If you have serious medical condition, perhaps even life threatening, it can be a terrifying time to discover that there are no traditional medicines and treatments available. At that point, you may be asked if you would like to take part in a clinical trial, which involves taking a drug or undergoing a treatment which is not yet approved for use.

Before a new drug or treatment is put on the market, it must be trialled and there are various different stages (or phases) that it must pass before it can be considered by the relevant regulatory authority and entered on to the market.

Phase I

Phase I trials typically involve a small number of healthy, non-patient volunteers, although recently there has been an increase in Phase I trials which involve patients. Patients taking part in such trials, even though they have the disease the new drug is seeking to treat, are not expected to gain any benefit from the drug at this stage. Essentially its aim is to monitor how the drug interacts with the human body, how the body tolerates the molecule, how safe it is and at what dose. As with all the other phases, taking a drug at this stage can result in the volunteer suffering from side effects. As the drug is new and experimental the researchers do not know what side effects, if any, will occur and they are therefore unable to warn the volunteer of all of the risks of taking the drug.

Phase II

Phase II trials test the effectiveness of the drug in a small groups of patients with the condition or disease the new drug is aiming to treat. The new drug is compared to an existing treatment or a placebo (this is a fake version of the drug which does not contain any of the active ingredients) and again, side effects are monitored.

Phase III

Phase III trials aim to confirm the effectiveness of the drug in larger trials. A larger group of patients are tested and monitored for side effects. Participants are usually placed into a group at random (randomisation). They may be placed in the group that receives the drug or in the group that receives the placebo. In addition, if they are placed in the group that receives the drug, they may be selected to receive a high dose or a low dose. Trials are usually blind tested, which means that the volunteer is not told (and neither are their treating doctors or trial doctors) what group they are in and, therefore, don’t know if they are receiving the drug or not. At this stage it is also assessed how the new drug or treatment compares to the tried and tested drug, or treatment, already on the market. The risks and benefits are weighed up. Typically, it must be shown that the new drug or treatment is better than the existing one.

Only when it has passed the different phases will it be approved for use. The whole process of getting a drug approved can take many years and involve thousands of participants.

If you suffer a serious injury as a result of taking part in a trial you may be able to claim compensation. The Clinical Trial Compensation Guidelines by the Association of the British Pharmaceutical Industry (‘ABPI’) sets out when the Trial Sponsor (this is usually the pharmaceutical company who is sponsoring or paying for the trial) will be required to pay compensation to the volunteer and it differs slightly depending on which phase you are in.

Phase I

Prior to taking part in a phase I trial the participant will be given a participant information sheet and a consent form to sign. This will typically include a clause which states that the Trial Sponsor will pay compensation to the volunteer if they suffer injury as a result of taking part in the trial.

Under the ABPI guidelines, the volunteer does not have to prove that they were injured as a result of negligence or prove that the drug they were given on the trial was “defective”. They should be given a “clear commitment” that compensation will be paid if they suffer injury as a result of taking part in the Trial. This is called “strict liability”.

Phases II and III

Volunteers taking part in a Phase II or Phase III trial will also be given a participant information sheet and consent form to sign. Unlike phase I trials, the ABPI guidelines recommend that compensation should be paid to patient volunteers if they can establish on the balance of probabilities (i.e. it is more likely than not) that the injury was attributable to their participation and that the injury would not have occurred but for their inclusion on the trial.

Although slightly more difficult, strict liability still applies and the participant does not have to show that the sponsor was negligent or that the drug was defective.

Compensation may be reduced or wiped out altogether if the participant who has taken part in a Phase II or Phase III trial has gained a significant benefit from taking the trial drug which they would not have gained from proceeding with traditional treatments. For example, if the trial drug has been successful in treating their illness or has prolonged life, but the participant has suffered injury or had an adverse reaction to the drug it may be considered that the benefits they gained outweighed the risks of taking the drug.

In addition, if the trial doctor administers the trial drug incorrectly (for example, they give too large a dose or inject it incorrectly and sever an artery) the trial sponsor would in all likelihood say that the actions of a third party caused the injury and not them and would probably not pay out. In those cases, the injured participant may be able to pursue a claim against the trial doctor in negligence. This would mean establishing that the trial doctor owed them a duty of care, that they breached that duty of care and that this breach of duty caused their injury.

While significant benefits can be gained from participating in a trial volunteers should be fully informed of the risks where possible, and of the fact that they may be entitled to compensation if they suffer an injury.