Clinical Trials – Types & Design
Submitted To – Mrs. Anuradha
Submitted by – Kirti
M. Pharm (Pharmacology)
Maharshi Dayanand University, Rohtak
Clinical Trials - Types & Design
• Clinical trials – Clinical trials are research studies performed in people that are
aimed at evaluation a medical, surgical or behavioural intervention.
• Clinical Trials are the primary way that researchers find out if a new treatment,
like a new drug or diet or medical devices is safe and effective in people.
• A clinical trial is used to learn if a new treatment is more effective and has less
harmful side effects than the standard treatment.
• Therefore the authorities like FDA approves a clinical trial to began, scientists
perform laboratory tests and studies in animals to test a potential therapy’s
safety and efficacy. If these studies show favourable results, the authorities
gives approval for the interventions to be tested in humans.
Phases of Clinical Trials
• Phase 0 (Microdosing Study)
• Phase 1 (Dose Ranging & Safety )
• Phase 2 (Therapeutic Exploratory Trial)
• Phase 3 (Therapeutic Confirmatory Trial)
• Phase 4 (Post Marketing Surveillance)
Phase 0 (Microdosing Study)
Use only a few small doses of a new drug in a few people. They might test whether drug
reaches tumor, how drug act in human body, how cancer cells in human body respond to
• An experimental treatment on a small group of often healthy people (20-80)
to judge it’s safety and side effects and to find the correct drug doses.
• Objective – To determine the metabolic and pharmacological actions and the
maximally tolerated dose.
• Factors to be identified – Pharmacokinetics, Pharmacodynamics,
Bioavailability, Metabolism, bioequivalence.
• Duration – upto 1 month.
• Sample Size – 20-80
• Population – Healthy volunteers or Individuals with the target disease (such
as – Cancer or HIV ).
• The Emphasis in phase II is on effectiveness. These trials also continue to study
safety, including short term side effects
• Objective – to evaluate effectiveness, determine the short term – side effects and
identify common risk for a specific population & diseases.
• Factors to be identified – Bioavailability, Drug – Disease interaction, Drug –Drug
interactions, Efficacy at various doses, Pharmacodynamics, pharmacokinetics,
• Duration – Several months.
• Sample Size – 200-300
• Population – Individuals with target disease
• It gather more information about safety & Effectiveness. Studying different
population & different dosages, using the drug in combination with other
• If the authorities like - FDA aggrees that the trials results are positive, it will
approve the experimental drug or devices.
• Objective – to evaluate the overall risk – benefits ratio in a demographically
• Factors to be identified – Drug-disease interaction’s, Drug-Drug interaction’s,
risk-benefit information, efficacy & safety for sub groups, dosage intervals.
• Duration- Several Years
• Sample Size -100-1000
• Population – individual with target diseases.
• Used for drugs or devices takes place after the authorities like FDA approves
their use. Sometimes the side effects of a drug may not become clear until
more people have taken it over a longer period of time.
• Objective – To monitor ongoing safety in large population’s & identify
additional uses of the agent that might be approved by the FDA.
• Factors to be identified – efficacy and safety within large, diverse population’s,
• Duration – ongoing (following FDA approval)
• Sample Size – thousands
• Population – individuals with target disease as well as new age group, genders
• Experimental studies also known as interventional studies. The national
institute of health (NIH) defined an interventional studies as individuals in
which “participants receive specific interventions according to the research
plan created by the investigator. These interventions may be drug, device ,
• It is further classified on the basis of randomization. Randomization is the
heart of the experimental studies.
A. Randomized Controlled Studies
Randomized controlled study design is the highly reliable design and it is high level
evidence to practice health profession. As the name indicates, control group is
present as a comparator to the interventional group.
In this study interventional group receives interventional drug and control group
receive either old drug or placebo.
For randomized controlled study is also named as
- Clinical Trials
- Gold standard study
1. Parallel Studies
• A parallel Study is a type of clinical study where treatment and controls are
allocated to different individuals.
