Ann: ISLA-101 Phase 2a clinical trial update, page-21

The below is 100% assumptions.

The compound was previously trialled as a cancer drug (by J&J). I wildly assume Island inherited the original IND when they purchased the rights to ISLA-101. Maybe they used the "old" IND for this small phase 1? But, unlike phase 1, phase 2 would require a different IND due to different therapeutic area.

And, to try to answer @hotcongo's questions (sorry I missed your original post), maybe the small sample size in the phase 1 trial was sufficient because drug safety was already proven in previous cancer phase 1 trials. Perhaps the FDA would have required a very small size to prove safety in the context of dengue patients.

Final note, one of the secondary endpoints of the PEACH study is to "Assess the safety of ISLA 101 in the challenge with DENV-1-LVHC" (see the PEACH slide 28 in investor presentation). Technically, this would make the PEACH trial phase 1/2 (not just phase 2) and will provide additional safety data with many more patients (4 cohorts/arms).