[vikramkr]

Off label use is allowed. Marketing for off label use is absolutely not allowed. Claims of off label efficacy are not remotely allowed. And the FDA has post approval powers to revoke approval for drugs not found effective. Doctor's autonomy leads to off label being allowed, and some of the legal arguments for it involve freedom of speech, not medical optimality.

Phase 3s already are no longer required, it looks like the article you linked was written in 2003? That was literally almost 17 years ago when we'd just barely sequenced the first human genome. There are entire fields of medicine - precision medicine - that literally address the whole subgroup question. Companion diagnostics are routine, rare disease approvals are up, plenty of Huntington trials in progress - that article might as well be about an alien civilization with how different things are today. Value based pricing, redefining cancer into separate genetically defined baubgroups and developing drugs for each, Gene therapy, ... It's no longer easier to get approval of a drug that's marginally successful in a large population, smaller populations with large effects make it way easier to see responses. And the 21st century cures act in 2016 evolved the regulatory landscape even more - it's like comparing Sputnik with the ISS. Yeah, they're both sattelites, but the field has come a long way in the time between the two.