Additional hepatic 166Ho-radioembolization in patients with neuroendocrine tumours treated with 177Lu-DOTATATE; a single center, interventional, non-randomized, non-comparative, open label, phase II study (HEPAR PLUS trial).

BACKGROUND: Neuroendocrine tumours (NET) consist of a heterogeneous group of neoplasms with various organs of origin. At diagnosis 21% of the patients with a Grade 1 NET and 30% with a Grade 2 NET have distant metastases. Treatment with peptide receptor radionuclide therapy (PRRT) shows a high objective response rate and long median survival after treatment. However, complete remission is almost never achieved. The liver is the most commonly affected organ in metastatic disease and is the most incriminating factor for patient survival. Additional treatment of liver disease after PRRT may improve outcome in NET patients. Radioembolization is an established therapy for liver metastasis. To investigate this hypothesis, a phase 2 study was initiated to assess effectiveness and toxicity of holmium-166 radioembolization (166Ho-RE) after PRRT with lutetium-177 (177Lu)-DOTATATE. METHODS: The HEPAR PLUS trial ("Holmium Embolization Particles for Arterial Radiotherapy Plus 177 Lu-DOTATATE in Salvage NET patients") is a single centre, interventional, non-randomized, non-comparative, open label study. In this phase 2 study 30-48 patients with > 3 measurable liver metastases according to RECIST 1.1 will receive additional 166Ho-RE within 20 weeks after the 4th and last cycle of PRRT with 7.4 GBq 177Lu-DOTATATE. Primary objectives are to assess tumour response, complete and partial response according to RECIST 1.1, and toxicity, based on CTCAE v4.03, 3 months after 166Ho-RE. Secondary endpoints include biochemical response, quality of life, biodistribution and dosimetry. DISCUSSION: This is the first prospective study to combine PRRT with 177Lu-DOTATATE and additional 166Ho-RE in metastatic NET. A radiation boost on intrahepatic disease using 166Ho-RE may lead to an improved response rate without significant additional side-effects. TRIAL REGISTRATION: Clinicaltrials.gov NCT02067988 , 13 February 2014. Protocol version: 6, 30 november 2016.

Subacute haematotoxicity after PRRT with (177)Lu-DOTA-octreotate: prognostic factors, incidence and course.

PURPOSE: In peptide receptor radionuclide therapy (PRRT), the bone marrow (BM) is one of the dose-limiting organs. The accepted dose limit for BM is 2 Gy, adopted from (131)I treatment. We investigated the incidence and duration of haematological toxicity and its risk factors in patients treated with PRRT with (177)Lu-DOTA(0)-Tyr(3)-octreotate ((177)Lu-DOTATATE). Also, absorbed BM dose estimates were evaluated and compared with the accepted 2 Gy dose limit. METHODS: The incidence and duration of grade 3 or 4 haematological toxicity (according to CTCAE v3.0) and risk factors were analysed. Mean BM dose per unit (gigabecquerels) of administered radioactivity was calculated and the correlations between doses to the BM and haematological risk factors were determined. RESULTS: Haematological toxicity (grade 3/4) occurred in 34 (11 %) of 320 patients. In 15 of the 34 patients, this lasted more than 6 months or blood transfusions were required. Risk factors significantly associated with haematological toxicity were: poor renal function, white blood cell (WBC) count <4.0 × 10(9)/l, age over 70 years, extensive tumour mass and high tumour uptake on the OctreoScan. Previous chemotherapy was not associated. The mean BM dose per administered activity in 23 evaluable patients was 67 ± 7 mGy/GBq, resulting in a mean BM dose of 2 Gy in patients who received four cycles of 7.4 GBq (177)Lu-DOTATATE. Significant correlations between (cumulative) BM dose and platelet and WBC counts were found in a selected group of patients. CONCLUSION: The incidence of subacute haematological toxicity after PRRT with (177)Lu-DOTATATE is acceptable (11 %). Patients with impaired renal function, low WBC count, extensive tumour mass, high tumour uptake on the OctreoScan and/or advanced age are more likely to develop grade 3/4 haematological toxicity. The BM dose limit of 2 Gy, adopted from (131)I, seems not to be valid for PRRT with (177)Lu-DOTATATE.

