Study to Evaluate Safety and Dosimetry of Lutathera in Adolescent Patients With GEP-NETs and PPGLs

The study schedule for each patient consists of the screening period (up to 2 weeks) followed by the treatment period (4 treatment administrations at 8-week interval), and the follow-up period (10 years). The treatment period will consist of 4 Lutathera treatments administered at 8-week intervals. Lutathera administration will occur on Week 1 Day 1 of each cycle. Each patient will receive a total of 4 doses of Lutathera (7.4 GBq/200 mCi x 4 administrations every 8 weeks; cumulative dose: 29.6 GBq/800 mCi). An infusion of 2.5% Lysine - Arginine amino acid (AA) solution will be co-administered with each Lutathera dose for renal protection according to the approved Lutathera local prescribing information. An antiemetic will be administered prior to infusion of the AA solution for prevention of infusion-related nausea and vomiting. The dosimetry and PK assessments will be performed during the first week after the 1st Lutathera dose, i.e. one time during the study treatment period for each patient. The dosimetry analysis will allow for estimation from the 1st Lutathera administration of the cumulative absorbed radiation dose from 4 Lutathera doses and also for taking a decision on the next dose levels. In the exceptional circumstances when dosimetry cannot be performed in a particular patient after the first Lutathera dose, it should be completed as soon as feasible upon a later dose. In order to minimize risk for each study subject, an accelerated analysis of dosimetry and safety data will be performed for each patient in the study, to enable the Investigator to take a decision for the subsequent Lutathera doses. The results of dosimetry assessments (imaging and blood dosimetry) will be provided to the investigators for their evaluation prior to administration of subsequent therapeutic cycles in each patient. A total follow-up period of 10 years (120 months) after the last Lutathera dose will take place for each patient who received at least one dose of Lutathera. This follow-up period will be comprised of a short-term follow-up of 6 months to evaluate cumulative Lutathera toxicities, followed by a long-term follow up of another 114 months. An external Data and Safety Monitoring Board (DSMB) will also operate in the study to evaluate accumulating safety and dosimetry data, to ensure the safety of adolescents enrolled in the study, and to provide recommendations to investigators as well as to the clinical team in charge of conducting the study.