In my experience most legitimate biotech companies working on promising drugs and therapies don’t want to touch the exemption with a 30 foot pole. Since they raise most of their money from the public to fund clinical trials, a single bad reaction could generate enough bad PR to derail fundraising and kill the drug. Sticking to clinical trials allows them to control that blast radius so even though the FDA approves >95% of applications, in practice very few drugs are available that way.

The biggest exception is oncology. Since everyone knows that chemotherapy is hell, cancer drugs tend to get a pass and pre-approval companies are (slightly) more willing to work with compassionate use exemptions.