The following are links to more information about the drug approval process, expanded access, compassionate use, right-to-try, etc.
FDA Drug Approval Process: https://www.fda.gov/Drugs/DevelopmentApprovalProcess/
FDA Expanded Access (aka, Compassionate Use): https://www.fda.gov/NewsEvents/PublicHealthFocus/ExpandedAccessCompassionateUse/default.htm
Right to Try: