TheraSphere SIRT Received FDA Approval for Treatment of Unresectable HCC

A selective internal radiation therapy from Boston Scientific Corporation, TheraSphere Y-90 Glass Microspheres, was granted FDA approval for the treatment of unresectable hepatocellular carcinoma.

FDA approval has been granted to the TheraSphere Y-90 Glass Microspheres for the treatment of unresectable hepatocellular carcinoma (HCC), according to Boston Scientific Corporation who is responsible for developing the technology.

Previously, TheraSphere was available under the humanitarian device exemption, which is a classification requiring institutional review board approval and allowing only a limited number of patients access to the treatment each year.

“The FDA approval and the recent NICE [National Institute for Health and Care Excellence] recommendation will expand access to TheraSphere, which has demonstrated improvement in both survivability and quality of life through 20 years of clinical trials and real-world outcomes in the more than 70,000 patients globally,” Peter Pattison, president of Interventional Oncology, Peripheral Interventions at Boston Scientific, said in a press release. “We expect to continue to focus our efforts on bringing this treatment to more patients, both by planning a randomized trial to study the combination of TheraSphere and immunotherapy in patients with HCC not eligible for curative treatments, as well as further investigating the therapy for different cancer segments, including prostate and brain.”

This selective internal radiation therapy, or SIRT, in made up of millions of microscopic glass beads containing radioactive yttrium (Y-90) for direct delivery to cancer cells within the liver via a catheter for minimal exposure to healthy tissue.

The decision by the FDA was based on results of the LEGACY study, which looked at efficacy and safety of this therapy in both early and advanced HCC. Data presented at the European Society for Medical Oncology 2020 Virtual Congress showed that the study met both primary end points of objective response rate (72.2% at 4 weeks) and duration of response (76.1% at 6 months) in the 162-patient cohort. Of the patients not achieving a response, all were considered not evaluable due to transplant or resection (n = 20), lack of confirmatory imaging (n = 20), or other reasons (n = 5).

The data also indicated that treatment with TheraSphere was suitable as either adjuvant therapy or as monotherapy. The median overall survival (OS) in the intent-to-treat population was 57.9 months and the rate of OS at 3 years was 86.6%. Liver function as determined by levels of albumin and bilirubin were maintained for 92.9% and 85.3% of patients, respectively.

These results led the investigators to conclude that TheraSphere therapy is suitable for the treatment of solitary HCC while preserving liver function.

“I am honored to have spearheaded the LEGACY trial in which we found that patients with early and advanced HCC exhibited very high response rates as well as clinically meaningful durations of response and survival, establishing TheraSphere as a standard treatment for this patient population,” Riad Salem, MD, MBA, interventional radiologist at Northwestern Memorial Hospital and principal investigator of the LEGACY trial, said in a press release. “The trial results, which have been accepted for publication in Hepatology, produced one of the most comprehensive databases for TheraSphere, empowering physicians to make informed, data-driven decisions for their patients.”

Notably, treatment with TheraSphere does not require hospitalization and is typically an outpatient process and this benefit may potentially alleviate pressure on the current health care system.


Boston Scientific Receives FDA Approval for TheraSphere Y-90 Glass Microspheres. News release. Boston Scientific Corporation. March 18, 2021. Accessed March 18, 2021.