Mary Catherine Riley: Living Cancer Free Thanks to a Precision Medicine Clinical Trial

In 2019, Mary Catherine Riley—a fifth-grade special education teacher from Belleville, Illinois—was living a full and active life. At 46, she was a devoted mother to a 9-year-old son and a 16-year-old daughter. She loved hiking, biking, yoga, and creating art, and she was in excellent health. That changed when she began experiencing persistent bloating and urinary frequency.

Initially, her symptoms were dismissed as minor. But when she visited her gynecologist in June 2019, he immediately ordered an ultrasound and an OVA1 test, both of which suggested something serious. A CT scan confirmed a mass on her ovaries with signs strongly indicative of ovarian cancer. “Once you hear that diagnosis, it’s devastating. I was pretty sure bad things were going to happen,” Mary said.

Mary’s partner at the time had lost his mother to ovarian cancer and recommended a trusted specialist, Dr. Premal Thaker, at Siteman Cancer Center at Barnes-Jewish Hospital and WashU Medicine in St. Louis. Mary called Dr. Thaker’s office directly and within days had an appointment and a treatment plan. Dr. Thaker confirmed the diagnosis: stage III ovarian cancer, already present in the lymph nodes.

Before surgery, Mary’s mind was flooded with worst-case scenarios, from a colostomy bag to permanent lifestyle changes. But Dr. Thaker’s calm confidence gave her hope. The surgery revealed that her cancer was low-grade serous ovarian cancer—less aggressive than the high-grade form but with a high likelihood of recurrence and no established treatments.

Initially, Dr. Thaker thought Mary might avoid chemotherapy, but final pathology results showed otherwise. Mary underwent 6 rounds of chemotherapy from August through November 2019. She arranged her treatments around her school schedule, often teaching right up to the infusion days and returning to class soon afterward. “The nurses told me I probably wouldn’t be teaching by the end, but I did. I only took off on chemo days.”

Her school district rallied behind her, organizing fundraisers, wearing “Good Vibes” T-shirts, and even installing extra sanitizing stations. Her students, often assumed to be too young for compassion, surprised her with unwavering support. The side effects were manageable: hair loss, fatigue, and “chemo brain,” but she maintained her daily routines and active lifestyle.

When chemotherapy ended, Mary showed no evidence of disease. To help prevent recurrence, her care team prescribed anastrozole, an estrogen-blocking drug typically used for breast cancer, the only available option for her tumor type. For three years, regular CT scans revealed stable results, until a lymph node grew large enough to be biopsied in 2023.

The biopsy confirmed the cancer had returned. Dr. Thaker recommended a clinical trial involving two targeted drugs, that later became known as avutometinib and defactinib. Mary agreed without hesitation, despite being warned about the time commitment: frequent blood draws, CT scans, and follow-ups. “If it’s a chance to help me, I’ll do it,” she thought.

The treatment worked better than anyone anticipated. Within a year, she had a complete response. Side effects—skin rashes, vision changes, fluid retention, and fluctuating lab values— were persistent but manageable with supportive care and dose adjustments. “Yes, the side effects were annoying. But I don’t have cancer right now. That’s worth it.”

Mary stayed on the trial for 2 years. She forged close relationships with her nurse, pharmacist, and other members of the study staff, all committed to advancing treatment for a cancer type that previously had no effective therapy. In May 2025, the drugs received FDA approval, and Mary transitioned from the trial to receiving the medications through a pharmacy.

Today, Mary continues taking the medication, now available as an FDA-approved combination called Avmapki Fakzynja Co- pack, with quarterly CT scans and monthly labs. She continues to have no evidence of disease.

Her children have grown up with her cancer journey as part of their family story. Her daughter, now in the medical field, often asks about the science behind her treatment. Both take pride in her role in a trial that has changed the future for others with low-grade serous ovarian cancer.

Outside of treatment, Mary continues to embrace life: traveling to see family; hiking any chance she gets; practicing yoga and meditation; drawing and painting. She has learned to live day by day, appreciating the small moments.

To members of Congress, she emphasizes the importance of federal funding for cancer research, not only for cancers like hers but for the wide spectrum of diseases that touch nearly every family. She sees her story as a call to action for more doctors to know about, and more patients to access, emerging treatments.

“Everyone is touched by cancer in some way,” she said. “Funding research means more options, more time, and more hope for people like me.”

For my type of cancer, there was no treatment. Now there is, because of research.