Trials that look at treatments usually take place in four stages, called phases. If a phase is successful, the trial moves onto the next phase.
Phase 1 trials test how safe a new treatment is.
Phase 2 trials look at how effective a treatment is.
The new treatment is given to a larger group of people with a particular disease, to see how effective the treatment is.
Phase 3 trials compare the new treatment with the existing treatment.
Phase 4 trials are carried out after a drug has been licensed. Further information is collected on long term risks and benefits.
Quality of life studies: Most well planned trials include a quality of life study.
Researchers may look at the impact treatment has on you, considering like how often you have to travel to the hospital.