Bingo. On Feb 18, China released the 6th edition of its treatment guidelines that included a Chloroquine recommendation. They've subsequently updated that guidance to reduce the dose
Everyone who was paying attention saw this. The U.S. gov should have started ramping up production at that time, but four days later Trump tweeted "The Coronavirus is very much under control in the USA... Stock market starting to look very good to me!"
On Feb 19, Chinese authorities published this paper: https://www.ncbi.nlm.nih.gov/pubmed/32074550 which provides basically no details except that Chloroquine works.
Everyone who was paying attention saw this. The U.S. gov should have started ramping up production at that time, but four days later Trump tweeted "The Coronavirus is very much under control in the USA... Stock market starting to look very good to me!"