A Phase 3 interventional study of 177Lu-Dotatate (7.4 Gigabecquerel/cycle) during 30 min intravenous infusion every 16 weeks (q8w) x 4 cycles; 2) and 3) as in the experimental arm. and 177Lu-Dotatate (7.4 Gigabecquerel/cycle) during 30 min intravenous infusion every 8 weeks (q8w) x 4 cycles; 2) and 3) as in the experimental arm. in Grade1-2 Advanced Midgut Neuroendocrine Tumors (NETs), sponsored by Grupo Espanol de Tumores Neuroendocrinos. Recruiting at 21 sites in 2 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-09-16.
Sponsored by Grupo Espanol de Tumores Neuroendocrinos · Phase 3, Interventional, and Treatment
This is a randomized Phase II/late phase I de-escalation clinical trial with approved investigational medicinal products in new use condition, low intervention.
Disease under study Patients with unresectable or metastatic, slowly progressive, well-differentiated (Grade1 and Grade2), somatostatin receptor-positive midgut neuroendocrine tumors (GEP-NETs).
It is planned to randomize 166 patients with a histologically confirmed diagnosis of slowly progressive grade 1 or grade 2 advanced midgut neuroendocrine tumors (NETs) candidates to receive 177Lu-Dotatate targeted radioligand therapy (RLT). Patients are required to have SSTR+ disease, as evidenced on somatostatin receptor imaging. Patients will be randomized into two arms:
Research hypothesis: Less intensive somatostatin-receptor (SST) targeted radioligand therapy (RLT) (7.4 GBq/cycle 177Lu-Dotatate every 16 weeks x 4 cycles) is associated with less severe hematological toxicities and may mitigate the risk to develop therapy-related myeloid neoplasms (t-MN) with similar antitumor efficacy in slowly growing gastrointestinal grade 1-2 NETs.
Objectives Primary Objectives
-To demonstrate decreased serious hematological toxicity with a less intensive RLT regimen in slowly progressive advanced Grade 1-2 midgut NETs.
Secondary Objectives
Secondary Trial Endpoints
Patients will be randomized in a 1:1 ratio to experimental or control arms respectively:
Experimental arm:
Control arm:
8. Ethical Considerations
The study will be conducted in accordance with the principles of the Helsinki Declaration Adopted by the 18th World Medical Assembly, Helsinki, Finland, June 1964 updated to its latest version Fortaleza, Brazil, October 2013. With the Good Clinical Practice (GCP) standards issued by the Working Party on Medicinal Product Efficacy of the European Economic Community (1990) (CPMP / ICH / 135/95).
Adequate organ function (hematological, renal and liver) based upon meeting all of the following laboratory criteria:
Exclusion Criteria:
Experimental arm: 1. Treatment with 177Lu-Dotatate (7.4 Gigabecquerel/cycle) during 30 min intravenous infusion every 16 weeks (q16w) x 4 cycles 2. Renal protection starting 30 minutes before targeted radioligand therapy (RLT) lasting 4 hours (iv amino acid solution of 14.4-20g of lysine and 14.9-20.7g of arginine in 1 to 2 liters of solution) 3. Long-acting standard doses of SSA (Lanreotide autogel 120 mg subcutaneous or Octreotide LAR 30 mg intramuscular, starting 24h after RLT every 4 weeks during RLT (q16w interval SSA administration should be adjusted to RLT administrations so that SSA is always given 24h after each RLT dose and at least 4 weeks prior to next RLT administration cycle) and q4w following last RLT administration until disease progression.
