Pfizer Public Policy: Clinical Trials

Clinical trials involve testing a promising new drug in human volunteers to determine the drug's safety and effectiveness. Clinical trials are critically important to the drug development process.

• Clinical trials are one of the most important, expensive and time-consuming parts of new drug development. This necessary process is part of the reason why drugs are priced as they are.
• The three phases of clinical trials best determine the safety and efficacy of an experimental drug by applying the highest scientific standards.
• Pfizer is one of the world's largest sponsors of clinical trials. Pfizer recognizes that ensuring patient safety is of utmost importance in clinical trials, and has taken steps beyond what is required by U.S. law by adopting internal procedures that ensure compliance with all international standards, and creating policy statements on a variety of clinical research topics so that there is a common policy and understanding within the company.

Clinical trials are broken into three parts, as shown in Chart 1:

Phase I

The main goal in phase I studies is to determine the safety of a drug. A small number of healthy volunteers participate in studies so that information can be gathered about how the drug is absorbed, distributed, metabolized, and eliminated by the body. The amount of acceptable toxicity of the drug depends on how serious the disease is that the drug is intended to treat and what other alternatives may exist. During the course of Phase I study, a series of gradually larger single doses are administered. If these increases do not cause problems, another study is undertaken on a wider range of doses to gather further information about safety, tolerance and pharmacological effects. About one experimental drug out of three fails during this phase.

Phase II

In this phase of study, for the first time after several years of difficult work, the experimental drug is carefully administered to selected patients suffering from the disease being targeted. Generally 100 to 300 patients are enrolled in these Phase II studies. These trials are usually "double-blinded," meaning that neither the patient nor the investigator giving the drugs to the patient knows who is getting the real drug and who is getting the placebo. These trials try to establish a signal of efficacy in the experimental drug. If this is achieved, new studies are designed to determine the amount and frequency of dosing that provides the most benefits with the smallest number of side effects Phase II trials can take upwards of two years.

Phase III

These studies usually involve thousands of patients over several years. They are almost always double-blinded and placebo controlled (meaning that one group of patients receives only a placebo). These trials give the best indication as to whether or not the drug will help many people and that it will be safe for the public.

The conduct of a clinical trial poses many challenges. Not only must the trial itself be designed and executed so as to provide credible scientific information, more importantly it must be conducted in way that affords information and protection for the patients who are involved in the trial.

Pfizer is one of the world's largest sponsors of clinical trials. Pfizer has taken a step further than what is required by U.S. law by adopting internal procedures that ensure compliance with all international standards. In addition, the company has created policy statements on a variety of clinical research topics so that there is a common policy and understanding within the company. These included policies on compassionate use of unapproved drugs, the public disclosure of trial results, and how investigators and patients are compensated.

As clinical trials become even more challenging and sophisticated, Pfizer remains committed to updating its policies and assuring compliance in all of its research projects.

Related Information

Conducting Ethical Research

Pfizer strives to maintain the highest ethical, scientific, and clinical standards in all clinical research that we undertake. Learn about the ethical standards that Pfizer applies in its global clinical programs.

• Learn more

"Duke Health Brief: Understanding Clinical Trials", Duke University Medical News Office, January 2004

This brief provides a perspective on the important role that clinical trials play in the drug discovery process and how patient safety is protected during the trials.

• Learn more

Last Updated September 2007