The mantra for a while has been that it's not good enough to get your drug approved, you've got to get it payed for, too. For gene therapy treatments, the payment is more complex, and you can add manufacturing and supply chain logistics to the list of challenges.

The Cushing's syndrome market is heating up with three second-generation drugs in late-stage development to join the two approved medications, Signifor (pasireotide, Recordati SpA) and Korlym (mifepristone, Corcept Therapeutics Inc.), as well as a couple of off-label options.