Start Of Peptide Receptor Radionuclide Therapy Research Articles

Peptide Receptor Radionuclide Therapy Is Effective for Clinical Control of Symptomatic Metastatic Insulinoma: A Long-Term Retrospective Analysis.

Metastatic insulinoma is a rare malignant neuroendocrine tumor characterized by inappropriate insulin secretion, resulting in life-threatening hypoglycemia, which is often difficult to treat. There is currently very limited information about the efficacy of peptide receptor radionuclide therapy (PRRT) for clinical control of hypoglycemia. The aim of this long-term retrospective study was to evaluate the therapeutic efficacy of PRRT for improving hypoglycemia, to evaluate the change of medication after PRRT, and to calculate progression-free survival (PFS) and overall survival (OS). Methods: Inclusion criteria were histologically proven somatostatin receptor-positive metastatic malignant insulinoma and at least 2 cycles of [90Y]Y-DOTATOC or [177Lu]Lu-DOTATOC therapy from early 2000 to early 2022. A semiquantitative scoring system was used to quantify the severity and frequency of hypoglycemic episodes under background antihypoglycemic therapy (somatostatin analog, diazoxide, everolimus, corticosteroids): score 0, no hypoglycemic episodes; score 1, hypoglycemic events requiring additional conservative treatment with optimization of nutrition; score 2, severe hypoglycemia necessitating hospitalization and combined medication or history of hypoglycemic coma. Hypoglycemic score before and after PRRT was analyzed. Time of benefit was defined as a time range of fewer hypoglycemic episodes in the observation period than at baseline. Information on antihypoglycemic medication before and after therapy, PFS, and OS was recorded. Results: Twenty-six of 32 patients with a total of 106 [90Y]Y-DOTATOC/[177Lu]Lu-DOTATOC cycles were included. The average observation period was 21.5 mo (range, 2.3-107.4 mo). Before therapy, 81% (n = 21) of the patients had a hypoglycemia score of 2 and 19% (n = 5) had a score of 1. After PRRT, 81% of patients (n = 21) had a decreased score, and the remaining 5 patients showed a stable situation. There was temporary worsening of hypoglycemia just after injection of [90Y]Y-DOTATOC/[177Lu]Lu-DOTATOC in 19% of patients. The average time of benefit in the observation period was 17.2 mo (range, 0-70.2 mo). Antihypoglycemic medication reduction was achieved in 58% (n = 15) of patients. The median OS and PFS after the start of PRRT were 19.7 mo (95% CI, 6.5-32.9 mo) and 11.7 mo (95% CI, 4.9-18.5 mo), respectively. Conclusion: To our knowledge, our study included the largest cohort of patients with malignant insulinoma to be evaluated. Long-lasting symptom control and reduction of antihypoglycemic medications were shown in most patients after late-line PRRT.

Peptide Receptor Radionuclide Therapy in Patients With Advanced Progressive Medullary Thyroid Cancer: Efficacy, Safety, and Survival Predictors.

