution

Modification of exendins or exendin analogs with branched polyethylene glycol (PEG) derivatives, specifically linking PEG molecules to amino acids, enhancing stability, bioactivity, and reducing immunogenicity, resulting in extended half-life and improved pharmacokinetic profiles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If exendin-4 is modified by linear or branched PEG, then physical and chemical stability is improved and half-life is extended, but bioactivity drops significantly

Engineering Contradiction:

Improvephysical and chemical stabilityVSAvoidbioactivity

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The patent applies parameter changes by systematically varying PEG molecular weights (500-20,000 Da), modification sites (N-terminus, C-terminus, side chains), and PEG structures (linear vs. branched) to optimize the balance between stability and bioactivity. This is evidenced by testing multiple PEG variants and selecting those that maintain GLP-1 receptor binding affinity while extending half-life.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements local quality by site-specifically modifying exendin-4 at particular amino acid residues (e.g., N-terminus, C-terminus, or specific side chains) rather than uniform modification. This selective modification approach preserves critical bioactive regions while conferring stability benefits, resolving the contradiction between maintaining bioactivity and improving stability.

Inventive Principle:

Principle #3Local quality

2Reliability

If exendin-4 is injected frequently to maintain therapeutic effect, then blood sugar control is improved, but immunogenicity increases leading to antibody production

Engineering Contradiction:

Improveblood sugar controlVSAvoidimmunogenicity

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent uses PEG as an intermediary molecule that mediates between the immunogenic exendin-4 peptide and the host immune system. The PEG chain acts as a steric barrier that reduces immune recognition and antibody binding, thereby decreasing immunogenicity while maintaining the drug's therapeutic effect on blood sugar control.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates composite structures by chemically conjugating PEG polymers with exendin-4 peptides to form PEG-exendin-4 conjugates. This composite material combines the therapeutic properties of exendin-4 with the immunoprotective and stability-enhancing properties of PEG, reducing antibody production while maintaining glucose-dependent insulinotropic activity.

Inventive Principle:

Principle #40Composite materials

3Duration of action of moving object

If PEG molecular weight is increased to reduce kidney clearance, then half-life is extended, but drug solubility and cell membrane penetration may be affected

Engineering Contradiction:

Improvehalf-life in bloodVSAvoidcell membrane penetration

Core Design Contradiction:

Duration of action of moving objectVSEase of operation

Solution Approach 1:

The patent systematically varies PEG molecular weight parameters (testing 500, 1,000, 2,000, 5,000, 10,000, and 20,000 Da variants) to identify the optimal range that extends half-life through reduced renal clearance while maintaining adequate solubility and membrane penetration characteristics for therapeutic efficacy.

Inventive Principle:

Principle #35Parameter changes

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 PEG-modified exendins or exendin analogs exhibit prolonged half-life, high bioactivity, and low immunogenicity, allowing for less frequent dosing and improved therapeutic efficacy in treating diabetes and adiposis.

Implementation Method 1

Methodology Applied

Scientific EffectPEG modification:

Implementation Method 2

an extension of half life in blood due to the increase in PEG molecular weight leading to reduced kidney clearance

Methodology Applied

Scientific EffectKidney clearance reduction:

Implementation Method 3

an improvement in drug solubility and cell membrane penetration

Methodology Applied

Scientific EffectSolubility enhancement:

Implementation Method 4

an increase in resistance to protease degradation

Methodology Applied

Scientific EffectProtease degradation resistance:

Implementation Method 5

a decrease in immunogenicity

Methodology Applied

Scientific EffectImmunogenicity reduction:

Data Source

PatentEP2081957B1Peg modified exendin or exendin analog and compositions and use thereof

Publication Date: 2019.08.14 SHANGHAI BENEMAE PHARMACEUTICAL CORP

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AI summary

Exendins or exendin analogs modified by one or more PEG derivatives that may be linked to one or more amino acids of the exendins or exendin analogs are provided. The PEG derivatives may have branched structure set forth in any one of formulas I-IV. Compositions including the PEG derivative modified exendin or exendin analog, methods of making or administering the modified exendin or exendin analog, and various uses thereof are also provided.