Clinical trials take a long time, but results may trickle in and further research may either confirm or disconfirm efficacy sooner. How long until we are relatively certain whether the drug works?

Resolves to the year in which the linked market stays continuously above 95% or below 5% for a full week, based on the beginning of the week if it matters. If the market resolves to YES or NO, that also counts. If it resolves to anything else (N/A, PROB) before having met that percentage criteria, this market resolves N/A.