Progressive metastatic medullary thyroid carcinoma (MTC) is often characterized by rapid disease progression and poor prognosis, with only few therapeutic options available. Peptide receptor radionuclide therapy (PRRT) has demonstrated remarkable success in the management of gastroenteropancreatic neuroendocrine tumors and has also been suggested to treat MTC. However, evidence on its effectiveness and long-term outcome for this indication is still limited. The objective of this study was to assess the safety and efficacy of PRRT in patients with advanced, progressive MTC and to determine survival. Potential predictors of survival were also evaluated. From September 2003 to June 2019, 28 patients (15 men and 13 women; mean age, 49 ± 14 years) with progressive, somatostatin receptor-positive advanced MTC received PRRT with 177Lu- or 90Y-labeled somatostatin analogs at Zentralklinik Bad Berka, Germany. Toxicity was graded according to Common Terminology Criteria for Adverse Events version 5.0. Treatment response was evaluated according to RECIST (Response Evaluation Criteria in Solid Tumors) 1.1, as well as molecular imaging criteria (European Organisation for Research and Treatment of Cancer). Kaplan-Meier analysis was used to calculate progression-free survival (PFS) and overall survival (OS), defined from the start of PRRT. Univariate and multivariate Cox regression analyses were performed to identify parameters associated with PFS and OS. Seventy-seven cycles of PRRT were administered (mean cumulative administered activity, 16.0 ± 7.8 GBq). No acute or long-term grade 3/4 toxicity was recorded with a follow-up of 3 to 140 months, except for 1 patient (4%) who suffered from grade 3 anemia (possibly related to disease progression). According to the RECIST criteria, the disease control rate after 3 to 4 months of PRRT was 56% (partial remission, 12%; stable disease, 44%). The disease control rate (72%) was higher by molecular response evaluation. Median OS and PFS were 63.7 and 10.1 months, respectively. The annual OS rates were 84% at 1 year, 65% at 3 years, 57% at 5 years, and 18% at 10 years. The annual PFS rates were 42% at 1 year, 21% at 2 years, and 13% at 5 years. Patients with bone metastases had poorer OS and PFS than those without metastases (median OS, 58.7 vs 92.3 months [P = 0.035; hazard ratio, 2.7; 95% confidence interval, 0.92-7.84]; median PFS, 8.5 vs 12.8 months [P = 0.592; hazard ratio, 1.2; 95% confidence interval, 0.56-2.76]). Peptide receptor radionuclide therapy was well tolerated and effective in patients with advanced, aggressive MTC. Bone metastasis was an independent adverse prognostic factor for OS.

177Lu-DOTATATE therapy in metastatic/inoperable pheochromocytoma-paraganglioma.

Introduction:177Lu-DOTATATE-based peptide receptor radionuclide therapy (PRRT) is a promising therapy for metastatic and/or inoperable pheochromocytoma and paraganglioma (PPGL). We aim to evaluate the efficacy and safety of and identify predictors of response to 177Lu-DOTATATE therapy in metastatic and/or inoperable PPGL.Methods:This retrospective study involved 15 patients of metastatic or unresectable PPGL, who received 177Lu-DOTATATE PRRT therapy. Clinical, biochemical (plasma-free normetanephrine), and radiological (anatomical and functional) responses were compared before and after the last therapy.Results:A total of 15 patients (4 PCC, 4 sPGL, 5 HNPGL, 1 PCC + sPGL, 1 HNPGL + sPGL) were included. The median duration of follow up was 27 (range: 11–62) months from the start of PRRT. Based on the RECIST (1.1) criteria, progressive disease was seen in three (20%), stable disease in eight (53%), partial response in one (7%), and minor response in three (20%) and controlled disease in 12 (80%). On linear regression analysis the presence of PGL (P= 0.044) and baseline SUVmax >21 (P < 0.0001) were significant positive predictors of early response to PRRT. Encouraging safety profiles were noted with no long term nephrotoxicity and hematotoxicity.Conclusion:177Lu-DOTATATE therapy is an effective and safe modality of treatment for patients with metastatic/inoperable PPGL. Although it is not prudent to withhold PRRT in metastatic PPGL with baseline SUVmax < 21, baseline SUVmax >21 can be used to predict early response to PRRT.

Effect of peptide receptor radionuclide therapy (PRRT) with tandem isotopes - [90Y]Y/[177Lu]Lu-DOTATATE in patients with disseminated neuroendocrine tumours depending on [18F]FDG PET/CT qualification in Polish multicentre experience - do we need [18F]FDG PET/CT for qualification to PRRT?

