Study design
We designed a study protocol for a randomized controlled study. Screening (Visit 0) was undertaken within 3 days prior to enrollment to assess eligibility and collect baseline data. Subjects who entered the primary screening were assessed for lung function, and those meeting all criteria were randomly assigned (2:1) into a TMP treatment group or a control group. Both groups received conventional treatment, and the TMP treatment group also received 100 mg oral TMP three times daily. Patients were followed up at 1 month after randomization (Visit 1), and then every month until end of treatment at 16 weeks. Data collected at Visit 0 included patient characteristics (name, sex, age), medical history, concomitant medications, laboratory and auxiliary examinations, and adverse events. Additionally, at each visit, medical history, medications, cardiac and pulmonary function, and adverse events will be collected. Additional items will be evaluated at Visits 2 and 4. A schedule of assessments is shown in Table 1. A study flow chart is shown in Figure 1.
Sampling
Based on the 6-minute walk distance (6MWD) as the main efficacy index, it is assumed that after treatment, the experimental group has an average distance of 60 m from the control group of 6 minutes, the standard deviation is 60 m, α is 0.05, and the efficacy is 90% (β is 0.10). The sample size is:
See supplemental files for the formula
q1 is the proportion of the experimental group, and q2 is the proportion of the control group, q1=2/3, q2=1/3, N≈107.
Assume that the sample shedding rate is 11%, the sample size is approximately 120 participants, comprising 40 patients with control, 80 patients in TMP group.
Study procedure
Eligibility criteria for enrollment
The selection of participants will be based on the following inclusion and exclusion criteria:
Inclusion criteria
1. In accordance with the diagnostic criteria for PH, mPAP measured by right cardiac catheterization above 20 mmHg and pulmonary capillary wedge pressure (PCWP) below 15 mmHg, at sea level and in a resting state.
2. Subjects with Type 1 or Type 4 PH classified according to the World Symposium on Pulmonary Hypertension (2015 ESC/ERS guideline.) [21] who are in a stable stage, including idiopathic PH, hereditary PH, PH induced by drugs or toxins, PH associated with connective tissue diseases or congenital heart diseases (with no surgery/intervention within the previous 6 months); and chronic thromboembolic PH (surgical treatment is preferred for patients with surgical indications. For patients who have PH after surgery, are without surgical indications, or are nonoperable ones, stabilization with anticoagulant drugs (such as warfarin) for at least 1 month prior to participation is required).
3. Age 15–70 years, male or female.
4. WHO PH functional classification II, IV, or V.
5. 6MWD of >100 m and <450 m at baseline.
6. Patients stable for at least 1 month after standard treatment, and patients who have not received treatment with interventional or surgical closure in the 6 months prior to participation.
7. Patient or his/her guardian agrees to participation of the patient in the study and provides written informed consent for participation.
Exclusion criteria
1. Absent or limited legal capacity.
2. Pregnant or lactating women.
3. Serious primary diseases in major organs.
4. Mental or physical disability preventing the completion of 6MWD.
5. Suspected or confirmed history of alcohol or substance abuse.
6. Known allergy to the components of the drug.
7. AST and ALT values above 3 times the upper limit of normal, or Ccr <50 ml/min.
8. Low systemic blood pressure (<90/50 mmHg) or uncontrolled hypertension (blood pressure >170/110 mmHg).
9. Prior use of the study drug and discontinuation or change in targeted drugs (e.g. endothelin receptor antagonists, phosphodiesterase type 5 inhibitors, and guanylate cyclase) in the 3 months prior to screening.
10. Presence of an active infectious disease such as hepatitis A, hepatitis B, AIDS, tuberculosis, or connective tissue diseases.
11. Presence of serious infection, especially pulmonary infections.
12. Shock or other hemodynamically unstable conditions.
13. Cirrhosis or portal hypertension caused by cirrhosis.
14. Severe bleeding or bleeding tendency such as active peptic ulcer, intracranial hemorrhage, trauma, or other bleeding events.
15. Acute or chronic organic diseases (except for dyspnea) or other conditions (such as limb diseases) which may result in the subject being unable to complete the study (especially the 6MWD).
16. Any other circumstances under which the investigator considers the patient to be unsuitable for participation in the study.
Withdrawal criteria
1. Subjects having poor compliance with the dosing regimen
2. Use or accidental use of foods or drugs that may impact test results during the treatment period (e.g., amirace, fenfluramine, dexfenfluramine, L-tryptophan, methamphetamine, and phenylflurazone)
3. Subjects with incomplete key data that may affect the statistical analysis.
Endpoint standards
1. Subjects experiencing serious adverse reactions leading to suspension or termination of treatment during the study
2. Subjects whose condition deteriorates during the study
3. Subjects who withdraw consent or are unable to complete the study because of other circumstances
4. Patients treated with targeted drugs for Type 1 or Type 4 PH prior to testing who stopped treatment with the targeted drug for any reason during the study and did not reinitiate treatment
5. Death (from PH or another cause).
Drugs and usage
Subjects satisfying all criteria are assigned (2:1) randomly into two groups as follows:
1. TMP treatment group: TMP 100 mg 3 times daily in addition to routine therapy.
2. Control group: routine therapy only.
TMP was produced by Livzon Pharmaceutical Group Inc. (Zhuhai, Guangdong Province, China), following the instructions of the People’s Republic of China Pharmacopoeia [22]. Routine therapy does not differ between two groups, and included phosphodiesterase type 5 inhibitors (sildenafil and tadalafil). Where subjects have previously received targeted drugs for the treatment of PH, the regimen will remain unchanged.
Outcome measurements
Efficacy indicators
The main efficacy indicators are the 6MWD and heart rate recovery at 1 minute (HRR1) after the 6MWD (Table 2).
Secondary efficacy measurements include the following 12 indicators (Table 2): PH WHO Classification, Borg Dyspnea Score, Minnesota Living with Heart Failure Questionnaire (MLHFQ), NT-proBNP (N-terminal pro-brain natriuretic peptide), cTNI (cardiac troponin I), right ventricular systolic pressure (RVSP) evaluated by echocardiogram, uric acid, volume of pericardial effusion, pulmonary artery diameter assessed by CT, diameter of the same layer of aorta assessed by CT, arterial oxygen saturation, and time of clinical deterioration.
Safety evaluation
Symptoms and signs including respiration rate, heart rate, and blood pressure are recorded at each visit. Laboratory tests are performed within 3 days prior to enrollment, and include routine blood tests and urinalysis, liver function, renal function, coagulation function, and electrocardiography. Adverse events are assessed and then recorded in the CRF.
Evaluation of adverse events
Adverse events, including symptoms, signs, and physical or laboratory examination abnormalities, are carefully evaluated. All adverse events must be judged for their character, severity, and potential relationship to the study treatment. The correlation between adverse events and study treatment is divided into five levels: definite, probable, possible, unrelated.
Data management and statistical analyses
Data from each subject visit will be captured in the CRF.
Statistical analysis of the efficacy of the study will be performed using statistical data sets that met the protocol. The data will be analyzed by two-sided test t test, with categorical variables analyzed by χ2 test and rank variables by paired Wilcoxon rank sum test. The test level α is 0.05, and the P values ≤0.05 will be considered statistically significant.
Ethics
The present study is being conducted in accordance with the Declaration of Helsinki and relevant clinical study research regulations in China. The protocol was approved by the Ethics Committee of the First Affiliated Hospital of Guangzhou Medical University. Prior to participation, all subjects must provide written informed consent.
