If you can find an existing drug, sure. If you are developing a drug, you won't be able to beat the vaccine to the market, anyway. There just isn't any sort of market for a drug that chloroquine would be a replacement for.
they are hoping to have some therapeutic drugs approved and available in a couple of months. the time frame i keep hearing for vaccines is 18 months.
beyond that, it is unknown if vaccines will offer temporary immunity or longer, and while it seems the virus is fairly stable, it is also still possible it mutates frequently enough that vaccines won't offer immunity for all strains. that is to say, it is unlikely to instantly disappear when a vaccine is developed, and it may not disappear at all.
we drove smallpox to extinction with vaccines and have almost done the same with polio, but those are the only two, afaik.