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Fibroblast activation protein (FAP) is a promising target for diagnosis and therapy of numerous malignant tumors. FAP-2286 is the conjugate of a FAP-binding peptide, which can be labeled with radionuclides for theranostic applications. We present the first-in-human results using 177Lu-FAP-2286 for peptide-targeted radionuclide therapy (PTRT). Methods: PTRT using 177Lu-FAP-2286 was performed in 11 patients with advanced adenocarcinomas of pancreas, breast, rectum and ovary after prior confirmation of uptake on 68Ga-FAP-2286/-FAPI-04- PET/CT. Results: Administration of 177Lu-FAP-2286 (5.8 ± 2.0 GBq; range, 2.4–9.9 GBq) was well tolerated, with no adverse symptoms or clinically detectable pharmacologic effects being noticed or reported in any of the patients. The whole-body effective doses were 0.07 ± 0.02 Gy/GBq (range 0.04 – 0.1). The mean absorbed doses for kidneys and red marrow were 1.0 ± 0.6 Gy/GBq (range 0.4 – 2.0) and 0.05 ± 0.02 Gy/GBq (range 0.03 – 0.09), respectively. Significant uptake and long tumor retention of 177Lu-FAP-2286 resulted in high absorbed tumor doses, e.g., 3.0 ± 2.7 Gy/GBq (range 0.5 – 10.6) in bone metastases. No grade (G) 4 adverse events were observed. G3 events occurred in 3 patients – 1 pancytopenia, 1 leukocytopenia and 1 pain flare-up; 3 patients reported pain-response. Conclusion:177Lu-FAP-2286 PTRT, applied in a broad spectrum of cancers, was relatively well-tolerated with acceptable side effects and demonstrated long retention of the radiopeptide. Prospective clinical studies are warranted.

(161)Tb has decay properties similar to those of (177)Lu but, additionally, emits a substantial number of conversion and Auger electrons. The aim of this study was to apply (161)Tb in a clinical setting and to investigate the feasibility of visualizing the physiologic and tumor biodistributions of (161)Tb-DOTATOC. Methods: (161)Tb was shipped from Paul Scherrer Institute, Villigen-PSI, Switzerland, to Zentralklinik Bad Berka, Bad Berka, Germany, where it was used for the radiolabeling of DOTATOC. In 2 separate studies, 596 and 1,300 MBq of (161)Tb-DOTATOC were administered to a 35-y-old male patient with a metastatic, well-differentiated, nonfunctional malignant paraganglioma and a 70-y-old male patient with a metastatic, functional neuroendocrine neoplasm of the pancreatic tail, respectively. Whole-body planar γ-scintigraphy images were acquired over a period of several days for dosimetry calculations. SPECT/CT images were reconstructed using a recently established protocol and visually analyzed. Patients were observed for adverse events after the application of (161)Tb-DOTATOC. Results: The radiolabeling of DOTATOC with (161)Tb was readily achieved with a high radiochemical purity suitable for patient application. Planar images and dosimetry provided the expected time-dependent biodistribution of (161)Tb-DOTATOC in the liver, kidneys, spleen, and urinary bladder. SPECT/CT images were of high quality and visualized even small metastases in bones and liver. The application of (161)Tb-DOTATOC was well tolerated, and no related adverse events were reported. Conclusion: This study demonstrated the feasibility of imaging even small metastases after the injection of relatively low activities of (161)Tb-DOTATOC using γ-scintigraphy and SPECT/CT. On the basis of this essential first step in translating (161)Tb to clinics, further efforts will be directed toward the application of (161)Tb for therapeutic purposes.

To determine prognostic factors and overall survival (OS) in therapy-related myeloid neoplasm (t-MN) of patients after receiving peptide receptor radionuclide therapy (PRRT). All patients treated from February 1999 until September 2019 at our center who had bone marrow biopsy-proven t-MN after PRRT were included. Patient characteristics, laboratory results, and all tumor-directed therapies before t-MN diagnosis were collected. Cox regression analysis was performed to identify parameters associated with OS. Receiver operating characteristic (ROC) curve analysis was used to define cutoff values as well as sensitivity and specificity of the parameters. Out of 1631 patients treated with PRRT, 30 patients developed t-MN comprising myelodysplastic syndrome (MDS) in 23 patients (77%) and acute myeloid leukemia (AML) in 7 patients (23%). The median OS of t-MN patients was 13 months (range 9.1–16.9 months): 6 months for AML and 15 months for the MDS subgroup, respectively. Higher platelet level was a significant prognostic parameter for longer OS (hazard ratio (HR): 0.99, P

The objective of this retrospective study was to determine the role of F-18-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 Lu-177- or Y-90-DOTATOC/DOTATATE PRRT between February 2002 and July 2018. All subjects received both Ga-68-DOTATOC/TATE/NOC and F-18-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. F-18-FDG PET/CT was positive in 382 (77.2%) patients and negative in 113 (22.8%) before PRRT, whereas 100% were Ga-68-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 F-18-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