Peptide receptor radionuclide therapy (PRRT) using radiolabelled somatostatin analogues is a treatment option for patients with disseminated neuroendocrine tumours (NET). The aim of the study was the evaluation of the role of [¹⁸F]FDG PET/CT in predicting response, progression-free survival (PFS) and overall survival (OS) after tandem therapy [⁹⁰Y]Y/[¹⁷⁷Lu]Lu-DOTATATE. Seventy-five patients with histopathologically proven NET G1 and G2 were included in the study. Before treatment [⁶⁸Ga]Ga-DOTATATE PET/CT and [¹⁸F]FDG PET/CT was performed. Patients were treated with [⁹⁰Y]Y/[¹⁷⁷Lu]Lu-DOTATATE (1:1) with mixed amino-acid infusion for kidney protection. Progression-free survival was 22.2 months for [¹⁸F]FDG-positive patients and 59.3 months for [¹⁸F]FDG-negative patients (p = 0.003). The OS from diagnosis (OS-D) and from the start of PRRT (OS-T) was not reached in [¹⁸F]FDG-negative patients, and in [¹⁸F]FDG-positive patients it was 71.8 months and 55.8 months, respectively. The observed overall one-year survival in [¹⁸F]FDG-positive vs. [¹⁸F]FDG-negative patients was 96.8% vs. 99.1%, two-year survival was 88.9% vs. 96%, and five-year survival was 58.8% vs. 88%, respectively. The one-year and two-year risk of progression was 15%vs. 58.9% in [¹⁸F]FDG-positive patients and 11% vs. 32% in [18F]FDG-negative patients. The objective response rate (ORR) [¹⁸F]FDG-positive vs. [¹⁸F]FDG-negative patients was 41.7% vs. 17%. [¹⁸F]FDG-positive patients have statistically significant shorter survival parameters than [¹⁸F]FDG-negative patients. The risk of progression in [¹⁸F]FDG-positive vs. [¹⁸F]FDG-negative patients in one-year follow-up is comparable, whereas in two-year follow-up it is nearly two times higher for [¹⁸F]FDG PET/CT-positive patients.

Prognostic Value of 18F-FDG PET/CT in a Large Cohort of Patients with Advanced Metastatic Neuroendocrine Neoplasms Treated with Peptide Receptor Radionuclide Therapy.

The objective of this retrospective study was to determine the role of 18F-FDG PET/CT in a large cohort of 495 patients with metastatic neuroendocrine neoplasms (NENs) who were treated with peptide receptor radionuclide therapy (PRRT) with a long-term follow-up. Methods: The 495 patients were treated with 177Lu- or 90Y-DOTATOC/DOTATATE PRRT between February 2002 and July 2018. All subjects received both 68Ga-DOTATOC/TATE/NOC and 18F-FDG PET/CT before treatment and were followed 3-189 mo. Kaplan-Meier analysis, log-rank testing (Mantel-Cox), and Cox regression analysis were performed for overall survival (OS) and progression-free survival (PFS). Results: One hundred ninety-nine patients (40.2%) presented with pancreatic NENs, 49 with cancer of unknown primary, and 139 with midgut NENs, whereas the primary tumor was present in the rectum in 20, in the lung in 38, in the stomach in 8, and in other locations in 42. 18F-FDG PET/CT was positive in 382 (77.2%) patients and negative in 113 (22.8%) before PRRT, whereas 100% were 68Ga-DOTATOC/TATE/NOC-positive. For all patients, the median PFS and OS, defined from the start of PRRT, were 19.6 mo and 58.7 mo, respectively. Positive 18F-FDG results predicted shorter PFS (18.5 mo vs. 24.1 mo; P = 0.0015) and OS (53.2 mo vs. 83.1 mo; P < 0.001) than negative 18F-FDG results. Among the cases of pancreatic NENs, the median OS was 52.8 mo in 18F-FDG-positive subjects and 114.3 mo in 18F-FDG-negative subjects (P = 0.0006). For all patients positive for 18F-FDG uptake, and a ratio of more than 2 for the highest SUVmax on 68Ga-somatostatin receptor (SSTR) PET to the most 18F-FDG-avid tumor lesions, the median OS was 53.0 mo, compared with 43.4 mo in those patients with a ratio of less than 2 (P = 0.030). For patients with no 18F-FDG uptake (complete mismatch imaging pattern), the median OS was 108.3 mo versus 76.9 mo for an SUVmax of more than 15.0 and an SUVmax of 15.0 or less on 68Ga-SSTR PET/CT, respectively. Conclusion: The presence of positive lesions on 18F-FDG PET is an independent prognostic factor in patients with NENs treated with PRRT. Metabolic imaging with 18F-FDG PET/CT complements the molecular imaging aspect of 68Ga-SSTR PET/CT for the prognosis of survival after PRRT. High SSTR expression combined with negative 18F-FDG PET/CT results is associated with the most favorable long-term prognosis.

