What is a platform trial? A plain English explainer
You may have seen the words ‘platform trial’ on this site, or elsewhere. This short article will explain briefly what a platform trial is, and how it differs from more common types of clinical trial you may have read about elsewhere.
WHAT IS A TRADITIONAL CLINICAL TRIAL?
At their simplest, most clinical trials are set up to see if a drug or other ‘intervention’ (think of things like psychotherapy, mindfulness, or new medical technologies) is a safe and effective treatment for some illness or condition.
Typically, a trial is set up to answer one very specific question about one single intervention. For example, if I give people with high blood pressure a new blood pressure lowering drug do they suffer fewer health complications than people who don’t get the new drug? Who gets the drug and who gets given the control or usual care is randomly assigned.
Figure 1: a simplified schematic of a 'traditional' clinical trial. Click to enlarge.
WHAT ARE SOME OF THE PROBLEMS WITH TRADITIONAL CLINICAL TRIAL DESIGN?
While this approach is effective at answering the question, there are times when it’s not the most efficient way to get an overall answer. With most trial designs, all the infrastructure – the labs, people, trial documentation, recruiting of participants, giving the intervention, and then assessing the outcomes – is closed or dismantled at the end of the study. So, if researchers or health professionals want to look at another intervention, then another study needs to be set up, which can be time consuming. And the cycle begins again.
There are, of course, many variations on the typical clinical trial design that allow testing of multiple different drugs, but most all share two things: a defined number of interventions and a defined end point for the study.
HOW DO PLATFORM TRIALS DIFFER?
Platform trials are different in that they are open ended, meaning new interventions can be added, assessed, and removed as time goes on, without having to specify what they might be at the start.
Compared to a more traditional intervention focussed trial design (is this drug better than usual care / placebo?), a platform trial can be better thought of as disease focussed (what is the best drug for this disease?).
As well as being able to add new interventions as time goes on, platform trials also have the flexibility to update the control, or ‘usual care’ group as the study progresses. This is useful for when, for example, the platform trial shows a drug it’s testing to be much more effective that ‘usual care’, then that drug can be rolled out to benefit patients right away and become the new ‘usual care’ against which all new drugs are tested in the trial, creating a potential cycle of improvement.
Figure 2: simplified schematic of a platform trial. Click to enlarge.
PLATFORM TRIALS IN THE REAL-WORLD
The COVID-19 pandemic gave platform trials a chance to shine, and really demonstrate their benefits.
At the outset of the pandemic, we had no treatments for COVID-19 and few ideas about what might work. Platform trials like PRINCIPLE and RECOVERY quickly identified effective treatments for COVID, that immediately changed how COVID was treated in hospitals and in the community.
The Primary Care Clinicals Trials Unit led the world in rolling out two nationwide platform trials for testing new treatments in community settings (i.e. outside of hospitals) called PRINCIPLE and PANORAMIC. PANORAMIC rapidly became the biggest ever and fastest recruiting trial of its kind.
The PRINCIPLE trial was originally set up to find existing drugs that we could repurpose for treatment of COVID-19 to treat the most vulnerable people in the community and prevent them needing hospitalisation. It has so far looked at seven different drugs and recruited over 10,000 participants, and changed national guidelines on treatment.
The PANORAMIC trial differs from PRINCIPLE in that it’s focus is on assessing antivirals that were specifically created for treatment of COVID-19. Launched during the first wave of the omicron variant in early December 2021, PANORAMIC recruited in excess of 25,000 people by mid-April. A phenomenal and record breaking achievement.
Two drugs have so far entered the PANORAMIC trial and, at the time of writing, the final data for one of them is being collected and we hope to have an answer soon about its benefits.
Find out more about PRINCIPLE at www.principletrial.org and PANORAMIC at www.panoramictrial.org.
