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A Guide to Successful Clinical Trial Design

Prior to the COVID-19 pandemic, the majority of clinical operations, studies, and development were conducted in person. But COVID changed everything, forcing an industry-wide paradigm shift in how clinical trials were conducted and designed.

Now, as we return to a sense of normalcy, experts rightly wonder how the changes in communication strategies, tactics, and tools will impact clinical operations and trial design in the years to come.

With a shift to more virtual clinical trials, what lessons can we apply toward clinical study design? And what novel technologies can further bolster their efficacy and the clarity of the results?

This guide covers everything you need to know about successful clinical trial design in a post-COVID world.


Using technology to improve clinical trial design

Whenever developing a new drug, therapy, procedure, or medical intervention, it must undergo rigorous testing before its release. These medical studies, also known as clinical trials, seek to confirm that the study subject of the trials is safe and does what it claims to do.

But knowing whether the objective of the trial is an effective intervention poses a significant challenge. It’s much easier to determine correlation than causation. As a result, for a clinical trial to be meaningful, there needs to be a union between observational studies and experimental studies. You must ensure that any treatment effect is isolated by controlling for potential biases, confounding factors, and by minimizing possible variants.

Clinical trial design can make or break a study

Put simply, clinical study design can make or break a study. It must be designed properly to mitigate or entirely eliminate such factors from confusing the results, or leading to improper conclusions.


Why is clinical trial design important?

The process of developing a new drug is complicated, to say the least.

5 in 5,000 drugs in preclinical testing progress to human testing

It can take years and millions of dollars for a drug to go from the lab to the pharmacy. In fact, only five in every 5,000 drugs that enter preclinical testing will ever progress to human testing. And of these, only one will ever actually make it to market.

A properly designed clinical trial can provide strong evidence supporting cause-effect relationships and form the basis for clinical and public health policy. But a poorly designed trial can bury a promising therapy before it ever has a chance to develop.

The vast majority of errors in clinical trials are the result of poor planning and design. As one 2019 study notes:

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Clinical trial design is an important aspect of interventional trials that serves to optimize, ergonomize, and economize the clinical trial conduct…A well-conducted study with a good design based on a robust hypothesis evolved from clinical practice goes a long way in facilitating the implementation of the best tenets of evidence-based practice.

Generally speaking, there are several types of study designs, including:

Systemic review
Controlled randomized clinical trial
Cohort study
Case-control study
Cross-sectional study
Case reports and series
Animal research studies

And within each one of these, there are design elements that must be factored into the process.


What are the key features of clinical trials?

There are many fundamental factors that researchers must weigh as they design a clinical trial, including:

Clearly defining the research question – Every clinical trial design begins with the fundamental clinical research question. Over time, the team must refine it from a vague concept to a testable and quantifiable hypothesis. Only after the question is well understood can a research team begin identifying the intrinsic challenges of the study.

Minimizing variation – The greater variation throughout the trial, the harder it will be to narrow down any treatment effect. Ways to reduce variation include:


Constructing consistent and uniform endpoint definitions


Using central labs for quantitating laboratory parameters


Using standardized parameters in how study participants are treated and evaluated

Promoting randomization and stratification – The more randomization that’s introduced into a trial design, the less chance there is for bias to creep in. And a stratified randomized trial helps ensure that treatment groups or study subjects are balanced regarding potential confounding variables.

Blinding – As one of the most fundamental design elements of any clinical trial, blinding ensures that a study’s participants and researchers are unaware of the assigned intervention, which prevents biases or behavioral changes from muddying the results.

Placebos – Similarly, placebos or sham interventions, help ensure that blinding is maintained, though such design features are typically limited to pharmaceutical interventions and not medical devices.

Selection of the control group – A control group gives researchers important data of what would have occurred had the study’s participants either not been treated or been given a different intervention. There are three types of control groups:

Historical controls
Placebo controls
Active controls

Selection of a population – Researchers have to consider the intended target use for the intervention. A study on a drug that helps men aged 65+ manage their heart pressure would be moot if the tested population consisted of young adult women.

Selection of endpoints – An endpoint is intended to address the main objective of the trial. That means it needs to be, “clinically relevant, interpretable, sensitive to the effects of intervention, practical and affordable to measure, and ideally can be measured in an unbiased manner.” Typically, endpoints fall into one of three categories:


Sample size – Statistically speaking, it’s impossible to draw conclusive results from a sample size that’s too small. Similarly, a sample that’s too large will be difficult to control and costly to conduct. As a result, researchers must calculate a happy medium based on the planned analyses.


Types of clinical trials

While there are several types of clinical trial designs and clinical studies, it’s helpful to break them down into four broad categories:

Pharmaceutical clinical trials – Every prescription drug on the market must be approved by various regulatory authorities, such as the USFDA. For that, it must undergo rigorous pharmaceutical clinical trials that include an 11-step approval process:


Animal testing


Investigational New Drug application


Phase I trials


Phase II trials


Phase III trials


Review meeting


NDA application


Application reviewal


Drug labeling


Facility inspection

For example, for the Pfizer COVID-19 vaccine, more than 43,000 participants underwent a randomized, placebo-controlled, observer, blinded, pivotal efficacy trial. Its primary endpoints were the efficacy of the vaccine against COVID.

