We should think about this from the customer’s, i.e., the patient’s, perspective. They notice that the “nail is ugly.” The doctor sees the same thing. They consider whether the nail is damaged or if there is fungus. A culture is taken. The result is positive, and treatment begins. It lasts 336 days, and after treatment, two out of a hundred patients see that the nail looks healthy. With the competing ciclopirox treatment, it’s 1.3 out of a hundred. Is the difference significant? It doesn’t seem to be. Or as a result after that nearly year-long treatment, where “no more than 10% of the nail is ugly,” the percentages 19.3/16 also don’t seem to differ significantly.
The fact that Terclara, or topical terbinafine, can suppress the fungus enough to achieve a “mycological cure”—meaning nothing grows in the fungal culture—likely won’t mean much to the patient if the nail still doesn’t look healthy. The same story can be applied to treatment done without a doctor, where the patient buys the same drug over-the-counter with the same results. I wouldn’t use that percentage as a measure of the treatment’s effectiveness.