Site-Specific Antibody Conjugates for Controlled Drug Loading
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Solution Overview
Problem
Conjugation of drugs to antibodies results in heterogeneous mixtures with varying drug attachment, making it difficult to control the administered dose accurately.
Innovation Solution
Incorporating a sulfatase motif-containing tag in the immunoglobulin heavy chain polypeptide, which is modified by a formylglycine-generating enzyme to form a formylglycine residue, allowing for site-specific and covalent binding of a payload, such as a drug, to achieve a controlled molar ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional drug conjugation methods are used, then drugs can be attached to antibodies, but the conjugation is difficult to control resulting in heterogeneous mixtures with varying drug attachment
Solution Approach 1:
The antibody heavy chain is segmented to include a specific tag sequence (e.g., LCTPSR, LSTPSR, or variants) at a defined location in the constant region. This segmentation provides a dedicated site for controlled payload attachment, separating the conjugation function from the rest of the antibody structure and enabling precise control over drug attachment stoichiometry and homogeneity.
2Manufacturing precision
If site-specific conjugation is achieved through tag incorporation, then manufacturing precision improves, but device complexity increases due to additional enzymatic modification steps
Solution Approach 1:
A formylglycine-generating enzyme (FGE) is introduced as an intermediary component that specifically modifies the tag sequence containing a sulfatase motif. This enzyme mediates the conversion of the tag to a formylglycine residue, which then serves as the specific attachment point for payloads. The intermediary enzyme enables site-specific conjugation without requiring complex direct coupling chemistry.
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
Enables precise control over the drug-antibody conjugation, ensuring consistent and controlled dosing of therapeutic agents.
Implementation Method 1
The sulfatase motif of the tag can be converted by a formylglycine-generating enzyme (FGE) to produce a formylglycine (fGly)-modified Ig heavy chain polypeptide
Implementation Method 2
An fGly-modified Ig heavy chain polypeptide of the antibody can be covalently and site-specifically bound to a moiety of interest (i.e., a payload, e.g., drug) to provide an antibody conjugate
Data Source
AI summary
Antibodies that include a sulfatase motif-containing tag in a constant region of an immunoglobulin (Ig) heavy chain polypeptide are disclosed. The sulfatase motif can be converted by a formylglycine-generating enzyme (FGE) to produce a formylglycine (fGly)-modified Ig heavy chain polypeptide. An fGly-modified Ig heavy chain polypeptide of the antibody can be covalently and site-specifically bound to a moiety of interest to provide an antibody conjugate. The disclosure also encompasses methods of production of such tagged Ig heavy chain polypeptides, fGly-modified Ig heavy chain polypeptides, and antibody conjugates, as well as methods of use of same.