Clinical Trial - Types
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Clinical Trial - Types
Admin on Fri May 30, 2008 12:09 pm
This article specifically talks about the oncology trials ( Cancer trials ) and how they are conducted…Read on…
Types of clinical trial
New cancer drugs are usually tested using the following process. Drugs are tested in the laboratory and if it seems that they may be helpful in the treatment of a particular cancer they are tested in phase 1 trials. If these are successful the drug is entered into phase 2 trials and then phase 3.
Manufacturers of drugs that have gone through phase 3 trials and have been shown to be safe and effective can apply for the drug to be granted a licence (also known as a marketing authorisation). Licensed drugs are then available to be used for use in healthcare. Licenses are granted by the European Medicines Evaluation Agency (EMEA) or the Medicines and Healthcare products Regulatory Agency (MHRA).
Drugs that are licensed may be further researched in phase 4 trials.
• Phase 1
• Phase 2
• Phase 3
• Phase 4
Phase 1
Phase 1 trials of new cancer treatments use drugs that have been tested on cancer cells in the laboratory and have had an effect. Phase 1 is the first stage in which the drugs are used to treat patients. These studies have small numbers of patients. Phase 1 drugs are offered to people whose cancer has come back or spread and there is no other standard treatment that may help them. It is not expected that the treatment will cure the cancer; rather, the trial aims to find out:
• how much of the treatment can be given without causing serious side effects
• what effect the drug has on the body
• what side effects it causes
• whether the drug has any effect on the cancer.
In a phase 1 trial, the first group of 3–6 patients are given a small dose that is expected to be safe. If none of the patients has any side effects the next group of patients will be given a higher dose. In this way the dose of the drug is increased until some people do have side effects. When side effects are seen that make it unsafe to increase the dose further it is known as the maximum tolerated dose and the dose is not increased any more.
However, it is impossible to predict whether a new treatment will cause harmful side effects in people, and patients in this type of trial need to be monitored very carefully. Phase 1 trials are usually carried out in clinical research units at specialist hospitals, rather than in local hospitals. Sometimes this may involve a lot of travelling to and from the ospital.
If the drug has an effect on the cancer, and a safe dose has been found, the drug will then be tested in phase 2 trials.
Phase 2
By the time a treatment reaches phase 2, researchers will know quite a lot about it. The phase 1 trials will have shown what most of the major side effects are and whether the drug actually has some effect on particular types of cancer. The aim of phase 2 trials is to look at how many people the treatment is effective for, and which types of cancer it might be used to treat. Researchers will know which side effects are likely to occur, so that they can deal with these straight away if necessary.
Phase 2 studies have more patients, perhaps a few dozen. These patients will be closely monitored to see whether their cancer is getting smaller. If the cancer shrinks, it is known as a response to the treatment. The trial will also look at any side effects caused by the treatment.
Sometimes, phase 2 studies include different ways of giving the new treatment; for example, patients may be given the same drug by injection, or as tablets. These trials may be randomised.
Phase 3
These studies follow phase 2 and the main aim is usually to compare the effectiveness of newer treatments with that of standard treatments. They also give more information about the side effects that the new treatment may cause.
Sometimes a trial may be testing whether a new treatment is as effective as the standard treatment but causes less side effects. An example is, testing a new way of giving radiotherapy, comparing it to the standard radiotherapy treatment.
Phase 3 trials are large and may include hundreds, or sometimes thousands, of patients from many different hospitals, often from several countries. Researchers can measure various aspects, such as:
• how long patients stay free of cancer (known as disease-free survival)
• whether the growth of the cancer slows
• how the treatment affects patients’ quality of life.
Phase 3 trials always involve randomisation.
Phase 4
Phase 4 trials are carried out after a drug has been shown to be effective and has been granted a license. These trials aim to find out:
• how well the drug works when it is used more widely than in clinical trials
• the long-term risks and benefits of the drug
• more about the possible rare side effects and safety of the drug.
