EpCAM-Binding FN3 Domains for Targeted Cancer Drug Delivery

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Solution Overview

Problem

Existing therapies for targeting EpCAM, a transmembrane glycoprotein involved in tumorigenesis and metastasis, lack high-affinity and specific non-antibody proteins that can efficiently bind to EpCAM for targeted drug delivery and cancer treatment.

Innovation Solution

Development of fibronectin type III (FN3) domains that specifically bind to EpCAM, which are recombinant, non-naturally occurring polypeptides, capable of high-affinity binding with a dissociation constant of 1×10−13 M or less, and can be conjugated to detectable labels or therapeutic agents for targeted delivery and imaging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If antibodies or antibody fragments are used to target EpCAM, then high affinity and specificity are achieved, but the molecule size is large and requires complex production systems

Engineering Contradiction:
Improvebinding affinity and specificityVSAvoidmolecule complexity and production system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent creates simplified copies of the antibody binding function using FN3 domains. These domains replicate the target recognition capability of antibodies against EpCAM but with a much simpler protein structure that can be produced in prokaryotic systems, eliminating the need for complex mammalian cell culture infrastructure

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The invention extracts only the essential binding function from the complex antibody structure. By using FN3 domains that contain just the binding domain without the full antibody structure, the patent achieves EpCAM targeting with a minimal protein structure that is easier to produce and modify

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If traditional antibodies are used for drug delivery, then target specificity is improved, but tissue penetration efficiency is reduced due to large size

Engineering Contradiction:
Improvetarget specificityVSAvoidtissue penetration efficiency
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The FN3 domains create a simplified copy of the antibody binding function with reduced molecular size. This smaller structure maintains EpCAM targeting specificity while enabling more efficient diffusion and penetration into tumor tissues compared to full-size antibodies

Inventive Principle:
Principle #26Copying

3Ease of manufacture

If non-antibody proteins are engineered to bind EpCAM, then ease of production and conjugation is improved, but high-affinity binding capability may be compromised

Engineering Contradiction:
Improveproduction and conjugation simplicityVSAvoidbinding affinity
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent optimizes the FN3 domain sequences and structural parameters to achieve high-affinity binding to EpCAM. By carefully selecting and optimizing the amino acid sequences in the FN3 domains, the invention achieves dissociation constants in the low picomolar range, matching or exceeding antibody affinity while maintaining production simplicity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates composite molecular structures by conjugating FN3 domains to therapeutic agents, diagnostic labels, or other functional moieties. This composite approach combines the high-affinity binding capability of the optimized FN3 domains with the desired therapeutic or diagnostic function, achieving both high reliability and ease of manufacture

Inventive Principle:
Principle #40Composite materials

Data Source

PatentUS12491255B2EPCAM binding fibronectin type III domains
Publication Date: 2025.12.09 ARO BIOTHERAPEUTICS CO

AI summary

The present disclosure relates to polypeptides, such as fibronectin type III (FN3) domains that can bind EpCAM, their conjugates, isolated nucleotides encoding the molecules, vectors, host-cells, as well as methods of making and using the molecules.