Introduction The impact of prior therapies, especially chemotherapy, on overall survival (OS) in patients with castration-resistant prostate cancer (CRPC) receiving [177Lu]Lu-PSMA-617 therapy has been the subject of controversy. Therefore, WARMTH decided to plan a multicenter retrospective analysis (the “617 trial”) to evaluate response rate and OS as well as the impact of prior therapies on OS in more than 300 patients treated with 177Lu-PSMA-617. Materials and methods The data of 631 metastatic CRPC (mCRPC) patients from 11 different clinics were evaluated. According to the inclusion and exclusion criteria, all patients had to have received at least abiraterone or enzalutamide prior to [177Lu]Lu-PSMA-617 therapy. The patients were divided into three groups: patients who had received prior chemotherapy, patients who avoided chemotherapy, and patients for whom a chemotherapy was contraindicated. Results The analysis included the data of 416 patients, with a median age of 71.9 years. At the time of analysis, 87 patients (20,9%) were still alive. A total of 53.6% of patients had received both abiraterone and enzalutamide; 75.5% and 26.4% had a history of chemotherapy with docetaxel and cabazitaxel, respectively. A total of 20.4% had had Ra-223. The median OS was 11.1 months. Prior chemotherapy, the existence of bone and liver metastases, as well as Eastern Cooperative Oncology Group (ECOG) status, were significant prognosticators of worse overall survival in both univariate and multivariate analyses. Patients without any prior chemotherapy showed a significantly longer OS (14.6 months). The median OS in patients who received one or two lines of chemotherapy with docetaxel or docetaxel followed by cabazitaxel, respectively, was 10.9 months and 8.9 months. There was no difference in OS between patients who had not received chemotherapy and patients for whom chemotherapy was contraindicated. The other prior therapies did not have any significant impact on OS. Conclusion In the present multicenter analysis, chemotherapy-naïve mCRPC patients receiving [177Lu]Lu-PSMA-617 therapy had a significantly longer OS than patients with a history of chemotherapy. This remained independent in the multivariate analysis besides presence of bone and liver metastases as negative prognosticators for survival, whereas an ECOG of 0–1 is associated with a longer OS.

Radiolabeled somatostatin analogs for somatostatin receptor (SSTR)-targeted imaging and peptide receptor radionuclide therapy (PRRT) have demonstrated remarkable success in the management of SSTR-expressing neuroendocrine neoplasms. Primary neuroendocrine breast carcinoma is rare. Heterogeneous SSTR overexpression has also been documented in breast cancer, in both human breast cancer specimens and clinical studies. We report here a case of a 69-year-old woman who had both breast invasive ductal carcinoma and primary large-cell neuroendocrine breast carcinoma (Ki-67 proliferation index of 20%), with disseminated bone and lymph node metastases, demonstrating exceptional tracer uptake on Ga-DOTATOC PET/CT, and remarkably partial remission after Lu-DOTATOC PRRT.

62 Background: PET/CT using Ga-68 PSMA-11, which received FDA approval, can detect early biochemical recurrence of prostate cancer at greater sensitivity than conventional imaging, as well as more accurately clinical stage and impact treatment management, particularly vital for high-risk patients. We present our first experience with Ga-68 PSMA-11 PET/CT using the total-body PET/CT scanner (uExplorer). Methods: PET/CT imaging (1-bed acquisition of the entire body for 5 minutes) was performed on the uExplorer scanner 56-65 minutes after administering 150-200 MBq of Ga-68 PSMA-11 (Illucix) in 14 patients with prostate cancer at our clinic. The medical records of these patients were reviewed. Results: Of the 14 patients who underwent Ga-68 PSMA-11 total-body PET/CT, 6 had high risk, 6 had intermediate risk and 2 had low risk cancers. The scan was negative in 1 patient, whereas local recurrence and pelvic lymph nodes could be identified in the other patient with low-risk prostate cancer. The smallest size of the lymph node identified was 2 mm. All patients with intermediate and high-risk cancers had metastatic disease – 2 had metastases to the lymph nodes only. Of the 10 patients with widespread metastases to bones and lymph nodes, 4 had additional visceral metastases – in 3 patients to the lungs and in 1 to the liver. The line of management changed in 10/13 patients with a positive scan – 5 were treated with Lu-177 PSMA radioligand, 4 with chemotherapy and 1 with local irradiation. Conclusions: Our pilot experience is consistent with the clinical value of Ga-68 PSMA-11 PET/CT (Illucix) imaging to better inform patient management, in addition to demonstrating the role of rapid and high-resolution imaging with the total-body PET/CT scanner (uExplorer). With the availability of PSMA PET/CT, it should be considered the new standard of care for men who have prostate cancer for staging or localization of recurrence.

