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

July 2, 2026 updated by: Tectonic Therapeutic

A Phase 2, Double-blind, Randomized, Placebo-Controlled Study to Assess the Efficacy and Safety of TX000045 After 24 Weeks of Treatment in Patients With Pulmonary Hypertension Secondary to Heart Failure With Preserved Ejection Fraction (PH-HFpEF)

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).

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Active, not recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

This study will enroll approximately 191 participants and eligible patients will be randomized to one of 3 treatment arms:

  • Arm 1: Treatment Group 1: Placebo delivered subcutaneously (SC) every 2 weeks (Q2W) for 24 weeks
  • Arm 2: Treatment Group 2: TX000045 SC at Dose A Q2W for 24 weeks
  • Arm 3: Treatment Group 3: TX000045 SC at Dose B Q2W alternating with Placebo Q2W for 24 weeks

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
191

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • Armenia
      • Yerevan, Armenia, 0006
        • Yerevan
      • Yerevan, Armenia, 0025
        • Yerevan
      • Yerevan, Armenia, 0087
        • Yerevan
  • Australia
      • Camperdown, Australia, 2050
        • Camperdown
      • New Lambton, Australia, 2305
        • New Lambton
    • New South Wales
      • Camperdown, New South Wales, Australia, 2050
        • Camperdown
      • Macquarie, New South Wales, Australia, 2109
        • Macquarie
      • New Lambton, New South Wales, Australia, 2305
        • New Lambton
      • Sydney, New South Wales, Australia, 2010
        • Sydney
      • Wollongong, New South Wales, Australia, 2500
        • Wollongong
    • Queensland
      • Chermside, Queensland, Australia, 4032
        • Chermside
    • Tasmania
      • Hobart, Tasmania, Australia, 7000
        • Hobart
    • Victoria
      • Malvern, Victoria, Australia, 3145
        • Malvern
  • Austria
      • Vienna, Austria, 1100
        • Austria
  • Belgium
      • Brussels, Belgium, 1070
        • Brussel
  • Bulgaria
      • Pleven, Bulgaria, 5800
        • Pleven
      • Plovdiv, Bulgaria, 4001
        • Plovdiv
  • Georgia
      • Tbilisi, Georgia, 0159
        • Tbilisi
      • Tbilisi, Georgia, 0167
        • Tbilisi
      • Tbilisi, Georgia, 0191
        • Tbilisi
    • Tb
      • Tbilisi, Tb, Georgia, 0186
        • Tbilisi
  • Germany
      • Mainz, Germany, 55131
        • Mainz
  • Latvia
      • Riga, Latvia, LV10002
        • Riga
  • Moldova
      • Chisinau, Moldova
        • Chisinau
  • New Zealand
      • Christchurch, New Zealand, 8011
        • Christchurch
  • Poland
      • Bialystok, Poland, 15-276
        • Białystok
      • Krakow, Poland, 31-202
        • Krakow
      • Lodz, Poland, 91-347
        • Łodź
      • Lublin, Poland, 20-090
        • Lublin
      • Warsaw, Poland, 04-628
        • Warsaw
      • Wroclaw, Poland, 50-556
        • Wrocław
  • Portugal
      • Almada, Portugal, 2805-267
        • Almada
      • Lisbon, Portugal, 1649-028
        • Lisboa
      • Porto, Portugal, 4099-001
        • Porto
  • Romania
      • Bucharest, Romania, 022328
        • Bucuresti
      • Craiova, Romania, 200642
        • Craiova
      • Târgu Mureş, Romania, 540136
        • Targu Mures
  • Serbia
      • Belgrade, Serbia, 11040
        • Serbia
      • Kamenitz, Serbia, 21204
        • Sremska Kamenica
      • Kragujevac, Serbia, 34000
        • Kragujevac
    • Nis
      • Belgrade, Nis, Serbia, 18108
        • Nis, Belgrade
  • Spain
      • Barcelona, Spain, 08035
        • Barcelona
      • Madrid, Spain, 28034
        • Madrid
      • Madrid, Spain, 28041
        • Madrid
      • Santiago de Compostela, Spain, 15706
        • Santiago de Compostela ( Coruña )
      • Valencia, Spain, 46010
        • Valencia
  • Ukraine
      • Kyiv, Ukraine, 01135
        • Ukraine
  • United States
    • Arizona
      • Phoenix, Arizona, United States, 85283
        • Phoenix
      • Scottsdale, Arizona, United States, 85258
        • Scottsdale
    • California
      • San Francisco, California, United States, 94143
        • San Francisco
      • Santa Rosa, California, United States, 95405
        • Santa Rosa
    • Colorado
      • Aurora, Colorado, United States, 80045
        • Aurora
    • Florida
      • Jacksonville, Florida, United States, 32216
        • Jacksonville
    • Georgia
      • Augusta, Georgia, United States, 30912
        • Augusta
      • McDonough, Georgia, United States, 30253
        • McDonough
    • Idaho
      • Boise, Idaho, United States, 83706
        • Boise
    • Kentucky
      • Louisville, Kentucky, United States, 40202
        • USA
    • Maryland
      • Baltimore, Maryland, United States, 21201
        • Baltimore
    • Massachusetts
      • Boston, Massachusetts, United States, 02180
        • Boston
    • Minnesota
      • Minneapolis, Minnesota, United States, 55414
        • Minneapolis
    • Missouri
      • St Louis, Missouri, United States, 63110
        • St Louis
    • Nebraska
      • Omaha, Nebraska, United States, 68198
        • Omaha
    • New York
      • New York, New York, United States, 10029
        • New York
      • New York, New York, United States, 10075
        • New York
    • North Carolina
      • Durham, North Carolina, United States, 27710
        • Durham
    • Pennsylvania
      • Philadelphia, Pennsylvania, United States, 19107
        • Philadelphia
      • Pittsburgh, Pennsylvania, United States, 15213
        • Pittsburgh
      • York, Pennsylvania, United States, 17403
        • York
    • Texas
      • Port Arthur, Texas, United States, 77642
        • Port Arthur
      • Waco, Texas, United States, 76712
        • Waco
    • Utah
      • Salt Lake City, Utah, United States, 84112
        • Salt Lake City
    • Virginia
      • Norfolk, Virginia, United States, 23507
        • United States

