This document summarizes a seminar on clinical trials and their design presented by Mhaske Sujit Ramesh. It discusses the different types of clinical trial designs including observational designs like cohort studies, cross-sectional studies, and case-control studies as well as experimental designs like randomized controlled trials. It provides details on each study design including their characteristics, strengths, and limitations. The document also discusses sources of bias in clinical trials and how they can be reduced or avoided in trial design, conduct, and analysis.

1. Seminar On
Clinical Trial And Its And Design
PRESENTED BY
Mhaske Sujit Ramesh
Roll No – 10
M.Pharm (Sem -02)
(Pharmacology Department)
GUIDANCE BY
Prof. Pagar Sir
M.Pharm
Pharmacology
DR. VITHALRAO VIKHE PATIL FOUNDATION’S
COLLEGE OF PHARMACY, VILAD GHAT,
AHMEDNAGAR (2022-2023)
1

2. *
1. Introduction
2. Types of clinical trials
3. Design of clinical trials
a) Observational designs
i. Cohort design
ii. Cross sectional design
iii. Case control study design
b) Experimental designs
i. RCT

3. *
*Definition given by WHO
*A clinical trial is any research study that prospectively
assigns human participants or groups of humans to one or
more health-related interventions to evaluate the effects on
health outcomes.
*Interventions include but are not restricted to drugs, cells and
other biological products, surgical procedures, radiological
procedures, devices, behavioural treatments, process-of-care
changes, preventive care, etc.

4. *

5. Phase 0 Phase I Phase II Phase III
Design
features:
• Single, ascending
dose tiers
• Unblinded
• uncontrolled
• Placebo controlled
comparisons
• active controlled
comparisons
• well-defined entry
criteria
• Randomized
• Controlled
• 2-3 treatment arms
• broader eligibility
criteria
• Uncontrolled
• observational
Duration Up to 1 month Several months Several years Ongoing (following
FDA approval)
Population: Healthy volunteers or
individuals with the
target disease (such as
cancer or HIV)
Individuals with target
disease
Individuals with
target disease
Individuals with
target disease, as
well as new age
groups, genders, etc.
Sample size: 20 to 80 200 to 300 Hundreds to
thousands
Thousands
Example: • Study of a single dose
of drug X in normal
subjects
• Double-blind study
evaluating safety
and efficacy of drug
X vs. Placebo in
patients with
hypertension
• Study of drug X vs.
Standard treatment
in hypertension
study
• Study of
economic benefit
of newly-
approved drug X
vs. Standard
treatment for
hypertension

6. *

7. *
Observational
(non experimental)
cohort
Case
control
cross-
sectional
Experimental
RCT
Non RCT

8. *
Population
(Sample)
Exposed
(smoking)
*A population at risk for the disease events is followed over time for the
occurrence of disease and events.
*This study used to estimate how often disease or life events happen in a
certain population.
*These are the best method for determining the incidence and natural
history of a condition.
Disease
(Lung cancer)
No disease
Unexposed
Disease
(Lung cancer)
No disease

9. *
• A group of people is chosen who do not
have the outcome of interest (for
example, myocardial infarction).
• The investigator then measures a variety
of Variables that might be relevant to the
Development of the condition.
Prospective
• These use data already collected for other
purposes. The methodology is the same
but the study is performed.
• Outcome is already developed.
Retrospective

10. *
*Prospective
*Studies carried out from present time to future
*Can be tailored to collect specific exposure rate
*But long wait for events to occur
*Expensive
*Prone to high dropout rates
* Retrospective
* Look at medical events from past to present
* Information is available immediately
* Difficulty in tracing subjects and doubt on quality of recorded
information

11. *
*Is a type of observational study that are primarily used to determine
prevalence.
*Prevalence equals the number of cases in a population at a given
point in time.
*All the measurements on each person are made at one point in time.
Cohort Cross sectional
Study group Population at risk Entire population
Common measures Risks and rates Prevalence

12. *
*An observational study that compares patients who have a disease or
outcome of interest (cases) with patients who do not have the disease or
outcome (controls), and looks back retrospectively to compare how
frequently the exposure to a risk factor is present in each group
Study base
Cases
50
exposed
40
Controls
50
unexposed exposed
10 15
unexposed
35
Odds ratio
(no of exposed cases)/(no of unexposed cases)
(no of exposed control)/(no of unexposed controls)

13. *
• Efficient- saves time and energy
• Used for rare diseases, small sample sizes
• Can generate hypothesis for future study
*
• Susceptible to bias-recall, reporting
• Prone to methodological errors
• Selection of an appropriate comparison group may be difficult

14. *
*Interventional study (clinical trial) A type of clinical study in
which participants are assigned to groups that receive one or
more intervention/treatment (or no intervention) so that researchers
can evaluate the effects of the interventions on health-related
outcomes.
Interventional study
Quasi-experimental designs
True experimental designs

15. *
Also called nonrandomized interventional study design
*In non randomly assigned control group studies, at least two separate
groups are evaluated—
*One of which receives the intervention of interest and another that
serves as a control or comparison group.
That means it is used to estimate the causal impact of an intervention
on its target population without random assignment.

16. *
• One group pre-test post-test design
• Non equivalent control group design
• Interrupted time series design

17. *
* An epidemiological experiment in which subjects in a population
are randomly allocated into groups, usually called study and control
groups, to receive or not receive an experimental preventive or
therapeutic
*Patients are randomly assigned to the study all groups that help in
avoiding bias in patient
Study
population
Intervention
group
Control group
Outcome
No
outcome
Outcome
No
outcome
(Randomized Clinical Trial)

18. *

19. Randomized Controlled Clinical Trial includes Diagnostic,
Therapeutic, Prophylactic
e.g. Evaluation of nitrates in reducing cardiovascular mortality
Randomized Controlled Field Trial: It is similar to an Randomized
Controlled Clinical Trial except that the intervention is preventive
and not therapeutic.
e.g. In this, the efficacy of a preventive intervention such as a
new vaccine is tested in one study group and the other group
receives a placebo or standard
Preventive Trial: Trial of primary preventive measures
e.g. Vaccines
Risk Factor Trial: Investigator intervenes to interrupt the usual
sequence in the development of disease for those individuals who
have risk factor for developing the disease
e.g. Primary prevention of CHD using simvastatin to lower
serum cholesterol

20. *
*Any systematic deviation from true results.
*It may be any error in the design, conduct or analysis of a study that
results in distortion of truth.
Experiment
Untruth
Untruth
Truth

21. *
Study design
treatment
Data collection
Data analysis and publication
Sources of Bias
Investigator
Participant
Statistician
Literature
Instrument

22. *
*Mann, C.J., 2003. Observational research methods. Research
design II: cohort, cross sectional, and case-control
studies. Emergency medicine journal, 20(1), pp.54-60.
*Grimes, D.A. and Schulz, K.F., 2002. Bias and causal
associations in observational research. The Lancet, 359(9302),
pp.248-252.
*www.who.int/topics/clinical_trials/en

23. THANKYOU
FORPATIENCE