Somatostatin receptor-targeted α-therapy using α-emitter 225Ac-labeled somatostatin analogs has been suggested as a treatment option in advanced metastatic neuroendocrine tumors (NETs) failing treatment with β-emitters, such as 177Lu or 90Y. Thymus NETs are rare and usually more aggressive than other neuroendocrine tumor entities. We present here a case with β-radiation refractory metastatic thymus NET, who demonstrated an excellent therapy response (molecular and morphological remission, as well as significantly improved clinical symptoms) after 225Ac-DOTATOC-targeted α-therapy, without any adverse effects during the treatment or in the follow-up period.

The objective of this study was to determine the safety, kinetics, and dosimetry of the (177)Lu-labeled prostate-specific membrane antigen (PSMA) small molecules (177)Lu-PSMA I&T and (177)Lu-PSMA-617 in a large cohort of patients with metastatic castration-resistant prostate cancer (mCRPC) undergoing PSMA radioligand therapy (PRLT). Methods: In total, 138 patients (mean age, 70 ± 9 y; age range, 46–90 y) with progressive mCRPC and PSMA expression verified by (68)Ga-PSMA-11 PET/CT underwent PRLT. Fifty-one patients received 6.1 ± 1.0 GBq (range, 3.4–7.6 GBq) of (177)Lu-PSMA I&T, and 87 patients received 6.5 ± 1.1 GBq (range, 3.5–9.0 GBq) of (177)Lu-PSMA-617. Dosimetry was performed on all patients using an identical protocol. The mean absorbed doses were estimated with OLINDA software (MIRD Scheme). Treatment-related adverse events were graded according to the Common Terminology Criteria for Adverse Events, version 5.0, of the National Cancer Institute. Results: The whole-body half-lives were shorter for (177)Lu-PSMA I&T (35 h) than for (177)Lu-PSMA-617 (42 h). The mean whole-body dose of (177)Lu-PSMA-617 was higher than that of (177)Lu-PSMA I&T (0.04 vs. 0.03 Gy/GBq, P < 0.00001). Despite the longer half-life of (177)Lu-PSMA-617, the renal dose was lower for (177)Lu-PSMA-617 than for (177)Lu-PSMA I&T (0.77 vs. 0.92 Gy/GBq, P = 0.0015). Both PSMA small molecules demonstrated a comparable dose to the parotid glands (0.5 Gy/GBq, P = 0.27). Among all normal organs, the lacrimal glands exhibited the highest mean absorbed doses, 5.1 and 3.7 Gy/GBq, for (177)Lu-PSMA-617 and (177)Lu-PSMA I&T, respectively. All tumor metastases exhibited a higher initial uptake when using (177)Lu-PSMA I&T than when using (177)Lu-PSMA-617, as well as a shorter tumor half-life (P < 0.00001). The mean absorbed tumor doses were comparable for both (177)Lu-PSMA I&T and (177)Lu-PSMA-617 (5.8 vs. 5.9 Gy/GBq, P = 0.96). All patients tolerated the therapy without any acute adverse effects. After (177)Lu-PSMA-617 and (177)Lu-PSMA I&T, there was a small, statistically significant reduction in hemoglobin, leukocyte counts, and platelet counts that did not need any clinical intervention. No nephrotoxicity was observed after either (177)Lu-PSMA I&T or (177)Lu-PSMA-617 PRLT. Conclusion: Both (177)Lu-PSMA I&T and (177)Lu-PSMA-617 PRLT demonstrated favorable safety in mCRPC patients. The highest absorbed doses among healthy organs were in the lacrimal and parotid glands—not, however, resulting in any significant clinical sequel. (177)Lu-PSMA-617 demonstrated a higher absorbed dose to the whole-body and lacrimal glands but a lower renal dose than did (177)Lu-PSMA I&T. The mean absorbed tumor doses were comparable for both (177)Lu-PSMA I&T and (177)Lu-PSMA-617. There was a large interpatient variability in the dosimetry parameters. Therefore, individual patient-based dosimetry seems favorable for personalized PRLT.

PSMA based radioligand is a new investigational drug for treatment of metastatic multidrug-resistant and castration-resistant prostate cancer. Prognostic factors point to above and below average overall survival (OS) after the treatment. Kessel et al. [Theranostics 2019;9:4841-8] reported for the first time that two sites of visceral metastases, lungs and liver, differed in impact on OS after treatment with 177Lu PSMA 617. Treatment with established drugs showed the same trend. The difference in OS between the sites is independent of the type of treatment and can reflect changes in tumor biology during the progression of metastatic prostate cancer.

We report here the 12-year survival after the first peptide receptor radionuclide therapy (PRRT) of a patient with metastatic rectal neuroendocrine neoplasms, who received 7 cycles of PRRT with Lu/Y-DOTATATE/DOTATOC in 4 treatment phases. The patient demonstrated excellent response to each cycle of treatment, without any adverse effect even after repeated PRRT cycles. Most recently, immunohistochemistry revealed a G3 neuroendocrine neoplasm and intraspinal metastasis were successfully resected by neurosurgical intervention. This case nicely demonstrates that several "salvage" PRRTs can be given over many years leading to repetitive benefit for the patient and saving patients of possible toxicity of alternative treatments.

