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Participate in a Clinical Trial

What is a Clinical Trial?

A clinical trial (i.e. clinical research) is a research study focusing on human subjects to answer specific health questions. Well conducted clinical trials are the safest and quickest methods to find treatments that work and improve health outcomes. Clinical trials are conducted in phases for different objectives which answers different research questions.

Phase I Clinical Trials

These are initial studies to determine what happens to the drug in the human body (e.g. how it is absorbed, metabolised, and excreted) as well as the pharmacologic actions of the drug in humans. In addition, these studies are designed to evaluate the safety of the drug, determine a safe dosage range, and identify its side effects. This initial phase of testing in humans is done with a small number of people (20 to 100), and usually involves healthy volunteers. However, patients may be recruited in some situations.

Phase II Clinical Trials

The study drug or treatment is given to a larger group of patients (100-300) to see if it is effective and to further evaluate its safety.

Phase III Clinical Trials

The study drug or treatment is given to even larger groups of patients (1,000-3,000) to confirm its effectiveness, benefits and side effects in comparison to other commonly used treatments. This information will then allow the drug or treatment to be used safely, and data from Phase III clinical trials are also used as the basis for the drug marketing application.

Most Phase II and Phase III studies are "randomised controlled" clinical trials. One group of patients will be randomly selected to receive the experimental drug while a second “control” group will receive a standard treatment or placebo. These studies are often “double-blinded”, where neither the patients nor the researchers know who is getting the experimental drug.

Phase IV / Post-Marketing Clinical Trials

Phase IV studies outline additional information including the drug's risks, benefits and optimal use after a drug has received the license to be marketed.

Phase IV studies are often designed to measure:

(1) The comparison of a drug with other drugs already on the market.
(2) A drug’s long-term effectiveness and impact on a patient’s quality of life.
(3) The cost-effectiveness of a drug therapy relative to other traditional and new therapies.

Who funds Clinical Trials?

Clinical trials are sponsored or funded by a variety of organisations such as medical institutions, foundations, pharmaceutical companies and government agencies such as National Medical Research Council (NMRC), Agency for Science, Technology and Research (A*STAR), Biomedical Research Council (BMRC). Clinical trials can take place in a variety of locations such as hospitals, universities and polyclinics.

What are the Benefits and Risks of participating in a Clinical Trial?

There are both benefits and risks associated with clinical trials.


Clinical trials that are well-designed and well-executed are the best approach for eligible participants to:

  • Play an active role in their health care.
  • Gain access to new research treatments before they are approved for the marketplace.
  • Get excellent care from the research staff during the course of the study.
  • Help others by contributing to medical research.


There are always risks when participating in clinical trials, some of which includes:

  • There may be unpleasant, serious or even life-threatening side effects from treatment.
  • The treatment may not be effective for the participant.
  • They may have to spend more time and attention compared to a standard treatment which may include trips to the study site, more treatments, hospital stays or complex dosage requirements.

How is the safety of the participant protected?

National and international regulations and policies have been developed to help ensure research involving people are conducted according to strict scientific and ethical principles.

Approval from the Institutional Review Board (IRB) must be obtained before any physician can conduct a clinical trial. The IRB is an independent board of physicians and non-medical people who are in charge of examining the study’s protocol to ensure that the participant’s rights and well-being are protected, and that the study does not present unnecessary risk to the participant. A study protocol describes what types of people may participate in the clinical trial alongside the schedule of tests, procedures, medications, dosages as well as the length of the study. While in a clinical trial, participants are seen regularly by the research staff to monitor their health and to determine the safety and effectiveness of their treatment.

Anyone participating in a clinical trial in Singapore is required to sign an “informed consent” form. This form details the nature of the study, the risks involved and what may happen to a participant in the study. Informed consent must be given voluntarily by the participant and there should be no pressure placed on the volunteer to participate. Even after consent has been given, the participant is free to withdraw from the study at any time without penalty.

Participant names will also remain anonymous and will not be disclosed when the results of the clinical trial are presented at scientific meetings, medical journals and to various government agencies.

Clinical trials at Changi General Hospital (CGH) are always performed in strict compliance with regulatory requirements in Singapore and in accordance with internationally accepted guidelines.

What should be considered before participating in a Clinical Trial?

Volunteers should have a full understanding of the clinical trial involvement and expectation before consenting to participate in the clinical trial. They should seek to understand the credentials and experience of the individuals and the facility involved in conducting the study.

The following questions might be helpful for the participant to discuss with the Clinical Trial staff before consenting to participate.

  • What is the objective of the clinical trial?
  • What kind of tests and treatments are involved?
  • How long will the clinical trial last?
  • Where is the clinical trial being conducted?
  • What are the risks involved?
  • What are the possible benefits?
  • What are the alternative treatments besides the one being tested in the clinical trial?
  • Who is sponsoring the clinical trial?
  • Do I have to pay for the tests and treatment?
  • Will I be reimbursed for other expenses?
  • What happens if I am harmed by the clinical trial?
  • Who will be in charge of my care?