Clinical Study of Inhaled GB002 for Treatment of WHO Group I Pulmonary Arterial Hypertension

The primary objective for this trial is to evaluate the safety and tolerability of GB002. The secondary objective for this trial is to evaluate the PK parameters of GB002. Exploratory objectives are to evaluate the PD readouts, change in WHO Group I functional class, and change in quality of life associated with GB002 treatment. In this Phase 1B study, two dose levels of GB002 will be tested in adult participants with PAH. Four participants in cohort 1 will be randomized to receive up to two daily doses of either active drug or placebo, with 3 subjects receiving GB002 and 1 subject receiving placebo. An additional 4 participants (3 active and 1 placebo) may be added to cohort 1 at the discretion of the Data Review Committee (DRC). The dose and dosing interval (i.e., once daily or twice daily) for the second cohort will be determined by review of the safety, tolerability, and drug levels in the blood from cohort 1. Cohort 2 participants will also be randomized such that 6 subjects receive GB002 and 2 subjects receive placebo. Eligible subjects who have completed the 2 week treatment period have the option to participate in a 24 week open label extension.