A drug called "Placonaril" by Viropharma.
Pleconaril (Picovir) failed FDA trials, but not necessarily for the reasons you might think at first glance. The problem is that the FDA considers common colds to be a trivial health issue for the general public, with very low mortality. Easily treatable with supportive care. However, the segment of the population that might take this drug is very, very large (most of the population). As a result, the FDA will demand perfection from any clinical trials, with the bar set at an impossible to meet standard. Back when this drug was in development, I knew this is exactly what would happen -- the moment Viropharma decided to go after the Common Cold patient population, I knew it was doomed.
The only way something like this could ever pass, is if they defined the drug's indications to be a more dangerous member of the Picornavirus, affecting a much smaller population. Like Enterovirus D68 post-exposure prophylaxis in a child, Poliovirus post-exposure prophylaxis in a non-immune patient, or something like Fulminant Hepatitis A or post-exposure prophyaxis in a non-immunized patient. They didn't understand the politics of drug approval, and so they got squashed. And so it is too late now.