Scientific research studies follow a common process. This framework helps scientists communicate and share their results with one another through presentations and publications.

1. Identify and define the problem. Why is this study important? What is the problem or question being examined?
2. Gather information. Review existing literature and resources on the topic. What is already known about the problem?
3. Form a hypothesis. Propose a possible explanation or answer to the question based on the current information. This idea forms the basis for further investigation and is developed before conducting any experiments.
4. Perform experiments and collect data. Determine what data is needed to support or refute the hypothesis. Decide how the study will be conducted, including the methodology, procedures, instruments and participants.
5. Analyze the data. What are the results? What does the data show?
6. Interpret the results. What conclusions can be drawn? What are the implications? Do the findings agree with previous studies? What are the study’s limitations? What questions remain, and what new questions arise?
7. Communicate the results. Share findings through scientific presentations, publications and communication with the general public.

Clinical trials are a key part of clinical research used to evaluate new ways to prevent, detect or treat disease. They may test the safety and effectiveness of new drugs or new combinations of drugs or evaluate a new way to use existing drugs or treatments. Trials also can test new medical devices, explore new ways to change behavior to improve health or evaluate new ways to improve the quality of life of patients. Clinical trials offer hope to patients and help advance future therapies.

Types of clinical research and trials

Research studies take many forms, each contributing to better understanding and advancing pulmonary hypertension care and treatment. Common study types include:

• Epidemiology studies examine the causes, risk factors and outcomes of disease in specific groups to improve diagnosis, prevention and care.
• Health services research looks at how patients access care, the cost of services and barriers to care.
• Observational studies track patients over time to study disease progression, treatment effects, quality of life and outcomes.
• Clinical trials test the safety and effectiveness of new treatments or interventions.

Within clinical trials, there are several key categories:

• Prevention trials evaluate ways to prevent disease or its progression through medications, vaccines or lifestyle changes.
• Screening and diagnostic trials test new methods for detecting or diagnosing disease.
• Behavioral trials and quality of life trials explore strategies to promote healthy behavior and improve patient well-being.
• Treatment trials access new drugs, drug combinations, devices or other therapies.

How clinical trials work

Clinical trials follow a detailed plan called a protocol that outlines the purpose of the study, who can participate, what tests or procedures will be done, how long the trial will last and what data will be collected. Each trial is overseen by a sponsor, which may be an individual, research institution, pharmaceutical company or government agency. Sponsors are responsible for managing and funding the trial, but the day-to-day research is conducted by a separate team of medical professionals and researchers.

Before any trial begins, the Institutional Review Board, an independent committee made up of doctors, statisticians and community members, reviews the protocol to protect participant rights and safety. The IRB continues to monitor the study throughout its duration.

If you are considering joining a clinical trial, you will be given an informed consent form that outlines the purpose of the trial, what will happen during the study, potential risks and benefits, how long it will last and who to contact with questions. This document is not a contract; it is your opportunity to understand the trial before you agree to participate. Signing it means you give permission to participate, but you can withdraw at any time, for any reason.

Some studies use specific designs to ensure fair and unbiased results. These include placebo-controlled, randomized and blinded trials. A placebo is an inactive treatment that looks like the treatment being tested. Placebos are used only when it is safe to do so and never when withholding treatment would put a patient at risk. You will be told in advance if a placebo is part of the study. In a randomized trial, participants are assigned to different groups by chance to avoid bias. In a blinded study, either the participant, the researchers or both may not know which treatment is being given. This helps prevent expectations from influencing results. If medically necessary, your treatment group can be disclosed.

When a clinical trial ends, researchers analyze the results to determine whether the treatment was safe and effective. In Phase I and II trials, the focus is on safety and early signs that the treatment may work. In Phase III, the new treatment is compared to existing therapies or a placebo to measure how well it performs in a larger and more diverse group. If the results show the treatment is effective and safe, the data is submitted to the U.S. Food and Drug Administration for review. If the FDA approves the treatment, it may become available to the public and could become part of standard care.

Results from clinical trials are often published in medical journals, shared at scientific conferences or reported in the news. You can also find published studies in public databases like the National Library of Medicine’s PubMed.

Before deciding to participate in a clinical research study or clinical trial, it is important for patients and their caregivers to know as much as possible about the study. Here is a checklist of questions to help guide a discussion with your pulmonary hypertension (PH) health care team about participating in a clinical trial.

Purpose of the clinical trial

• Why is this clinical trial being done?
• What phase (or stage) is this clinical trial in?
• Who is sponsoring and funding this study?
• Why do researchers believe this new treatment might be effective?
• Has this treatment been tested before?
• Have there been other trials like this one? If yes, what were the results?
• What kinds of patients will be in the clinical trial?
• How many patients are needed for the clinical trial?
• How long will the trial take?
• If the trial is successful, what will the results show?
• Will I be able to find out about the results of the clinical trial?
• What has already been learned about the treatment tested in the study and are there any clinical results published?
• Where can I find out more about this clinical trial?

Who is eligible to participate?

