Chimeric Polypeptide HSA Fusion for Serum Half-Life Extension
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Solution Overview
Problem
Proteins and therapeutic agents often have short serum half-lives, leading to rapid clearance from the body, which can limit their therapeutic effectiveness, necessitate frequent dosing, and increase the risk of side effects due to higher doses required for prolonged activity.
Innovation Solution
Development of chimeric polypeptides comprising a human serum albumin (HSA) portion with a neonatal FcRn binding fragment, which includes amino acid substitutions to enhance affinity for the FcRn receptor, thereby increasing serum half-life and binding affinity, particularly at acidic pH without altering neutral pH affinity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If proteins are used as therapeutic agents, then therapeutic activity is achieved, but serum half-life is short leading to rapid clearance
Solution Approach 1:
The patent merges the therapeutic protein of interest with human serum albumin (HSA) to create a chimeric polypeptide. This combination allows the therapeutic protein to utilize HSA's long serum half-life and FcRn recycling mechanism, thereby extending its own circulation time in the body without losing its therapeutic activity.
Solution Approach 2:
The patent uses HSA as an intermediary carrier that facilitates the extension of therapeutic protein half-life. HSA acts as a mediator by binding to the therapeutic protein and utilizing its own FcRn binding capacity to protect the therapeutic protein from rapid clearance, effectively transferring the longevity benefit to the therapeutic agent.
2Reliability
If frequent dosing is used to maintain therapeutic levels, then therapeutic effectiveness is maintained, but side effects increase due to higher cumulative doses
Solution Approach 1:
The patent dynamically adjusts the dosing frequency by extending the half-life of the therapeutic protein through HSA conjugation. This allows for less frequent dosing while maintaining therapeutic effectiveness, thereby reducing cumulative dose-related side effects without compromising treatment reliability.
3Reliability
If amino acid substitutions are made in HSA domain III, then FcRn binding affinity increases, but protein structure complexity increases
Solution Approach 1:
The patent applies local quality by making targeted amino acid substitutions specifically in HSA domain III, the region responsible for FcRn binding. This localized modification approach enhances FcRn binding affinity while minimizing disruptions to the overall protein structure and function, as only a specific region is altered rather than the entire protein.
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 chimeric polypeptides exhibit increased serum persistence and FcRn binding, reducing the need for frequent dosing and minimizing side effects by maintaining therapeutic levels and activity over a longer period.
Implementation Method 1
The neonatal Fc receptor (FcRn) prolongs the lifespan of both IgG and human serum albumin (HSA), by a pH dependent mechanism, specifically binding both molecules at the acidic pH of the endosome
Data Source
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AI summary
Provided are human serum albumin (HSA) compositions with improved properties over native HSA.