If NNVC and its crew called efficacy studies "IND-enabling studies" then NNVC and its crew are lying. No other company in the history of the world calls it that except the biowreck scam NNVC. Efficacy study data are not required as part of an IND application.
But hey, maybe we can pop open a Swiss company that did some efficacy studies, still didn't call them "IND-enabling studies," and then run with it.