PRAN is a good example of why companies run such non-informative ph ii's—because they can't easily fail and can be spun positive easily.
From a design standpoint, PRAN’s HD trial was rather like a typical phase-1b/2a PoC study—not a trial intended to inform an educated go/no-go decision for advancing to phase-3.
Among the various arguments promulgated by PRAN longs, the one I find most lacking in merit is that the HD program has conclusively been shown to be phase-3-ready.