"MAURITIUS": Tumour dose in patients with advanced carcinoma

Radioimaging of various human tumours by means of somatostatin analogues an d vasoactive intestinal peptide has been introduced into clinical practice in recent years. The finding that human tumours express various subtypes of somatostatin receptors has led to the development and characterization of a navel peptide tracer termed MAURITIUS. MAURITIUS identifies a broad range of somatostatin receptors with high binding affinity, and somatostatin rec eptor 1 with low binding affinity. In order to evaluate patients for tumour radiotherapy with Y-90-MAURITIUS, tumour dose calculation is performed wit h In-111-MAURITIUS [In-111-DOTA-lanreotide]. Treatment is initiated in pati ents presenting a tumour uptake of greater than or equal to 10 Gy/GBq (i.e. , standard dose for 1 treatment cycle with Y-90-MAURITIUS). In 25 patients with advanced cancer refractory to conventional antineoplastic treatment In -111-MAURITIUS (similar to 150 MBq; 10 nmol/patient), scintigraphy and dosi metry was performed Dosimetry data were calculated based on scintigraphic r esults as well as urine, faeces and blood data. In all patients, at least o ne tumour site was visualized during the initial few minutes of application . Additional tumour sites not seen on conventional imaging (computerized to mography, magnetic resonance imaging bone scan) could be detected in 6 pati ents with carcinoids, one patient with prostate cancer and one patient with lymphoma. Liver metastases were visualized in all patients with gastrointe stinal cancers, while the primary tumour was not detected in 2 patients wit h pancreatic, and in I patient wish rectal, cancel: The calculated radiatio n dose for tumours and/or metastases ranged between 3-60 Gy/GBq for Y-90-MA URITIUS. MAURITIUS is a universal receptor ligand for a large variety of di fferent human tumours, and is suitable for treatment when labelled with Y-9 0.