Fc Polypeptide Dimer Fusion Protein for Brain Metastasis Targeting
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Solution Overview
Problem
Current therapies for brain metastases of HER2-positive breast cancer are ineffective due to the inability of therapeutic agents to cross the blood-brain barrier and target HER2 in the brain parenchyma.
Innovation Solution
Development of an Fc polypeptide dimer-antibody variable region fusion protein that includes an antibody variable region capable of binding HER2 and a modified Fc polypeptide dimer with a TfR-binding site, allowing for transcytosis across the blood-brain barrier and targeting of HER2 in the brain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional anti-HER2 therapies are used, then extracranial tumors are controlled, but intracranial lesions (brain metastases) cannot be controlled due to inability to cross the blood-brain barrier
Solution Approach 1:
The patent uses the transferrin receptor (TfR) as an intermediary to facilitate BBB crossing. The Fc polypeptide is modified to bind TfR, which is naturally expressed on BBB endothelial cells. This intermediary mechanism allows the therapeutic agent to be transported across the BBB without directly penetrating the barrier, thereby resolving the contradiction between maintaining therapeutic efficacy and overcoming BBB obstruction.
Solution Approach 2:
The patent modifies the Fc polypeptide structure by introducing specific amino acid changes to create a TfR-binding site. This parameter change in the molecular structure enables the therapeutic agent to interact with TfR and utilize the TfR-mediated transcytosis pathway, allowing it to cross the BBB and treat brain metastases while maintaining its anti-HER2 activity.
2Reliability
If therapeutic agents are designed to cross the blood-brain barrier, then brain metastases can be targeted, but the complexity of the therapeutic agent increases
Solution Approach 1:
The patent creates a composite therapeutic agent by fusing the antibody variable region (which provides anti-HER2 specificity) with a modified Fc polypeptide (which provides TfR-binding capability). This composite structure integrates multiple functions into a single molecule, enabling BBB crossing and HER2 targeting simultaneously, thereby achieving brain metastasis treatment efficacy without requiring separate delivery systems.
Solution Approach 2:
The modified Fc polypeptide serves multiple functions: it maintains the ability to engage Fc receptors for immune effector functions, binds to TfR for BBB crossing, and provides structural stability. This multi-functionality reduces the need for additional separate components, managing the complexity while achieving the desired therapeutic effect in brain metastases.
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 fusion protein effectively crosses the blood-brain barrier and targets HER2, providing a therapeutic solution for HER2-positive brain metastases by enhancing drug delivery and efficacy.
Implementation Method 1
allowing for transcytosis across the blood-brain barrier and targeting of HER2 in the brain
Implementation Method 2
an antibody variable region that is capable of binding human epidermal growth factor receptor 2 (HER2)
Data Source
AI summary
The present disclosure relates to anti-HER2 constructs, such as Fc polypeptide dimer-antibody variable region fusion proteins, that cross the BBB and bind to HER2 in the brain parenchyma. In some embodiments, the anti-HER2 constructs (e.g., Fc polypeptide dimer-antibody variable region fusion proteins) retain effector function upon binding to HER2, but do not substantially deplete reticulocytes in vivo. The present disclosure also relates to methods for transcytosing an anti-HER2 antibody variable region across the BBB and treating HER2-positive cancers and metastatic lesions thereof.