177Lu-DOTATATE Therapy of Advanced Pancreatic Neuroendocrine Tumors Heavily Pretreated with Chemotherapy: Analysis of Outcome, Safety, and Their Determinants

Objective: To retrospectively analyze toxicity, progression-free survival (PFS), overall survival (OS), and their determinants in patients with advanced pancreatic neuroendocrine tumors (PanNETs), previously pretreated with chemothe­r­apy, undergoing peptide receptor radionuclide therapy (PRRT) with ¹⁷⁷Lu-DOTATATE. Methods: A total of 102 patients with advanced PanNETs, previously pretreated with one (67%) or several (33%) lines of chemotherapy, were included, of whom 90% had progressive disease and the majority (74.5%) had grade 2 tumors. ¹⁷⁷Lu-DOTATATE, 7.4 GBq per cycle, was administered with 6- to 8-week intervals in 88% of patients utilizing a dosimetry-guided protocol until an absorbed dose of 23 Gy to the kidneys was reached. Results: A mean dose of 32 ± 10.9 GBq per patient was administered in 1–10 cycles starting a median of 36 months after PanNET diagnosis. The median follow-up was 34 months, the median PFS was 24 months, and the median OS was 42 months from start of PRRT. Independent risk factors for both progression and death were liver tumor burden >50%, more than one line of previous chemotherapy, and elevated alkaline phosphatase. Resection of the primary tumor was linked to longer survival. Bone marrow toxicity grade 3–4 occurred in 10.8%. One patient (1.0%) developed acute myeloid leukemia. Bone marrow toxicity was unrelated to type and length of previous chemotherapy, amount of administered activity, and absorbed dose to the bone marrow. Conclusion: ¹⁷⁷Lu-DOTATATE therapy was feasible, highly effective, and safe in patients with advanced PanNETs heavily pretreated with chemotherapy. More than one line of chemotherapy was a therapy-related independent risk factor for shorter PFS and OS.

Highly favourable outcomes with peptide receptor radionuclide therapy (PRRT) for metastatic rectal neuroendocrine neoplasia (NEN).

Rectal neuroendocrine neoplasia (NEN) is more common than other NEN origins, but is less commonly metastatic. However, when present, distant disease carries a particularly poor prognosis. Evidence guiding optimal treatment of such patients is lacking. We assessed PRRT outcomes in patients with somatostatin receptor (SSTR) positive metastatic rectal NEN from two referral centres. Patients treated with PRRT were retrospectively reviewed. Morphologic (RECIST 1.1), SSTR imaging responses and toxicity were assessed 3months post-PRRT. Kaplan-Meier estimate was used to determine progression-free survival (PFS) and overall survival (OS) from start of PRRT. Twenty-seven consecutive patients (M = 20, age 31-81 years) were reviewed. The majority (70%) had ENETs grade 2 disease (19 patients), three had Grade 3, one Grade 1, and four not documented. Overall, 63% (10/16 patients with available FDG PET/CT) had FDG avid disease. Twenty-six patients were treated for disease progression. Most had 177Lu-DOTA-octreotate with median cumulative activity of 30GBq, median fourcycles. 14 patients had radiosensitising chemotherapy (5FU or capecitabine). At 3months post-PRRT, CT disease control rate (DCR) was 96%: partial response was observed in 70% (19/27) and stable disease in 26%. All but one had partial SSTR imaging response. The median PFS was 29months. Ten patients died, with median overall survival 81months with a median follow-up of 67months. Seventeen patients had further treatments after initial PRRT (10 had further cycles of PRRT). Three patients had grade 3 lymphopenia, without significant renal toxicity, MDS or leukaemia. Our results indicate high efficacy and morphologic responses with minimal toxicity and very encouraging survival from PRRT in patients with metastatic rectal NEN despite the adverse prognostic features of this cohort. Further prospective PRRT trials are warranted in this subgroup.

Peptide Receptor Radionuclide Therapy in Grade 3 Neuroendocrine Neoplasms: Safety and Survival Analysis in 69 Patients.

