Chuck. I haven't read these but I did see some older work on SARS that stated the timing of administration made a large difference. It only appeared to have a benefit when given very early on. Are these new studies stratified for the timing of when the drug is given in terms of early or late?
Edit: After a quick scan of this one it doesn't appear they looked at the timing of drug administration. This can have a large effect on outcomes. It might not be time to dismiss it yet as it may still be beneficial for some people.