The Factory Is Alive

Merck sold $31.7 billion of Keytruda and its Qlex formulation in 2025. The cancer medicine's main ingredient is an antibody, a protein made by engineered Chinese hamster ovary cells. Scientists give the cells the genetic instructions to make it, then grow them in a nutrient broth. The cells assemble the antibody and release it into the surrounding liquid.

Putting living cells to work like this, making something useful at industrial scale, is called biomanufacturing. The same broad approach supplies ingredients for food and laundry detergent, as well as fuel and medicines. What comes out of the cells can be worth very different amounts, and separating it from everything else they produce can be a business in its own right.

Yeast makes ethanol for gasoline. One kind of mold makes most of the world's citric acid, the ingredient that gives many soft drinks their tartness. Bacteria make enzymes used in laundry detergent, and since 1982 they have also made human insulin to treat diabetes. Different organisms suit different products, but the manufacturer starts with the same practical question: can a living system make enough of the desired substance, reliably, at an acceptable cost?

These products are made in tanks of very different sizes, and price is a big reason why. Fuel ethanol sells for less than a dollar a kilogram, so it has to be made in enormous volumes: one Iowa plant ferments it in tanks of about 3 million liters each. Keytruda's price works out to tens of millions of dollars a kilogram, so its makers can use much smaller tanks and still pay for careful production and purification. At the far end of the range, a cell therapy made for one patient is supplied in an infusion bag.

Antibody production became much more productive as scientists improved the cells and the conditions in which they grew. A 2009 review described yields rising from well below one gram per liter to one to five grams. A large tank could produce tens of kilograms of antibody in a run. However, the improvements created a problem downstream, in the equipment that purified the liquid leaving the tank.

The liquid contains much more than the intended medicine. The cells make other proteins as they grow, and some of those end up in the harvest. In one study of antibody purification, researchers identified 1,066 kinds of hamster-cell protein in the starting material for one process. Those proteins had to be removed while preserving the antibody.

One early separation step uses protein A, a substance that binds to antibodies. The protein A is fixed to material packed inside a column, and as the liquid flows through, the antibody sticks to it while much of the unwanted material washes away. The manufacturer then releases the captured antibody and passes it through further purification steps. Each separation removes impurities the preceding one left behind.

Purification has to do more than remove cell proteins. Manufacturers must also demonstrate that the process can remove or inactivate viruses. Each step loses some of the antibody along the way, and the 2009 review put overall purification recovery at 70 to 80 percent. Recovering more of it means more medicine to sell from the same tank run.

Repligen supplies equipment and materials for this work. Its filters can retain cells inside a bioreactor while liquid containing the product flows out. It makes protein A for antibody capture, sells columns packed with the customer's chosen separation material, and supplies membranes that concentrate the purified drug.

Filtration accounted for $402.8 million of Repligen's $738 million in product revenue in 2025. The company says most of its revenue comes from consumable or single-use products. Customers keep buying production materials after the initial equipment purchase, giving Repligen repeat business as those factories operate.

Replacing a proven component takes work. Drugmakers have to test replacements to show that product quality is preserved, and major purification changes can require FDA approval before the revised product can be distributed. That gives an established supplier an advantage over a cheaper alternative, although customers can still qualify other products.

New factories are adding room for this kind of production. In Holly Springs, near Raleigh, Amgen opened a plant and broke ground on another on the same day in January 2025. Fujifilm followed that September with a site containing eight 20,000-liter bioreactors. Each is the size of the tank at the beginning of this story.

For products sold in bulk, biological production has to compete with other manufacturing methods at much lower selling prices. Riboflavin, or vitamin B2, provides a successful example. BASF began producing it by fermentation in 1990, alongside its existing chemical process. Biology proved cheaper, and the company closed the chemical plant in 1996.

Liberation Bioindustries shows the difficulty of getting a new facility into production. Its Richmond, Indiana plant is designed to make food ingredients using fermentation. The major construction elements are complete, but finishing the plant still requires money.

On September 29, investor Agronomics said the project would miss its end-of-2026 completion target. Liberation needs about $25 million more and expects to need six months after securing it to finish and begin production. A process that works biologically still has to support the cost of completing and operating a factory.

Luniter added Biomanufacturing as its twentieth theme on October 1. It brings together companies serving different parts of this production system, including Repligen, West Pharmaceutical Services, Maravai LifeSciences, Twist Bioscience and IFF. Thermo Fisher also participates through its broader laboratory and manufacturing business.

Anthony

The Luniter Observatory

Research and educational analysis only — not financial advice. Every investment carries risk.