If A New Drug Doesn’t Show Efficacy In Phase 1 Trials What Are The Odds That It Will Be More Effective Later

Yep, nitram is right. Phase 1 trials are not meant to show efficacy, but safety. In non-cancer drugs, phase 1 trials are done in normal healthy volunteers. These guys do not even have the disease, so you’re not likely to be able to show any efficacy here (well, you can to an extent, but that’s not the point of phase 1 studies). Preliminary efficacy (or a better term is pharmacology, or pharmacodynamic response) will be assessed in phase 2, along with further safety analyses. If phase 2 trials prove promising, then the drug will be taken into phase 3 and hopefully on to marketing approval.