Feed media

What is this patent about?

’168 is related to the field of cell culture media and methods for large-scale protein production. In the biopharmaceutical industry, mammalian cells like Chinese Hamster Ovary (CHO) cells are grown in fed-batch cultures to produce therapeutic proteins. To maximize productivity, these cultures are supplemented with concentrated feed media containing essential nutrients. However, at high concentrations and near-neutral pH, critical but poorly soluble amino acids often precipitate out of solution, creating significant manufacturing uncertainties and regulatory hurdles.

The underlying idea behind ’168 is that high concentrations of pyruvate can act as a stabilizing agent to prevent the precipitation of amino acids in concentrated feed media. The inventors discovered that while cysteine and tyrosine are essential for increasing protein titers, they are notoriously difficult to keep in solution at the concentrations required for effective feeding. By incorporating specific ranges of pyruvate, the invention maintains these nutrients in a soluble state for extended periods, even under refrigerated storage conditions.

The claims of ’168 focus on a concentrated feed medium and methods for its stabilization and use, characterized by a specific chemical profile. The independent claims require a pyruvate concentration between 10 mM and 100 mM (or more narrowly 25-45 mM) in combination with cysteine (7-40 mM) and tyrosine (1-4.6 mM). The claims further define a comprehensive suite of essential amino acids at specific concentration ranges, a pH between 5.8 and 7.4, and a restriction on added cystine to no more than 1.0 mM to ensure the medium remains stable for at least one week at 4-8° C.

In practice, this invention allows for the preparation of highly concentrated nutrient boluses that remain clear and homogeneous during storage. By controlling the ratio of pyruvate to the less soluble amino acids, the formulation avoids the formation of solids that would otherwise alter the intended nutrient profile. This stability is achieved without resorting to extreme pH levels that would be toxic to the cells, ensuring that the feed can be added directly to a bioreactor without disrupting the physiologic range of the culture.

This approach differs from prior methods that often relied on heating media to 45° C. or maintaining extreme pH levels to force solubility, both of which are impractical for large-scale commercial manufacturing. Unlike traditional formulations where cysteine readily oxidizes into the highly insoluble cystine, the ’168 invention utilizes pyruvate-mediated stabilization to keep the feed media robust. This ensures consistent protein titers and simplifies the logistics of supplying nutrients to high-density mammalian cell cultures.