Drug: 177Lu-Dotatate (7.4 Gigabecquerel/cycle) during 30 min intravenous infusion every 16 weeks (q8w) x 4 cycles; 2) and 3) as in the experimental arm. · Drug: Amino acid solution · Drug: Lanreotide (Autogel formulation) or Octreotide LAR
1. Treatment with 177Lu-Dotatate (7.4 Gigabecquerel/cycle) during 30 min intravenous infusion every 8 weeks (q8w) x 4 cycles 2. Renal protection starting 30 minutes before targeted radioligand therapy (RLT) lasting 4 hours (iv amino acid solution of 14.4-20g of lysine and 14.9-20.7g of arginine in 1 to 2 liters of solution); 3. Long-acting standard doses of SSA (Lanreotide autogel 120 mg subcutaneous or Octreotide LAR 30 mg intramuscular, starting 24h after RLT every 4 weeks during RLT (q8w interval SSA administration should be adjusted to RLT administrations so that SSA is always given 24h after each RLT dose and at least 4 weeks prior to next RLT administration cycle) and q4w following last RLT administration until disease progression
Drug: 177Lu-Dotatate (7.4 Gigabecquerel/cycle) during 30 min intravenous infusion every 8 weeks (q8w) x 4 cycles; 2) and 3) as in the experimental arm. · Drug: Amino acid solution · Drug: Lanreotide (Autogel formulation) or Octreotide LAR
Treatment with 177Lu-Dotatate (7.4 Gigabecquerel/cycle) during 30 min intravenous infusion every 16 weeks 177Lu-Dotatate, a radiopharmaceutical medicine which is an somatostatin analogue derived from octreotide that complexes via DOTA with non-carrier added (n.c.a) 177Lu radioconjugate. 177Lu-Dotatate will be supplied as a 370 MBq/mL solution for infusion. One mL of solution contains 370 MBq The total amount of radioactivity per single-dose vial is 7 400 MBq at the date and time of infusion. Given the fixed volumetric activity of 370 MBq/mL at the date and time of calibration, the volume of the solution in the vial ranges between 20.5 and 25.0 mL in order to provide the required amount of radioactivity at the date and time of infusion of lutetium (177Lu) oxodotreotide at the date and time of calibration.
Also known as: 177Lu-DOTA0-Tyr 3-Octreotate, 177Lu-DOTATE, LUTATHERA, lutetium (177Lu) oxodotreotide
Treatment with 177Lu-Dotatate (7.4 Gigabecquerel/cycle) during 30 min intravenous infusion every 8 weeks (q8w) x 4 cycles 177Lu-Dotatate, a radiopharmaceutical medicine which is an somatostatin analogue derived from octreotide that complexes via DOTA with non-carrier added (n.c.a) 177Lu radioconjugate. Synonyms are: 177Lu-DOTA0-Tyr 3-Octreotate, 177Lu-DOTATE LUTATHERA, lutetium (177Lu) oxodotreotide 177Lu-Dotatate will be supplied as a 370 MBq/mL solution for infusion One mL of solution contains 370 MBq The total amount of radioactivity per single-dose vial is 7 400 MBq at the date and time of infusion. Given the fixed volumetric activity of 370 MBq/mL at the date and time of calibration, the volume of the solution in the vial ranges between 20.5 and 25.0 mL in order to provide the required amount of radioactivity at the date and time of infusion of lutetium (177Lu) oxodotreotide at the date and time of calibration.
Renal protection starting 30 minutes before RLT and lasting 4 hours (iv) amino acid solution of 14.4-20 g of lysine and 14.9-20.7 g of arginine in 1 to 2 liters of solution)
Long-acting standard doses of SSA (Lanreotide autogel 120 mg subcutaneous (sc) or Octreotide LAR 30 mg im, starting 24h after RLT and every 4 weeks during RLT (q16w interval SSA administration should be adjusted to RLT administrations so that SSA is always given 24h after each RLT dose and at least 4 weeks prior to next RLT administration cycle) and q4w following last RLT administration until disease progression.
