166Ho-QuiremSpheres
December 26, 2024
Description
166Ho-QuiremSpheres (also known as 166Ho-PLLA-MS) is a medical device developed at the University Medical Center Utrecht in the Netherlands. The product consists of microparticles loaded with the radioactive isotope Holmium-166. These microparticles are created by activating 165Ho pre-loaded poly-L-lactic acid (PLLA) particles with neutron flux in a reactor, using the process [165Ho(n,γ)166Ho]. The particles have a mean diameter of 30 µm. The specific activity of 166Ho-QuiremSpheres is limited due to the degradation of microspheres when exposed to neutron beams for more than one hour.
The product was developed by Quirem Medical BV, a private company. In September 2015, Terumo Corp. of Tokyo, Japan, made an equity investment in Quirem Medical BV, and the product was marketed under the name QuiremSpheres®. In April 2015, QuiremSpheres® received a CE mark, confirming it as a medical device. In July 2020, Terumo Corp. fully acquired Quirem Medical BV. While the product has been filed as a brachytherapy drug, it is still classified as a medical device.
Clinical Applications
QuiremSpheres® is designed to treat unresectable liver tumors by implantation into hepatic tumors through the hepatic artery. It delivers radiation directly to tumors that are otherwise not operable. More detailed information about the product is available on the Quirem website. In the U.S., seven clinical trials involving QuiremSpheres® have been registered, with two still actively recruiting participants. Information on these trials and related publications can be found on the Quirem Medical web pages.
Availability
166Ho-QuiremSpheres is directly available from Quirem Medical BV.
Competition
166Ho-QuiremSpheres competes in the market with two other microparticle-based devices for hepatocellular carcinoma (HCC) treatment: 90Y-SIR-Spheres and 90Y-TheraSphere. The primary advantage of 166Ho-QuiremSpheres over its competitors is its labeling with Holmium-166. This allows imaging of the product’s biodistribution, a capability that is absent in pure beta emitters like 90Y.
Comments
As the only product labeled with Holmium-166, QuiremSpheres® offers a potential marketing advantage over 90Y-based products. However, this distinction has not yet been enough to significantly reduce market shares of established products like SIR-Spheres and TheraSphere, likely due to the smaller size of Quirem Medical BV.
It is noteworthy that similar products, such as SIR-Spheres® and TheraSphere®, are classified as medical devices rather than drugs, although they meet the criteria for implantable medical devices. These include properties like chemical neutrality, non-interaction with body tissues, and the mechanical nature of their action (such as embolization and trapping in tissues). Recently, regulatory authorities have started reconsidering the definition of medical devices, especially those that cannot be removed from the body after use. This shift could impact the classification of radioactive microparticles, gels, and similar carriers of radionuclides.
In the future, these types of microparticles may no longer be classified as medical devices but instead as pharmaceuticals, which would require them to undergo the same clinical trials as drugs. This evolution is important for developers of such treatments to consider.