To date, limited data are available concerning peptide receptor radionuclide therapy (PRRT) of grade 3 (G3) neuroendocrine neoplasms (NENs) with a Ki-67 proliferation index of greater than 20%. The purpose of this study was to analyze the long-term outcome, efficacy, and safety of PRRT in patients with somatostatin receptor (SSTR)-expressing G3 NENs. Methods: A total of 69 patients (41 men; age, 28-81 y) received PRRT with 177Lu- or 90Y-labeled somatostatin analogs (DOTATATE or DOTATOC). Twenty-two patients had radiosensitizing chemotherapy. Kaplan-Meier analysis was performed to calculate progression-free survival (PFS) and overall survival (OS), defined from the start of PRRT, including a subgroup analysis for patients with a Ki-67 index of less than or equal to 55% and a Ki-67 index of greater than 55%. Treatment response was evaluated according to RECIST 1.1 as well as molecular imaging criteria (European Organization for Research and Treatment of Cancer). Short- and long-term toxicity was documented (Common Terminology Criteria for Adverse Events, v 5.0) using a structured database (comprising >250 items per patient) and retrospectively analyzed. Results: Forty-six patients had pancreatic NENs, 11 had unknown primary cancer, 6 had midgut NENs, 3 had gastric NENs, and 3 had rectal NENs. The median follow-up was 94.3 mo. The median PFS was 9.6 mo, and the median OS was 19.9 mo. For G3 NENs with a Ki-67 index of less than or equal to 55% (n = 53), the median PFS was 11 mo and the median OS was 22 mo. Patients with a Ki-67 index of greater than 55% (n = 11) had a median PFS of 4 mo and a median OS of 7 mo. For patients with positive SSTR imaging but no 18F-FDG uptake, the median PFS was 24 mo and the median OS was 42 mo. A significant difference was found for both PFS and OS, with median PFS of 16 mo and 5 mo and median OS of 27 mo and 9 mo for an SUVmax of greater than 15.0 and an SUVmax of less than or equal to 15.0, respectively, on SSTR PET. In the group with 18F-FDG uptake scored as 3 or 4, the median PFS was 7.1 mo and the median OS was 17.2 mo. In the group with 18F-FDG uptake scored as 0-2, the median PFS was 24.3 mo and the median OS was 41.6 mo. PRRT was well tolerated by all patients; no grade 3 or grade 4 hematotoxicity occurred, and no clinically significant decline in renal function was observed. There was no hepatotoxicity. Conclusion: PRRT was tolerated well, without significant adverse effects, and was efficacious in G3 NENs; the clinical outcome was promising, especially in patients with a Ki-67 index of less than or equal to 55% and even in patients for whom chemotherapy had failed. Baseline 18F-FDG along with SSTR molecular imaging was useful for stratifying G3 NEN patients with high uptake on SSTR PET/CT and no or minor 18F-FDG avidity-a mismatch pattern that was associated with a better long-term prognosis.

Clinical Response Profile of Metastatic/Advanced Pulmonary Neuroendocrine Tumors to Peptide Receptor Radionuclide Therapy with 177Lu-DOTATATE.

