It's a complicated drug (really three drugs in one with some careful work put into their interaction) for a rare condition with little in the way of treatment o

It's a complicated drug (really three drugs in one with some careful work put into their interaction) for a rare condition with little in the way of treatment options. The R&D costs are horrendous with no guarantee that the result will work or that it won't be promptly obsoleted by some other drug from a competitor (as happened with Vertex's hepatitis C treatment).