Boston Scientific’s TheraSphere Y-90 Glass Microspheres Evaluated in Phase 3 EPOCH Trial to Treat Metastatic Colorectal Cancer

September 20, 2021—Boston Scientific Corporation announced that the EPOCH clinical trial of the company’s TheraSphere yttrium-90 (Y-90) glass microspheres met both primary endpoints, including progression-free survival (PFS) and hepatic progression-free survival (hPFS) of patients with metastatic colorectal cancer (mCRC) of the liver.

TheraSphere treatment is selective internal radiation therapy (SIRT) composed of microscopic glass beads containing radioactive Y-90 that are specifically delivered to target tumors via catheter, which minimizes radiation exposure to surrounding healthy tissue.

In the EPOCH trial, TheraSphere was used as a second-line treatment in combination with standard of care systemic chemotherapy for patients with disease progression during or after first-line chemotherapy. The clinical findings were presented as late-breaking data at the European Society for Medical Oncology’s ESMO Congress 2021, held virtually September 16-21, and published by Mary F. Mulcahy, MD, et al online ahead of print in Journal of Clinical Oncology.

Dr. Mulcahy, a medical oncologist, and Riad Salem, MD, an interventional radiologist, are Coprincipal Investigators of EPOCH. Both Drs. Mulcahy and Salem are with Northwestern Memorial Hospital in Chicago, Illinois.

According to Boston Scientific, the global, prospective EPOCH pivotal clinical trial is a phase 3 study designed to assess therapeutic benefit compared to standard of care systemic chemotherapy. EPOCH randomized 428 patients with mCRC to second-line chemotherapy with or without the addition of TheraSphere treatment.

The investigators found that both primary endpoints were met and included PFS and hPFS. The addition of TheraSphere treatment significantly increased both PFS (P = .0013) and hPFS (P < .0001). Patients receiving TheraSphere treatment with second-line chemotherapy were 31% less likely to show disease progression or death (hazard ratio [HR] = 0.69) and 41% less likely to show hepatic disease progression or death versus with chemotherapy alone (HR = 0.59), reported Boston Scientific.

“In the second line of therapy for mCRC, with disease isolated to the liver, the addition of TheraSphere with chemotherapy resulted in a significant delay in overall tumor progression,” commented Dr. Mulcahy in Boston Scientific’s press release. “Additionally, chemotherapy-related adverse events were comparable between the trial arms.”

Dr. Salem added, “The EPOCH trial not only demonstrated positive safety and efficacy data for the patients treated in this study but underscores the success of integrating a device-based therapy like TheraSphere treatment in the continuum of care with systemic chemotherapy and biologic regimens, thereby providing the rationale and setting the stage for future investigation in other cancer types.”

TheraSphere treatment is indicated for use in patients with hepatic neoplasia/malignancies including liver-dominant mCRC in Canada, Europe, and regions of Asia. In the United States, the use of TheraSphere for mCRC is for investigational use only as the safety and effectiveness have not been established, advised Boston Scientific.

In March 2021, the company announced FDA approval of TheraSphere for the treatment of unresectable hepatocellular carcinoma. Additionally, the FDA granted Breakthrough Device designation for expedited review as a treatment of patients with glioblastoma, noted Boston Scientific.