Precision oncology is being driven by rapid advances in novel diagnostics and therapeutic interventions, with treatments targeted to the needs of individual patients on the basis of genetic, biomarker, phenotypic, or psychosocial characteristics that distinguish a given patient from other patients with similar clinical presentations. Inherent in the theranostics paradigm is the assumption that diagnostic test results can precisely determine whether an individual is likely to benefit from a specific treatment. As part and integral in the current era of precision oncology, theranostics in the context of nuclear medicine aims to identify the appropriate molecular targets in neoplasms (diagnostic tool), so that the optimal ligands and radionuclides (therapeutic tool) with favorable labeling chemistry can be selected for personalized management of a specific disease, taking into consideration the specific patient, and subsequently monitor treatment response. Over the past two decades, the use of gallium-68 labeled peptides for somatostatin receptor (SSTR)-targeted PET/CT (or PET/MRI) imaging followed by lutetium-177 and yttrium-90 labeled SSTR-agonist for peptide receptor radionuclide therapy has demonstrated remarkable success in the management of neuroendocrine neoplasms, and paved the way to other indications of theranostics. Rapid advances are being made in the development of other peptide-based radiopharmaceuticals, small molecular-weight ligands and with newer radioisotopes with more favorable kinetics, potentially useful for theranostics strategies for the clinical application. The present review features the Bad Berka experience with first-in-human studies of new radiopharmaceuticals, for example, prostate-specific membrane antigen ligand, gastrin-releasing peptide receptor, neurotensin receptor 1 ligand, novel SSTR-targeting peptides and nonpeptide, and bone-seeking radiopharmaceuticals. Also new radioisotopes, for example, actinium (225Ac), copper (64Cu), scandium (44Sc), and terbium (152Tb/161Tb) will be discussed briefly demonstrating the development from basic science to precision oncology in the clinical setting.

Peptide receptor radionuclide therapy (PRRT) is an effective treatment for patients with neuroendocrine neoplasms. The aim of this study was to identify clinical and treatment parameters associated with progression-free survival (PFS) and overall survival (OS). Methods: All patients treated from October 2002 until March 2016 at the Zentralklinik Bad Berka with at least 3 administrations of PRRT (maximal interval of 6 mo between consecutive administrations) were included. Data were collected in 5 categories: general patient characteristics, tumor characteristics, prior treatments, radioisotope used for PRRT, and blood chemistry. Survival was analyzed using Kaplan-Meier curves. Univariate and multivariate Cox regression analyses were performed to identify parameters associated with PFS and OS. Results: In total, 782 patients were included, with a median follow-up of 36 mo. The median PFS and OS were 22 and 53 mo, respectively. Parameters associated with lower PFS in the multivariate analysis were a Ki-67 of more than 5%, previous treatment with interferon-alpha and chemotherapy, presence of diabetes, and chromogranin-A (CgA) levels higher than 336 mu g/L. Parameters associated with lower OS were a Ki-67 of more than 10%, performance status of at least 1, previous chemotherapy and ablation, and CgA levels higher than 112 mu g/L. Conclusion: Higher Ki-67 values, as well as higher CgA levels and previous chemotherapy, had a negative outcome on both PFS and OS. Furthermore, PFS was negatively associated with previous interferon-alpha treatment and diabetes, whereas lower OS was related to prior ablation and higher performance status.

PURPOSE: Prostate-specific membrane antigen (PSMA)-targeted positron emission tomography (PET) imaging has impacted the management of patients with prostate cancer (PCa) in many parts of the world. PSMA-targeted endoradiotherapies are also being increasingly utilized and for these applications, the radiopharmaceutical distribution in normal organs is particularly important because it may limit the dose that can be delivered to tumors. In this study, we measured both interpatient and intrapatient variability of [(18)F]DCFPyL uptake in the most relevant normal organs. PROCEDURES: Baseline and 6-month follow-up PSMA-targeted [(18)F]DCFPyL PET/computed tomography (CT) scans from 39 patients with PCa were reviewed. Volumes of interest were manually drawn using the best visual approximation of the organ edge for both lacrimal glands, all four major salivary glands, the liver, the spleen, and both kidneys for all patients. The average SUV(mean), the COVs, and intraclass correlation coefficients (ICCs) across scans were calculated. Bland-Altman analyses were performed for all organs to derive repeatability coefficients (RCs). RESULTS: The liver demonstrated the lowest interpatient variability (13.0 and 16.6 % at baseline and follow-up, respectively), while the spleen demonstrated the largest interpatient variability (44.6 and 51.0 % at baseline and follow-up, respectively). The lowest intrapatient variability was found in the spleen (ICC 0.86) while the highest intrapatient variability was in the kidneys (ICCs 0.40–0.50). Bland-Altman analyses showed 95 % repeatability coefficients for mean uptake >40 % for multiple organs and were highest for the lacrimal glands, kidneys, and spleen. CONCLUSIONS: Normal organs demonstrate significant variability in uptake of the PSMA-targeted radiotracer [(18)F]DCFPyL. Depending on the organ, different contributions of interpatient and intrapatient factors affect the intrinsic variability. The RCs also vary significantly among the different organs were highest for the lacrimal glands, kidneys, and spleen. These findings may have important implications for the design of clinical protocols and personalized dosimetry for PSMA-targeted endoradiotherapies.