The aims of this study were to perform multiparametric response assessment of metastatic/advanced pulmonary neuroendocrine tumors (NETs) to Lu-DOTATATE peptide receptor radionuclide therapy (PRRT) (clinical, biochemical, molecular/structural imaging, and survival assessment) and to study the relationship between response, mortality, and overall survival with dual-tracer molecular imaging parameters. Twenty-two patients (6 women, 16 men; median age, 44 years; range, 16-72 years) of histopathologically proven pulmonary NETs with metastatic/advanced disease were included and analyzed retrospectively. Lu-DOTATATE PRRT was administered using standardized protocol (150 mCi [5.55 GBq] per cycle, cycles repeated at 12-16 weeks' intervals [range, 1-5 cycles; average, 4 cycles]) with amino acid-based renal protection. Assessment with Tc-HYNIC-TOC (in the initial years of PRRT development, n = 11)/Ga-DOTATATE PET/CT (presently, n = 11) and F-FDG PET/CT (n = 22), symptomatic and biochemical parameters (serum CgA and urinary 5-HIAA levels), and anatomical response using contrast-enhanced CT (after 3 cycles) was part of routine pretreatment and response evaluation. The patients were designated as responders and nonresponders based on predefined response assessment criteria. Kaplan-Meier product-limit method was calculated for overall survival (OS) curve after the first PRRT, and corresponding 95% confidence intervals (95% CIs) were estimated for annual survival at 1, 2, 3, and 4 years. The various prognostic variables were also investigated for association with mortality, OS, and treatment response following PRRT. Of 22 patients, 6 had undergone surgical resection of primary tumors. All patients were symptomatic before start of PRRT. Two patients did not qualify for PRRT, and 1 received single cycle with follow-up less than 3 months, hence excluded from the present analysis. Thus, a total 19 patients were analyzed in our study. Symptomatic response following PRRT was observed in 15 (79%) of 19 patients. Based on predefined 3-scale response evaluation criteria, of 19 patients, 12 patients (63%) were finally characterized as responders, and 7 patients (37%) were overall nonresponder to PRRT. All 7 nonresponders had moderate to intense FDG-avid primary lung lesion (SUVmax >5 in 4 of 7 patients), and 5 had FDG-avid metastatic liver disease (SUVmax >5). Peptide receptor radionuclide therapy was well tolerated in all with no major hematologic and renal toxicity (except for 2 patients showing mild grade I renal and hematologic toxicity in the initial cycles and recovery in subsequent follow-up). Seven (37%) of 19 died at the time of analysis. The observed annual OS rates were as follows: 1 year: 94.7% (95% CI, 68.1%-99.2%), 2 years: 66% (95% CI, 35.5%-84.5%), 3 years: 57.7% (95% CI, 28-78.9%), and 4 years: 38.5% (95% CI, 8.1%-69.5%); median OS was 40 months with 39% (95% CI, 13.1%-64.8%). In conclusion, Lu-DOTATATE PRRT was found safe and well tolerated in receptor-positive pulmonary NET. FDG positivity appeared to forecast aggressive tumor behavior.

Outcomes of peptide receptor radionuclide therapy (PRRT) in metastatic grade 3 neuroendocrine tumors (NETs).

e15694 Background:Grade 3 (G3) NETs have a poor prognosis and limited treatment options (usually chemotherapy). PRRT is a potential treatment option if all sites of disease demonstrate high uptake on somatostatin-receptor imaging (SSRI). We retrospectively evaluated the efficacy of PRRT in G3 NETs. Methods: We reviewed records of patients with metastatic G3 NETs (Ki-67 &gt; 20%) who received PRRT at our institution. Patients were treated with up to 5 cycles of PRRT, predominantly 177Lu-DOTA-octreotate. Further maintenance PRRT was administered upon progression if deemed suitable on SSRI. Radio-sensitizing chemotherapy was administered unless contra-indicated. Kaplan-Meier estimate was used to determine median overall survival (OS) and median time to new treatment/death (TNTD) defined from start of PRRT. Subgroup-analysis was performed for patients with Ki67 &lt; 55% and ≥55%. Results: 26 patients with metastatic G3 NET received PRRT; 22 combined with chemotherapy (capecitabine/temozolomide (n = 12), 5-fluorouracil or capecitabine (n = 8), other (n = 2)). 58% were male. The median age was 62 (range 16-78 years). 61% had pancreatic NET, 19% small bowel, 8% lung, 8% unknown primary, 4% rectal. 77% had received at least one line of prior chemotherapy. 54% received prior platinum-based chemotherapy. Median follow-up was 33 months (range 8-83 months). Patients received a median of 4 cycles of PRRT (range 1-15). The estimated median OS from start of PRRT was 18 months: for Ki-67 &lt; 55% (n = 21), 20 months; and Ki-67≥ 55% (n = 5), 9 months. The estimated median TNTD was 12 months: for Ki-67 &lt; 55%, 16 months; and Ki-67≥55%, 4 months. 31% of patients were alive without a change in treatment modality following PRRT. Conclusions: In thispoor prognosis G3 NET cohort of whom 77% had received prior chemotherapy, a median OS of 18 months from start of PRRT is encouraging and warrants further study. PRRT is a promising treatment option for patients with G3 NET with high somatostatin-receptor expression selected by SSRI.