[fnord77]

They had very good, robust Phase II results.

Thinks can go wrong in Phase III.

Relyvrio (HIV vaccine) did well in P2 but flopped on P3.

Cancer drug xevinapant failed in P3 after Merck executives were reassuring analysts that the failure of a phase 3 trial of xevinapant was “unlikely.”

[sargun]

Relyvrio was ALS drug.

I don't think any HIV vaccines have gotten to phase III yet.

[Vecr]

I don't know if the trials were technically phase 3, but the 2008 Canarypox attempt was pretty big and failed.