The Drug Development and Approval Process

Every year, new drugs as well as innovative uses of existing drugs are made available to cancer patients. What transforms a research or study in a laboratory to labeled medication found in hospitals? The process of drug development and approval takes a lot of time and is expensive. Generally, this process requires millions of dollars in investments and takes many years to complete. However, the amount of money and time required varies depending on the type of drug.

The FDA and CDER

The FDA's (Food and Drug Administration) primary responsibility is to ensure that drugs available in the US market are safe and effective for the treatment and prevention of specific conditions for which they may have been prescribed. In the United States, all types of drugs sold, be it prescription drugs or over-the-counter (nonprescription) drugs, first require FDA's approval for being safe and effective. The Center for Drug Evaluation and Research (CDER) which functions within the FDA, reviews research studies carried out on investigational drugs. The CDER uses the available information to determine whether or not a drug should be given approval. The FDA has established a Critical Path Initiative to speed along development of some medical technologies.

Drug developers and sponsors

The actual development or testing of drugs is not done by the FDA. These tasks are carried out by pharmaceutical companies and various other organizations, for example, university medical centers as well as certain government agencies including the National Cancer Institute (NCI). The FDA seeks information from the organization that is involved with the development of a drug and is the drug's sponsor. The research is done by the sponsor in order to make available the necessary information to the CDER, as required for getting approval for a drug.

Preclinical research: New drug discovery and initial testing phase

New drug discovery can happen in a several different ways:

Accidental discovery: Sometime during the early 1940s, a few sailors were exposed to poisonous mustard gas due to an explosion. When low white blood cell counts was observed amongst these sailors, doctors started administering nitrogen mustard (mechlorethamine [Mustargen]) for the treatment of Hodgkin lymphoma, which is a cancer of the lymph system and affects the white blood cells. Even today, Mechlorethamine is used to treat cancer. However, accidental drug discoveries are rare.

Testing fungi, animals and plants: Paclitaxel (Taxol), which is used for the treatment of several different types of cancer, was originally discovered in the bark of the Pacific Yew tree. Collected from all around the world, the samples available with the NCI cover around 30,000 bacteria and fungi, 10,000 marine organisms and about 70,000 plants.

Analyzing the characteristics of cancer cells: Initially, researchers involved with cancer-related drug development try to compare the cellular and genetic processes occurring naturally in normal and cancerous cells. Researchers use this information to identify significant phases in cancer development that can possibly be altered by using a drug. For instance, there are drugs that prevent cancer cells from producing new cancer cells. In recent times, specific proteins and genes are being tested as potential drugs to treat cancer cells. Sometimes, researchers test thousands of chemical compounds in order to identify one that can reach a specific target inside the body and deliver desired results, for example, elimination of cancer cells.

Evaluating the chemical composition of a drug target: Using a computer, researchers may simulate the potential action of a drug on its target. This is similar to putting together two different pieces of a puzzle. Using information gathered from the simulation exercise, researchers can then focus on designing new chemical compounds that may be effective against the specific drug target.

After identifying potential drugs, scientists test these drugs on human tumor cell lines. These tests are carried out in a lab to check whether the new drug is able to stop cancer cells from dividing. After this, the drug is tested on animals to check if it is still able to stop cancer cell growth. Usually, these drugs are tested on two or more kinds of animal species. It allows researchers to understand how the drug is absorbed by the body and the side effects it may have. It also helps in determining a dose that will be suitable for human research trials.

New drug research: Testing in humans

Prior to initiating testing on humans, the drug's sponsor is required to provide the FDA with an Investigational New Drug (IND). This application has information about results derived during the preclinical (laboratory and animal) testing phase and details about the planned clinical trial to be conducted on humans. New drugs are approved by the FDA for human testing only when there is evidence (based on the preclinical research) that the drug is safe and effective, and also if the planned clinical trials are appropriately designed.

Clinical trials, basically research studies carried out in humans, are used to evaluate the safety and effectiveness of a new drug, or to check if they work better than existing care standards pertaining to a specific diagnosis. Typically a clinical trial has three (at times four) consecutive phases. Each subsequent phase includes more patients and generates more detailed information on the safety and effectiveness of the new drug. Often, clinical trials involve thousands of patients and may take many years to complete.

Clinical trials: Getting FDA approval

In the event of successful completion of the clinical trial, the drug sponsor files a New Drug Application (NDA) with the FDA to get approval for the public use of the drug. The NDA contains information pertaining to results achieved during the preclinical and clinical studies, details about the drug manufacturing process and the proposed labeling. The drug may get FDA approval if there is substantial evidence to prove the safety and effectiveness of the drug, as stated in the labeling. Prior to giving its approval, the FDA compares the risks and benefits associated with the new drug. No drug is entirely safe or without side effects, but a new drug may be considered safe in case its benefits outweigh the potential risks.

Post-approval research

Once FDA approves a particular drug, it can be introduced in the market and made available to healthcare professionals and patients. Still, the FDA may require the sponsor to carry out additional clinical trials (usually phase IV trials) to identify other possible side effects; to evaluate the drug in new population groups (for example children or the elderly); or to assess the long-term effects of the drug. Some drug manufacturers may carry out their own post-approval trials (phase IV trials) or conduct new research in order to secure FDA's approval regarding a new way to use the drug or for using it in a different population group.

Post-marketing surveillance

Ongoing safety monitoring of existing drugs is also conducted by the FDA, and it is the responsibility of drug manufacturers to report any new or severe adverse reactions of the drug to the FDA. A drug may be withdrawn from the market (based on FDA directives) in case there is evidence available from ongoing surveillance that the drug is not safe or if does not offer effective treatment.

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