Clinical Trials for cancer therapies

They collect data on the safety of the new intervention under study, as well as their efficacy as compared with both placebo (no treatment) and the current treatment for a given disease. In the United States, clinical trials are performed under the auspices of the Food and Drug Administration (FDA) to gain approval for a new intervention, such as a new chemotherapy drug.

Clinical trials for a new intervention are conducted as a series of studies. They begin with the identification of a drug, device, or intervention which has shown promise in the laboratory in at least two different species of non-human mammals. This intervention is then studied in separate trials for its safety in patients, its efficacy against placebo, and its efficacy against the known existing treatments for a given type of disease, such as cancer.

Clinical trials for cancer research typically begin with a “phase 0” study. This type of study, which was officially recognized by the United States FDA in 2006, is designed for the purposes of understanding how the drug is distributed throughout the body, and how it is metabolized. In these studies, healthy volunteers without cancer are given very small doses of the drug under investigation.

A phase 1 clinical trial focuses on the safety of a new intervention for cancer. It is typically conducted with a small group of healthy volunteers, although in special cases patients with cancer can join these types of studies. The volunteers reside as inpatients in a clinic or hospital, and are typically given small ascending doses of the intervention under study at increases doses (or shorter dosing intervals) and monitored for side-effects and drug toxicities. In many cases, blood and urine samples will be collected for analysis.

If a drug, such as a new chemotherapy agent, can be shown to be safe in a phase 1 clinical trial, it is then studied further in a phase 2 clinical trial. This kind of trial is conducted with a larger group of volunteers, typically patients with the cancer or disease under study, and collects data on dosing requirements (how much of a drug, and how often, are required by different types of patients) as well as efficacy as compared with a placebo, or no treatment.

When the dosing requirements of a new drug are satisfactorily understood from a phase 2 clinical trial, and its efficacy against placebo has been demonstrated, the drug is then approved for the final stage of a cancer clinical trial, the phase 3 study. Phase 3 studies are performed with very large numbers of subjects (typically in the thousands to tens of thousands), and are focused on intensive assessment of the efficacy of the new treatment compared with the current, “state-of-the-art” treatment. In the United States, the FDA typically requires two successful phase 3 trials, showing equal or better efficacy of the new treatment or intervention as compared with the “state-of-the-art” treatment, for approval to marketing.