Oncology clinical trials – Cancer-related clinical trials are intended to test new ways to:


Treat cancer


Improve clinical oncology


Find and diagnose cancer


Prevent cancer


Manage symptoms of cancer and side effects of treatment

For these types of studies, the clinical study is often the last step in a multi-year process that began years earlier with lab research. But that’s not always the case. For instance, in 2020, the National Cancer Institute conducted an observational cohort study to help researchers determine how COVID impacted the outcomes of patients undergoing cancer treatment and how having cancer affects COVID.


Disease-specific complexities


Shared challenges with similar disorders or rare diseases


Difficulty in selecting a large enough sample size

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According to an article published in the Journal of Child Neurology:

The randomized controlled trial is often considered the gold standard for establishing efficacy in a research setting. This design minimizes selection bias and distributes confounders, known and unknown, between study groups.

Medical device clinical trials – Medical devices go through a different approval process than a drug study. Typically, it starts with a small pilot study, followed by a larger pivotal trial. If successful, the manufacturer can then submit the device for FDA approval. From there, manufacturers often choose to also conduct post-marketing trials.

A recent medical device trial was conducted on an epinephrine auto-injector for patients with Anaphylaxis. This randomized, cross-over, unicentric trial was intended to evaluate the following:


Primary outcome measures Patient satisfaction after three months of use through a questionnaire.


Secondary outcome measures Adverse events related to the medical device and patient adherence to the medical device.


How to design a clinical trial

Wondering how to design a clinical trial that is effective and actionable?

Form a testable hypothesis – Remember, the entire process begins with clearly defining your research question in terms of clinical interest. In doing so, you can logically identify the appropriate study design and the necessary components to test your question.

Recruit the right patients and associated professionals – A robust study requires engagement from a diverse group of stakeholders, including researchers, regulators, doctors, scientists, execs, sponsors, and patients.

Design the study – At this stage, communication and collaboration are critical. There needs to be an easy way for patients and investigators to participate and provide feedback. Here, engagement technologies can help optimize study design and engage all crucial stakeholders in the process.

Plan the phases – Typically, a clinical trial will need to undergo four primary phases, including:

Phase I A small group of healthy volunteers assesses the safety, effects, and side effects of a drug.

Phase II Randomized trials allow you to study the drug’s efficacy in terms of safety and effectiveness.

Phase III A much larger randomized and blind testing study will be conducted on a few hundred or several thousand patients. This provides a larger sample size, creating a much greater data pool to measure its benefits, effectiveness, or adverse reactions.

Phase IV Post-marketing trials are used to compare the effectiveness of the drug with other competitors and gauge its long-term safety and efficacy.

Set a budget and milestones – For a lengthy trial to be effective, you must regularly monitor your costs and measure your performance. This allows you to make improvements as you go instead of after the trials. It also creates accountability between all stakeholders.

Test the design – Before trials begin, perform an environmental scan to check for unanticipated factors or events that could throw off the trial or poke holes in the results.


The biggest challenges in clinical trials & how to avoid them

Designing a clinical trial that is effective throughout all phases can be a herculean task, but it’s critical if you wish to bring your drug, therapeutic, or medical device to market. While there are several factors that add to the difficulty, some of the most significant challenges include:


Complexity of trials


Time constraints


Financial demands


A lack of communication


Slow recruitment


Increasing complexity of regulations and compliance standards


Data collection hurdles

And such issues were only exacerbated during the COVID-19 Pandemic.

As the Lancet notes,

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The COVID-19 pandemic has not only re-emphasized the importance of well-designed randomized clinical trials but also highlighted the need for large-scale clinical trials structured according to a master protocol in a coordinated and collaborative manner.

So, how do you avoid or address these common issues?


Using technology to improve clinical trial design

Here is yet another place where, increasingly, technology is filling the gap—especially in response to COVID restrictions and limitations.

For instance, shifting a virtual advisory board or other type of interaction to a virtual engagement platform like Within3, allows for seamless communication, coordination, and collaboration, which helps sites, patients, and payers optimize a study’s design and then execute that vision. It allows for on-demand training, makes it possible to design trial protocols and materials then receive instant feedback, and keeps all critical stakeholders engaged.

By using the platform, you can streamline the entire clinical trial design process. This results in improved trial execution, smarter decisions, and fewer logistical headaches.

Want to see how modern engagement technology can improve your clinical trial designs? Read our case study to learn more.


  1. Medicine Net. Drug Approvals - From Invention to Market … A 12- Year Trip.
  2. NCBI. Clinical Trial Designs.
  3. NCBI. Fundamentals of Clinical Trial Design.
  4. FDA. Drug Approval Process.
  5. New England Journal of Medicine. Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine.
  6. NIH. What are Clinical Trials?
  7. NCI. Clinical Trials, NCI COVID-19 in Cancer Patients, NCCAPS Study.
  8. NCBI. Clinical Trials in Rare Disease: Challenges and Opportunities.
  9. NIH. Clinical Tirals.Gov. Satisfaction of Patient With Anaphylaxis in the Use of a Medical Device.
  10. The Lancet. How COVID-19 Has Fundamentally Changed Clinical Research.