STING PROTAC Degraders for Sustained Inhibition With Lower Off-Target Risk

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Solution Overview

Problem

Existing STING inhibitors require high systemic drug exposures to maintain inhibition, leading to a risk of unwanted off-target effects and are less effective against constitutive activation of STING, which is associated with various diseases.

Innovation Solution

Development of proteolysis targeting chimeric (PROTAC) compounds that induce STING degradation by binding to both STING and an E3 ubiquitin ligase, without forming covalent bonds and exhibiting agonist activity, using a STING ligand connected to an E3 ubiquitin ligase ligand via a linker.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional STING inhibitors are used to maintain inhibition, then STING activity is suppressed, but high systemic drug exposures are required leading to unwanted off-target effects

Engineering Contradiction:
ImproveSTING inhibition efficacyVSAvoidoff-target effects
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The inhibitor molecule is divided into two distinct functional modules: a STING-binding module (containing a STING ligand) and a protein degradation module (PROTAC component with E3 ligase binding domain). These modules are connected via a linker, allowing the molecule to simultaneously bind STING and recruit the proteasome degradation machinery, thereby achieving reliable STING suppression through degradation rather than reversible inhibition

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the mechanism of action from reversible inhibition to irreversible degradation. By designing the inhibitor as a PROTAC that recruits the ubiquitin-proteasome system, the STING protein is permanently degraded rather than temporarily inhibited, maintaining suppression efficacy without requiring continuous high drug exposure, thus reducing off-target effects

Inventive Principle:
Principle #35Parameter changes

2Reliability

If traditional STING inhibitors are used, then STING activity is inhibited, but the approach is less effective against constitutive activation of STING

Engineering Contradiction:
ImproveSTING inhibition efficacyVSAvoideffectiveness against constitutive activation
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The PROTAC inhibitor is designed to bind to constitutively activated STING and recruit the E3 ubiquitin ligase complex, initiating protein degradation before the constitutive activation can cause harm. The molecule contains a STING ligand module that recognizes and binds to STING regardless of its activation state, followed by a PROTAC module that triggers degradation, effectively neutralizing constitutive activation

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention transitions from reversible inhibition to irreversible degradation, which is particularly effective against constitutive activation. By degrading the STING protein rather than merely inhibiting its activity, the PROTAC approach eliminates the source of constitutive activation, providing reliable efficacy where traditional inhibitors fail

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 compounds achieve effective STING degradation with reduced off-target effects, providing therapeutic benefits in diseases driven by unwanted or uncontrolled STING activation.

Implementation Method 1

the degrader binds to both the target protein and E3 ubiquitin ligase simultaneously to form a ternary complex

Methodology Applied
Scientific EffectProtein-protein binding interaction:

Implementation Method 2

The E3 ligase then recruits an E2 conjugating enzyme to the ternary complex, which ubiquitinates the target protein

Methodology Applied
Scientific EffectUbiquitination:

Implementation Method 3

The ubiquitinated target proteins are recognized and degraded by the cell's proteasome machinery

Methodology Applied
Scientific EffectProteasomal degradation:

Data Source

PatentEP4663632A1Compounds useful for the modulation of the activity of sting
Publication Date: 2025.12.17 SULIS THERAPEUTICS APS
  • EP4663632A1 patent drawingFigure 1
  • EP4663632A1 patent drawingFigure 2A~2C
  • EP4663632A1 patent drawingFigure 3

AI summary

The invention relates to agents capable of degrading STING, composition comprising said agents and medical uses thereof.