• Why is this clinical trial a good fit for me?
• What other treatment options do I have?
• Will my treatment and care change if I join this study? If yes, how?
• How will the test in this trial compare to the test that I would have as part of my routine care?
• Are there other clinical trials that might be a good fit for me?

Potential risks and benefits

• How could this trial help me?
• What are the potential short-term and long-term side effects of this treatment?
• How do the possible risks and benefits of this clinical trial compare with my standard of care? How do they compare with other potential experimental treatment options?
• Who has reviewed and approved this study for protecting participants rights and safety?
• What steps will be put in place to monitor my safety?
• How will I know if the treatment is working?
• If the treatment works for me, can I keep using it after the trial ends?

Practical concerns

• What will I have to do if I join this trial?
• Will I need to come to the hospital or clinic for specific tests or treatments? Is yes, how often?
• How will this study affect my daily life?
• Where will I receive my medical care?
• Who will be managing my care? Will I be able to see my own PH care team?
• Can anyone find out whether I am participating in this clinical trial?
• Can I talk to other people who are participating in this trial?
• Will I receive any follow-up care after the study has ended?
• Do the researchers/clinicians have any financial or special interests in this clinical trial?
• Who do I contact if I have questions during the trial?

Financial concerns

• Will I have to pay for any part of the treatment during the study?
• If yes, what will the charges likely be?
• Will there be any travel or childcare costs that I will need to consider while participating in this study?
• Will my health insurance cover any of the expenses from participating in this trial?
• Who can help answer any questions from my insurance company about this clinical trial?

Search ClinicalTrials.gov

ClinicalTrials.gov is a searchable database maintained by the U.S. National Library of Medicine. It lists clinical studies being conducted in the United States and in more than 200 other countries.

Talk to your PH care team

Your PH care team can help you explore clinical trial opportunities that may be right for you. To prepare for the conversation, review the section on What to ask before joining a trial section for a helpful list of topics to discuss including:

• The purpose of the clinical trial.
• Who is eligible to participate.
• Potential risks and benefits.
• Practical considerations.
• Financial concerns.

Having this information can help you make informed decisions about whether a clinical trial is a good fit for you.

Enrolling in the PHA Registry

The PHA Registry  is the largest active U.S.-based, prospective and longitudinal observational PH patient registry. PHAR includes individuals diagnosed with pulmonary arterial hypertension, chronic thromboembolic pulmonary hypertension and pediatric PH due to developmental lung disease. Learn more about how to participate.

PHA Conference Research Room

At every PHA International PH Conference and Scientific Sessions, patients can contribute to research in the Research Room by answering surveys or donating biological samples such as cheek swabs or blood. Find information about the next conference.

PVDOMICS study

The PVDomics study (Redefining Pulmonary Hypertension through Pulmonary Vascular Disease Phenomics) is a research partnership between PHA and the National Heart, Lung and Blood Institute at the National Institutes of Health. PVDOMICS uses clinical and biological “omics” data from patients across all five PH groups to improve disease classification and understanding. Learn more about PVDomics and participating centers.

The drug discovery and development process is complex, time-consuming and costly. Its goal is to bring safe, effective new treatments to patients. New treatments begin in the laboratory. Scientists first test potential therapies in cells and animal models to understand how a drug behaves and whether it may be effective. If the results look promising, the therapy moves into human studies, i.e., clinical trials.

Phases of clinical trials

New treatments are tested through several phases to evaluate their safety, effectiveness and side effects. Each phase builds on what was learned in the previous phase:

Preclinical phase: Before running human studies, researchers study the drug’s biological and safety profile using lab and animal models. This helps guide future testing and identify any risks.

• Phase I: A small group (20–80 healthy volunteers or patients) receives the drug to evaluate its safety, determine the right dosage and identify possible side effects.
• Phase II: The drug is given to a larger group (100–300 people, including patients with the condition) to further study its safety and assess whether it helps.
• Phase III: This larger trial (often 1,000+ participants) compares the new treatment to a placebo or existing standard of care to confirm its effectiveness and monitor side effects in a more diverse group.
• Phase IV: After the drug is approved by the U.S. Food and Drug Administration and made available to the public, researchers continue to monitor its safety, effectiveness and optimal use.

This infographic shows what the drug development process looks like. 

How long does it take? 

The timing and success rate of candidate drugs through the different phases of clinical trials varies.  

The full process from preclinical studies to FDA approval can take 4 to 10 years or more. Enrollment speed, trial design and success at each phase can affect timing. Most trials do not succeed at every step. The FDA explains its investigational new drug process and timeline as follows:  

• Phase 1: Length of study lasts several months, approximately 70% of drugs move to next phase. 
• Phase 2: Length can be several months to 2 years, approximately 33% of drugs move to next phase. 
• Phase 3: Length ranges from 1 to 4 years, approximately 25-30% of drugs move to FDA approval. 

Why participation matters 

With rare diseases like PH, trials can’t move forward without patients. Researchers need volunteers at every stage, especially in early and pivotal trials, to test whether therapies are safe and effective. Without participation, no amount of lab progress can lead to real-world treatments.