It is a large step from the laboratory to the clinic, particularly when it comes to the discovery and testing of new cancer treatments. After extensive laboratory research of a potential new cancer treatment, an Investigational New Drug (IND) application is filed with the Food and Drug Administration( FDA ). Following FDA approval, the three phases of clinical trials may begin. As there are significantly more adults with cancer than children, Phase 1 testing is usually begun in adult patients. After initial information is gathered on a new drug's safety, Phase 1 testing may begin in children with cancer. Clinical protocols are designed by experts in various fields of cancer therapy and then reviewed by an independent group of people who comprise the Institutional Review Board (IRB). Every medical center performing clinical trials must have an IRB, which reviews the protocol and approves its design before the clinical trial can begin.

The primary objectives of a Phase 1 trial are to determine the optimal dose of an experimental drug (or a standard drug which is being administered in a new way), the behavior of the drug in the human body and the side effects or toxicities. The optimum dose is usually the maximum dose which can be administered. Phase 1 trials are for patients with cancer that no longer responsive to standard treatment. In a Phase 1 trial, small groups of patients are treated with the same dose of a new drug. Based on how the patients tolerate the drug, small adjustments are then made in dose and administered to another group of patients. The dose is usually increased, but in some instances, the dose may have to be lowered. For pediatric Phase 1 trials, patients are treated with doses that are close to the dose recommended for further testing in children with cancer (Phase 2 trial). Children treated on a Phase 1 study continue to receive the experimental drug only if the drug is helping the child. If the child's tumor continues to grow, Pediatric Oncology Branch physicians then meet with the family to discuss what other therapeutic options are available.

Following completion of the Phase 1 trial, the new drug is then tested in Phase 2 trials, which test the ability of the drug or combination of drugs to produce measurable tumor shrinkage. In a Phase 2 trial, groups of 14 to 30 patients with the same type of tumor are treated with the new drug. As for Phase 1 trials, only children with cancers that are no longer responding to standard treatment are eligible for treatment on a Phase 2 trial.

Phase 3 trials compare two or more treatments for a particular kind of cancer. Typically an experimental treatment is compared to a standard treatment, although in some cases two standard treatments or two promising new treatments may be compared. The objective is to see if the new treatment produces better results than standard treatments. Phase 3 trials are normally randomized, meaning that patients are randomly assigned to either one or the other treatment. Phase 3 trials have more patients than Phase 1 or 2 trials, often hundreds or sometimes thousands. Phase 3 trials are performed cooperatively by a large number of medical centers across the country. For children with cancer, there is the Children's Oncology group in the United States. The Pediatric Oncology Branch of the NCI usually does not perform Phase 3 testing, but does perform smaller clinical trials termed "pilot trials" that incorporate the latest information from laboratory and clinical trials into a new protocol. These pilot trials may then form the basis for the design of future cooperative group Phase 3 trials.

Last Updated:July 26, 2006

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