Nephrotoxicity after PRRT with (177)Lu-DOTA-octreotate.

PURPOSE: After peptide receptor radionuclide therapy (PRRT), renal toxicity may occur, particular in PRRT with (90)Y-labelled somatostatin analogues. Risk factors have been identified for increased probability of developing renal toxicity after PRRT, including hypertension, diabetes and age. We investigated the renal function over time, the incidence of nephrotoxicity and associated risk factors in patients treated with PRRT with [(177)Lu-DOTA(0),Tyr(3)]-Octreotate ((177)Lu-Octreotate). Also, radiation dose to the kidneys was evaluated and compared with the accepted dose limits in external beam radiotherapy and PRRT with (90)Y-radiolabelled somatostatin analogues. METHODS: The annual decrease in creatinine clearance (CLR) was determined in 209 Dutch patients and the incidence of grade 3 or 4 renal toxicity (according to CTCAE v4.03) was evaluated in 323 patients. Risk factors were analysed using a nonlinear mixed effects regression model. Also, radiation doses to the kidneys were calculated and their association with high annual decrease in renal function were analysed. RESULTS: Of the 323 patients, 3 (1 %) developed (subacute) renal toxicity grade 2 (increase in serum creatinine >1.5 - 3.0 times baseline or upper limit of normal). No subacute grade 3 or 4 nephrotoxicity was observed. The estimated average baseline CLR (± SD) was 108 ± 5 ml/min and the estimated average annual decrease in CLR (± SD) was 3.4 ± 0.4 %. None of the risk factors (hypertension, diabetes, high cumulative injected activity, radiation dose to the kidneys and CTCAE grade) at baseline had a significant effect on renal function over time. The mean absorbed kidney dose in 228 patients was 20.1 ± 4.9 Gy. CONCLUSION: Nephrotoxicity in patients treated with (177)Lu-octreotate was low. No (sub)acute grade 3 or 4 renal toxicity occurred and none of the patients had an annual decrease in renal function of >20 %. No risk factors for renal toxicity could be identified. Our data support the idea that the radiation dose threshold, adopted from external beam radiotherapy and PRRT with (90)Y-labelled somatostatin analogues, does not seem valid for PRRT with (177)Lu-octreotate.

Hypocalcaemia after treatment with [177Lu-DOTA 0,Tyr3]octreotate.

PURPOSE: The aim of this study was to explore the possible mechanisms involved in an observed decline in serum calcium levels in patients with a neuroendocrine tumour (NET) treated with [(177)Lu-DOTA(0),Tyr(3)]octreotate ((177)Lu-octreotate). METHODS: In 47 patients with NET who were normocalcaemic at baseline, serum calcium, albumin, creatinine, alkaline phosphatase, gamma glutamyl transpeptidase, magnesium, phosphate and 25-hydroxyvitamin D were prospectively analysed at baseline and up to 6 months after treatment. Parathyroid hormone (PTH), 1,25-dihydroxyvitamin D3, type 1 aminoterminal propeptide of procollagen, bone-specific alkaline phosphatase, carboxyterminal crosslinking telopeptide of bone collagen, collagen type I crosslinked N-telopeptide, and creatinine and calcium in 24-h urine samples, were evaluated at baseline and at 3 and 6 months. Another 153 patients with NET were included in a retrospective study to estimate the occurrence of hypocalcaemia in a larger patient group. RESULTS: In the prospectively included patients, the mean serum calcium level decreased significantly after treatment (2.31 ± 0.01 to 2.26 ± 0.02 mmol/l, p = 0.02). Eight patients (17%) showed a marked decrease in serum calcium levels with a nadir of ≤ 2.10 mmol/l. In five patients (11%), calcium substitution therapy was prescribed. PTH increased significantly (5.9 ± 0.6 to 6.7 ± 0.8 pmol/l, p = 0.02), presumably in response to the decreasing serum calcium levels. 25-Hydroxyvitamin D remained stable after treatment. Creatinine levels increased significantly (73 ± 3 to 77 ± 3 µmol/l, p = 0.01), but not enough to explain the hypocalcaemia. Phosphate levels remained unaffected. In the retrospectively analysed patients, the mean serum calcium level decreased significantly from 2.33 ± 0.01 at baseline to a nadir of 2.24 ± 0.01 mmol/l at 18 months after treatment (p < 0.001). Of the 153 patients, 33 (22%) showed a serum calcium nadir of ≤ 2.10 mmol/l, and 11 (7%) received calcium substitution therapy. CONCLUSION: The mean serum calcium level decreased significantly after treatment with (177)Lu-octreotate, resulting in mild hypocalcaemia in about 20% of patients. We excluded several potential causes of this hypocalcaemia, so the cause remains unknown. Serum calcium levels should be monitored after peptide receptor radionuclide therapy, and calcium substitution therapy should be initiated if appropriate.

