A Study of TX000045 in Patients With Pulmonary Hypertension Secondary to Heart Failure With Preserved Ejection Fraction (the APEX Study)

Eligibility Criteria

• 1. Is a male or female of non-childbearing potential between the ages of 18 and 80 years.
• 2. Has a diagnosis of PH-HFpEF based on baseline echocardiogram and right heart catheterization (RHC).
• 3. Has NYHA functional class II- III heart failure.
• 4. Has 6MWT distance from 100 to 450m.
• 5. Chronic medication for heart failure or cardiovascular disease is at a stable dose prior to screening.
• 6. Is able to understand and provide documented consent for participation.
• 1. Diagnosis of PH in World Health Organization (WHO) Group 1, WHO Group 3, WHO Group 4, or WHO Group 5.
• 2. Current or recent hospitalization prior to screening.
• 3. Recently received vasoactive drugs, pulmonary arterial hypertension-specific therapies, or relaxin receptor agonist.
• 4. Initiated a new exercise program for cardiopulmonary rehabilitation or plans to initiate such a program during the study.
• 5. Has a body mass index \<18 kg/meter square or \>45 kg/ meter square.
• 6. Was previously administered TX000045, relaxin, or a relaxin fusion protein.
• 7. Historical or current evidence of a clinically significant disease or disorder such as significant lung disease, cardiovascular comorbitiies, liver disease, infectious disease, or malignancy.
• 8. Has any of the following clinical laboratory values during screening:
• 1. Serum alanine aminotransferase or aspartate aminotransferase levels \> 3 x the upper limit of normal (ULN) or total bilirubin \> 3 x ULN;
• 2. eGFR \<30 mL/min/1.73 metersquare;
• 3. HbA1c (glycosylated hemoglobin) \>9%;
• 4. Platelet count \<50,000/millimeter cube;
• 5. Hemoglobin \<10.0g/dL;
• 9. History of hypersensitivity or reactions to drugs with a similar chemical structure or class to TX000045.
• 10. Is pregnant or breastfeeding.
• 11. Has a history of cancer other than basal cell carcinoma, cervical carcinoma, or squamous cell carcinomas of the skin.
• 12. Has a history of drug or alcohol abuse.
• 13. Was recently dosed in any clinical research study.