Vinay Prasad is a cancer expert and an outspoken critic of too fast approvals of drugs. He has done research on it, I could e.g. find this:
https://jamanetwork.com/journals/jamainternalmedicine/fullar...
The results for conventional fixed-sample randomized clinical-trial designs suggest that for terminal illnesses with no existing therapies such as pancreatic cancer, the standard threshold of 2.5% is substantially more conservative than the BDA-optimal threshold of 27.9%. However, for relatively less deadly conditions such as prostate cancer, 2.5% is more risk-tolerant or aggressive than the BDA-optimal threshold of 1.2%. We compute BDA-optimal sizes for 25 of the most lethal diseases and show how a BDA-informed approval process can incorporate all stakeholders’ views in a systematic, transparent, internally consistent, and repeatable manner.
Interestingly, the paper linked shows that in some respects, fast tracked drugs have a better track reccord. This shouldnt be surprising as the best drugs are fast tracked.
>18 drugs failed to improve overall survival (in 6 of 15 accelerated approvals and in 12 of 21 traditional approvals)