The placebo is administered the same way as the drug product via an inhaler device. clinical trials

A Phase 3, Randomized, Double-Blind, Placebo-Controlled Study to Evaluate the Efficacy and Safety of Oral Inhalation of Seralutinib for the Treatment of Pulmonary Arterial Hypertension (PAH)

This study is testing a new inhaled medicine, saralutinib, for people with pulmonary arterial hypertension (PAH). Researchers want to see if it helps patients walk further in six minutes and improves their health compared to a dummy inhaler.