In an interview with IO Learning, Andrew Kennedy, MD, Sarah Cannon Research Institute, Nashville, Tennessee, shared insights from an investigational device exemption (IDE) study, presented at the Society of Interventional Radiology 2024 Annual Meeting in Salt Lake City, Utah. This pivotal study is evaluating the safety and efficacy of the unique imageable glass Y90 microspheres (Eye90 microspheres®) for radioembolization of hepatocellular carcinoma.

At this time, there have been 4 patients successfully treated with no immediate complications or significant treatment-related adverse events. Analyses found there was multimodal imagining capability with visualization of the imageable Y-90 microspheres on x-ray, cone beam CT, 4-phase CT, SPECT/CT, and TOF PET/CT. Additionally, there was good correlation between microsphere radiopacity and radioactivity in target tissue.

Dr Kennedy describes how the imageable glass Y90 microspheres differ from other commercially available microspheres, shares early results from the Route90 IDE study, and discusses the possibly of CT dosimetry.

IO Learning: What are the Eye90 microspheres ®, and how do they differ from other microspheres available?

Andrew Kennedy, MD: As your readers may know, there are 2 commercially available radioactive microparticles that we use in the liver: TheraSpheres™ are glass, and SIR-spheres® are plastic or resin. The new Eye90 microspheres® are glass, but they also have a property that allows us to image them when they are in the body, unlike the other 2 spheres. They carry the same radioisotope, they are likely to be just as effective at killing tumor cells, but they have the added advantage of us being able to see them in real time. And that imaging is permanent, so we can check back in the future to make sure that where we implanted the radiation is where the response is happening.

IO Learning: What is the background for this IDE study?

Dr Kennedy: The current study is a pivotal investigational device exemption, or IDE. The company, ABK Biomedical, plans to petition the FDA for permission to sell this product [at the conclusion of this study]. It was developed to meet an unmet clinical need. The FDA agreed it was reasonable to proceed with this trial. This trial will establish its safety and efficacy, and hopefully also iron out some of the details on best way to deliver it.

We already know the patient population really well, so this is more of a technical operational study in sorts, because the delivery kit is brand new, and obviously the spheres are brand new, but the properties of the spheres fit very nicely into what we've done for 25 to 30 years with Y90 treatment.

The study hopefully will not only establish that this is a pretty effective way to treat, but with its added imaging component, we hope to be able to tell very accurately how much radiation the tumor received, and also how much the normal nearby liver was spared.

IO Learning: What were the study methods?

Dr Kennedy: The study is a single arm. The patients have a very rigorous screening process to make sure they're eligible. As you can imagine, with a new microsphere, the first one in 30-some years being introduced, the FDA made pretty significant requirements for safety and observation. This is a little more rigorous than the usual standard of care. There are more visits, there's more imaging, there are more questions for the patients, a the quality of life study. But as a single-arm, it's not being compared to an ongoing role but it could be compared to several recently completed hepatocellular carcinoma trials.

The trial will allow for not just the first treatment, but, in the future, you can give a second treatment. It is very tightly describing the limited amount of disease the patient can have, and focusing our results on just what we treated. These patients have a high likelihood that they will develop new cancers in the future, and we wouldn't want that new tumor to somehow obscure some really good results in what was treated before.

It's a late breaking abstract [at the SIR Meeting], so there are some early results on the first few patients and that's what we were allowed to present, the first few patients’ experiences, to get awareness out there that it so far has been safe and very effective. It is quite novel, that there's a new microsphere available, because conservatively there are tens of thousands of patients in North America treated with this type of technology every year. And now you have a new product, only the third product available, for it. We were pleased that SIR thought this would be worthy of a late-breaking discussion. But it's very early on, only a handful of patients out of 120.

IO Learning: What is the significant of these results?

Dr Kennedy: The significance is, as expected, no complications and excellent technical results of delivering a high dose of radiation just to the tumor. This is building on a first-in-human study in New Zealand where 6 patients were treated and that was done last year. We do have some results from there that we're still following, and those were excellent outcomes. And again, safety was proven there. These patients often require 6 to 12 months of follow-up to know that the tumor is destroyed and that the liver is compensated.

IO Learning: What are the next steps for this research?

Dr Kennedy: Our hope is twofold. One, is that the sponsor gets all of the centers up and operational. I'm not part of the sponsor, I’m the PI of the study, so our clinic has been open for a couple months. We're actively screening and we're hoping that 20 or so centers will be doing the same thing there's only 4 to 5 open right now. With any type of highly selective trial like that, it usually takes 20 or more centers getting that small number of eligible patients put in.

Our first goal is to accrue patients over the next 18 to 24 months. But within that study, there is a research component to see if our hypothesis is correct, that the imaging of the spheres allows us to do more accurate, more timely, almost real-time dose calculation [using a conventional CT scanner] while we're treating the patient. And if that's proven within the study, I think that will be a significant change on how all patients are treated with Y90.

Source:

Abraham RJ, Verma A, Dobrowski D. Route90 US IDE pivotal study early results in radioembolization of hepatocellular carcinoma (HCC) with imageable Y90 microspheres. Presented at the Society of Interventional Radiology Annual Meeting. March 23-29, 2024; Salt Lake City, UT.