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Is a male or female of non-childbearing potential between the ages of 18 and 83 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.

Exclusion Criteria:

  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 a 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 m2;
    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 within 5 years of screening 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.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: TX000045 Dose A
Participants will receive a single dose of TX000045 Dose A subcutaneously every 2 weeks for 24 weeks from Day 1 to Day 155.
Drug: TX000045- Dose A
The participants will receive a subcutaneous injection of Dose A of TX000045 every 2 weeks for 24 weeks.
Experimental: TX000045 Dose B
Participants will receive alternating single doses of TX000045 Dose B and placebo subcutaneously every 2 weeks for 24 weeks from Day 1 to Day 155.
Drug: TX000045- Dose B
The participants will receive subcutaneous injection of Dose B of TX000045 every 4 weeks for 24 weeks where they will alternate between TX000045 and placebo every 2 weeks.
Placebo Comparator: Placebo
Participants will receive a single placebo dose SC for 24 weeks from Day 1 to Day 155
Drug: Placebo
The participants will receive a subcutaneous injection of placebo every 2 weeks for 24 weeks.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Assess safety of TX000045 by the incidence of adverse events, adverse events of special interest and SAEs.
Time Frame: Baseline up to Week 30 post first dose
Baseline up to Week 30 post first dose
Number of participants with abnormal laboratory values and/or adverse events that are related to treatment.
Time Frame: Baseline up to Week 30 post first dose
Baseline up to Week 30 post first dose
Mean change from baseline in Pulmonary Vascular Resistance (PVR) in participants with a combined pre- and post-capillary pulmonary hypertension (CpcPH).
Time Frame: Baseline up to Week 24 post first dose
Measured by right heart catheterization (RHC) between those who received TX000045 and those with placebo.
Baseline up to Week 24 post first dose
Number of participants with treatment-related adverse events.
Time Frame: Baseline up to Week 30 post first dose
Baseline up to Week 30 post first dose
Number of participants with changes in the physical examination findings.
Time Frame: Baseline to Week 30 post first dose
Baseline to Week 30 post first dose

