Initial Triple Therapy Including Parenteral Treprostinil vs Initial Double Oral Therapy in PAH Group I Patients

TripleTRE is prospective, randomized, two-arm, open-label, low-interventional, phase IV, multi-centre clinical trial comparing efficacy and safety of initial triple therapy including parenteral treprostinil to initial double oral therapy (standard of care (SoC)) by proportion of patients achieving low risk status according to the simplified four-strata risk-assessment tool from week 24 up to 48 weeks in 110 (55/group) treatment-naïve adult intermediate-high risk or intermediate-low risk participants with severe hemodynamic impairment with pulmonary arterial hypertension (PAH) (group I). Severe hemodynamic impairment is defined in current European Society of Cardiology (ESC)/European Respiratory Society (ERS) Guidelines as at least one of following conditions: mean right atrial pressure (RAP) ≥ 20 mmHg, cardiac index (CI) < 2.0 L/min, stroke volume index (SVI) < 31 mL/m2 and/or pulmonary vascular resistance (PVR) ≥ 12 WU. Risk status will be assessed with the simplified four-strata risk-assessment tool as per ESC/ERS Guidelines for the diagnosis and treatment of pulmonary hypertension (2022).

TripleTRE will be performed in adult participants with a confirmed diagnosis of idiopathic PAH (IPAH), hereditary PAH (HPAH), drug and toxin-induced PAH (DPAH), PAH associated with Connective Tissue Disease (PAH-CTD) and PAH with corrected congenital heart disease (PAH-CHD).

Participants will be randomized to one of the two treatment arms in 1:1 ratio. All patients will start with double oral background medication (endothelin receptor antagonist (ERA) and phosphodiesterase type-5 inhibitor (PDE-5i)). Choice of double oral drug combination underline the discretion of the investigator and applicable treatment guidelines. In both treatment arms all drugs (i.e., background medication in double oral group, background medication and parenteral treprostinil in initial triple group) will be initiated within 3 weeks after randomization. Patients randomized to treprostinil arm will receive training on infusion pump and medication after that investigational medicinal product will be handed out. All patients will be handed out diaries for documentation of treprostinil dose and used vials.

Primary objective of TripleTRE is to investigate the effect of initial triple combination therapy compared to initial double oral therapy on risk status. The effect of initial triple combination therapy vs initial double oral therapy (SoC) will be measured by primary endpoint: (non)response to the assigned treatment, whereas therapy responders/non-responders are defined as:

1. Therapy-responder: achievement of low-risk status between week 24 and week 48
2. Therapy-non-responder:
3. pulmonary hypertension (PH) related deterioration to high-risk status, lung transplantation or death between week 12 and week 48 and/or
4. additional medication or change of initial PH specific medication due to unsatisfactory efficacy between week 12 and week 48 and/or
5. low risk status not achieved up to week 48

Risk status is assessed with the simplified four-strata risk-assessment tool as per ESC/ERS Guidelines for the diagnosis and treatment of pulmonary hypertension (2022).

Commonly used variables such as hemodynamics, echocardiogram (ECHO) and time to clinical worsening will be evaluated as secondary endpoints. In addition, the emPHasis-10 questionnaire will be used as disease specific and validated patient-reported outcome tool for PAH patients. The European Quality of Life 5 Dimensions 5 Level Version (EQ-5D-5L) will be used as general patient-reported outcome tool independent from disease.

TripleTRE trial is organized as a low-intervention trial consistent with definition in Clinical Trial Regulation (Regulation (EU) No 536/2014). Participants will not undergo any invasive examinations or laboratory evaluations, diagnostic or monitoring procedures specifically for the purposes of this trial that would expose them to increased risk compared to standard of care. Trial-related procedures as well as the frequency of assessments are in alignment with ESC/ERS Guidelines for the diagnosis and treatment of pulmonary hypertension (2022) and are not expected to pose additional risks to patients.

Planned trial duration per patient is minimum 12 weeks and maximum 48 weeks with up to 10 visits depending on achievement of therapy responder (i.e., low risk status) or therapy non-responder status. The visits 2 and 3 can be performed on phone. Other visits will be performed on-site. The trial will only be conducted in countries where ERA and PDE-5i treatments are standard of care and treprostinil is available to patients. At the end of trial, patients will be treated according to routine medical care at the PH expert centers receiving locally reimbursed medications. Approximately 10 countries and 20 sites are planed.

Statistical considerations:

The complete statistical analysis plan (SAP) was finalized before first patient in (FPI) in meaning of first act of recruitment. A one-sided Boschloo exact test at 2.5% significance level will be used to test the following primary hypothesis:

H0: Proportion of patients achieving low risk status (therapy responders) between week 24 and week 48 after baseline in the initial Triple treatment group is less or equal to the proportion of patients achieving low risk status between week 24 and week 48 after baseline in the initial Double oral treatment group.

The null hypothesis will be rejected if the 97.5% CI of the difference of proportions of therapy responders (triple minus double) is greater than 0.

To account for the variable time on treatment of therapy responders, a secondary sensitivity analysis will be performed by comparing the median time to the achievement of the low-risk status between the treatment groups.

Further sensitivity and subgroup analyses are defined in detail the statistical analysis plan (SAP) including the handling of missing values.