{"entity":{"id":"ho-166-microspheres","kind":"drug","name":"Holmium-166 microspheres","aka":["QuiremSpheres","166Ho-PLLA microspheres"],"tldr":"Tiny plastic beads carrying a radioactive, slightly magnetic metal are injected into the artery feeding a liver tumour. Because the metal shows up on both nuclear scans and MRI, doctors can check exactly where the beads went.","summary":"QuiremSpheres are holmium-166-labelled poly-L-lactic acid microspheres for radioembolisation (SIRT) of unresectable liver tumours, developed at University Medical Center Utrecht and commercialised by Quirem Medical (later acquired by Terumo). Holmium-166 has a physical half-life of 26.8 hours, so more than 90% of the radiation dose is delivered within the first four days after administration.\n\nThe product received CE marking as an active implantable medical device in April 2015, and a matching low-activity test dose (QuiremScout, identical size and shape) was CE-marked in 2018-2019 to predict lung shunting and biodistribution before therapy. Holmium-166 emits both beta particles (for therapy) and a gamma photon, and is paramagnetic, which allows quantitative SPECT and MRI-based dosimetry after treatment, alongside the more usual post-treatment imaging used for yttrium-90 products.\n\nQuiremSpheres has not obtained FDA approval and is used in Europe and other CE-mark-recognising markets; NICE (UK) technology appraisal TA985 reviewed its use in advanced HCC. It is one of three commercially available liver radioembolisation microsphere products, alongside the yttrium-90 resin (SIR-Spheres) and glass (TheraSphere) microspheres.","status":"approved","asOf":"2026-09-22","links":[{"label":"Holmium-166 radioembolisation: current status and future perspectives, PMC 2022","url":"https://pmc.ncbi.nlm.nih.gov/articles/PMC9626412/"},{"label":"NICE TA985: QuiremSpheres for advanced HCC","url":"https://www.nice.org.uk/guidance/ta985/chapter/2-Information-about-QuiremSpheres"},{"label":"Terumo: QuiremScout CE mark announcement, 2019","url":"https://www.terumo.com/newsrelease/detail/20190107/234"}],"tags":["radioembolisation","liver","beta emitter","CE mark"],"related":["y-90-resin-microspheres","y-90-glass-microspheres","y-90","ho-166"],"indications":["hcc"],"sections":[],"technologies":["radioembolisation-tare"],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"brand":"QuiremSpheres","modality":"radioembolisation","mechanism":"Poly-L-lactic acid (PLLA) microspheres loaded with holmium-166 (a beta emitter that also emits an imageable gamma photon and is paramagnetic, so uptake can be checked on SPECT or MRI as well as CT), infused through a hepatic artery catheter to treat unresectable liver tumours.","approvals":[{"region":"EU","year":2015,"indication":"Treatment of unresectable liver tumours (radioembolisation)"}],"mechanismSteps":[],"dosing":{"route":"Intra-arterial infusion into the hepatic artery via catheter","schedule":"Single administration, typically with a QuiremScout test dose beforehand for dosimetry","source":"https://www.nice.org.uk/guidance/ta985/chapter/2-Information-about-QuiremSpheres"},"toxicity":[],"access":[],"regulatoryEvents":[]},"route":"/drugs/ho-166-microspheres/","neighbours":{"drug":[{"id":"y-90-glass-microspheres","kind":"drug","name":"Yttrium-90 glass microspheres","route":"/drugs/y-90-glass-microspheres/"},{"id":"y-90-resin-microspheres","kind":"drug","name":"Yttrium-90 resin microspheres","route":"/drugs/y-90-resin-microspheres/"}],"isotope":[{"id":"ho-166","kind":"isotope","name":"Holmium-166","route":"/isotopes/ho-166/"},{"id":"y-90","kind":"isotope","name":"Yttrium-90","route":"/isotopes/y-90/"}],"indication":[{"id":"hcc","kind":"indication","name":"Hepatocellular carcinoma","route":"/indications/hcc/"}],"technology":[{"id":"radioembolisation-tare","kind":"technology","name":"Radioembolisation (TARE / SIRT, yttrium-90)","route":"/technologies/radioembolisation-tare/"}]}}