A physician-scientist at Stephenson Cancer Center at OU Medicine co-directed an international clinical trial that yielded findings considered unprecedented in the field of gynecological cancer. The study's findings were published Sunday in the New England Journal of Medicine.
The research is groundbreaking because it showed that a targeted cancer therapy helped a subset of women with ovarian cancer live three years longer without a cancer recurrence than those who did not receive the therapy. That length of cancer-free survival has never been seen in an ovarian cancer study. Kathleen Moore, M.D., served as one of two international principal investigators for the SOLO-1 study, which evaluated the use of olaparib, a PARP inhibitor that targets cancer cells without affecting normal cells.
"It's exciting to work in a place where we can conduct research and clinical trials that will allow each patient to have the best chance at fighting their cancer," said Moore, who is associate director for clinical research at the Stephenson Cancer Center. "This study is an example of how transformative research can improve the lives of women who have been or will be diagnosed with ovarian cancer."
Cancer cells divide rapidly in a person's body, but they make many mistakes in the process and must repair those mistakes in order to live. Olaparib takes away one of the key proteins needed for the cancer cell to fix these mistakes. In the study, olaparib was given to women with advanced stage ovarian cancer who also have a BRCA mutation. Women with the mutation face a higher risk of cancer but, ironically, the mutation also means their cancer will respond better to chemotherapy.
Olaparib was given as maintenance therapy following patients' first round of chemotherapy to determine if it would improve survival time without a return of cancer.
"Women with ovarian cancer often have remarkable responses to their first round of chemotherapy, and they can do well for quite a while," Moore said. "The challenge is that in the vast majority of patients, the disease will recur. It's still treatable when it recurs, but it's typically no longer curable. One of our highest unmet needs is finding things we can do during that first treatment to optimize the length of time that a woman survives without disease."
The clinical trial began in 2013, and the Stephenson Cancer Center was one of dozens of sites worldwide that enrolled patients. Women in the study, after responding well to chemotherapy, were randomized to receive either olaparib or a placebo pill, and neither the physicians nor the patients knew which they were receiving. The patients were followed on their assigned treatments for up to two years or until the time of disease recurrence, whichever came first.
As expected, women who received the placebo pill survived for an average of 13.5 months before their ovarian cancer recurred. But the surprise came in the women who had been assigned to take olaparib - and the good news was even better than imagined.
"For the women who received olaparib, their average survival without disease has not even been met yet," Moore said. "With at least three years of follow-up for every patient enrolled, we haven't even reached the point where half of the women receiving olaparib have seen their cancer recur. That is a much more marked effect than we were expecting."
Because of that success, study leaders estimate that olaparib reduces the risk of cancer recurrence by 70 percent in women with advanced-stage ovarian cancer who have a BRCA mutation.
A secondary finding of the trial was also encouraging: Among the women whose ovarian cancer did recur, their second treatment with chemotherapy was successful and was not affected by having taken olaparib. That provides further reassurance that olaparib is best used following first-line therapy as opposed to later lines of therapy.
"This is truly a landmark trial in gynecological cancer," Moore said. "The results of the study will lead to changes in the way we treat women with ovarian cancer."
She also pointed to the selflessness of women who agreed to enroll in the trial not knowing whether they would receive the drug or the placebo. They did so knowing that their participation would improve doctors' ability to improve cancer treatment in the future.
As part of the OU Medicine academic medical center, Stephenson Cancer Center is dedicated to conducting clinical trials that give patients access to cutting-edge treatments. The center's recent designation as a National Cancer Institute facility expands that ability. Every physician at the Stephenson Cancer Center is also a scientist who has chosen the academic setting because it allows them to pursue research that may lead to better cancer treatments.