The earliest phase trials might focus at whether a drug is safe or the side effects it causes.

1. Types Of Clinical Trials And Its Significance
Clinical trials means medical research studies involving people. They are divided into
different stages, called phases. The earliest phase trials might focus at whether a drug is
safe or the side effects it causes.A later phase trial aims to test and compare whether a
new treatment is better than existing ones.
Types of Classifications:
In one way of classification it is based on the behavior of researches:
• Clinical observational study: The investigators observe the subjects and
measure their outcomes. They don't actively manage the study.
• Intervention study: The investigators give the research subjects a particular
medicine to compare the treated subjects with those receiving no treatment or
the standard treatment. Based on inferences the investigator measures the
health changes if any.
Another method of classification is based on their purpose. The U.S. National Institutes
of Health (NIH) organizes trials into five different types:
• Prevention trials : It attempts to find better ways to prevent diseases in people
who were never susceptible or to prevent a disease from returning. These
approaches include medicines, vitamins, vaccines, minerals, or lifestyle changes.
An example of a prevention trial is the IBIS 2 breast cancer prevention trial.
• Screening trials: The best way to detect certain diseases or health conditions. The
study of causes and patterns of disease is called epidemiology. Most
epidemiological studies are observational studies.
There are three types of observational studies – cohort studies,case
control studies and cross sectional studies.
• Diagnostic trials : To find better alternative for diagnosing a particular disease or
condition. For example to study tests or procedures that could be used to identify
cancer more accurately. Diagnostic trials usually include people who have signs or
symptoms of the disease.
• Treatment trials : It efforts testing experimental treatments, new combinations of
drugs, or new approaches to surgery or radiation therapy. They are conducted with
diseased people as test subject. They aim answering specific questions about and
evaluate the effectiveness of a new treatment or a new drug or a new approach of
using a standard treatment.
• Supportive care trials : It attempts find the quality of trials. It aims finding
ways to improve the comfort and quality of life for individuals with a chronic
illness.

2. • Expanded access trials : Also known as compassionate use trials. It provides
partially tested, unapproved therapeutics to a small number of patients who have
lost all realistic options. Usually this involves disease for which no effective therapy
has been yet approved.
A third classification is whether the trial design allows changes based on data
accumulated during the trial.
• Fixed trials : It considers existing data only during the trial's design, and does not
modify the trial after it begins and even not assess the results until the study is
complete.
• Adaptive clinical trials: This use existing data to design the trial and then use
inferred results to modify the trials as it proceeds. Modifications include dosage,
sample size, drug undergoing trial, patient selection criteria and "cocktail" mix.
Adaptive trials often employ a Bayesian experimental design to assess the trial's
progress.
Phases of clinical trials
Clinical trials are a kind of clinical research designed to evaluate and test new interventions
such as psychotherapy or medications. Clinical trials are often conducted in four phases.
The trials at each phase have a different purpose and help scientists answer different
questions.
Phas
e
Aim Commen
t
Phas
e 0
Pharmacodynami
csand pharmacokinetics preliminary data on the agent's act in the body and
what the
in
humans
First-in-human trials.
Single sub therapeutic doses of the study drug or
treatmentare given to a small number of subjects (10 to 15) to
gather
body does to the
drugs.
Phas
e 1
Safety
screening
Testing within a small group of people (20–80) to
evaluate safety, determine safe dosage ranges, and
begin to identify side effects. Phase 1 trial can't detect
all the side effects as it might happen with only a
handful of people.
Testing with a larger group of people (100–300) to see
if it is effective and to further evaluate its safety.
Gradually the test size is increased to find out most
common side effects.
Testing with large groups of people (1,000–3,000) to
confirm its effectiveness, monitor side effects, compare
it to traditional treatments and collect information that
will allow it to be used safely.
Post marketing studies depict additional
information, including the treatment's risks, benefits,
and optimal use.
Phas
e 2
The drug's efficacy
is established
,usually against a
remedy
Phase Final confirmation
of
3 safety and efficacy
Phase Safety studies
during
4 sales
CRB Tech Solution's Clinical Research review is sufficient to make you consider and
take up a career in this field.