Miller JE, Ross JS, Moch KI, Caplan AL. Characterizing expanded access and compassionate use programs for experimental drugs. (2017). BMC Res Notes. DOI: 10.1186/s13104-017-2687-5.
Most (76%) provided drugs in expanded access programs eventually received FDA approval. Thus, provided drugs in registered expanded access programs are, more times than not, eventually deemed safe by the FDA.