Rate of Grade 2-5 hematological toxicity
The primary endpoint for the RIALTO trial is the frequency of Grade 2-5 hematological toxicity (worst per patient) from initiation of treatment with RLT up to 24 months thereafter according to National Cancer Institute Common Terminology Criteria for Adverse Events version 5 (NCI-CTCAE v5)
Time frame: Throughout the study period, from initiation of treatment with RLT up to 24 months
Best hormonal response
Best hormonal response defined as greatest decrease, or \>30% decrease, of chromogranin A and 5HIAA from baseline if baseline levels were \>2x ULN or 5xULN
Time frame: 24 months
Best radiological response
Best radiological response according to local investigator RECIST V1.1
Time frame: 24 months
Duration of response (DoR)
Duration of response (DoR) according to local investigator RECIST v1.1. Time from first response (CR or PR), according to ORR definition for the trial, to the date of the documented PD as determined using RECIST v1.1 criteria or death due to any cause, whichever occurs first. Those patients with response and without PD or death event will be censored on the date of their last tumor assessment.
Time frame: Throughout the study period, from initiation of treatment with RLT up to 24 months
Objective response rate (ORR)
Objective response rate (ORR) according to local investigator RECIST v1.1. Assessed by the investigator through imaging follow-up (CT scan/MRI) using RECIST v1.1 (Appendix 3). This will be considered as the percentage/proportion of randomized patients with complete response (CR) or partial response (PR) as their overall best response throughout the study period. The investigator will report the change in size of tumors as compared with baseline, before the first dose of study treatment.
Time frame: Throughout the study period, from initiation of treatment with RLT up to 24 months
Disease control rate (DCR)
Disease control rate (DCR) RECIST v1.1 according to local investigator RECIST v1.1. Assessed by the investigator through imaging follow-up (CT scan/MRI) using RECIST v1.1. This will be considered as the percentage/proportion of randomized patients with complete response (CR) or partial response (PR) as their overall best response throughout the study period. The investigator will report the change in size of tumors as compared with baseline, before the first dose of study treatment.
Time frame: Throughout the study period, from initiation of treatment with RLT up to 24 months
Progression-free survival (PFS)
Progression-free survival (PFS) (investigator assessed) defined as the time between randomization date and disease progression according to RECIST v1.1 or death from any cause (primary analysis of PFS) .PFS will be censored at the date of the last adequate tumor assessment if no PFS event is observed prior to the analysis cut-off date.
Time frame: Throughout the study period, up to 3 months from radomization
Progression-free survival (PFS)
Progression-free survival (PFS) (investigator assessed) defined as the time between randomization date and disease progression according to RECIST v1.1 or death from any cause (primary analysis of PFS). PFS will be censored at the date of the last adequate tumor assessment if no PFS event is observed prior to the analysis cut-off date.
Time frame: Throughout the study period, up to 12 months from radomization
Progression-free survival (PFS)
Progression-free survival (PFS) (investigator assessed) defined as the time between randomization date and disease progression according to RECIST v1.1 or death from any cause (primary analysis of PFS) .PFS will be censored at the date of the last adequate tumor assessment if no PFS event is observed prior to the analysis cut-off date.
Time frame: Throughout the study period, up to 24 months from radomization
Overall survival
Overall survival defined as the time elapsed from randomization until death from any cause. Patients alive and free of events at the date of the analysis will be censored at their last known contact.
Time frame: Throughout the study period, up to 6 months from radomization
Overall survival
Overall survival defined as the time elapsed from randomization until death from any cause. Patients alive and free of events at the date of the analysis will be censored at their last known contact.
Time frame: Throughout the study period, up to 12 months from radomization
Overall survival
Overall survival defined as the time elapsed from randomization until death from any cause. Patients alive and free of events at the date of the analysis will be censored at their last known contact.
Time frame: Throughout the study period, up to 18 months from radomization
Overall survival
Overall survival defined as the time elapsed from randomization until death from any cause. Patients alive and free of events at the date of the analysis will be censored at their last known contact.
Time frame: Throughout the study period, up to 24 months from radomitation
Worst grade non-hematological toxicity per patient
Percentage of patients with Non-hematological toxicity. Non-hematological toxicity: defined as worst grade non-hematological toxicity per patient according to NCI-CTCAE v 5.0 criteria.
