A Rapid and Safe Infusion Protocol for ¹⁷⁷Lu Peptide Receptor Radionuclide Therapy

Peptide receptor radionuclide therapy (PRRT) with ¹⁷⁷Lu-labeled somatostatin analogs in patients with somatostatin receptor-expressing tumors is often performed using administration protocols prescribing a 30-min infusion time. The most often used method of infusion is the gravity method, by which the complete dose is effectively administered exponentially. However, there is no evidence to explicitly support an infusion time of 30 min. This study aims to investigate the safety of an infusion time of less than 5 min. Methods: A cohort study was performed, examining the biochemical and clinical toxicity after PRRT when using a fast-infusion protocol with a maximum infusion time of 5 min. Data on patient characteristics, laboratory tests, follow-up visits, and pre- and posttreatment imaging using ⁶⁸Ga-DOTATOC PET/CT from patients treated with PRRT at the University Medical Center Utrecht (UMC Utrecht) were collected. All patients receiving PRRT using the fast-infusion protocol were included. If no laboratory or clinical follow-up was available, patients were excluded. In addition, a laboratory experiment was performed, simulating the standard-infusion protocol using the gravity method. Results: Thirty-one patients, treated using the fast-infusion protocol, were included. Clinical toxicity mainly consisted of grade 1/2 fatigue (87.1%) and grade 1 nausea or vomiting (67.7%) during follow-up. No acute or long-term clinical toxicity possibly related to the fast-infusion protocol was reported. Grade 3/4 hematologic toxicity occurred after PRRT in 1 patient (3.2%). No grade 3/4 renal toxicity occurred. The laboratory experiment showed that when using the gravity method for infusion, half of the activity is infused after 3.5 min, and 95% is infused within 15 min. Conclusion: A faster infusion of PRRT using an infusion time of less than 5 min is safe and feasible in clinical practice.