Study Methods: The trial consists of two phases, both including a placebo control.
Phase Ia (single-dose, dose-escalation): Three dose groups (low, medium, high) are set. This is a multicenter, randomized, double-blind, placebo-controlled, single-dose, dose-escalation trial. Dose escalation to the next level is permitted only after safety assessment at 28 days post-dose in the previous group.
Phase Ib (multiple-dose): Based on Phase Ia results, two dose groups will be selected. The product is administered on Day 0, Day 7, and Day 14 (3 doses total). The trial remains randomized, double-blind, and placebo-controlled.