Engineered IL-2 PEG Conjugates for Longer Half-Life and Lower Toxicity

Solution Overview

Problem

Wild-type IL-2 therapies for cancer treatment suffer from severe side effects like capillary leak syndrome and require frequent intravenous infusion due to short half-life and toxicity concerns, limiting their widespread application.

Innovation Solution

Development of modified IL-2 proteins with engineered glutamine residues and PEG conjugates that enhance circulating half-life and reduce IL-2Rα subunit binding, while maintaining or slightly affecting IL-2Rβ and γc subunit binding, thereby improving pharmacokinetic profiles and reducing immunosuppressive activities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If wild-type IL-2 is used for cancer treatment, then immune system activation occurs, but severe side effects like capillary leak syndrome and short half-life limit its application

Engineering Contradiction:

Improvecancer treatment efficacyVSAvoidside effects and toxicity

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces specific amino acid substitutions at defined positions in the IL-2 molecule to selectively alter its binding properties. The F122Y substitution specifically enhances binding to IL-2Rβ/γc while the F122L substitution reduces binding to IL-2Rα, creating localized functional changes that improve the therapeutic index by preferentially activating NK cells and effector T cells over Treg cells

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent modifies the molecular structure of IL-2 through site-specific amino acid substitutions that change its pharmacokinetic and pharmacodynamic parameters. These substitutions alter the dissociation constants (Kd) for different IL-2 receptor subtypes, extending serum half-life from minutes to hours and reducing immunosuppressive activity while maintaining or enhancing anti-tumor efficacy

Inventive Principle:

Principle #35Parameter changes

2Reliability

If wild-type IL-2 is administered, then lymphocyte activation occurs, but frequent intravenous infusion is required due to short half-life

Engineering Contradiction:

Improveimmune response activationVSAvoidserum half-life

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent modifies the molecular structure of IL-2 through site-specific amino acid substitutions that change its pharmacokinetic and pharmacodynamic parameters. These substitutions alter the dissociation constants (Kd) for different IL-2 receptor subtypes, extending serum half-life from minutes to hours and reducing immunosuppressive activity while maintaining or enhancing anti-tumor efficacy

Inventive Principle:

Principle #35Parameter changes

3Reliability

If wild-type IL-2 is used, then broad immune activation occurs, but immunosuppressive activity through Treg cell activation limits its therapeutic window

Engineering Contradiction:

Improveanti-tumor immune responseVSAvoidimmunosuppressive activity

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent introduces specific amino acid substitutions at defined positions in the IL-2 molecule to selectively alter its binding properties. The F122Y substitution specifically enhances binding to IL-2Rβ/γc while the F122L substitution reduces binding to IL-2Rα, creating localized functional changes that improve the therapeutic index by preferentially activating NK cells and effector T cells over Treg cells

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent inverts the traditional approach by designing IL-2 variants that actively avoid Treg cell activation through reduced IL-2Rα binding, rather than attempting to enhance anti-tumor activity. This inverse strategy of reducing immunosuppression achieves better therapeutic outcomes by shifting the balance toward effector cell activation

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS12559534B2Modified IL-2 proteins, peg conjugates, and uses thereof

Publication Date: 2026.02.24 CSPC MEGALITH BIOPHARMACEUTICAL CO LTD

AI summary

The present application provides a modified interleukin-2 (IL-2) protein comprising an engineered glutamine (Q) residue. The present application also provides a modified IL-2 protein-polyethylene glycol (PEG) conjugate comprising a modified IL-2 protein comprising an engineered Q residue and a PEG moiety, wherein the PEG moiety is conjugated to the modified IL-2 protein via the engineered Q residue. Pharmaceutical compositions, kits, methods of making, and methods of treatment (e.g., for cancer) are also provided.