Treatment of gastroenteropancreatic neuroendocrine tumors with peptide receptor radionuclide therapy.

The primary treatment of gastroenteropancreatic neuroendocrine tumors (GEPNETs) is surgery with curative intent or debulking of the tumor mass. In case of metastatic disease, cytoreductive options are limited. A relatively new therapeutic modality, peptide receptor radionuclide therapy (PRRT) with radiolabeled somatostatin analogs, is currently available in a number of mostly European centers. Complete and partial responses obtained after treatment with [90Y-DOTA0,Tyr3]octreotide are in the same range as after treatment with [177Lu-DOTA0,Tyr3]octreotate (i.e. 10-30%). However, significant nephrotoxicity has been observed after treatment with [90Y-DOTA0,Tyr3]octreotide. Options to improve PRRT may include combinations of radioactive labeled somatostatin analogs, intra-arterial administration, and the use of radiosensitizing drugs combined with PRRT. Other therapeutic applications of PRRT may include additional therapy cycles in patients with progressive disease after benefit from initial therapy, PRRT in adjuvant or neoadjuvant setting, or PRRT combined with new targeted therapies, such as sunitinib or everolimus. Randomized clinical trials comparing PRRT with other treatment modalities, or comparing various radioactive labeled somatostatin analogs should be undertaken to determine the best treatment options and treatment sequelae for patients with GEPNETs.

Clinical Pharmacology of Radiotheranostics in Oncology.

The combined use of diagnostic and therapeutic radioligands with the same molecular target, also known as theranostics, enables accurate patient selection, targeted therapy, and prediction of treatment response. Radioiodine, bone-seeking radioligands and norepinephrine analogs have been used for many years for diagnostic imaging and radioligand therapy of thyroid carcinoma, bone metastases, pheochromocytoma, paraganglioma, and neuroblastoma, respectively. In recent years, radiolabeled somatostatin analogs and prostate-specific membrane antigen ligands have shown clinical efficacy in the treatment of neuroendocrine tumors and prostate cancer, respectively. Several candidate compounds are targeting novel theranostic targets such as fibroblast activation protein, C-X-C chemokine receptor 4, and gastrin-releasing peptide receptor. In addition, several strategies to improve efficacy of radioligand therapy are being evaluated, including dosimetry-based dose optimization, multireceptor targeting, upregulation of target receptors, radiosensitization, pharmacogenomics, and radiation genomics. Design and evaluation of novel radioligands and optimization of dose and dose schedules, within the complex context of individualized multimodal cancer treatment, requires a multidisciplinary approach that includes clinical pharmacology. Significant increases in the use of these radiopharmaceuticals in routine oncological practice can be expected, which will have major impact on patient care as well as (radio)pharmacy utilization.

Effects of therapy with [177Lu-DOTA 0,Tyr 3]octreotate on endocrine function.

