Overview To Evaluate the Efficacy and Safety of SR419 in Patients With Postherpetic Neuralgia (PHN) Status: Not yet recruiting Trial end date: 2023-07-31 Target enrollment: Participant gender: Summary This is a Phase II, international multicenter, double-blind, placebo-controlled, crossover study to assess the efficacy of SR419 in PHN subjects. Phase: Phase 2 Details Lead Sponsor: Shanghai SIMR Biotechnology Co., Ltd.