177Lu-PSMA radioligand therapy (LuPRLT) is mainly used for patients with metastatic castration-resistant prostate cancer who are resistant to established drugs. This study describes LuPRLT, either LuPSMA I&T or LuPSMA RLT-617, for 45 patients with predominant lymph node metastatic prostate cancer (LNM PC). Thirty-five patients had LNM and ten patients had LNM and one or two bone metastases. Before LuPRLT, the patients had prostate specific antigen (PSA) of median 18 µg/l (interquartile range (IQR): 3.3–39). LuPRLT was given with a cumulative injected 177Lu activity of median 14.5 GBq (IQR: 12.2–20.4). Maximum percentage decline of PSA was median 92% (IQR: 70–99). Thirty-five patients with only LNM had a better overall survival (OS) than ten patients with LNM and one or two bone metastases. Thirty-three docetaxel-naïve patients had a longer PSMA PET/CT progression-free survival than twelve patients who were resistant to docetaxel. Twenty-two patients who received LuPRLT with a cumulative injected 177Lu activity ≥ 14.8 GBq had a better PSMA PET/CT progression-free survival than 23 patients who received LuPRLT with a lower cumulative injected 177Lu activity. Seventeen patients with relapse after LuPRLT who received rechallenge LuPRLT or ActPRLT had a better OS than five patients who received other forms for relapse treatment. LuPRLT gave mild and transitory adverse effects. The findings of the present study suggest that LuPRLT of patients with LNM may be effective and safe. The promising results motivate randomized phase II trials to further quantify the impact of LuPRLT as treatment of patients with LNM.

OBJECTIVE The aim of the study was to compare impact on survival after resection of primary tumors (PTs) after peptide receptor radionuclide therapy (PRRT). BACKGROUND PRRT is a highly effective therapeutic option to treat locally advanced or metastatic neuroendocrine neoplasms (NENs). METHODS We retrospectively analyzed the data of 889 patients with advanced NEN (G1-G3, stage IV) treated with at least 1 cycle of PRRT. In 486 of 889 patients (55%, group 1), PT had been removed before PRRT. Group 2 constituted 403 patients (45%) with no prior PT resection. Progression-free survival (PFS) and overall survival (OS) was determined by 68Ga SSTR-PET/CT in all patients applying RECIST and EORTC. RESULTS Most patients had their PT in pancreas (n = 335; 38%) and small intestine (n = 284; 32%). Both groups received a mean of 4 cycles of PRRT (P = 0.835) with a mean cumulative administered radioactivity of 21.6 ± 11.7 versus 22.2 ± 11.2 GBq (P = 0.407). Median OS in group 1 was 134.0 months [confidence interval (CI): 118-147], whereas OS in group 2 was 67.0 months (CI: 60-80; hazard ratio 2.79); P < 0.001. Likewise, the median progression-free survival after first PRRT was longer in group 1 with 18.0 (CI: 15-20) months as compared to group 2 with 14.0 (CI: 15-18; hazard ratio 1.21) months; P = 0.012. CONCLUSIONS A previous resection of the PT before PRRT provides a significant survival benefit in patients with NENs stage IV.

Peptide receptor radionuclide therapy (PRRT) with radiolabeled somatostatin analogues has been shown to be highly efficacious concerning progression-free survival and response rates in patients with advanced, progressive, well-differentiated, somatostatin-receptor-positive neuroendocrine neoplasm. We report here delayed response of a midgut neuroendocrine neoplasm patient, who had stable disease after 4 cycles of PRRT and over a long period of 5 restaging admissions with excellent quality of life (full working hours), persisting for 3 years of follow-up, and presented as further partial remission according to both Response Evaluation Criteria in Solid Tumors and EORTC criteria, respectively, 36 months after the last PRRT cycle.

