OU Health Stephenson Cancer Center Researcher Leads Global Trial for Promising New Drug for Ovarian Cancer

Results of a global clinical trial published recently in The New England Journal of Medicine show that a new drug significantly improves survival in women with epithelial ovarian cancer, a deadly gynecologic cancer that often becomes resistant to chemotherapy. The lead author of the study is Kathleen Moore, M.D., associate director of clinical research at OU Health Stephenson Cancer Center at OU Health Sciences and a professor of obstetrics and gynecology in the OU College of Medicine.

The most common type of ovarian malignancy, epithelial ovarian cancer develops in the epithelial tissue, a thin lining that covers the outside of an ovary. It can also form in the lining of a fallopian tube or in the peritoneum, the tissue that lines the abdomen. Platinum-based chemotherapy is often effective initially, but the cancer almost always returns and becomes resistant to it. The new drug that was tested, mirvetuximab soravtansine (MIRV), is effective because it targets a specific protein on the surface of epithelial ovarian cancer cells. The protein, called folate receptor alpha, is found in greater quantities on ovarian cancer cells than normal cells, which makes it an attractive target for drugs.

“Epithelial ovarian cancer is particularly aggressive and often shows no symptoms until a patient is diagnosed with advanced cancer,” Moore said. “In 2020, an estimated 313,959 new cases of ovarian cancer occurred worldwide, as well as 207,252 ovarian cancer-related deaths. With a five-year survival rate of approximately 50%, it is the deadliest type of gynecologic cancer. The success of this clinical trial is welcome news for patients at Stephenson Cancer Center and around the world.”

The recent clinical trial studying MIRV was considered Phase III, which compares the safety and effectiveness of a new drug against the current standard treatment. Most patients enrolled had high-grade epithelial cancer, meaning it is aggressive and faster to spread, and most had been previously treated with various therapies.

About half of the patients enrolled were randomly assigned to receive MIRV as a treatment for their platinum-resistant ovarian cancer; the other half received a standard type of chemotherapy. The results show that patients who received MIRV fared significantly better than those who received chemotherapy – 42.3% of patients receiving MIRV saw their cancer shrink, compared to 15.9% of those receiving chemotherapy. Patients taking MIRV responded to the drug longer without their cancer growing and spreading, and in 2.6% of patients taking MIRV, the cancer was undetectable after treatment was complete. Patients taking MIRV also experienced fewer negative side effects from the medication, compared to those undergoing chemotherapy.

MIRV is considered an antibody-drug conjugate, which is sometimes called “smart chemo” or a “biological missile” for its ability to target and kill cancer cells without harming healthy cells. Through complex engineering, MIRV is composed of an antibody linked to a drug that directs itself to the cancer cells. Because MIRV spares more of the healthy cells than chemotherapy does, patients do not suffer from the severe side effects that can lead them to stop treatment.

In November 2022, the Food and Drug Administration granted accelerated approval to MIRV. Moore’s study provides additional evidence that the drug would be an effective initial treatment for epithelial ovarian cancer.

“The importance of this study is that it provides even more validation of MIRV’s effectiveness in treating epithelial ovarian cancer that has a high expression of the folate receptor alpha and has become resistant to platinum-based chemotherapies,” Moore said. “Ovarian epithelial cancer is a lethal disease that, until now, has had few effective, targeted treatments. This clinical trial is exciting because it appears that this new drug can improve survival, with fewer severe side effects, thereby bringing new hope to women with this type of cancer.”

The journal article is titled “Mirvetuximab Soravtansine in FRa-Positive, Platinum-Resistant Ovarian Cancer” and can be found at link.ou.edu/3H6qMlp. Participating researchers around the world are members of the Gynecologic Oncology Group Partners in the United States and the European Network of Gynaecological Oncological Trial Groups. Moore serves as executive director of Gynecologic Oncology Group Partners.