A clinical trial has shown that patients and their physicians are eager to jump into next-era cancer care, which is analysis of a patient’s tumor to find and target genetic mutations that drive the cancer. The results of the study, CUSTOM, are being presented at the 2013 annual meeting of the American Society of Clinical Oncology, held in Chicago, Illinois from May 31 to June 4.
The presentation is occurring years before investigators thought they would be ready. Patients were willing to undergo an additional cancer biopsy to seek out the best treatment for their tumor type.
CUSTOM is the first completed prospective trial that used genetic analysis alone to assign cancer treatment for patients with one of three different cancers.
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“We expected it would take five years to enroll 600 patients into CUSTOM. But in less than two years, 668 patients were recruited,” said the study’s lead investigator, Giuseppe Giaccone, MD, PhD, of Georgetown Lombardi Comprehensive Cancer Center in Washington, DC.
“This was a surprise to all of us, especially since patients with advanced cancer who already had biopsies needed to undergo an additional biopsy for the study. But we found patients and their doctors are quite interested in this type of personalized medicine. They know that the molecular profile of the tumor is important,” said Giaconne.
CUSTOM has proved to be a model for more efficient clinical trials, he added. It showed that patients want to participate in this kind of research, and that it is feasible to do extensive genetic testing on a tumor biopsy in a timely manner, which took only two weeks to complete in this case. It also demonstrated that it is safe to take new biopsies from patients with advanced cancer to provide the tissue needed for the analysis.
One of the other endpoints of the study, however, was not achieved. Researchers discovered that, in many cases, they did not have enough patients with rare cancer mutations to provide an accurate statistical analysis of response to novel drugs, said Giaccone.
CUSTOM enrolled patients diagnosed with advanced stage non-small cell lung cancer, small cell lung cancer, or thymic cancer. Researchers used next-generation sequencing, which was novel at the time, to look at almost 200 genes. From this, patients were assigned to different treatment groups based on genetic mutations or amplification.
Results for the patients with small cell lung or thymic cancers were inconclusive, primarily because the investigated mutations were rare—not enough patients had specific mutations to adequately test response to therapy. “When we started the study, we didn’t know how frequently the mutations occurred,” Giaccone said. “Now we know that many mutations represent only one to two percent of patients and to do this right, you need to screen thousands of patients. That is only possible with a global study that involves, potentially, hundreds of institutions.”
