Clinical Trial Design Service — Making Everything Sure

There are several types of Clinical trial design. They can be classified as follows:

1. According to the method used to assign participants to groups of treatment or control (randomized controlled trials or randomized not).
2. According to the knowledge of the participants, the investigators, or both of which group the participants were assigned (double-blind or single-blind studies).
3. According to the magnitude of the difference between the treatment and control groups expected (superiority or non-inferiority trials).

Controlled and non-randomized clinical trial designs

In the case of non-randomized Clinical trial design, the investigator assigns participants to the control and treatment groups. In these assays, the control groups can be simultaneous controls or historical controls. If a historical control is used, all trial participants receive the study drug, and the results are compared to the patient’s history (for example, patient with a chronic disease) or a previous control group.

Randomized controlled clinical trial designs

In the case of randomized controlled trials, participants are randomly assigned to treatment or control groups. The process of randomizing a trial participant to treatment or control groups is called ‘ randomization ‘. Various tools can be used for randomization (sealed envelopes, computer-generated sequences, and random numbers). There are two components associated with randomization: the generation of a random sequence and the implementation of that random sequence, ideally in a way that the participants do not know the sequence.

There are several types of randomized trial designs.

Clinical trial design with parallel groups

In the case of parallel-group randomization, after randomization, each participant remains in the assigned treatment group throughout the study.

Trial design with crossover groups

In the case of crossover randomization, participants receive a series of different treatments.

Trial design with paired data

In the case of the paired data design, first, the participants are matched in pairs according to specific characteristics. Each member of a pair is then randomly assigned to one of the two study subgroups.

Stratification

The stratification allows the comparison between similar participants who study different procedures apply.

Cluster sampling

Cluster sampling can also be used in randomized Clinical trial design. In cluster sampling, the corresponding geographic areas (e.g. city, region, etc.) are determined.

Factorial design

Factorial design clinical trials allow testing the effect of various treatments. This allows the evaluation of possible interactions between treatments.

Comparative Clinical trial design

There are different types of comparative tests:

• Superiority to show that the investigational drug is better than the control.
• Equivalence to show that the endpoint is similar (neither worse nor better) compared to the control.
• Non-inferiority to show that the investigational drug is no worse than the control.