The Personal Cancer Genome and Precision Cancer Trials
Clinical trials traditionally have been designed to treat patients with a specific disease and to treat all patients on the trial the same way. For example, we would evaluate a new drug for breast cancer by giving the agent to a group of breast-cancer patients, and if enough of them benefited, we would judge the drug a good one. If few patients benefited, the drug would likely be abandoned.
During such disease-based trials, a small number of participants, maybe 1-10 percent, can benefit amazingly from the drug, but further development of the agent is unlikely because clinical trials as usually done are impractical for small numbers of patients.
Genomics is now helping us understand why some patients respond differently to therapy; although all the women in our hypothetical trial have cancer of the breast, not all breast cancers are the same, because there is no routine cancer.
Traditionally, we diagnose breast cancer, leukemia or prostate cancer by examining the way cells appear under a microscope. This tissue-of-origin approach has provided a histology-based or “microscopic classification” of cancer that has been used for decades.
Histologically, malignancies such as breast and prostate cancer appear to be the same. But cancer genomic studies, such as The Cancer Genome Atlas, demonstrate that these cancers are dissimilar, with sets of mutations and other genetic changes that allow their grouping into subtypes (breast cancer may have more than 25). Each subtype may be a different disease that requires different therapy based on the tumor’s genomics. These molecular subtypes are driving the development of targeted drugs and influencing how we do clinical trials.
Some cancer centers, including the OSUCCC – James, are developing a new type of trial design that “baskets” different diseases that share a molecular target in one trial.
In some instances, if we know enough about the molecular subsets of a disease, we may be able to enroll patients into trials that have a drug that matches the molecular makeup of their cancer. To facilitate these trials, cancer centers must be capable of providing a personalized molecular view of an individual’s cancer.
Gene sequencing technology called next-generation sequencing will enable oncologists to determine which of 200-plus significant genes are altered in a patient’s cancer and to use this information to guide therapy. Ohio State is among the leaders in the country in promoting and championing this precision oncology strategy.
Read “The Power of Genomics” to learn about the molecular differences in cancers.