Lu-177-labeled prostate-specific membrane antigen (PSMA) radioligand therapy using PSMA-617 and PSMA-I&T ligands (Lu-177-PRLT) is an emerging treatment in metastatic castration-resistant prostate cancer (mCRPC). This retrospective study evaluates clinical outcomes of Lu-177-PRLT in earlier and later phases of mCRPC grouped by previous taxane chemotherapy. Methods: A retrospective analysis was performed on 167 patients with mCRPC who underwent Lu-177-PRLT between March 2013 and December 2016. Patients were classified as either taxane chemotherapy pretreated (T-pretreated) or naive (T-naive) depending on whether they had received taxane-based chemotherapy prior to Lu-177-PRLT. Clinical outcome for T-pretreated and T-naive patients was assessed by overall survival (OS), radiographic progression-free survival, and prostate-specific antigen (PSA) response rate. Univariate and multivariable analyses were performed for both T-pretreated and T-naive patients to determine predictors of outcome. Toxicity was categorized by the Common Terminology Criteria for Adverse Events (version 4.03). Results: Of the 167 patients treated with Lu-177-PRLT, 83 were T-pretreated and 84 were T-naive. At baseline, T-pretreated patients had overall poorer performance status, a higher prevalence of bone metastases, higher PSA levels, lower hemoglobin levels, higher alkaline phosphatase (ALP) levels and had received more additional therapies compared with T-naive patients. Median OS was 10.7 mo for T-pretreated patients and 27.1 mo for T-naive patients. Median radiographic progression-free survival was 6.0 mo for T-pretreated patients and 8.8 mo for T-naive patients. PSA response assessment was evaluable in 132 patients and seen in 25 of 62 (40%) T-pretreated patients and 40 of 70 (57%) T-naive patients. Significant determinates of inferior OS in multivariable analysis for T-pretreated patients were poorer performance status, lower cumulative administered activity, and lower baseline hemoglobin. Higher baseline alkaline phosphatase was the only significant determinate of inferior OS in multivariable analysis for T-naive patients. Overall Lu-177-PRLT was safe, with minimal adverse effects evident during follow-up in both T-pretreated and T-naive patients. Conclusion: Lu-177-PRLT is a promising therapy in mCRPC, with encouraging outcomes and minimal associated toxicity seen in both our T-naive and heavily pretreated patient cohorts.

ZusammenfassungMaligne Erkrankungen sind mit Veränderungen auf der molekularen Ebene assoziiert. Präzisionsonkologie meint einen personalisierten Therapieansatz, der auf spezifische molekulare Signale in Tumorzellen abzielt und mit optimaler Wirksamkeit bei minimalen Nebenwirkungen verbunden ist. Tumore können hochwirksam mit Radiopharmaka behandelt werden, die auf spezifische, zelluläre Mechanismen abzielen (z. B. Metastasen von gut differenzierten neuroendokrinen Neoplasmen mittels 177Lu markierten Somatostatinanaloga). Die molekulare Bildgebung mit PET/CT oder PET/MRT spielt eine entscheidende Rolle bei der Patientenauswahl sowie bei der Überwachung des Therapieansprechens und ist daher in der Lage, die molekulare Radiotherapie zu steuern („wir sehen, was wir behandeln“ und umgekehrt). Theranostik in der Nuklearmedizin fügt sich daher in die Definition der Präzisionsonkologie ein, da sie beispielhaft die Kombination von molekularer Bildgebung und molekularer Radiotherapie beinhaltet, wobei derselbe Vektor, markiert mit unterschiedlichen Radionukliden, zum einen für die Diagnose und zum anderen für die Behandlung verwendet wird. Während die Anwendung von 131I durch Saul Hertz Mitte des letzten Jahrhunderts erstmals den Weg für eine gezielte molekulare Radiotherapie eröffnete, fasst dieser Übersichtsartikel die Therapie mit in den letzten Jahren neuentwickelten Radiopharmaka zusammen.

Fibroblast activation protein (FAP) is a promising target for diagnosis and therapy of numerous malignant tumors. FAP-2286 is the conjugate of a FAP-binding peptide, which can be labeled with radionuclides for theranostic applications. We present the first-in-humans results using

The aim of the review was to evaluate patient and treatment characteristics for patients with metastatic castration-resistant prostate cancer (mCRPC) treated with PSMA radioligand therapy (PRLT) associated with above-average outcome. The systematic review and meta-analysis followed recommendations by the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA). We searched for publications in PubMed, Embase, and ClinicalTrials.gov up to 31 September 2020. Thirty-six publications and four duplicates reported 2346 patients. Nearly two-thirds of the patients had bone metastases. Median overall survival (OS) was 16 months. Asymptomatic patients and patients with only lymph node metastases lived longer than symptomatic patients and patients with more extensive metastases. Patients treated with an intensified schedule of 177Lu PRLT lived longer than those treated with a conventional schedule. Half of the patients obtained a PSA decline ≥ 50% and these patients lived longer than those with less PSA decline. Approximately 10% of the patients developed hematologic toxicity with anemia grade 3 as the most severe adverse effect. Characteristics for patients, cancer, restaging, and PRLT predict above average overall survival following treatment with PRLT.