• In this two groups of treatments are given so that one group recieves only one
type of treatment and another group receives other treatment.
2. Cross over studies
• In this type of studies each patient serves as his own control. Each
patient gets both treatment.
• Each patient receives first treatment then wash out time is provided
then other treatment is provided to the same patient.
Randomized Uncontrolled Studies
• In this study there is no control group present only one group present
with randomization. It is so weaker when this study compared with
the randomized controlled study.
randomized study population
B. Non-randomized Studies
1. Non randomized controlled Study-
• The study is same that of the randomized control study but without
• The control group receive placebo or old drug and interventional group receives
interventional drug and then outcomes measured. Sometimes hospital records
data obtained from published literature can be used as a control group, such non-
randomized or non-current studies named as historical control study.
2. Non-randomized uncontrolled study -
• This study is also same as that of randomized Uncontrolled study but without
randomization & control group.
• Outcomes measured finally after the collection.
Non Randomized Population
1. Latin Square
• Latin Square design helpful to study more than the one treatment
simultaneously to understand the usefulness of each treatment by the
For example, four treatments namely – A,B,C,D then latin Square is applied ( four
replications of each treatment) as follows and do comparison.
2. Factorial Randomized Study
• Studies involving two or more factors while randomizing are called factorial.
• In this study, only one control group and two interventional groups are present.
• The results of each group comparing with the control group, and with the help
of this study we can access at a time two factors ( treatment and doses form).
• Used when it is desired to study the influence of a number of factors on the
treatments compared as well as their interaction with different treatments
factors on a dependent variables
3. Cluster Randomized Design -
• In cluster Design group of participants are randomized & made into clusters
• Individuals are randomized in a group.
• Example- A group include, school in a city, religion, occupation in an area,
hospitals in a city.
• It is simple to randomized the participants by groups.
• The data are also collected group wise.
9. M N Parikh, Nithya Gogtay. ABC of research methodology and applied biostatistics a
primer for clinicians and researchers. Published by Jaypee Brothers medical Publishers (P)
Ltd, New Delhi, India, 2009.
10. P S S Sundar Rao, J Richard. Introduction to biostatistics and research methodology.
Published by Phi Learning (P) Ltd, New Delhi, India, 2009.
11. R Raveendran, B Gitanjali, S Manikandan. A practical approach to PG dissertation.
Published by Pharma Med Press, Hyderabad, 2014.
12. Center for Disease Control and Prevention Principles of Epidemiology in Public
Health Practice, 3rd ed, Published by U.S Department of Health and Human Services, 2010.
13. K G Revi Kumar, B D Miglani. A text book of pharmacy practice. Published by
Career Publications, Maharashtra, India, 2012.
14. Justin Besen, Stephanie D Gan. A critical evaluation of clinical research study designs.
Journal of Investigative Dermatology, 134, 2014.
16. Jesper Hallas, pharmacoepidemiolog-current oppurtunities and challenges,
Norwegian Journal of Epidemiology, 11(1):7-12, 2001.
17. Brian L.Strom, Stephen E.Kennel, Sean Hennessy. Text book of
pharmacoepidemiology. Published by Wiley Black Well, UK, 2013.
18. Mohit Bhandari, Parag Sachet. Clinical research made easy. Published by Jaypee
Brothers medical Publishers (P) Ltd, New Delhi, India, 2010.
19. D Sudheer Kumar, Dr.J.Krishna Veni, Dr.P.Manjula. Fundamentals of clinical
pharmacy practice. Published by Pharma Med Press, Hyderabad, 2010.
20. Dr.H.P.Tipnis, Dr.Amrita Bajaj, Clinical pharmacy, Published by Carrer Publications,
India, 2013. 21. httpwww.iarc.frenpublicationspdfs-onlineepicancerepiCancerEpi-5.pdf
22. B Gitanjali, Pharmacoepidemiology in India: falling into a rut. IJP, 35:137-138, 2003.