Time frame: Throughout the study period, up to 24 months
Rate of clonal hematopoiesis
Rate of clonal hematopoiesis by Next-Generation Sequencing (NGS) of ctDNA calculated by mutations frequency in ctDNA samples
Time frame: Throughout the study period, at baseline
Rate of clonal hematopoiesis
Rate of clonal hematopoiesis by Next-Generation Sequencing (NGS) of ctDNA calculated by mutations frequency in ctDNA
Time frame: Throughout the study period, up to 3 months from the start of treatment of the study
Rate of clonal hematopoiesis
Rate of clonal hematopoiesis by Next-Generation Sequencing (NGS) of ctDNA calculated by mutations frequency in ctDNA samples
Time frame: Throughout the study period, up to 12 months from the start of treatment of the study
Rate of clonal hematopoiesis
Rate of clonal hematopoiesis by Next-Generation Sequencing (NGS) of ctDNA calculated by mutations frequency in ctDNA samples.
Time frame: Throughout the study period, up to 24 months from the start of treatment of the study
Number of RLT cycles per patient
Number of RLT cycles per patient
Time frame: Throughout the study period, up to 24 month
Acumulative dose received each patient
Number acumulative dose received each patient
Time frame: Throughout the study period up to 24 month
Treatment compliance analyzing treatment delays and interruptions due to toxicity
Treatment compliance analyzing treatment delays and interruptions due to toxicity, rate of patients completing planned schedule, time from first to last RLT dose
Time frame: Throughout the study period, time from first to last RLT dose
Rate of Grade 2-5 hematological toxicity (worst per patient)
Rate of Grade 2-5 hematological toxicity (worst per patient) from initiation of treatment with RLT up to 12 months after the last PRRT
Time frame: Throughout the study period, from initiation of treatment with RLT up to12 months after the last PRRT
PFS centralized based only on morphological imaging
PFS will also be centrally assessed according to RECIST 1.1 based only on morphological imaging (CT/MRI scans), regardless of SRI-PET scan results.
Time frame: Throughout the study period, up to 24 mounth from radomization
PFS will also be centralized on both morphological and functional imaging.
Progression-free survival will also be centrally assessed according to RECIST 1.1 based on both morphological (CT/MRI scans) and functional imaging.
Time frame: Throughout the study period up to 24 mounth from radomization
PFS will also be assessed according to RECIST 1.1 based only on morphological imaging, functional imaging and clinically progression of the functional syndrome
PFS will also be assessed according to RECIST 1.1 based only on morphological imaging (CT/MRI scans), functional imaging and clinically progression of the functional syndrome, defined as unequivocal worsening of the functioning syndrome at the investigator criteria
Time frame: Throughout the study period, up to 24 mounth from radomization
Adverse events (AE) and serious adverse events (SAE).
Number patients that suffered a Adverse event (AE) or serious adverse events (SAE) specific
Time frame: Throughout the study period. 24 months
Treatment-related AEs (TRAEs).
Number Treatment-related AEs (TRAEs).
Time frame: Throughout the study period, 24 month
Patients reported outcomes through the EORTC QLQ-C30 and GINET21 questionnaires.
Patients reported outcomes through the EORTC QLQ-C30 and GINET21 questionnaires.
Time frame: Throughout the study period, 24 months
Rate of myeloid neoplasms
Porcentatge patients with myeloid neoplasms
Time frame: Throughout the study period
Incidence of severe infection/sepsis
Incidence of severe infection/sepsis (antibiotics prescription, hospitalization)
Time frame: Throughout the study period
Rate of adverse events ≥ Grade 2
Rate of adverse events ≥ Grade 2 under subsequent next line of systemic treatment
Time frame: Throughout the study period
Duration of adverse events ≥ Grade 2
Duration of adverse events ≥ Grade 2 (median, %\>6 months)
Time frame: Throughout the study period
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Grupo Espanol de Tumores Neuroendocrinos