It's incredibly good to see Medicare covers these drugs, considering how expensive they are. Meanwhile, my diabetic friend can't get their insulin covered by Medicaid...

It's expensive because it's categorized as an "orphan drug". I have to wonder if the underestimation of the prevalence of CA was part of that.

Presumably your friend wants a particular brand of insulin, not the insulins that Medicaid covers because they are the most cost effective?

Medicaid negotiates with manufacturers to get the best price. When they are successful in securing a low price, they preferentially cover them.

Usually if the doctor can show why those brands aren’t good enough, Medicaid will cover alternatives that aren’t covered, but it can be a lot of work for the doctor.