FDA Approves TheraSphere Y-90 Glass Microspheres for HCC

The FDA has approved TheraSphere™ Yttrium-90 (Y-90) Glass Microspheres for the treatment of patients with hepatocellular carcinoma.¹

The approval is based on findings from the retrospective LEGACY trial, in which TheraSphere, a personalized radiotherapeutic cancer treatment, elicited an overall response rate of 72.2% at 4 weeks per blinded independent central review (BICR) as neoadjuvant or stand-alone treatment in 162 evaluable patients with unresectable HCC.²

Data also showed that 76.1% of patients derived a duration of response rate at 6 months with TheraSphere per modified RECIST (mRECIST) criteria, meeting both primary end points of the study.

TheraSphere is now the only radioembolization technology indicated for the treatment of patients with unresectable HCC in the United States, according to Boston Scientific Corporation, the developer of the product.

"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 lead investigator Riad Salem, MD, MBA, an interventional radiologist at Northwestern Memorial Hospital. "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."

The multicenter, single-arm LEGACY study included patients with unresectable solitary liver lesions that were 8 cm or smaller in size. Eligible patients had to have Child-Pugh A and Barcelona Clinic Liver Cancer (BCLC) A or BCLC C disease (ECOG 1 performance status). Patients could not have had prior liver transplantation, resection, locoregional treatment, or systemic therapy. Additionally, patients with portal vein thrombosis or extrahepatic disease were excluded.

The median age of eligible patients (n = 162) was 66; 17.9% of patients were 75 or older. More than half of patients (60.5%) had BCLC A disease, and 39.5% had BCLC C disease. The median tumor size was 2.6 cm (range, 0.9-8.1). Of the eligible patients, 45 were unevaluable because of transplant or resection (n = 20), lack of confirmatory imaging (n = 20), among other reasons (n = 5).

Patients received selective, lobar, or mixed administration of TheraSphere at a median dose to perfused liver volume of 410 Gy. TheraSphere was given as neoadjuvant therapy with the intent to bridge patients to transplant or resection or as stand-alone treatment. The majority of patients (80.2%) received 1 TheraSphere infusion, and the remainder of patients received 2 or more treatments.

Additional data from the LEGACY trial showed that 100% of evaluable patients derived a partial or complete response with TheraSphere per localized mRECIST criteria. Responses were defined as a response within the Y-90 microsphere treatment area.

The results revealed a 3-year overall survival (OS) rate of 93% in patients who had undergone transplant or resection following treatment with TheraSphere. Additionally, the rate of best response with TheraSphere was 88% per localized mRECIST criteria.

Almost all (93.9%) patients who received TheraSphere were alive and progression free by localized mRECIST criteria at 24 months. Per mRECIST and RECIST v1.1 criteria, these percentages were 78.8% and 76.7%, respectively.

Regarding safety, the results indicated that the majority of adverse effects (AEs) were mild and resolved without medical intervention. Maintained albumin and bilirubin liver function was observed in 92.9% and 85.3% of patients, respectively.

"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

1. Boston Scientific Receives FDA Approval for TheraSphere™ Y-90 Glass Microspheres. Boston Scientific Corporation. News release. March 18, 2020. Accessed March 18, 2020. https://prn.to/3qWiKRr

2. TheraSphere Y-90 glass microspheres LEGACY study. Boston Scientific. 2021. Accessed January 21, 2021. http://bit.ly/35THMsX