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Mean change from baseline in pulmonary capillary wedge pressure (PCWP).
Time Frame: Baseline to Week 24 post first dose
Measured by RHC between those who received TX000045 and those with placebo.
Baseline to Week 24 post first dose
Mean change from baseline in PVR for all participants.
Time Frame: Baseline to Week 24 post first dose
Measured by RHC between those who received TX000045 and those with placebo.
Baseline to Week 24 post first dose
Mean change from baseline in cardiac output (CO) for all participants and in participants with CpcPH.
Time Frame: Baseline to Week 24 post first dose
This is measured by RHC between those who received TX000045 and those with placebo.
Baseline to Week 24 post first dose
Mean change from baseline in exercise capacity in all participants and in participants with CpcPH.
Time Frame: Baseline to Week 30 post first dose
This is measured by mean change from baseline in 6-minute walk test (6MWT) distance between those who received TX000045 and those with placebo.
Baseline to Week 30 post first dose
Mean change from baseline in total pulmonary resistance (TPR) for all participants and in participants with CpcPH.
Time Frame: Baseline to Week 24 post first dose
This is measured by RHC between those who received TX000045 and those with placebo.
Baseline to Week 24 post first dose
Mean change from baseline in mean pulmonary arterial pressure (mPAP) for all participants and in participants with CpcPH.
Time Frame: Baseline to Week 24 post first dose
This is measured by RHC between those who received TX000045 and those with placebo.
Baseline to Week 24 post first dose
Mean change from baseline in N-terminal pro-brain natriuretic peptide (NT-proBNP) for all participants and in participants with CpcPH between those who received TX000045 and those with placebo.
Time Frame: Baseline to Week 30 post first dose
Baseline to Week 30 post first dose
Number of participants with change in antibody titers following treatment with TX000045 (Immunogenicity).
Time Frame: Day 1, Week 2, Week 4, Week 8, Week 16, Week 24 and Week 30 post first dose
Day 1, Week 2, Week 4, Week 8, Week 16, Week 24 and Week 30 post first dose
Mean change from baseline responses on the Kansas City Cardiomyopathy Questionnaire (KCCQ) for all participants and in participants with CpcPH.
Time Frame: Baseline to Week 24 post first dose
To evaluate the effect of TX000045 vs. Placebo on Kansas City Cardiomyopathy Questionnaire (KCCQ) scores. Kansas City Cardiomyopathy Questionnaire (KCCQ-12) is a validated tool to assess quality of life in patients with heart failure. It contains 4 subdomains: physical limitation, symptom frequency, QOL, and social limitations. Each subdomain provides an individual score from 0 to 100, with 0 denoting the worst and 100 the best possible health status.
Baseline to Week 24 post first dose
Evaluate the incidence of immunogenicity of TX000045 by the number of participants with detectable anti-drug antibody titers.
Time Frame: Day 1, Week 2, Week 4, Week 8, Week 16, Week 24 and Week 30 post first dose
Day 1, Week 2, Week 4, Week 8, Week 16, Week 24 and Week 30 post first dose

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Tectonic Therapeutic

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Director: Robert Rogers, MD, Tectonic Therapeutic

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
September 4, 2024

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
November 24, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
January 5, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
September 19, 2024

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 25, 2024

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
September 27, 2024

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
July 7, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 2, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
March 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • TX000045-003

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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