Clinical Trials for DIPG
Many researchers are working hard to develop new treatments for DIPG. To date, no therapies are available that provide a lasting cure for this disease. As new treatments become more readily available, parents will be given additional opportunities to enroll their children in clinical trials. Parents who are familiar with study design terminology and who have a basic understanding of the purpose of clinical trials are better equipped to make informed treatment decisions. Every child is unique, and treatment decisions are also unique to individual children and families.
What is a Clinical Trial?
A clinical trial is a way to test possible new treatments. Clinical trials are done in cancer to find out:
- whether a treatment is safe;
- whether a treatment has the effects on cancer cells that scientists think it will;
- whether it is effective at shrinking tumors, delaying growth of tumors, or making people live longer.
A clinical trial is a scientific experiment that must follow certain rules to ensure patient safety and that the results are true and not due to chance or bias. A clinical trial may test several different types of experimental treatments including:
- A brand new drug (usually not already FDA approved for other cancers or uses).
- A new combination of drugs (that could include new or existing drugs).
- A new technology.
- An old drug that is being used in a new way or on a new population of patients.
There are many types of clinical trials. When participating in a clinical trial, it is important to know:
- What kind of trial it is.
- What the purpose of the trial is.
- What is new and experimental about the trial.
Clinical trials are an essential part of medical research. Without clinical trials, medical knowledge cannot grow and new treatments that may save or improve the lives of future cancer patients would not be identified.
What a Clinical Trial Is and Is Not
Clinical trials must have specific characteristics that qualify them as well-designed scientific experiments. Not every study is a clinical trial. In this section, we give examples of studies that are not clinical trials and give some of the qualities of a good clinical trial.
Clinical trials must study a predetermined group of people, given a predetermined treatment and use statistics to analyze results. “Case reports” or “case series” are reports by physicians giving the results of a specific treatment observed in just a few patients. While potentially useful to other physicians, case reports of one or two patients are not true clinical trials because not enough patients are treated with a specific therapy to know if the results are due to luck, to the treatment given, or to some unknown factor. Because everyone likes a happy ending, examples of patients who seemed to respond to a treatment are much more likely to be published than examples of patients who did not respond to a treatment.
Retrospective series are also not true clinical trials, but generally provide more data and reliability than case reports. Retrospective studies look backward in time to study a group of patients with the same disease. Retrospective series are not clinical trials because the group of people and the treatment were not defined before the treatment was given. Therefore, the results may be biased by the choices both doctors and patients make. For example, healthy people tend to be treated aggressively, and healthy people tend to live longer; but that does not mean that more aggressive treatments make people live longer.
A well-designed clinical trial needs to include:
- A clear research question.
- A hypothesis.
- A specifically defined population.
- A description of the treatment so that everyone in the trial gets treated the same way.
- A follow-up plan that describes how often the effects of the treatment will be reassessed.
- A statistical plan that describes how to determine at the end of trial, the answer to the initial question.
A clear research question describes the purpose of the clinical trial. Examples of clear questions are:
- How often do people taking this drug experience severe side effects?
- How often do tumors shrink when people take this drug?
- Which drug makes people with a brain tumor live longer?
A clear question prevents misinterpreting unexpected results that could be due to chance.
The hypothesis is the researcher’s educated guess at the answer to the question. The hypothesis spells out how safe or effective a treatment should be for the trial to be considered a success. The hypothesis also makes it clear how to know if the trial does not succeed, so that unsafe or ineffective treatments are not studied again.
Clinical trials are conducted in specific, well-defined populations. The population may be limited by specific diagnoses (cancers), ages, symptom levels, overall health, or other factors. These limitations are called the inclusion and exclusion criteria. For example, a clinical trial of brainstem gliomas may allow adults and children, just children under 18, or just children under 12, etc. Most, but not all, clinical trials require participants to have normal liver and kidney function and exclude patients with other major medical problems or multiple cancer types. Limiting the population for clinical trials helps to ensure the scientific validity of the trial. However, clinical trial results may not apply to people outside of these limits. For instance, results from a clinical trial allowing adults with brainstem glioma may not apply to children with diffuse intrinsic pontine glioma if they were excluded from that trial.
A clinical trial must have a treatment plan, follow-up plan, and statistical plan set out before starting the trial. This ensures that everyone in the trial is treated the same way and that the doctors running the trial cannot change things to make the trial results appear better than they actually are. It also potentially limits the treating doctor because tests or treatments may need to be done at specific times that are less flexible than they would be with treatments outside of a clinical trial.