For more than a decade, Dr. Sai-Hong Ignatius Ou has searched for ways to identify and attack mutations in non-small cell cancer tumors, and extend the lives of patients with this aggressive disease. He has conducted some of the leading research for crizotinib and other targeted therapies for non-small cell cancer patients who harbor specific genetic abnormalities, including ROS1 and ALK.
Last month, the UC Irvine Health oncologist’s commitment paid off, as the Food and Drug Administration approved the first treatment for non-small cell lung cancer patients with the rare molecular ROS1 mutation — crizotinib.
“This is the first time a treatment for ROS1-driven solid tumors has received approval from the FDA,” Ou says. “The clinical significance of formal FDA approval is that crizotinib is now a standard of care for ROS1 non-small cell lung cancer patients, giving them a new option for this difficult-to-treat cancer that does not respond to traditional therapies.”
“In addition, ROS1-driven cancer has been found in colon cancer, stomach cancer, angiosarcoma, anaplastic large cell lymphoma, bile duct cancer and glioblastoma multiforme,” he says. “Thus, this FDA approval will lead to other cancer patients with ROS1-driven cancers to benefit in the future, not just those with non-small cell lung cancer.”
Instrumental in gaining FDA approval
Ou is co-author of a study published in the September 2014 New England Journal of Medicine that was instrumental in the drug gaining FDA approval. The study cited a 72 percent positive response rate for crizotinib in patients with advanced non-small cell lung cancer and the ROS1 mutation. These patients had complete or partial shrinkage of their tumors, and their response lasted for a median of 17.6 months.
Though he acknowledges that more work needs to be done, Ou said FDA approval validates the efforts he and his colleagues have achieved, as well as the resources of the drug’s manufacturer, Pfizer.
Lung cancer is the leading cause of cancer death in the U.S. Non-small cell lung cancer, prevalent among patients who have never smoked, is the most common form diagnosed. Researchers estimate that non-small cell lung cancer will account for about 83 percent of the 224,390 new lung cancer cases expected to be diagnosed this year.
A leader in research
Crizotinib had received FDA approval in August 2011 for treating patients with ALK-positive non-small cell lung cancer after it was shown to shrink tumors in half the patients receiving the drug. ALK and the ROS1 proteins are closely related, prompting researchers to investigate whether crizotinib could also benefit non-small lung cancer patients with the ROS1 mutation.
The brain is a common place for advanced ALK-positive non-small cell lung cancer to spread. In 2013, Ou presented findings at the European Cancer Congress on the effectiveness of the targeted therapy alectinib in reducing brain metastasis.
For these patients, radiotherapy or surgery had been their only treatment options. Alectinib received FDA approval in 2015 for advanced ALK-positive non-small cell lung cancer for people who could not tolerate crizotinib or whose disease worsened after taking it.
Ou’s work with non-small cell lung cancer and crizotinib is cited as an advance in targeted therapy in the American Society of Clinical Oncology’s 2016 annual report on clinical cancer advances.
There is an urgent and unmet need to provide new treatments for those diagnosed with the most aggressive and hard-to-treat cancers, Ou says. Not all treatments work for all patients, because each tumor has its own set of mutations that drive the cancer’s growth. The key to personalized cancer treatments is to identify the genetic pathways that control the tumor’s growth and block those pathways.
"At UC Irvine Health Chao Family Comprehensive Cancer Center," he says, “we continue to focus our research on finding ways to match patients with cancer to specific targeted treatments, which I believe is an important step toward increasing survival.”