Sienna Biopharmaceuticals Announces Its Topical, Non-Steroidal TrkA Inhibitor SNA-120 (0.05%) Demonstrated Significant Impact on Psoriasis in Phase 2b Study and Plans to Initiate Phase 3 Psoriasis Trials in Second Half of 2019 -- 27% of subjects achieved 75% reduction in PASI score (PASI 75) vs 13% with vehicle; 29% of subjects achieved two-grade improvement on IGA and ‘clear’ or ‘almost clear’ skin vs 13% with vehicle...