PURPOSE: Peptide receptor radionuclide therapy (PRRT) with radiolabelled somatostatin analogues is a novel therapy for patients with somatostatin receptor-positive tumours. We determined the effects of PRRT with [(177)Lu-DOTA(0),Tyr(3)]octreotate ((177)Lu-octreotate) on glucose homeostasis and the pituitary-gonadal, pituitary-thyroid and pituitary-adrenal axes. METHODS: Hormone levels were measured and adrenal function assessed at baseline and up to 24 months of follow-up. RESULTS: In 35 men, mean serum inhibin B levels were decreased at 3 months post-therapy (205 +/- 16 to 25 +/- 4 ng/l, p < 0.05) and follicle-stimulating hormone (FSH) levels increased (5.9 +/- 0.5 to 22.7 +/- 1.4 IU/l, p < 0.05). These levels returned to near baseline levels. Total testosterone and sex hormone binding globulin (SHBG) levels decreased (15.0 +/- 0.9 to 10.6 +/- 1.0 nmol/l, p < 0.05 and 61.8 +/- 8.7 to 33.2 +/- 3.7 nmol, p < 0.05), respectively, whereas non-SHBG-bound T did not change. An increase (5.2 +/- 0.6 to 7.7 +/- 0.7 IU/l, p < 0.05) of luteinizing hormone (LH) levels was found at 3 months of follow-up returning to baseline levels thereafter. In 21 postmenopausal women, a decrease in levels of FSH (74.4 +/- 5.6 to 62.4 +/- 7.7 IU/l, p < 0.05) and LH (26.8 +/- 2.1 to 21.1 +/- 3.0 IU/l, p < 0.05) was found. Of 66 patients, 2 developed persistent primary hypothyroidism. Free thyroxine (FT(4)) levels decreased (17.7 +/- 0.4 to 15.6 +/- 0.6 pmol/l, p < 0.05), whereas thyroid-stimulating hormone (TSH) and triiodothyronine (T(3)) levels did not change. Reverse triiodothyronine (rT(3)) levels decreased (0.38 +/- 0.03 to 0.30 +/- 0.01 nmol/l, p < 0.05). Before and after therapy adrenocorticotropic hormone (ACTH) stimulation tests showed an adequate response of serum cortisol (> 550 nmol/l, n = 18). Five patients developed elevated HbA(1c) levels (> 6.5%). CONCLUSION: In men (177)Lu-octreotate therapy induced transient inhibitory effects on spermatogenesis, but non-SHBG-bound T levels remained unaffected. In the long term, gonadotropin levels decreased significantly in postmenopausal women. Only a few patients developed hypothyroidism or elevated levels of HbA(1c). Therefore, PRRT with (177)Lu-octreotate can be regarded as a safe treatment modality with respect to short- and long-term endocrine function.

Bone marrow dosimetry in peptide receptor radionuclide therapy with [177Lu-DOTA(0),Tyr(3)]octreotate.

PURPOSE: Adequate dosimetry is mandatory for effective and safe peptide receptor radionuclide therapy (PRRT). Besides the kidneys, the bone marrow is a potentially dose-limiting organ. The radiation dose to the bone marrow is usually calculated according to the MIRD scheme, where the accumulated activity in the bone marrow is calculated from the accumulated radioactivity of the radiopharmaceutical in the blood. This may underestimate the absorbed dose since stem cells express somatostatin receptors. We verified the blood-based method by comparing the activity in the blood with the radioactivity in bone marrow aspirates. Also, we evaluated the absorbed cross-dose from the source organs (liver, spleen, kidneys and blood), tumours and the so-called "remainder of the body" to the bone marrow. METHODS: Bone marrow aspirates were drawn in 15 patients after treatment with [(177)Lu-DOTA(0),Tyr(3)]octreotate. Radioactivity in the bone marrow was compared with radioactivity in the blood drawn simultaneously. The nucleated cell fraction was isolated from the bone marrow aspirate and radioactivity was measured. The absorbed dose to the bone marrow was calculated. The results were correlated to the change in platelet counts 6 weeks after treatment. RESULTS: A strong linear correlation and high agreement between the measured radioactivities in the bone marrow aspirates and in the blood was found (r=0.914, p<0.001). No correlation between the calculated absorbed dose in the bone marrow and the change in platelets was found. There was a considerable contribution from other organs and the remainder of the body to the bone marrow absorbed dose. CONCLUSION: (1) After PRRT with [(177)Lu-DOTA(0),Tyr(3)]octreotate, the radioactivity concentration in the bone marrow is identical to that in the blood; (2) There is no significant binding of the radiopharmaceutical to bone marrow precursor stem cells; (3) The contribution of the cross dose from source organs and tumours to the bone marrow dose is significant; and (4) There is considerable variation in bone marrow absorbed dose between patients. These findings imply that for individual dose optimization, individual calculation of the bone marrow absorbed dose is necessary.

Symptomatic and Radiological Response to 177Lu-DOTATATE for the Treatment of Functioning Pancreatic Neuroendocrine Tumors.

