FDA Approves TheraSphere Y-90 Glass Microspheres for Unresectable HCC

The FDA has approved TheraSphere yttrium-90 (Y-90) glass microspheres for the treatment of patients with unresectable hepatocellular carcinoma (HCC).¹

Previously, TheraSphere Y-90 microsphere were used through an FDA humanitarian device exemption classification, which limited the number of patients able to be treated with this form of selective internal radiation therapy per year. This approval now expands access to this technology and represents the only approved radioembolization technology for the treatment of patients with unresectable HCC in the United States.

Approval for TheraSphere was granted based on the results of the LEGACY study, the complete results of which are expected to be published in the near future in Hepatology.

"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," said principal investigator Riad Salem, MD, MBA, an interventional radiologist at Northwestern Memorial Hospital, in a statement. "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."

LEGACY is a retrospective, single-arm, multi-center study that enrolled patients with early and advanced HCC between January 2014 and December 2017. Eligible patients had a Child-Pugh A score, an ECOG performance status of 0 or 1, and solitary tumors up to 8 cm.

The primary end point of the study was objective response rate (ORR) and duration of response (DOR).

According to earlier findings of the study, among 162 eligible patients, the ORR was 72.2% (95% CI, 64.9%-78.5%). About a quarter of patients (27.8%) were considered to be unevaluable due to transplant or resection, lack of confirmatory imaging, or other reasons. Of the responders (n = 117), 76.1% (95% CI, 67.6%-82.9%) had a DOR of 6 months or more.²

In the study, TheraSphere microspheres served as suitable neoadjuvant therapy prior to transplant or resection in 27.8%.

The median overall survival was 57.9 months in the intention-to-treat population and the overall survival rate at 3 years was 86.6%.

Additionally, liver function in terms of albumin and bilirubin levels were maintained throughout the study for 92.9% and 85.3% of the patients, respectively.

The investigators noted that TheraSphere microspheres provided comparable overall survival to existing curative therapies in HCC.

Radioembolization with TheraSphere can be performed as an outpatient procedure and has gained recommendation for use from the National Institute for Health and Care Excellence (NICE) for the treatment of patients with HCC.

"The FDA approval and the recent NICE 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," said Peter Pattison, president of Interventional Oncology, Peripheral Interventions, Boston Scientific. "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."

_References

_{Boston Scientific Receives FDA Approval for TheraSphere™ Y-90 Glass Microspheres. News release. Boston Scientific. March 18, 2021. Accessed March 18, 2021. https://bit.ly/2NzoCCG}

_{Salem R, Johnson GE, Riaz A, Bishav V, Kim E, Padia S. 992P Yttrium-90 glass microspheres in the treatment of early and advanced hepatocellular carcinoma: The LEGACY study. Ann Oncol. 2020;31(suppl 4):S692-693. doi:10.1016/j.annonc.2020.08.1108}