Introduction The impact of prior therapies, especially chemotherapy, on overall survival (OS) in patients with castration-resistant prostate cancer (CRPC) receiving [177Lu]Lu-PSMA-617 therapy has been the subject of controversy. Therefore, WARMTH decided to plan a multicenter retrospective analysis (the “617 trial”) to evaluate response rate and OS as well as the impact of prior therapies on OS in more than 300 patients treated with 177Lu-PSMA-617. Materials and methods The data of 631 metastatic CRPC (mCRPC) patients from 11 different clinics were evaluated. According to the inclusion and exclusion criteria, all patients had to have received at least abiraterone or enzalutamide prior to [177Lu]Lu-PSMA-617 therapy. The patients were divided into three groups: patients who had received prior chemotherapy, patients who avoided chemotherapy, and patients for whom a chemotherapy was contraindicated. Results The analysis included the data of 416 patients, with a median age of 71.9 years. At the time of analysis, 87 patients (20,9%) were still alive. A total of 53.6% of patients had received both abiraterone and enzalutamide; 75.5% and 26.4% had a history of chemotherapy with docetaxel and cabazitaxel, respectively. A total of 20.4% had had Ra-223. The median OS was 11.1 months. Prior chemotherapy, the existence of bone and liver metastases, as well as Eastern Cooperative Oncology Group (ECOG) status, were significant prognosticators of worse overall survival in both univariate and multivariate analyses. Patients without any prior chemotherapy showed a significantly longer OS (14.6 months). The median OS in patients who received one or two lines of chemotherapy with docetaxel or docetaxel followed by cabazitaxel, respectively, was 10.9 months and 8.9 months. There was no difference in OS between patients who had not received chemotherapy and patients for whom chemotherapy was contraindicated. The other prior therapies did not have any significant impact on OS. Conclusion In the present multicenter analysis, chemotherapy-naïve mCRPC patients receiving [177Lu]Lu-PSMA-617 therapy had a significantly longer OS than patients with a history of chemotherapy. This remained independent in the multivariate analysis besides presence of bone and liver metastases as negative prognosticators for survival, whereas an ECOG of 0–1 is associated with a longer OS. Electronic supplementary material The online version of this article (10.1007/s00259-020-04797-9) contains supplementary material, which is available to authorized users.

Radiolabeled somatostatin receptor (SSTR) antagonists have shown promise for imaging neuroendocrine neoplasms and the superiority to SSTR agonists, with lower liver background especially for the sensitive detection of liver metastases, higher tumor-to-background ratio, and favorable pharmacokinetics. The clinical data of radiolabeled SSTR antagonists for therapy are still limited. We report our experience treating a young patient with DOTATOC-negative high-grade liver metastases of a pancreatic neuroendocrine neoplasm who underwent intra-arterial peptide receptor radionuclide therapy using SSTR antagonist Lu-DOTA-LM3, demonstrating an excellent response, nearly complete remission according to molecular imaging criteria and morphological partial remission, without any significant toxicity.

We present here a case with β-radiation-refractory metastatic neuroendocrine tumors, who demonstrated an excellent therapy response after 1 cycle of Ac-DOTATOC, without any significant adverse effects even after 10 cycles of β-emitter peptide receptor radionuclide therapy followed by α-peptide receptor radionuclide therapy.

Peptide receptor radionuclide therapy (PRRT) with radiolabeled somatostatin analogues has been proven to be very useful in the management of advanced, well-differentiated neuroendocrine neoplasms (NENs). We present here the pregnancy outcome in a NEN patient, who naturally conceived and gave birth to a healthy baby, after 4 cycles of PRRT administering a cumulative radioactivity of 27.1 GBq. This case underlines that pregnancy and birth without sequelae are possible in patients with NEN who have been treated with PRRT and offers a definitive prospect for patients of reproductive age group who plan conception despite having received or due to undergo PRRT.

// Richard P. Baum 1 , Harshad R. Kulkarni 1 , Aviral Singh 1 , Daniel Kaemmerer 2 , Dirk Mueller 1 , Vikas Prasad 3 , Merten Hommann 2 , Franz C. Robiller 4 , Karin Niepsch 1 , Holger Franz 5 , Arthur Jochems 6 , Philippe Lambin 6, 7 and Dieter Horsch 8 1 THERANOSTICS Center for Molecular Radiotherapy, Zentralklinik Bad Berka GmbH, Bad Berka, Germany 2 Department of General and Visceral Surgery, Zentralklinik Bad Berka GmbH, Bad Berka, Germany 3 Clinic for Nuclear Medicine, Charite, Berlin, Germany 4 Center of Molecular Imaging, Zentralklinik Bad Berka GmbH, Bad Berka, Germany 5 Lohmann and Birkner, Berlin, Germany 6 Department of Radiology, GROW - School for Oncology and Developmental Biology, Maastricht University Hospital, Maastricht, The Netherlands 7 Department of Radiation Oncology (The D-Lab), GROW - School for Oncology and Developmental Biology, Maastricht University, Maastricht, The Netherlands 8 Department of Gastroenterology/Endocrinology, Center for Neuroendocrine Tumors Bad Berka – ENETS Center of Excellence, Zentralklinik Bad Berka GmbH, Bad Berka, Germany Correspondence to: Dieter Horsch, email: dieter.hoersch@zentralklinik.de Keywords: peptide receptor radionuclide therapy; neuroendocrine tumors; survival; functional syndromes Received: November 11, 2017 Accepted: February 01, 2018 Epub: February 15, 2018 Published: March 30, 2018 ABSTRACT Introduction: Peptide receptor radionuclide therapy (PRRT) of patients with somatostatin receptor expressing neuroendocrine neoplasms has shown promising results in clinical trials and a recently published phase III study. Methods: In our center, 2294 patients were screened between 2004 and 2014 by 68 Ga somatostatin receptor (SSTR) PET/CT. Intention to treat analysis included 1048 patients, who received at least one cycle of 90 Yttrium or 177 Lutetium-based PRRT. Progression free survival was determined by 68 Ga SSTR-PET/CT and EORTC response criteria. Adverse events were determined by CTCAE criteria. Results: Overall survival (95% confidence interval) of all patients was 51 months (47.0-54.9) and differed significantly according to radionuclide, grading, previous therapies, primary site and functionality. Progression free survival (based on PET/CT) of all patients was 19 months (16.9-21), which was significantly influenced by radionuclide, grading, and origin of neuroendocrine neoplasm. Progression free survival after initial progression and first and second resumption of PRRT after therapy-free intervals of more than 6 months were 11 months (9.4-12.5) and 8 months (6.4-9.5), respectively. Myelodysplastic syndrome or leukemia developed in 22 patients (2.1%) and 5 patients required hemodialysis after treatment, other adverse events were rare. Conclusion: PRRT is effective and overall survival is favorable in patients with neuroendocrine neoplasms depending on the radionuclide used for therapy, grading and origin of the neuroendocrine neoplasm which is not exactly mirrored in progression free survival as determined by highly sensitive 68 Ga somatostatin receptor PET/CT using EORTC criteria for determining response to therapy.

