How expensive can it be to enroll JUST ONE PATIENT for a Phase III study? As reported by Moe Alsumidaie at Applied Clinical Trials, the cost to enroll a single patient can be as high as $26,000 for a Phase III study. So… Patient recruitment is slow and expensive. That’s now a given. It’s also a given that for each day a new drug or device is not commercialized, millions of dollars are left on the table.