As set forth in a recent MD Anderson Cancer Center publication, targeted therapy makes it possible to personalize cancer treatment. It is also known as “precision medicine”.
For about forty years “one-size-fits-all” was the standard-of-care. The initial and very aggressive treatment (induction) was designed to kill cancer. In doing so it also damaged many healthy cells. The resulting side effects were devastating to many patients, especially the elderly.
Each Cancer Patient is Unique
Dr. Vivek Subbiah, the clinical director at MD Anderson’s Center for Targeted Therapy, explained that to accommodate a patient’s uniqueness the center considers not only their diagnosis but also medical history and treatment preferences.
Treatment can be personalized further by analyzing a tumor’s genetic characteristics and administering a drug accordingly.
Cancer takes hold whenever genes change in normal cells. Then these cells divide, multiply and are out of control. There are many factors that cause cancer. Some are genetic, having been passed from a parent to a child. No matter how the mutations are formed, targeted therapy will treat the cancers in like manner.
Therapy That Targets the Tumor, Not the Type
Dr. Subbiah pointed out that targeted therapy is concerned with the genetic change inside a cancer cell and not the type of tumor. The team does not focus on the location of the tumor such as breast, lung, or prostate but on the cancer cell’s DNA.
Targeted Therapy vs. Traditional Chemotherapy
A notable difference is the way in which each method attacks cancer cells. Traditional chemotherapy kills all cancer cells that reproduce rapidly, including some noncancerous cells. While targeted therapy locates and slows cell growth in cells that exhibit a specific mutation. These cells can be found through next-generation sequencing (NGS) that removes and tests a small tissue sample from the tumor.
Fewer Adverse Events
Targeted therapy takes direct aim at cancer cells. Therefore fewer patients should report having significant side effects. However, patients who receive certain types of targeted therapy may still experience blood clots, bleeding, high blood pressure, diarrhea, and various skin changes such as rash, itching or in skin pigmentation.
About Phase I Clinical Trials
Researchers readily acknowledge that just as chemotherapy may not be suitable for every patient, targeted therapy may not work for all patients. But teams of researchers are constantly identifying genes that cause cancer so that the therapy landscape is always changing.
The FDA has recently approved targeted therapies for a host of genetic mutations that are linked to lung cancer, colorectal cancer, breast cancer, and melanoma to name a few. These targeted therapies begin their journey for approval with Phase I clinical trials.
The researchers utilize already approved and successful targeted therapies. These therapies are combined with chemotherapy, radiation therapy, immunotherapy, and alternative targeted therapies.
Dr. Subbiah asks patients to speak with their doctors about genetic testings and to ask if they would be eligible to enroll in a Phase I clinical trial.
The Goal of the Phase I Clinical Trial
The group (cohort) of patients generally involves fifteen to thirty patients who are treated with the new drug. The goal is to determine the safety of the drug, whether to administer the drug through the vein or in pill form, and to test its effect on the cancer.
If there are no adverse side effects evidenced in the first group, the dose will be increased and administered to a second cohort. This regimen will continue until the doctors determine the optimum dose for testing in the future. If the treatment is found to be safe then the research teams continue to Phase II.
Treating Seventeen Cancer Types with One Drug
An example of a successful clinical trial involved the development of a drug called larotrectinib. The trial was conducted by Dr. David Hong who led the MD Anderson team. The team was able to identify the TRK gene mutation. Larotrectinib now treats seventeen cancer types harboring this gene mutation.
On any given day a patient can search for and find thousands of clinical trials all over the country. Researchers are discovering mutations, developing new treatments, and testing new therapies for many different types of cancer.
Have you or anyone you know participated in a clinical trial?