Method of Purifying Albumin-Fusion Proteins A Two-Step Clean-Up That Keeps a Long-Lasting Drug Protein Intact

This patent describes a method for purifying albumin-fusion proteins, a type of engineered drug molecule, in a way that minimises chemical damage to sensitive parts of the protein. It uses a two-step chromatography process to deliver a clean, stable and active product.

The Problem

Many modern biological medicines are made by fusing a therapeutic protein to serum albumin, the most abundant protein in blood, because albumin helps the drug stay in the body longer. Producing these biopharmaceuticals means growing them in cells and then purifying them away from everything else. During purification, certain amino acid residues in the protein are vulnerable to oxidation, a chemical change that can reduce the drug’s stability, activity or the extended half-life that made the albumin fusion worthwhile in the first place. Cleaning up the protein without letting it oxidise is therefore a delicate balance.

What This Invention Does

The patent provides a purification method that combines an affinity matrix chromatography step with an anion exchange chromatography step. Affinity chromatography captures the target protein specifically, while anion exchange chromatography separates molecules by electrical charge to remove remaining impurities. Run together as described, the two steps yield purified albumin-fusion proteins with low levels of oxidation, so the molecules keep their enhanced half-life in the body and their biological activity. In some versions the albumin-fusion protein includes a scaffold such as a human tenascin C scaffold. The patent also covers compositions containing the purified protein.

Key Features

• Two-step chromatography. The method pairs affinity matrix chromatography with anion exchange chromatography.
• Low oxidation. The process keeps susceptible amino acid residues from oxidising.
• Preserved half-life. Purified protein retains the extended in-body half-life that albumin fusion provides.
• Retained activity. The biological activity of the drug protein is preserved through purification.
• Scaffold compatible. The approach works with fusion proteins that include scaffolds such as human tenascin C.

Who Is Behind It

The applicant is MedImmune, LLC, the biologics arm associated with AstraZeneca. The named inventors are Timothy Pabst, Mariko Fonseca, Christopher Thompson, Alan Hunter, Xiangyang Wang, Liu Tie and Yiming Li. The application is a divisional of an earlier filing.

Why It Matters

Albumin fusion is a widely used strategy for making protein drugs last longer between doses, and the value of that strategy depends on purifying the product without degrading it. A method that reliably keeps oxidation low protects both the stability and the performance of these medicines, which matters for manufacturing quality and shelf life. Securing the method in Australia supports the company’s biologics manufacturing and supply interests in the region.

Related Concepts

• Fusion protein – the engineered drug format being purified.
• Serum albumin – the blood protein fused to extend a drug’s half-life.
• Protein purification – the overall process this method improves.
• Affinity chromatography – the specific-capture step in the method.
• Biopharmaceutical – the class of medicines this work supports.

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AU 2026201911 was published in the Australian Official Journal of Patents on 2 April 2026 and is open for public inspection. Patent applications represent inventions that are sought to be protected and do not necessarily reflect commercially available products.