Patients with neuroendocrine tumours (NET) who are found to be eligible will receive up to 4 doses of Lutathera on this trial. All participants will receive ASTX727 orally (cedazuridine 100mg + 35mg decitabine) Days 0-5 prior to receiving Lutathera Day 8 +/- 2days. Each cycle will be repeated every 2 months for 4 cycles unless unacceptable toxicity, progression of disease or withdrawal of patients' consent. Restaging will occur after 2 cycles of Lutathera and at the end of treatment. Patients will be followed 3 monthly until disease progression, death or withdrawal of patients' consent.
Patients entered into the study will receive ASTX727 orally up to 3 to 8 days prior to receiving Lutathera treatment to determine whether pre-treatment with ASTX727 results in re-expression of somatostatin receptor-2 in patients with metastatic neuroendocrine tumours. The study will use [68Ga]-DOTA-TATE PET to image epigenetic modification of the receptor locus.