Doctors and scientists are always looking for better ways to care for people with cancer. To do this, they create and study new drugs. They also look for new ways to use drugs that are already available.
A drug goes from being an idea in the lab to something that a doctor prescribes. To do this, it must go through a long development and approval process. During this process, researchers make sure the drug is safe for people to take and effectively treats cancer. This process often takes many years and significant resources. But the actual amount of time and money needed depends on the drug.
There are 3 main steps in finding and developing a new drug:
- Preclinical research, which is when the drug is found and first tested
- Clinical research, which is when the drug is tested in people
- Post-clinical research, which takes place after the drug is approved
Drug discovery and initial testing
The discovery of new cancer drugs can happen in different ways:
Accidental discovery. In the early 1940s, an explosion exposed sailors to poisonous mustard gas. Doctors found that these sailors had low white blood cell counts. So they began using nitrogen mustard, or mechlorethamine (Mustargen) to treat Hodgkin lymphoma. This is a cancer of the lymphatic system involving the white blood cells. Nitrogen mustard is still a cancer treatment used today. But accidental discoveries such as this are rare.
Testing plants, fungi, and animals. Paclitaxel (Taxol) treats several types of cancer. This was first found in the bark of the Pacific yew tree. More recently, a primitive animal called a sea sponge was used to create the drug eribulin (Halaven). The National Cancer Institute (NCI) has samples of thousands of plants, marine organisms, bacteria, and fungi. These are collected from around the world in the hopes of finding new cancer treatments.
Studying the biology of cancer cells. Most cancer researchers start by comparing both the genes found in DNA and growth patterns of cancer cells to healthy cells. This identifies important steps in the cancer growth process that a drug could fix.
For example, researchers learned that about 20% of all breast cancers have an abnormal amount of a certain protein. It is called HER2 and controls the growth and spread of cancer cells. Five drugs were created to target HER2: trastuzumab (Herceptin), lapatinib (Tykerb), pertuzumab (Perjeta), ado-trastuzumab emtansine (Kadcyla), and neratinib (Nerlynx). Now, a person with breast cancer has the tumor tested to check for HER2. It will show if these drugs can treat the cancer. Learn more about these targeted treatments.
Understanding the chemical structure of a drug target. Scientists may use computers to mimic how a potential drug interacts with its target. This is similar to fitting 2 puzzle pieces together. Researchers can then make chemical compounds that interact with the specific drug target.
After drugs are created, researchers test them on human tumor cells in the lab. They see if the drugs stop the growth of cancer cells. Next, they test the drug in animals to find out if it is still effective at treating cancer. Researchers test the drug in 2 or more animal species. They learn how the body uses the new drug. They also learn what side effects the drug may cause and what dose of the drug to test in people.
Drug developers and sponsors
The U.S. Food and Drug Administration (FDA) does not develop or test drugs. Instead, medical research universities, government agencies such as the NCI, and drug companies find and test new drugs. The sponsor is the group that develops a drug. It does the research needed for the FDA to approve the drug.
Drug developers are creating different types of biologic medicines to treat cancer. One kind of biologic medicine is called biosimilars.
Biosimilars are a variation of drugs already approved by the FDA. They offer a growing number of new treatment options for people. They also often cost less than similar drugs.
The FDA requires a biosimilar drug to be compared with an existing one. The existing drug is called a reference drug. The biosimilar must be highly similar in structure and function and have no large differences compared to the reference drug.
Biosimilars have to meet a strict approval process by the FDA to make sure it is a safe and effective treatment option. Talk with your health care team to find out if biosimilars could be a part of your treatment plan.
Before new drugs are tested in people, the sponsor must submit an Investigational New Drug (IND) application to the FDA. The IND provides information about past and future research plans, such as:
- Preclinical studies done in the lab and in animals
- Plans for clinical trials in people
- How the new drug is made
The FDA approves potential drugs for testing in people under certain conditions:
- The research shows that the drug is likely to work and be safe.
- The proposed clinical trials must be designed correctly.
- The drug can be made the same way every time.
Clinical trials are research studies involving volunteers. They are used to find out if a new drug is safe, effective, and better than the standard treatments. Each phase involves a larger number of people than the previous phase. It also provides more detail about the new drug’s safety and effectiveness.
Clinical trials may involve hundreds or thousands of people. They usually take years to complete. But sometimes, if a small clinical trial shows very promising results, the process may be sped up.
Early phases of clinical trials focus on safety, dosing, and how the body processes the drug. Later phases center on how well the drug works. Learn more about clinical trials.
Clinical review and FDA approval
If the clinical trials are successful, the drug sponsor submits a New Drug Application (NDA) to the FDA. The NDA requests approval for the drug to be prescribed by doctors. The request includes:
- Results from the preclinical and clinical studies.
- Details about how the drug will be made and labeled.
- The drug’s possible side effects and any interactions with food or other drugs.
The FDA may approve the drug if the evidence shows it is effective and safe for use. No drug is completely safe or free from side effects. But a drug is approved if there are more benefits than risks.
After FDA approval
A drug is ready for the market when it receives FDA approval. This means it can be prescribed by doctors and sold to people. But the FDA may require that the sponsor conduct more clinical trials. These are called phase IV clinical trials.
Phase IV clinical trials look for other possible side effects or confirm the benefits of the treatment. They may study the drug in different doses, new combinations, or in different schedules. They may also study the treatment in new groups of people, such as older adults or children. Or they may assess the drug’s long-term effects.
Some drug makers may conduct their own phase IV clinical trials. They may do more research to get FDA approval to use the drug in a new way, such as for another type of cancer.
The FDA also monitors the safety of drugs currently on the market. They do this to make sure that drug makers report any new or serious side effects. The FDA may withdraw a drug from the market if new research shows it is not safe or effective.