Tutorial

Clinical Trials

The medical knowledge evolves from basic research to clinical trials. The patients enrolled in clinical trials are protected by ethical and methodological regulations. When browsing through the items below, you will understand how the doctors have conducted and validated the results of the clinical trial.

  • Basic research is carried out in tumor biology laboratories, involving cell cultures and xenographts (tumor implanted in experimental animals). It includes studies on cellular biology, signaling transduction pathways, expression of oncogenes, proteins and membrane receptors in cancer cells. Basic research also investigates new cancer drugs, describing their mechanism of action and pharmacokinetics. It is a very creative step in the acquisition of new technologies. The patients are enrolled in clinical research, only when the knowledge developed in basic science allows technical and ethical support for a rational and well-designed clinical trial. In an attempt to protect the patients, the clinical trials looking for new anti-cancer drugs or new cancer treatment strategies are classified in progressive phases.

  • Phase I clinical trials are designed to study new anti-cancer drugs, testing their mechanism of action, therapeutic doses, bioavailability, metabolism and excretion sustained by a well-selected patient accrual. All adverse effects should be carefully reported, allowing to better defining the drug therapeutic index.

  • Phase II clinical trials are designed to test the tumor response to a new anti-cancer drug. Usually, the phase II applies to patients in palliative care, trying to improve the survival or the quality-of-life. A high response rate observed with the new tested drug in a phase II trial indicates the need for a well-designed phase III trial.

  • Phase III trials require the distribution of the patients into two arms. The patients are randomly assigned to a standard treatment arm and to an experimental arm, evaluating the new drug or new therapeutic strategy. The phase III trial is only justified when the new proposed treatment has shown impressive results in phase II trials, that go beyond the one expected with the conventional treatments or when, despite the same outcome, there was a significant reduction in adverse effects.

  • Patient’s eligibility for clinical trials is supported by specific inclusion criteria and expressed informed consent. Cancer research projects are conducted only in authorized institutions with appropriate clinic and laboratory facilities. All projects should pass through an ethical committee, whose primary role is to ensure patient’s safety.