Abstract No. 150 ▪ FEATURED ABSTRACT Multimodal Imageable Eye90 microspheres Radioembolization for Hepatocellular Carcinoma: 6-Month Interim Safety and Efficacy and 3-Month Liver Volume Results from a First-in-Human Trial

To describe 6-month safety and efficacy and 3-month liver volume changes after multimodal imageable glass Y-90 radioembolization for hepatocellular carcinoma (HCC) in a first-in-human clinical trial. Eye90 microspheres (Eye90) is a unique imageable glass Y-90 microsphere providing therapeutic beta radiation with multi-modality imaging capabilities through CT, SPECT/CT, and TOF PET/CT. In a prospective trial, 6 patients underwent selective (≤ 2 segments) Eye90 therapy. Inclusion criteria included liver only HCC, ECOG ≤ 1, total lesion length 2 cm, Child–Pugh A, BCLC A-B. Prospective partition dosimetry was utilized. Clinical safety, ECOG status, hematological/hepatic/renal biochemistry, incidence of toxicity ≥ Grade 3 and related treatment-emergent serious adverse events (TESAEs) were assessed at intervals up to 6 months. Tumor response was evaluated by local modified RECIST (mRECIST) at 3 and 6 months. CT volumes were obtained with semi-automated software (MIM SurePlan Y90) for liver, ipsilateral lobe, contralateral lobe, caudate and spleen. Percent change of combined average volumes between baseline and 90-day imaging were analyzed. Six patients with LIRADS 5 HCC were treated with Eye90 (≤ 2 segments) and followed to 180 days in this interim analysis (Table 1501.). The technical success rate was 100%. Eye90 radiopacity distribution on CT confirmed tumor targeting and correlated with post Eye90 SPECT/CT. At 90 and 180 days, complete response (CR) was observed in 3 of 6 patients (50%) and stable disease (SD) in one (17%). 2 patients with partial response (PR) (33%) at 90 days were treated with TACE. All patients reported adverse events. 5 of 6 (83.3%) reported AEs related to treatment but no treatment related serious adverse events (SAEs). There was no evidence of radioembolization induced liver disease (REILD) or radiation induced lung injury (RILI). At 90 days, there was significant increase in contralateral lobe (20.9%) and caudate segment (26.9%) volume with no change in bilirubin, platelet count or splenic volume and no ascites or portal hypertension. Eye90 Radioembolization was demonstrated to be safe and effective in HCC patients up to 6 months after selective Eye90 microsphere radioembolization. Significant contralateral and caudate hypertrophy was observed 3 months after selective Eye90 radioembolization.