Findings of a retrospective analysis of real-world data indicate that retreatment with 2 extra cycles of peptide receptor radionuclide therapy (PRRT) with 177Lu-DOTATATE provided survival benefit in patients with disease progression after initial PRRT.
To evaluate the role of retreatment with PRRT + 177Lu-DOTATATE in neuroendocrine tumors (NETs), a retrospective analysis of real-world data was conducted to evaluate safety and efficacy in patients who have shown initial response to prior PRRT; the results of this analysis were reported at the 2020 North American Neuroendocrine Tumor Society Annual Symposium.
In this multicenter, retrospective study, eligible patients treated at 3 independent sites (Erasmus Medical Center, Royal Free Hospital, and Universitätsklinikum Bonn) were enrolled. Eligible patients had ≥18 months of progression-free survival (PFS) after initial PRRT with 177Lu-DOTATATE (3-4 cycles; total 800 mCi ± 10%), had progressive somatostatin receptor–positive NETs, and received retreatment with 2 extra cycles of PRRT with 177Lu-DOTATATE (total 400 mCi ± 10%).
A total of 224 patients were included, with a median age of 62 years (range, 32-85 years). The primary NET site was pancreas (29%) or midgut (36%). The majority of patients had grade 2 NETs (42%) and had either received or were receiving somatostatin analog therapy (62%). In the overall population, 37% had bone lesions and 92% had liver lesions. The mean cumulative 177Lu-DOTATATE dose in the total population was 29.1 GBq for initial PRRT and 15.0 GBq for retreatment PRRT. The mean follow-up from the start of initial PRRT was 83.4 months. Grade 3 hematologic toxicities occurred in 23/237 patients (10%) after initial PRRT and in 18/237 patients (8%) after retreatment PRRT; grade 4 hematologic toxicities occurred in 1/237 (0%) and 3/237 (1%), respectively. Overall, the incidence of secondary malignancies per 100 person-years was 0.243 (95% confidence interval [CI], 0.066-0.622).
Meta-analysis showed that the median PFS after initial PRRT (follow-up, 70.6 months) was 33.0 (95% CI, 29.5-36.6); median PFS after retreatment PRRT (follow-up, 23.9 months) was 16.7 (95% CI, 14.5-18.6). The median overall survival from start of initial PRRT was 83.1 months (95% CI, 68.4-93.9).
These results indicate that retreatment with 2 extra cycles of PRRT was associated with a safety profile consistent with that previously reported for initial PRRT, and provided survival benefit in patients with disease progression after initial PRRT with 177Lu-DOTATATE.
Source: Navalkissoor S, et al. North American Neuroendocrine Tumor Society 2020 Annual Symposium; October 1-3, 2020. Abstract C27.
