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Clinical Trials

In this series of articles, medical students from across the country will discuss a range of topics from medical ethics to the NHS to public health to medical conditions to clinical governance.


🏥COVID19 & Hydroxychloroquine

Due to the current COVID-19 pandemic the topic of clinical trials has been very prevalent within the news. Clinical trials are the gold standard way to find treatment for new diseases and work by comparing one treatment with another or a placebo (a “fake” medication). The trials may involve patients, healthy people or both. Currently there are many clinical trials for COVID-19 working to develop treatments for the disease from primary care level to critical care.

The initial focus for COVID-19 trials is “drug repurposing”. This is where trials are using already licensed medications to speed up developing a safe, effective antiviral therapy (a license means that the medications are available on prescription). An example of this is using hydroxychloroquine to treat COVID-19, which is a licensed anti-malarial and disease-modifying anti-rheumatic drug. Drug repurposing will ensure that the treatment is safe and effective, but the trial will also need to help identify the correct dose, the right demographic of patients and the correct time in the illness to provide the treatment.

⚕️ Phases of Trials

  • Phase 1 - This is when the new drug is being trialled in human volunteers for the first time. A small number of usually healthy volunteers are given the drug in a small dose. The dose is only increased if the volunteers do not experience side effects.

  • Phase 2 - The treatments that have been found to be safe in phase 1 are tested in this phase on a larger group of targeted individuals (those that are ill) to monitor for any adverse side effects.

  • Phase 3 - This is the stage before the treatment is approved. Several thousands of ill patients are given the drug and it is compared against current treatment or a placebo to see the impact of the treatment in clinical practice and identify any further side effects.

  • Phase 4 - This phase is not required for all medications and is only carried out medications that have passed all the previous phases and have a license. It is the continuous monitoring of safety, side effects and effectiveness of treatment in clinical practice.


Most phase 3 and some phase 2 trials are randomised. Randomised trials have at least 2 treatment groups and individuals are randomised into either group. Randomisation usually takes place by a computer generator, which eliminates selection and allocation bias.

The baseline characteristics of the two groups are also taken to ensure that the two groups are similar and confounding factors (a variable that influences both the dependent and independent variable, assuming association) are taken into account.

A randomised trial that has a control group is called a randomised controlled trial (RTC). The control group is given the standard treatment that they would have had if they weren’t in the trial and the other group has the new treatment that is being tested. RTC’s are therefore interventional and prospective.


Blinding refers to the act of masking the nature of the treatment that participants in the RCT receive. The two treatment groups are given medication that looks, smells and feels the same as the other group. It is a way of eliminating bias. RTC’s can be blinded in the following ways;

  • Single blind trials - researcher knows, patient does not.

  • Double blind trials - researcher and patient does not know.

  • Triple blind trials - researcher, patient and doctor does not know.

📜 Further Reading


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