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Clinical Trials and Studies

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Clinical trials are a key component of clinical research and are at the heart of all medical advances in mitochondrial disease. A clinical trial or study adds to medical knowledge by seeking to answer a scientific or medical question about the safety or potential benefit of an intervention, such as a medication, device, teaching concept, or behavioral change.

Many clinical trials are conducted to assess the safety and efficacy of new or investigational drugs, devices, or procedures. Typically, researchers first test new therapies or procedures in the laboratory and in animals. The treatments that prove to be safe and show promise are moved into clinical trials, often requiring multiple phases (Phases I – III) to move the drug or therapy toward approval by the Food and Drug Administration (FDA).

A volunteer’s participation in a clinical trial helps researchers to ultimately uncover better ways to treat, prevent, diagnose, and understand human disease. This participation is critical to the advancement of clinical trials and, ultimately, therapy development.

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Commonly Used Terms

This list was developed to provide easy-to-understand definitions of commonly used terms in clinical trials.

Randomized — The arm of the study (active treatment arm or placebo arm) that the patient will follow is determined by a flip of a coin (or like randomizing procedure).

— Some patients exclusively receive the study drug or treatment and some patients exclusively receive a placebo, a harmless substance that has no effect and is used as a control.

Placebo crossover — Study includes a point whereby participants change study arms, although the timing of that change and whether drug or placebo is received remains blind to all. Some may take placebo for 4 weeks, have a 2-week wash-out with no drug or placebo, and then switch to taking taking the study for 4 weeks, for example. Others in the same study would begin with study drug for 4 weeks, 2-week wash-out and then cross over to take the placebo for 4 weeks.

Safeguards and Ombudsmen — Many checks and balances are in place to ensure safety.

Active, not recruiting — The study is ongoing, and particpants are receiving an intervention or being examined, but potential particpants are not currently being recruited or enrolled.

Adverse Event — An unfavorable change in the health of a participant, including adnormal laboratory finidings, that happens during a clinical study or within a certain amount of time after the study has ended. This change may or may not be caused by the intervention/treatment being studied. ...

Accepts healthy volunteeers — A type of eligibility criteria that indicates whether people who do not have the condition/disease being studied can participate in the clinical study.

Active comparator arm — An arm type in which a group of participants receives an intervention/treatment considered to be effective or actuve by health care providers.

Arm type — A general description for the clinical trial arm. It identifies the role of the intervention that participants receive. Types of arms include the experiemental arm, active comparter arm, placedo comparter arm, sham comparter arm and no intervention arm.

Behavioral Trials — A research study in which one or more human participants are assigned to one or more interventions. In order to evaluate the effects of the intervention on health related biomeducal or behavorial outcomes.

Baseline characteristics — Data collected at the beginning of a clinical study for all participants and for each arm or comparison group. These data demographics such as age, sex/gender, race and ethnicity, and study-specific measures (for example, systolic blood presssure, prior antidepressant treatment).

Clincial Trials — Another name for an interventional study.

Cohort — A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.

Completed — The study has eneded normally, and partipants are no longer being examined or treated.

Cross-over assignment — A type of invterventional model describing a clinical trial in which groups of partitipants receive two or more interventions in a specific order. For example two by two cross-over assignment involves two groupes of participants. One group receives drug A during the inital phase of the trial, followed by drug B during a later phase. The other group receives drug B during the intial phase followed by drug A. So during the trial, participants "cross over" to the other drug. All participants receive drug And drug B at some point during the trial but ina diffrent order, depending on the group to which they are assigned.

Data-Monitoring Committee (DMC) — A group of independent scientists who monitor the safety and scentific integrity of a clinical trial. The DMC can recommend to the sponsor that the trial be stopped if it is not effective, is harming participants or is unlikely to serve its scientific purpose. Members are chosen based on the scientific skill and knowledge neeeded to monitor the particular data.

Diagnositc Trials — Diagnostic trials are trials that are conducted to find better tests or procedures for diagnosing a particular disease or condition.

Double-Blind Study — A type of clinical trial in which neither the participants nor the researcher knows which treatment or intervention participants are receiving until the clinical trial is over.

Early Phase 1 — A phase of research used to describe exploratory trials conducted before traditional phase 1 trials to investigate how or whether a drug affcts the body. They involve very limited human exposure to the drug and no theraputic or diagnostic goals.

Eligibility Criteria — The key requirements that people who want to participate in a clinical must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria and exclusion criteria. Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

End-points — An endpoint is the primiary outcome that is being measured by a clinical trial.

Enrolling by invitation — A clinical study that selects its participants froma population or group of people decided on in advsnce by reseachers

Exclusion Criteria — A type of eligibility criteria. These are reasons that a person is not allowed to participate in a clinical study.

Enrollment — The number of participants in a clinical study. The "estimated" enrollment is the target number of participants that the researchers need for the study.

Expanded Access — A way for patients with serious diseases or conditions who cannot participate in a clinical trial to gain access to a medical product that has not been approved by the U.S. Food and Drug Administration. This is also called compassionate use.

