05-02-2015, 01:27 AM
(This post was last modified: 05-02-2015, 01:40 AM by MannBhargavi.
Edit Reason: extra line break
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Clinical trials are the clinical studies that involve human volunteers; here termed as subjects or patients that are designed to improve the medical knowledge, determine the efficacy of a new drug in the humans for diseases which has no certified or proven treatment/therapy, or sometimes done just for comparison with another drug for same ailment to determine whichever is more effective with lesser side effects. It also helps determine which dose/concentration of a particular drug would be best for different stages of the same disease. Clinical trials are highly crucial to be conducted before the drug is marketed to make sure the drugs are tested and certified for usage.
These studies always involve a team of experts from Medical & Pharmaceutical sectors to make sure there is compliance in trials with the protocols. The government of the country where the study is held is also involved to make sure the protocols follow the standards set by that particular government and also to make sure that the practice is ethical and patient safety is of highest importance. This study may either be interventional or observational type. In interventional, the patients or the subjects are given specific medical products as per the designed protocol by medical experts or investigators. This medical product could be drugs, devices, vaccine, etc.
In the observational studies, the interventions maybe given to a group of the population but it is mainly for the investigator to observe the health consequences or development in that group with respect to their lifestyles.
A complete clinical trial includes four main stages, collectively known as the Phases of clinical trials. The four clinical phases and drug development in each phase is defined below. However these phases may not always occur in the same chronological order. Sometimes a drug is evaluated in just 2 phases and sometimes the clinical trials may occur in such a fashion that two different phases may overlap each other.
Phase I: This is the primary stage where the first safety trials on a new drug is done in order to establish the exact dose range that is tolerated by the subjects. The dosage type maybe single or multiple. Usually this trial is conducted on severely ill patients like in cases of cancer, and in case of less ill patients, it involves pharmacokinetic studies. Pharmacokinetic studies are generally considered as phase I study. Pharmacokinetic study can be easily defined as the study of what the body of living organism does to the drug from the moment it is absorbed by the body, distribution within the body, its metabolism to excretion.
Phase IIa: This is the first part of the 2nd phase of the clinical trial that involves the evaluation of the efficacy and safety of the drug in a group of selected population. The population here is usually patients with ailments to be treated or to prevent it. This phase concentrated on the dose-response , what type of patients are involved, Objectives may focus on frequency of intervention, dose-response, type of patient, and many other factors that are crucial in determining the safety and efficacy level. This phase may be referred to as pilot trials.
Phase IIb: The objectives of this phase is same as that of the phase IIa, and may sometimes be referred to as pivotal trials. The conditions and factors for evaluation of efficacy and safety may also be same as phase IIa, however this phase represents absolutely thorough and careful, uncompromising display of the drug efficacy.
Phase IIIa: Phase III begins after the drug efficacy has been demonstrated but before the regulatory submission of New Drug. This phase is conducted on the group of population for whom the drug was actually intended to begin with. In IIIa clinical trials a data is generated based on both safety and efficacy but in relatively large numbers of subjects or patients in both controlled and uncontrolled trials. This trial may involve 2 group of patients for comparison of the drug interaction in the body against a placebo. This phase often provides much of the information needed for the labeling of the drug.
Phase IIIb: This phase is conducted after regulatory submission of dossier or an NDA, but prior to the drugs approval by the regulatory body and marketing of the drug. These trials may add on to earlier studies, sometimes may be the end of the clinical studies, or sometimes be directed towards Phase IV evaluations. This is the period between regulatory submission and approval of the drug for marketing authorization.
Phase IV: This phase is generally for observational purpose, but can sometimes be interventional too. This phase is conducted in order to provide with additional information about the drug’s efficacy or safety profile. Different age groups, or population from different ethnicity, races, are targeted in this phase. Previously unidentified reactions can be observed in this phase gradually adverse reactions or serious adverse effects are determined along with related risk factors. This is very important for Phase IV because if a marketed medicine is to be evaluated for unknown indication, then those clinical trials are considered first as interventional and then continued as Phase II clinical trials. The term post-marketing surveillance is generally used to describe the study period following the marketing of drug. During this the studies conducted are observational or non-experimental.
These studies always involve a team of experts from Medical & Pharmaceutical sectors to make sure there is compliance in trials with the protocols. The government of the country where the study is held is also involved to make sure the protocols follow the standards set by that particular government and also to make sure that the practice is ethical and patient safety is of highest importance. This study may either be interventional or observational type. In interventional, the patients or the subjects are given specific medical products as per the designed protocol by medical experts or investigators. This medical product could be drugs, devices, vaccine, etc.
In the observational studies, the interventions maybe given to a group of the population but it is mainly for the investigator to observe the health consequences or development in that group with respect to their lifestyles.
A complete clinical trial includes four main stages, collectively known as the Phases of clinical trials. The four clinical phases and drug development in each phase is defined below. However these phases may not always occur in the same chronological order. Sometimes a drug is evaluated in just 2 phases and sometimes the clinical trials may occur in such a fashion that two different phases may overlap each other.
Phase I: This is the primary stage where the first safety trials on a new drug is done in order to establish the exact dose range that is tolerated by the subjects. The dosage type maybe single or multiple. Usually this trial is conducted on severely ill patients like in cases of cancer, and in case of less ill patients, it involves pharmacokinetic studies. Pharmacokinetic studies are generally considered as phase I study. Pharmacokinetic study can be easily defined as the study of what the body of living organism does to the drug from the moment it is absorbed by the body, distribution within the body, its metabolism to excretion.
Phase IIa: This is the first part of the 2nd phase of the clinical trial that involves the evaluation of the efficacy and safety of the drug in a group of selected population. The population here is usually patients with ailments to be treated or to prevent it. This phase concentrated on the dose-response , what type of patients are involved, Objectives may focus on frequency of intervention, dose-response, type of patient, and many other factors that are crucial in determining the safety and efficacy level. This phase may be referred to as pilot trials.
Phase IIb: The objectives of this phase is same as that of the phase IIa, and may sometimes be referred to as pivotal trials. The conditions and factors for evaluation of efficacy and safety may also be same as phase IIa, however this phase represents absolutely thorough and careful, uncompromising display of the drug efficacy.
Phase IIIa: Phase III begins after the drug efficacy has been demonstrated but before the regulatory submission of New Drug. This phase is conducted on the group of population for whom the drug was actually intended to begin with. In IIIa clinical trials a data is generated based on both safety and efficacy but in relatively large numbers of subjects or patients in both controlled and uncontrolled trials. This trial may involve 2 group of patients for comparison of the drug interaction in the body against a placebo. This phase often provides much of the information needed for the labeling of the drug.
Phase IIIb: This phase is conducted after regulatory submission of dossier or an NDA, but prior to the drugs approval by the regulatory body and marketing of the drug. These trials may add on to earlier studies, sometimes may be the end of the clinical studies, or sometimes be directed towards Phase IV evaluations. This is the period between regulatory submission and approval of the drug for marketing authorization.
Phase IV: This phase is generally for observational purpose, but can sometimes be interventional too. This phase is conducted in order to provide with additional information about the drug’s efficacy or safety profile. Different age groups, or population from different ethnicity, races, are targeted in this phase. Previously unidentified reactions can be observed in this phase gradually adverse reactions or serious adverse effects are determined along with related risk factors. This is very important for Phase IV because if a marketed medicine is to be evaluated for unknown indication, then those clinical trials are considered first as interventional and then continued as Phase II clinical trials. The term post-marketing surveillance is generally used to describe the study period following the marketing of drug. During this the studies conducted are observational or non-experimental.
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