Future Updates : “Placebos”,” Participating in a clinical trial ” etc …
Types of clinical trial
New cancer drugs are usually tested using the following process. Drugs are tested in the laboratory and if it seems that they may be helpful in the treatment of a particular cancer they are tested in phase 1 trials. If these are successful the drug is entered into phase 2 trials and then phase 3.
Manufacturers of drugs that have gone through phase 3 trials and have been shown to be safe and effective can apply for the drug to be granted a licence (also known as a marketing authorisation). Licensed drugs are then available to be used for use in healthcare. Licenses are granted by the European Medicines Evaluation Agency (EMEA) or the Medicines and Healthcare products Regulatory Agency (MHRA).
Drugs that are licensed may be further researched in phase 4 trials.
• Phase 1
• Phase 2
• Phase 3
• Phase 4
Phase 1
Phase 1 trials of new cancer treatments use drugs that have been tested on cancer cells in the laboratory and have had an effect. Phase 1 is the first stage in which the drugs are used to treat patients. These studies have small numbers of patients. Phase 1 drugs are offered to people whose cancer has come back or spread and there is no other standard treatment that may help them. It is not expected that the treatment will cure the cancer; rather, the trial aims to find out:
• how much of the treatment can be given without causing serious side effects
• what effect the drug has on the body
• what side effects it causes
• whether the drug has any effect on the cancer.
In a phase 1 trial, the first group of 3–6 patients are given a small dose that is expected to be safe. If none of the patients has any side effects the next group of patients will be given a higher dose. In this way the dose of the drug is increased until some people do have side effects. When side effects are seen that make it unsafe to increase the dose further it is known as the maximum tolerated dose and the dose is not increased any more.
However, it is impossible to predict whether a new treatment will cause harmful side effects in people, and patients in this type of trial need to be monitored very carefully. Phase 1 trials are usually carried out in clinical research units at specialist hospitals, rather than in local hospitals. Sometimes this may involve a lot of travelling to and from the ospital.
If the drug has an effect on the cancer, and a safe dose has been found, the drug will then be tested in phase 2 trials.
Phase 2
By the time a treatment reaches phase 2, researchers will know quite a lot about it. The phase 1 trials will have shown what most of the major side effects are and whether the drug actually has some effect on particular types of cancer. The aim of phase 2 trials is to look at how many people the treatment is effective for, and which types of cancer it might be used to treat. Researchers will know which side effects are likely to occur, so that they can deal with these straight away if necessary.
Phase 2 studies have more patients, perhaps a few dozen. These patients will be closely monitored to see whether their cancer is getting smaller. If the cancer shrinks, it is known as a response to the treatment. The trial will also look at any side effects caused by the treatment.
Sometimes, phase 2 studies include different ways of giving the new treatment; for example, patients may be given the same drug by injection, or as tablets. These trials may be randomised.
Phase 3
These studies follow phase 2 and the main aim is usually to compare the effectiveness of newer treatments with that of standard treatments. They also give more information about the side effects that the new treatment may cause.
Sometimes a trial may be testing whether a new treatment is as effective as the standard treatment but causes less side effects. An example is, testing a new way of giving radiotherapy, comparing it to the standard radiotherapy treatment.
Phase 3 trials are large and may include hundreds, or sometimes thousands, of patients from many different hospitals, often from several countries. Researchers can measure various aspects, such as:
• how long patients stay free of cancer (known as disease-free survival)
• whether the growth of the cancer slows
• how the treatment affects patients’ quality of life.
Phase 3 trials always involve randomisation.
Phase 4
Phase 4 trials are carried out after a drug has been shown to be effective and has been granted a license. These trials aim to find out:
• how well the drug works when it is used more widely than in clinical trials
• the long-term risks and benefits of the drug
• more about the possible rare side effects and safety of the drug.
Future Updates : “Placebos”,” Participating in a clinical trial ” etc …
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