Expanded Access Status: Available — Expanded access is curently available for the investigational treatment, and patients who are not participants in the clinical study may be able to gain access to the drug, biologic, or medical device being studied.

Expanded Access Status: No Longer Available — Expanded Access was available for intervention previously but is not current;ly available and not be availa ble in the future.

Expanded Access Status: Temporarily not Avaiable — Expanded Access is not currently available for this intervention but is extended to be available in the future.

Expanded Access Status: Approved for marketing — The intervention has been approved by the U.S. Food and Drug Administration for use by the public.

Expanded Access Type: Indiviual Patients — Allows a single patients, with a serious disease or condtion who cannot participate in a clinical trial, access to a drug or biological product that has not been approved by the FDA. This category also includes access in an emergency siuation.

Expanded Access Type: Intermediate-size Population — Allows more than one patient access toa drug or biological product that has not been approved by the FDA. This type of expanded access is used when multiple patients with the same disease or condition seek access to a specific drug or biological product has not been approved by the FDA.

Expanded Access Type: Treatment IND/ Protocol — Allows a large, widespread population access to a drug or biological product that has not been approved by the FDA. This type of expanded access can only be provided if the product is already devolped for marketing for the same use as the expanded access use.

Experimental Arm — The identified role of the intervention that the participant receives that is the focus of the study.

Extension request — In certain circumstances, a sponsor or investigatior may request an extension to delay the standard results submission deadline. The request for an extension must demonstrate good cause. All requests must be reviewed and granted by the national Institue of Health. This process for review and granting of extension requests is being devolped.

Factorial Assignment — A type of intervention model describing a clinical trial in which groups of participants receive one of several combinatons of interventionals. For example, all possible combinations of 4 partipiants receiving one pair of the four interventionsof which are drug A and B, drug A and a placebo, a placebo and drug b or a placebo and a placebo are given.

FDA — An agency within the U.S. Department of Health and Human Services. The FDA is responsible for protecting the public health by making sure that human and veterinary drugs, vaccines and other biological products, medical devices, the nation's food supply, cosmetics, dietary supplements, and products that give off radiation are safe, effective, and secure.

First posted — The date on which the study was first available on ClinicalTrials.gov after the National Library of Medicine quality review has been conducted. There is typically a delay of a few days between the date the study sponsor or investigate submitted the study record and the first posted date.

Human subjects protection review board — A group of people who review, approve, and monitor the clinical study's protocol. Their role is to protect the rights and welfare of people participating in a study such as reviewing the informed consent form. The group typically includes people with varying backgrounds, including a community member, to make sure that research activities conducted by an organization are completely and adequately reviewed.

Inclusion Criteria — A type of eligibility criteria. These are the reasons that a person is allowed to participate in a clinical study.

Informed Consent — A process used by researchers to communicate to potential and enrolled participants the risks and potetntial benefits of participanting in a clinical study.

Interventional model — The general design of the strategy for assigning intervention to participate in a clinical study. Types of intervention models include: single group assignment, parallel assigment, cross over assignment and factorial assignment.

Interventional study (clinical trial) — A type of clinical study in which participants are assigned to groups thay receive one or more interventions/treatments so that researchers can evaluate the effects of the intervention on biomedical or health related outcomes. The asssignents are determined by the study's protocol. Participants may recive diagnostic, theraputic, or other types of interventions.

Investigator — A researcher involved in a clinical study.

IRB — Insitutional Review Board- an independent ethics committee for the methods of research.

Masking — A clinical trial design strategy in which one or more parties involved in the trial, such as the investigator or participants, do not know which participants have been assigned which interventions. Types of masking include: single blind masking and double-blind masking.

NIH — National Institute of Health

Not yet recruiting — The study has not started recrutiting participants.

Observational Trials — Studies geared to find what happens to people in diffrent situations based on people observing others.

Outcome Measure — The result of a treatment or intervention that is used to objectively determine the baseline function of a patient at the beginning of the clinical trial.

Parallel Assignment — A interventional model in which two or more groups of participants receive diffrent interventions.

Patient Registry — A type of observational study that colllects information about patients' medical condition and/or treatments to better understand how a condition or treatment affects patients in the real world.

Phase 1 — A phase of research to describe clinical trials that focuses on the safety of a drug. The goal is to determine the drug's most frequent and serious adverse effects and, often, how the drug is brken down and excreted by the body. These trials usually involve a small number of participants.

Phase 2 — A phase of research to describe clinical trials that gather preliminary data on whether a drug works in people who have a certain condition/disease.

Phase 3 — A phase of research to describe clinical trials that gather more information about a drug's safety and effectveness by studying diffrent populations and different dosages and by using the drug in combination with other drugs. These studies typially involve more participants.

Phase 4 — A phase of research to describe clinical trials occuring after FDA has approved a drug for marketing. They include postmarketing requirements and commitment studies that are required of or agreed to by the study sponsor. These trials gather additional information about a drug's safety, efficacy, or optimal use.

Placebo — An inactive substance or treatment that looks the same as, and is given in the same way as, an active drug or intervention/treatment being studied.

Prevention Trials — FInding ways to prevent particular medical conditions or if people have them already, to prevent them from reoccuring.

