Risk and Benefits

Phase 0

  • Phase 0 trials are not always done. They have a small chance of helping, but also a small chance of harming. Doses start very low and patients are closely monitored. Patients usually stay in a hospital during treatment.

Phase I

  • Phase I studies mainly look at safety issues. But Phase I studies do help some patients. Phase I studies also have the most potential risk of any of the different Phases because the treatments usually have not been tried in humans before. For those with life-threatening illnesses, weighing the potential risks and benefits carefully is key.

Phase II

  • Potential benefits depend on the goal of the treatment. For example, a tumor may shrink, or grow more slowly, or stop growing.  In some studies, the benefit may be improved quality of life, or improved educational achievement. Some studies look to see if people getting the new treatment live longer than they would have been expected to without the treatment.
  • Phase II trials may cause some patients to have side effects that were not seen in the smaller Phase I group. Also, there is the risk that the treatment will not benefit a patient even if some others do benefit.
  • Most Phase II studies do not involve a control group (some patients are randomly assigned to a “no treatment” group). But some Phase II studies do have a no treatment group that is compared to the treatment group. You can find out if a trial uses a placebo or control group by reading about it or asking the researchers. If it does have a control group, you may be randomly assigned to the control group.

Phase III

  • When a treatment makes it to Phase II, it has already shown effectiveness and safety. This makes it promising for providing benefits to patients. Like Phase II, there is the risk that the treatment will not benefit a particular patient, even if some others do benefit.
  • Phase III clinical trials compare the safety and effectiveness of the new treatment against the current standard treatment. Thus there will be a control group, and you might be randomly assigned to it. Sometimes, if researchers find a clear advantage to the treatment during the trial, patients in the control group will be switched over to the new treatment.

Sources: www.clinicaltrials.govwww.genome.govwww.cancer.org