Activatable Anti-VEGF scFv Masking Strategy

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Solution Overview

Problem

There is a need for a strategy to provide the features of a prodrug to protein-based therapeutics, which are not currently available.

Innovation Solution

The development of activatable binding polypeptides (ABPs) that contain a target binding moiety (TBM), a masking moiety (MM), and a cleavable moiety (CM), allowing for increased specificity and selectivity by activating only in the presence of a cleaving agent.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a protein drug is designed to bind its target continuously, then therapeutic effect is maintained, but side effects increase due to lack of selectivity

Engineering Contradiction:

Improvetherapeutic effectVSAvoidside effects

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The protein drug is pre-modified with a masking moiety that blocks the target binding site before administration. The drug is prepared in an inactive state and only becomes active when the cleavable moiety is removed by a specific cleaving agent at the target site, ensuring selective activation and reduced side effects

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A masking moiety is introduced as an intermediary element that temporarily blocks the target binding site. This intermediary is removed by a specific cleaving agent (such as a protease or reducing agent) at the target location, allowing selective activation of the drug only where needed

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a masking moiety is added to block the target binding site, then selectivity is improved, but the drug structure becomes more complex

Engineering Contradiction:

ImproveselectivityVSAvoiddrug structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The masking moiety, cleavable moiety, and target binding site are merged into a single integrated protein structure. The masking moiety and cleavable moiety are covalently linked to form a unified construct that can be processed as one molecule, simplifying the overall design despite the added functionality

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The masking moiety serves multiple functions: it blocks the target binding site to prevent off-target effects, provides a cleavable link for selective activation, and can be designed to respond to various cleaving agents (proteases, reducing agents), making the system universally applicable to different drug targets

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If a cleavable moiety is incorporated to enable activation, then specificity is enhanced, but the manufacturing process becomes more difficult

Engineering Contradiction:

ImprovespecificityVSAvoidmanufacturing process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The cleavable moiety is designed to be automatically cleaved by endogenous cleaving agents (such as proteases or reducing agents) present in the biological system. The drug self-activates at the target site without requiring external processing or complex manufacturing steps to control activation timing

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The cleavable moiety is designed with specific biochemical parameters (such as protease recognition sequences or disulfide bonds) that allow it to be cleaved under specific physiological conditions. This enables control of drug activation through biochemical parameter changes rather than complex manufacturing processes

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

ABPs exhibit an activatable conformation where the TBM is less accessible to the target in the uncleaved state but becomes accessible after cleavage of the CM, enhancing specificity and reducing side effects.

Implementation Method 1

The MM comprises a cysteine residue and steric hindrance is achieved via disulfide bond linkage between said cysteine residue and an additional cysteine residue adjacent to or within the TBM

Methodology Applied

Scientific EffectDisulfide bond: Chemical Bonding

Implementation Method 2

The CM comprises a protease substrate, which can be, for example, a plasmin substrate, a caspase substrate or a matrix metalloprotease (MMP) substrate

Methodology Applied

Scientific EffectProtease cleavage: Enzyme

Data Source

PatentUS12209120B2Activatable anti-VEGF scFv

Publication Date: 2025.01.28 CYTOMX THERAPEUTICS INC

AI summary

The present disclosure provides activatable binding polypeptides (ABPs), which contain a target binding moiety (TBM), a masking moiety (MM), and a cleavable moiety (CM). The present disclosure provides activatable antibody compositions, which contain a TBM containing an antigen binding domain (ABD), a MM and a CM. Furthermore the present disclosure also provides ABPs which contain a first TBM, a second TBM and a CM. The ABPs exhibit an “activatable” conformation such that at least one of the TBMs is less accessible to target when uncleaved than after cleavage of the CM in the presence of a cleaving agent capable of cleaving the CM. The disclosure further provides libraries of candidate ABPs, methods of screening to identify such ABPs, and methods of use. The disclosure further provides ABPs having TBMs that bind VEGF, CTLA-4, or VCAM, ABPs having a first TBM that binds VEGF and a second TBM that binds FGF, as well as compositions and methods of use.