PURPOSE: Peptide receptor radionuclide therapy (PRRT) with the radiolabeled somatostatin analogue [Lutetium-177-DOTA0-Tyr3]octreotate (177Lu-DOTATATE) is widely applied for inoperable metastatic small intestinal and nonfunctioning pancreatic neuroendocrine tumors (pNETs). The aim of this study is to describe the safety and efficacy of the treatment of functioning pNETs. METHODS: Patients were treated with up to four cycles of 177Lu-DOTATATE with an intended dose of 7.4 Gbq per cycle. Radiological (Response Evaluation Criteria in Solid Tumors 1.1), symptomatic, and biochemical response were analyzed retrospectively for all patients with a functioning pNET (insulinoma, gastrinoma, VIPoma, and glucagonoma) treated with 177Lu-DOTATATE. Quality of life (QOL) was assessed with the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core Module questionnaire. RESULTS: Thirty-four patients with a metastatic functioning pNET (European Neuroendocrine Tumor Society grade 1 or 2) were included: 14 insulinomas, 5 VIPomas, 7 gastrinomas, and 8 glucagonomas. Subacute hematological toxicity, grade 3 or 4 occurred in 4 patients (12%) and a hormonal crisis in 3 patients (9%). PRRT resulted in partial or complete response in 59% of patients and the disease control rate was 78% in patients with baseline progression. 71% of patients with uncontrolled symptoms had a reduction of symptoms and a more than 80% decrease of circulating hormone levels was measured during follow-up. After PRRT, median progression-free survival was 18.1 months (interquartile range: 3.3 to 35.7) with a concurrent increase in QOL. CONCLUSION: Treatment with 177Lu-DOTATATE is a safe and effective therapy resulting in radiological, symptomatic and biochemical response in a high percentage of patients with metastatic functioning pNETs. Hormonal crises occur relatively frequent and preventive therapy should be considered before and/or during PRRT.

Treatment of inoperable or metastatic paragangliomas and pheochromocytomas with peptide receptor radionuclide therapy using 177Lu-DOTATATE.

OBJECTIVES: Inoperable or metastatic paragangliomas (PGLs) and malignant pheochromocytomas (PCCs) are rare tumours with limited options for systemic treatment. Aim of this study was to assess the safety and efficacy of the radiolabelled somatostatin analogue (177LutetiumDOTA0-Tyr3)octreotate (177Lu-DOTATATE) for the treatment of PGLs and PCCs. METHODS: Patients with histologically proven inoperable or malignant PGLs and PCCs treated with 177Lu-DOTATATE at our centre were retrospectively analysed. Patients were treated with up to four cycles of 177Lu-DOTATATE with an intended dose of 7.4 Gb per cycle. Response was assessed with use of RECIST 1.1. RESULTS: Thirty patients were included: 17 with parasympathetic, 10 with sympathetic PGLs and 3 with PCCs. Grade 3/4 subacute haematotoxicity occurred in 6 (20%) of patients. A reversible subacute adverse event due to cardiac failure following possible catecholamine release occurred in two patients. Best tumour response was partial response in 7 (23%) and stable disease in 20 (67%), whereas 3 (10%) patients had progressive disease. In 20 patients with baseline disease progression, tumour control was observed in 17 (85%); the median progression-free survival was 91 months in patients with parasympathetic PGLs, 13 months in patients with sympathetic PGLs and 10 months in patients with metastatic PCCs. CONCLUSION: This study suggests that PRRT with 177Lu-DOTATATE is a safe and effective treatment option for patients with inoperable or malignant PGL and PCC.

Successful neoadjuvant peptide receptor radionuclide therapy for an inoperable pancreatic neuroendocrine tumour.

