Decreasing ornithine production to decrease high mannose glycoform content of recombinant proteins

What is this patent about?

’723 is related to the field of recombinant protein production and biopharmaceutical manufacturing, specifically focusing on the control of post-translational modifications. The background context involves the challenge of managing N-linked glycosylation, where the presence of high mannose glycoforms can significantly impact the therapeutic efficacy, pharmacokinetics, and clearance rates of glycoprotein drugs like monoclonal antibodies.

The underlying idea behind ’723 is that the accumulation of the amino acid ornithine within a host cell acts as a metabolic driver for the production of high mannose glycans. By recognizing that ornithine levels—which are influenced by the urea cycle and polyamine synthesis pathways—correlate directly with glycan branching completeness, the invention provides a mechanism to tune the quality of the protein by strategically accelerating or decelerating ornithine metabolism.

The claims of ’723 focus on methods for decreasing the high mannose glycoform content of a recombinant protein by manipulating the cell culture environment to reduce internal ornithine production. Specifically, the independent claims cover the addition of an arginase inhibitor to the culture medium or the titration of spermine concentrations to suppress the metabolic pathways that lead to ornithine accumulation.

In practice, the invention works by intervening in the enzymatic conversion of arginine to ornithine or by utilizing the feedback loops of the polyamine pathway. For instance, adding inhibitors like BEC or DFMO blocks the arginase enzyme, thereby lowering the pool of ornithine available to the cell. Alternatively, reducing spermine levels relieves the suppression of ornithine decarboxylase, allowing the cell to process ornithine into downstream polyamines rather than letting it accumulate and interfere with Golgi glycosylation processes.

This approach differs from prior methods that primarily focused on genetic factors or general physical parameters like temperature and pH. By identifying a specific metabolic marker—extracellular ornithine—and providing chemical means to regulate it, the invention allows for precise control over glycan profiles in various bioreactor scales. This metabolic tuning ensures that therapeutic proteins meet strict quality attributes without requiring complex genetic engineering of the host cell lines.