RE: Starting to see Limited stock available7 Jan 2021 14:47
Some good background reading
The most effective medicines in the world are of limited value if they can’t be produced in bulk, and at a reasonable cost. Therapeutic antibodies take years to develop. Without good oversight, each stage of development risks operating in a vacuum, with teams concentrating solely on their task before passing the candidate antibody onto the next team. An antibody developed with this “pass the parcel” approach may tick all the boxes for moving into clinical trials; it may even ace clinical trials. But if production cannot be scaled up for bulk manufacturing at a reasonable cost, the antibody is simply not commercially viable. Early engagement with manufacturing and commercialization experts and a helicopter view of the whole project from start to finish keeps the focus on developing an antibody that’s fit for purpose.
Scaling up determines cost of goods
Developers should look further than affinity alone when selecting a lead antibody. It would be a cruel twist of irony to develop a safe and effective antibody that cannot be manufactured in sufficient supply to treat all patients. Therapeutic antibodies are administered in high quantities to achieve the therapeutic effect – this can be in the range of milligrams to grams per patient per treatment cycle. For example, patients treated with the therapeutic antibody adalimumab (Humira™) take 80 mg on day one and then 40 mg every other week. The manufacturing process must keep up with the demand created by such dosing requirements.
Production is a key factor determining the ultimate cost of goods. Antibodies are churned out by genetically modified mammalian cells, grown in suspension in bioreactors. The antibody sequence is a critical “part” for the recombinant cell line “machinery”. As any mechanic will tell you, simple robust parts allow the machinery to run smoothly. In this case, well designed antibody sequence “parts” are easier for the cellular “machinery” to churn out in quantity.
Ideally, affinity maturation and sequence optimisation should optimise the antibody for ease of expression by mammalian cells. The yield, or titre, of antibody produced by these cells determines the ease of manufacturing and therefore the cost of goods. A yield of 2 g of antibody per litre of cell suspension is the threshold for a commercially viable antibody (1). Titre up to 4-5 g/L and higher have been reported by some companies.
The titre determines how many cells are needed to harvest enough antibody – this in turn determines the size and number of bioreactors needed and the size of the factory needed to house them. Bioreactors typically range from containing 1,000 litres of cell culture up to 20,000 litres. The cost and time required to purify the antibody out of the cell suspension is another factor in scaling up production, and the ultimate cost of goods.
Production for clinical trials versus the market
Drug development is a race against the clock. Time and in