Association of Clinical Research Professionals (ACRP) Certified Professional Practice Exam

In which study design are subjects randomized to different treatment arms, each with their own investigational product?

1. Open-label study

2. Crossover

3. Parallel

4. Single-arm study

The correct answer is: Parallel

In a study design where subjects are randomized to different treatment arms, each with their own investigational product, the parallel design is the appropriate framework. In this design, participants are assigned to one of two or more groups simultaneously, with each group receiving a different intervention. This allows for direct comparisons between treatment arms, as subjects in each group are treated independently and do not switch between groups during the trial, thereby maintaining the integrity of each treatment's evaluation. This approach is particularly useful in clinical trials for assessing the efficacy and safety of new therapies against a control or comparator group. Each group may experience different treatments over the same period, which helps in determining the effectiveness of the interventions being tested. In contrast, the other study designs listed do not fit the criteria specified in the question. Open-label studies involve no blinding, where both the participants and the researchers know which treatment is being administered. Crossover studies allow participants to receive multiple treatments in a sequential manner, which is not the same as being randomized into separate treatment arms from the outset. Single-arm studies consist of a single group of participants receiving one intervention without comparison to a control group, hence lacking the randomization aspect across different treatments.