Principal Investigator — The person who is responsible for the scientific and techanical direction of the entire clinical study.

Protocol — Documents that describe the objectives, design, methology, statistical considerations and aspects related to the organization of clincal trials.

Quality Control — Procedures which insure protection of human subjects from research risk, reliability of the data, and thereby assures internal consistency.

Quality of life trials — Clinical trials that invovlve the best way to improve quality of life conditions for patients with a chronic illness.

Randomized Allocation — A type of allocation strategy in which participants are assigned to the groups of participants of a clinical trial by chance.

Recruiting — Patient recruitment includes a variety of services typically performed by a Patient Recruitment Service Provider to increase enrollment into clinical trials.

Recruitment Status — In a clinical trial, the current status for participants, indicates what stage the trial is in.

Reporting group — A grouping of participants in a clinical study that is used for summarizing the data colllected during the study. This grouping may be the same as or diffrent froma study arm or group.

Results database — A structured online system that provides the public with access to registration and summary results information for completed or terminated clinical studies. The ClinicalTrials.gov results database became available in September 2008. Older studies are unlikely to have results available in the database.

Screening Trials — The process to determine if you qualify for the trial.

Sham Comparter arm — An arm type in which a group of participants receives a procedure or device that appears to be the same as the actual procedure or device being studied but does not contsins active processes or components.

Single group Assignment — A type of intervention model describing a clinical trial in which all of the participants receive the same intervention/treatment.

Sponsor — A person, company, institutuion, group, or organization that oversees or pays for a clinical trial and collects and analyses the data.

Suspended — The study has stopped early but may start again.

Study registry — A structured online system, such as ClinicalTrials.gov , that provides the public with access to summary information about ongoing and completed clinical studies.

Study record — An entry on Clinicaltrials.gov that contains a summary of a clinical study's protocol information, including the recruitment status; eligiblity criteria; contact information; and in some cases, summary results.

Study results — A study record that includes the summary results posted in tne ClinicalTrials.gov results database. Summary results information includes participat flow, baseline characteristics, outcome measures, and adverse events (including serious adverse events.).

Terminated — The study has stopped early and will not start again.

Treatment Trials — Clinical trials advance through four phases to test a treatment, find the appropiate dosage, and look for side effects. If after the first three phases, researchers find a drug or other intervention to be safe and effective, the FDA approves it for clinical use and continues to monitors its effects.

Unknown — A study on Clinicaltrials.gov whose last known status was recruiting; not yet recruiting; or active, not recruiting but that has passed its completion date, and the status has not been last verified witihin the past 2 years.

Withdrawn — The study stopped early, before enrolling its first participants.

Types of Clinical Trials

Test new treatments or devices, new combination of drugs, or new approaches to surgery or radiation therapy. Treatment trials are often categorized by phases I through III.

Provide information about how health and disease progress over time.

Evaluate the effectiveness of ways to reduce the risk of developing a disease or preventing a disease from returning.

Develop better tests or procedures to identify/diagnose a particular disease or condition.

Assess new ways of detecting disease earlier in healthy people.

Evaluate measures to improve comfort of and quality of life for people with chronic illnesses through better therapies or psychosocial interventions.

Orphan Designation

Trials involving orphan or rare diseases may be awarded a special status that grants permission to run trials with much lower numbers of participants. Orphan designations include:

  • Rare disease is defined as fewer than 200,000 people in the United States having the disease, with some diseases considered to be “ultra orphan.”
  • Awarded by FDA to drugs developed explicitly for serious and life-threatening rare diseases, for which there is no treatment.
  • Awarded to drugs that have shown promise of being effective to treat these diseases.
  • Incentives awarded to help get the drug through the FDA approval process.
  • Additional incentives gained once drug has FDA approval, again to encourage companies to help develop drugs for rare diseases.

Clinical Trial Phases

Each clinical trial phase has a different purpose and helps answer different questions.

Researchers test an experimental drug or treatment in a small group of people (20–80) for the first time, often using healthy volunteers to test drug metabolism, safety, and dose ranges.

The purpose is to evaluate its safety and identify side effects.

The experimental drug or treatment is administered to a larger group of people (100–300) to determine its effectiveness, optimal therapeutic dose, and to further evaluate its safety. This phase may be blinded (unknown if patient receives the study drug) or open label studies (known if patient receives study drug) in the target population.

The target population encompasses the group for which the drug is ultimately intended. Any drug metabolism, safety, or dosing difference between the Phase I healthy individuals and the Phase II target population is also evaluated.

Hints of efficacy may be obtained as well.

The experimental drug or treatment is administered to large groups of people (1,000–3,000*) to confirm its effectiveness, monitor side effects, compare it with standard or equivalent treatments, and collect information that will allow the experimental drug or treatment to be used safely.

Phase II studies are randomized, double-blind, placebo-controlled in target population for hard data on safety and efficacy.

Phase II studies are needed to ensure that bias does not affect study results.

After a drug is approved by the FDA and made available to the public, researchers track its safety, seeking more information about a drug or side effects.

Current Clinical Trials



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