Dosimetry Based PRRT Versus Standard Dose PRRT With Lu-177-DOTATOC in NEN Patients
Status:
Recruiting
Trial end date:
2025-12-01
Target enrollment:
Participant gender:
Summary
In this study, we want to randomize patients with neuroendocrine neoplasms (NENs) who are
eligible for peptide receptor radionuclide therapy (PRRT), to either standard PRRT consisting
of 4 treatments with 7.4 GBq Lu-177-DOTATOC (standard arm) or 4 treatments with
individualized doses of Lu-177-DOTATOC (dosimetry arm). In the dosimetry arm, the first dose
depends on the patients' kidney function and thereafter the absorbed dose to the kidneys at
the previous treatment. A max of 20GBq will be administered at the first treatment and 25GBq
at treatment 2-4. We aim to reach an accumulated kidney dose of 24Gy.
After the first treatment all patients will go through three SPECT/CT scans 24 hours, 4 days,
and 7 days, after treatment to calculate absorbed kidney dose. The patients in the standard
dose treatment arm will have one SPECT/CT scan after each of the last three treatments; all
performed 24 hours after treatment, used to approximate the kidney dose assuming the
clearance of the Lu-177 DOTATOC is the same after all treatments. The patients in the
dosimetry based treatment arm will go through three SPECT/CT scans after all four treatments
for dosimetry calculation.
Bone marrow dosimetry is calculated after all treatments in the dosimetry based treatment arm
and after the first treatment in the standard treatment arm. For bone marrow dosimetry, blood
samples are drawn right before administration of Lu-177 DOTATOC (time 0) and 3 minutes, 45
minutes, 2 hours, 4 hours, 7-8 hours, 24 hours, 4 days, and 7 days after administration of
Lu-177 DOTATOC.
Standard blood samples are routinely drawn every 2nd week after every treatment in all
included patients and analysed regarding liver, kidney and bone marrow function. Kidney
clearance is evaluated with Tc-DTPA clearance at baseline.
Blood and urinary samples will be collected at baseline and 3 months after the last treatment
for kidney fibrosis analyses.
At baseline, blood and urine samples are collected for a biobank. All included patients fill
in validated quality of life questionaires at all treatments.
To evaluate the effect of the treatment, all patients will be evaluated with standard CT
scans prior to treatment and 3 and 9 months after the 4th treatment. Ga-68 DOTATOC PET will
be performed at baseline and 6 and 12 months after the last treatment.