Exhibit 99.1 Krystal Biotech Announces Fourth Quarter and Full Year 2023 Financial Results and Provides Business Updates • Net product revenue of $42.1M in 4Q and $50.7M for the year • New England Journal of Medicine publication of the use of B-VEC eyedrop formulation • Reached alignment with FDA to enable approval of B-VEC eyedrop formulation for the treatment of lesions in the eye of DEB patients • First patient dosed in Phase 1 KB408 trial for the treatment of AATD; five active clinical trials in 2024 • ...