RecruitingPhase 2Drug trialA Study of TX000045 in Patients With Pulmonary Hypertension Secondary to Heart Failure With Preserved Ejection Fraction (the APEX Study)TX000045-003 is a double-blind, randomized, parallel group, placebo-controlled, proof- of-concept (POC) study, evaluating 2 dose regimens of TX000045 over the course of a 24-week treatment period (the APEX study).