Non-functional pancreatic neuroendocrine tumours (NETs) can present with advanced local or distant (metastatic) disease limiting the possibility of surgical cure. Several treatment options have been used in experimental neoadjuvant settings to improve the outcomes in such cases. Peptide receptor radionuclide therapy (PPRT) using beta emitting radiolabelled somatostatin analogues has been used in progressive pancreatic NETs. We report a 55-year-old female patient with a 12.8 cm pancreatic NET with significant local stomach and superior mesenteric vein compression and liver metastases. The patient underwent treatment with [177Lutetium-DOTA0,Tyr3]octreotate (177Lu-octreotate) for the treatment of local and metastatic symptomatic disease. Six months after 4 cycles of 177lutetium-octreotate, resolution of the abdominal complaints was associated with a significant reduction in tumour size and the tumour was rendered operable. Histology of the tumour showed a 90% necrotic tumour with abundant hyalinized fibrosis and haemorrhage compatible with PPRT-induced radiation effects on tumour cells. This report supports that PPRT has a role in unresectable and metastatic pancreatic NET. LEARNING POINTS: PRRT with 177Lu-octreotate can be considered a useful therapy for symptomatic somatostatin receptor-positive pancreatic NET.The clinical benefits of PRRT with 177Lu-octreotate can be seen in the first months while tumour reduction can be seen up to a year after treatment.PRRT with 177Lu-octreotate was clinically well tolerated and did not interfere with the subsequent surgical procedure.PRRT with 177Lu-octreotate can result in significant tumour reduction and may improve surgical outcomes. As such, this therapy can be considered as a neoadjuvant therapy.

Persistent Hematologic Dysfunction after Peptide Receptor Radionuclide Therapy with 177Lu-DOTATATE: Incidence, Course, and Predicting Factors in Patients with Gastroenteropancreatic Neuroendocrine Tumors.

Peptide receptor radionuclide therapy (PRRT) may induce long-term toxicity to the bone marrow (BM). The aim of this study was to analyze persistent hematologic dysfunction (PHD) after PRRT with 177Lu-DOTATATE in patients with gastroenteropancreatic neuroendocrine tumors (GEP NETs). Methods: The incidence and course of PHD were analyzed in 274 GEP NET patients from a group of 367 patients with somatostatin receptor-positive tumors. PHD was defined as diagnosis of myelodysplastic syndrome (MDS), acute myeloid leukemia (AML), myeloproliferative neoplasm (MPN), MDS/MPN, or otherwise unexplained cytopenia (for >6 mo). Using data from The Netherlands Cancer Registry, the expected number of hematopoietic neoplasms (MDS, AML, MPN, and MDS/MPN) was calculated and adjusted for sex, age, and follow-up period. The following risk factors were assessed: sex, age over 70 y, bone metastasis, prior chemotherapy, prior external-beam radiotherapy, uptake on the [111In-DTPA0]octreotide scan, tumor load, grade 3-4 hematologic toxicity during treatment, estimated absorbed BM dose, elevated plasma chromogranin A level, baseline blood counts, and renal function. Results: Eleven (4%) of the 274 patients had PHD after treatment with 177Lu-DOTATATE: 8 patients (2.9%) developed a hematopoietic neoplasm (4 MDS, 1 AML, 1 MPN, and 2 MDS/MPN) and 3 patients (1.1%) developed BM failure characterized by cytopenia and BM aplasia. The median latency period at diagnosis (or first suspicion of a PHD) was 41 mo (range, 15-84 mo). The expected number of hematopoietic neoplasms based on The Netherlands Cancer Registry data was 3.0, resulting in a relative risk of 2.7 (95% confidence interval, 0.7-10.0). No risk factors for PHD could be identified for the GEP NET patients, not even bone metastasis or estimated BM dose. Seven patients with PHD developed anemia in combination with a rise in mean corpuscular volume. Conclusion: The prevalence of PHD after PRRT with 177Lu-DOTATATE was 4% in our patient population. The median time at which PHD developed was 41 mo after the first PRRT cycle. The relative risk for developing a hematopoietic neoplasm was 2.7. No risk factors were found for the development of PHD in GEP NET patients.

Treatment of patients who have endocrine gastroenteropancreatic tumors with radiolabeled somatostatin analogues.

Treatment with radiolabeled somatostatin analogs is a promising new tool in the management of patients who have inoperable or metastasized endocrine tumors. Symptomatic improvement may occur with all (111)In-, (90)Y-, or (177)Lu-labeled somatostatin analogs that have been used for peptide receptor radionuclide therapy. The results that were obtained with [(90)Y-DOTA degrees ,Tyr(3)]octreotide and [(177)Lu-DOTA degrees ,Tyr(3)]octreotate are encouraging in tumor regression. Also, if kidney-protective agents are used, the side effects of this therapy are few and mild. These data compare favorably with the limited number of alternative treatment approaches.

