The cost of drugs like these is nontrivial, but much of that is dedicated to ensuring that what gets produced and delivered is actually what you wanted it to be

The cost of drugs like these is nontrivial, but much of that is dedicated to ensuring that what gets produced and delivered is actually what you wanted it to be. That is, you can make low quality mabs in a garage if you really knew what you were doing, but producing enough to sell without having patients dying of bacterial infections can't be done in a garage. Quality control combined with experienced production folks is critical.