CD46 Radioimmunoconjugates With PEG Linkers for Lower Off-Target Toxicity

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Solution Overview

Problem

Current Actinium-225-based radioimmunotherapy for cancer is limited by toxicities from healthy tissue irradiation, non-specific accumulation, lack of optimized chelators, and inadequate labeling methods, necessitating new strategies to minimize toxicity and enhance anti-tumor efficacy.

Innovation Solution

Development of radioimmunoconjugates comprising an antibody that binds to CD46, coupled with a radionuclide via a poly(ethylene glycol) linker, which includes a chelator that chelates the radionuclide, specifically using alpha-emitting radionuclides like 225Ac, to target and treat CD46-expressing cancers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If Actinium-225 based radioimmunotherapy is used to treat cancer, then anti-tumor efficacy is improved, but toxicity to healthy tissues increases

Engineering Contradiction:

Improveanti-tumor efficacyVSAvoidtoxicity to healthy tissues

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by using a PEG linker with specific length (n=4, 6, 8, or 12) to create a conjugate with optimized spatial distribution. The PEG linker length is specifically tuned to achieve optimal distance between the radionuclide and healthy tissues while maintaining tumor targeting capability, thereby locally optimizing the therapeutic effect at the tumor site while minimizing damage to surrounding healthy tissues

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent employs parameter changes by systematically varying the PEG linker length (n=4, 6, 8, 12) to optimize the balance between tumor uptake and healthy tissue exposure. By changing this critical parameter, the invention achieves different biodistribution profiles and therapeutic indices, allowing selection of the optimal linker length for maximizing anti-tumor efficacy while minimizing healthy tissue toxicity

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If radiopharmaceutical is administered for cancer treatment, then tumor targeting is improved, but non-specific accumulation in clearance organs increases

Engineering Contradiction:

Improvetumor targeting specificityVSAvoidnon-specific accumulation in clearance organs

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent uses the PEG linker as an intermediary component between the antibody and radionuclide. This intermediary element modifies the pharmacokinetic properties of the radiopharmaceutical, improving its circulation time and tumor accumulation while reducing non-specific uptake in clearance organs such as the liver and kidneys. The PEG linker acts as a mediator that optimizes the biodistribution profile

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention creates a composite radiopharmaceutical structure consisting of antibody-PEG-chelator-radionuclide. This composite material combines the tumor-targeting capability of the antibody with the optimized pharmacokinetics provided by the PEG linker and the therapeutic effect of the radionuclide, achieving superior tumor specificity while reducing non-specific accumulation compared to conventional conjugates

Inventive Principle:

Principle #40Composite materials

3Ease of manufacture

If conventional chelators and radiolabeling methods are used, then radionuclide conjugation is achieved, but optimization for Actinium-225 is insufficient

Engineering Contradiction:

Improveradionuclide conjugation capabilityVSAvoidchelator optimization for 225Ac

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-conjugating the PEG linker to the antibody before radionuclide attachment. This sequential approach ensures optimal positioning and orientation of the chelator relative to the antibody, creating a pre-optimized structure that enhances radionuclide stability and tumor targeting efficiency. The PEG linker is attached in advance to provide the necessary spatial buffer and chemical functionality

Inventive Principle:

Principle #10Preliminary action

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 radioimmunoconjugates enhance tumor uptake and reduce radiation burden on non-target organs, improving treatment efficacy and safety by utilizing short PEG linkers that promote higher tumor localization and lower radiation exposure to healthy tissues.

Implementation Method 1

a chelator, wherein the chelator chelates the radionuclide

Methodology Applied

Scientific EffectChelation:

Implementation Method 2

produces a total of 4 α and 2 β—particles in its decay chain

Methodology Applied

Scientific EffectAlpha radiation: Radiation

Data Source

PatentUS20250339570A1Radioimmunoconjugates and therapeutic uses thereof

Publication Date: 2025.11.06 RGT UNIV OF CALIFORNIA

AI summary

Provided are radioimmunoconjugates comprising an antibody that specifically binds to CD46; a radionuclide which may be an alpha emitter or a beta emitter such as 225Ac or 177Lu and a chelator such as DOTA or NOTA, and derivatives thereof, wherein the chelator chelates the radionuclide, and wherein the chelator is coupled to the antibody through a linker comprising poly(ethylene glycol) moieties and methods of using the radioimmunoconjugates for treating cancer and for detecting tumor cells.