Staging and treatment of differentiated thyroid carcinoma with radiolabeled somatostatin analogs.

In patients with progressive metastatic (or recurrent) differentiated thyroid carcinoma that either do not take up radioiodine or are unresponsive to continued radioiodine therapy, staging is difficult and treatment options are few. However, in most of these patients uptake of radiolabeled somatostatin analogs is evident on somatostatin-receptor scintigraphy (SRS). Using SRS, patients with sufficient uptake of radiolabeled somatostatin analogs can be selected for high-dose peptide receptor radionuclide therapy (PRRT) as an alternative targeted-treatment option. PRRT with the beta-particle-emitting radionuclides (90)yttrium ((90)Y) and (177)lutetium ((177)Lu) gives the best results in terms of objective tumor response. Promising, novel, radiolabeled somatostatin analogs that have a broader receptor affinity profile and, thus, a potentially wider therapeutic range are being tested clinically.

Pitfalls in the response evaluation after peptide receptor radionuclide therapy with [177Lu-DOTA0,Tyr3]octreotate.

Peptide receptor radionuclide therapy (PRRT) with [177Lu-DOTA0,Tyr3]octreotate (177Lu-DOTATATE) is a treatment with good results in patients with metastatic gastroenteropancreatic neuroendocrine tumours (GEPNETs). However, there are some pitfalls that should be taken into consideration when evaluating the treatment response after PRRT. 354 Dutch patients with GEPNETs who were treated with 177Lu-DOTATATE between March 2000 and December 2011 were retrospectively selected. Liver function parameters and chromogranin A were measured before each therapy and in follow-up. Anatomical imaging was performed before therapy and in follow-up. An increase in aminotransferases by ≥20% compared to baseline was observed in 83 of 351 patients (24%). In patients with an objective response (OR) and stable disease (SD) this increase was observed in 71/297 (24%) and in patients with progressive disease (PD) it was observed in 12/54 patients (22%). An increase in chromogranin A by ≥20% compared to baseline was observed in 76 patients (29%). This was present in 34% of patients who eventually had PD and 27% of patients who had OR/SD. In 70% of patients this tumour marker returned to baseline levels after therapy. An increase in liver enzymes and chromogranin A is not uncommon after PRRT. In the vast majority of patients this will resolve in follow-up. Clinicians should be aware that these changes may occur due to radiation-induced inflammation or disease progression and that repeated measurements over time are necessary to differentiate between the two.

Long-Term Efficacy, Survival, and Safety of [177Lu-DOTA0,Tyr3]octreotate in Patients with Gastroenteropancreatic and Bronchial Neuroendocrine Tumors.

Purpose: Bronchial and gastroenteropancreatic neuroendocrine tumors (NET) are slow-growing tumors, which frequently express somatostatin receptors on their cell membranes. These receptors are targets for therapy with Lutetium-177-labeled somatostatin analogues. We have treated over 1,200 patients with peptide receptor radionuclide therapy (PRRT) with [177Lu-DOTA0,Tyr3]octreotate (177Lu-DOTATATE) since the year 2000 and present the results on efficacy, survival, and toxicity of this therapy.Experimental Design: For safety analysis, 610 patients treated with a cumulative dose of at least 100 mCi (3.7 GBq) 177Lu-DOTATATE were included. A subgroup of 443 Dutch patients who were treated with a cumulative dose of at least 600 mCi (22.2 GBq) 177Lu-DOTATATE before 2013 was further analyzed for efficacy and survival.Results: The objective response rate of the total group of patients was 39%. Stable disease was reached in 43% of patients. Progression-free survival (PFS) and overall survival (OS) for all NET patients were 29 months [95% confidence interval (CI), 26-33 months] and 63 months (95% CI, 55-72 months). Long-term toxicity included acute leukemia in four patients (0.7%) and myelodysplastic syndrome in nine patients (1.5%). No therapy-related long-term renal or hepatic failure occurred.Conclusions: PRRT with 177Lu-DOTATATE is a favorable therapeutic option in patients with metastatic bronchial and gastroenteropancreatic NETs that express somatostatin receptors. PRRT with 177Lu-DOTATATE is safe with few side-effects and shows good response rates with PFS of 29 months and OS of 63 months. Clin Cancer Res; 23(16); 4617-24. ©2017 AACR.

