Difficult to implement, difficult to identify patients. Phages are specific to particular bacteria, more specific than an antibiotic. This means you need to de

Difficult to implement, difficult to identify patients. Phages are specific to particular bacteria, more specific than an antibiotic. This means you need to develop many more varieties of phage to cover the same ground. These phages are perishable, and alive. That means you have to put much more effort into developing, and maintaining stocks. Lastly, you need to have specific diagnoses of patients. You need to know which phage to give, based on the bacteria infecting the patient. This means more patient tests, and more time between arrival and treatment. This all adds up the costs. Phage therapy is better suited to targeted diseases like MRSA than a replacement of chemotherapy.