The US Food and Drug Administration (FDA) have granted approval of the TheraSphere Y-90 glass microspheres (Boston Scientific), developed for the treatment of patients with hepatocellular carcinoma (HCC). The approval expands access to this life-prolonging therapy for a greater number of patients, which, to date, has been utilised under a humanitarian device exemption (HDE)—an FDA classification that required institutional review board approval and limited the number of patients treated with the therapy per year. TheraSphere is now the only radioembolization technology indicated for the treatment of unresectable HCC in the USA.
HCC is one of the most prevalent cancers in the world and the most common type of primary liver cancer, with more than half a million new global cases diagnosed annually. The American Cancer Society estimates that approximately 32,000 new cases of HCC will be diagnosed in the USA in 2021. It is most often treated through surgery, liver transplantation, chemotherapy, or embolization, including both chemoembolization and radioembolization (selective internal radiation therapy [SIRT]). TheraSphere treatment, a type of SIRT with low toxicity, is comprised of millions of microscopic glass beads containing radioactive yttrium (Y-90), which are delivered directly to liver tumours via a catheter and result in minimal exposure to surrounding healthy tissue.
Approval of TheraSphere was based on results from the LEGACY study, designed to evaluate the safety and efficacy of the therapy for the treatment of early and advanced HCC. The study analysed data from 162 patients and met both primary endpoints of objective response rate and duration of response rate (72.2% at four weeks and 76.1% at six months, respectively). Data demonstrated 100% complete or partial patient response up to two TheraSphere treatments—disappearance of all lesions or ≥30% decrease in target lesion diameter —and a 93% overall survival rate in patients with transplant or resection following treatment at three years.
“I am honoured 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,” comments Riad Salem, an interventional radiologist at Northwestern Memorial Hospital (Chicago, USA) and principal investigator of the LEGACY trial. “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.”
Treatment with TheraSphere does not require hospitalisation and is typically performed as an outpatient procedure in as little as an hour, potentially alleviating pressure on healthcare systems in an increasingly complex care environment. Recognition of the benefits of SIRT (both to patients and hospitals) were reflected in recently issued guidance from the National Institute for Health and Care Excellence (NICE) when they recommended the use of TheraSphere for the treatment of patients with HCC through the National Health Service (NHS) in England, Wales, and Northern Ireland.