Radiolabeled somatostatin analog [177Lu-DOTA0,Tyr3]octreotate in patients with endocrine gastroenteropancreatic tumors.

PURPOSE: There are few treatment options for patients with metastasized or inoperable endocrine gastroenteropancreatic (GEP) tumors. Chemotherapy can be effective, but the response is usually less than 1 year. Here, we present the results of treatment with a radiolabeled somatostatin analog, [177Lu-DOTA0,Tyr3]octreotate (177Lu-octreotate). PATIENTS AND METHODS: One hundred thirty-one patients with somatostatin receptor-positive tumors were treated with up to a cumulative dose of 600 to 800 mCi (22.2 to 29.6 GBq) of 177Lu-octreotate. RESULTS: One patient developed renal insufficiency, and another patient developed hepatorenal syndrome. Creatinine clearance did not change significantly in the other patients. WHO hematologic toxicity grade 3 or 4 occurred after less than 2% of the administrations. We observed complete remission in three patients (2%), partial remission in 32 patients (26%), minor response (tumor diameter decrease of 25% to 50%) in 24 patients (19%), stable disease (SD) in 44 patients (35%), and progressive disease (PD) in 22 patients (18%). Higher remission rates were positively correlated with high uptake on pretherapy somatostatin receptor imaging and a limited number of liver metastases, whereas PD was significantly more frequent in patients with a low performance score and extensive disease. Median time to progression in 103 patients who either had SD or tumor regression was more than 36 months. CONCLUSION: Treatment with 177Lu-octreotate results in tumor remission in a high percentage of patients with GEP tumors. Serious side effects are rare. The median time to progression compares favorably with chemotherapy. Results are better in patients with a limited tumor load. Therefore, early treatment, even in patients who have no PD, may be better.

Peptide receptor radionuclide therapy of neuroendocrine tumours.

In the past decades, the number of neuroendocrine tumours that are detected is increasing. A relative new and promising therapy for patients with metastasised or inoperable disease is peptide receptor radionuclide therapy (PRRT). This therapy involves an infusion of somatostatin analogues linked to radionuclides like Yttrium-90 or Lutetium-177. Objective response rates are reported in 15-35%. Response rates may vary between type of tumour and radionuclide. Besides the objective response rate, overall survival and progression free survival increase significantly. Also, the quality of life improves as well. Serious side-affects are rare. PRRT is usually well tolerated, also in patients with extensive metastasised disease. Recent studies combined PRRT with other types of therapies. Unfortunately no randomised trials comparing these strategies are available. In the future, more research is needed to evaluate the best therapy combinations or sequence of therapies.

Quality of life in patients with gastroenteropancreatic tumors treated with [177Lu-DOTA0,Tyr3]octreotate.

PURPOSE: To evaluate the quality of life (QoL) in patients with metastatic somatostatin receptor positive gastroenteropancreatic tumors treated with [(177)Lu-DOTA(0),Tyr(3)]octreotate ((177)Lu-octreotate) therapy. PATIENTS AND METHODS: Fifty patients who had been treated with 600 to 800 mCi of (177)Lu-octreotate and had a follow-up of at least 3 months were studied. The patients completed the European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire C30 before therapy and at follow-up visit 6 weeks after the last cycle. Overall QoL and specific QoL domains of both the total group of patients and subgroups according to treatment outcome were analyzed. Twenty-four patients had regression, 19 had stable disease, six had progressive disease, and one had nonassessable disease status. Analysis of variance was used for statistical comparison. RESULTS: A significant improvement in the global health status/QoL scale was observed after therapy with (177)Lu-octreotate (P <.01). The score increased significantly six weeks after therapy to a mean of 78.2, up from 69.0 (scale range, 0 to 100). Furthermore, significant improvement was observed in the role, emotional, and social function scales. The symptom scores for fatigue, insomnia, and pain were significantly decreased. Patients with proven tumor regression most frequently had an improvement of QoL domains. Unexpectedly, patients with progressive disease also indicated an improvement in their global health/QoL score. CONCLUSION: (177)Lu-octreotate therapy significantly improved the global health/QoL and several function and symptom scales in patients with metastasized gastroenteropancreatic tumors, but especially in those patients with proven tumor regression.