Neurotensin receptor 1 (NTR1) is overexpressed in ductal pancreatic adenocarcinoma, which is still one of the deadliest cancers, with a very poor prognosis. Eligible patients were offered salvage radiopharmaceutical therapy with the novel NTR1 antagonist 177Lu-3BP-227. Methods: Six patients with confirmed ductal pancreatic adenocarcinoma who had exhausted all other treatment options received 177Lu-3BP-227 for evaluation of NTR1 expression in vivo. Three patients received treatment activities of 5.1-7.5 GBq. Results: Administration of 177Lu-3BP-227 was well tolerated by all patients. The kidneys were identified as the dose-limiting organ. The most severe adverse event was reversible grade 2 anemia. One patient achieved a partial response and experienced significant improvement of symptoms and quality of life. This patient survived 13 mo from diagnosis and 11 mo from the start of 177Lu-3BP-227 therapy. Conclusion: This initial report provides clinical evidence of the feasibility of treatment of ductal pancreatic adenocarcinoma using 177Lu-3BP-227.

Gastrin-releasing peptide receptors (GRPRs) represent attractive targets for cancer diagnosis and therapy owing to their overexpression in widespread human tumors. Bombesin (BBN) analogues coupled to suitable chelators for stable radiometal binding have been proposed for diagnostic imaging and radionuclide therapy (theranostics) of GRPR-positive tumors. Recently, interest has shifted from BBN-like receptor agonists to GRPR-radioantagonists, because radioantagonists do not induce adverse effects after injection to patients and display superior pharmacokinetic in vivo profiles. Thus, they seem more advantageous for clinical use compared to agonists. Newer developments highlighting the theranostic potential of GRPR-radioantagonists in cancer patient management are presented herein.

44Sc is a promising positron emission tomography (PET) radionuclide (T1/2 = 4.04 hours, Eβ+average = 632 keV) and can be made available, using a cyclotron production route, in substantial quantities as a highly pure product. Herein, the authors report on a first-in-human PET/CT study using 44Sc-DOTATOC prepared with cyclotron-produced 44Sc. The production of 44Sc was carried out through the 44Ca(p,n)44Sc nuclear reaction at Paul Scherrer Institut, Switzerland. After separation, 44Sc was shipped to Zentralklinik Bad Berka, Germany, where radiolabeling was performed, yielding radiochemically pure 44Sc-DOTATOC. Two patients, currently followed up after peptide receptor radionuclide therapy of metastatic neuroendocrine neoplasms, participated in this proof-of-concept study. Blood sampling was performed before and after application of 44Sc-DOTATOC. PET/CT acquisitions, performed at different time points after injection of 44Sc-DOTATOC, allowed detection of even very small lesions on delayed scans. No clinical adverse effects were observed and the laboratory hematological, renal, and hepatic profiles remained unchanged. In this study, cyclotron-produced 44Sc was used in the clinic for the first time. It is attractive for theranostic application with 177Lu, 90Y, or 47Sc as therapeutic counterparts. 44Sc-based radiopharmaceuticals will be of particular value for PET facilities without radiopharmacy, to which they can be shipped from a centralized production site.

99mTc-labeled MAA is commonly used for single photon emission computed tomography SPECT. In contrast, positron emission tomography/CT (PET/CT) delivers images with significantly higher resolution. The generator produced radionuclide 68Ga is widely used for PET/CT imaging agents and 68Ga-labeled MAA represents an attractive alternative to 99mTc-labeled MAA. We report a simple and rapid NaCl based labeling procedure for the labeling of MAA with 68Ga using a commercially available MAA labeling kit for 99mTc. The procedure delivers 68Ga-labeled MAA with a high specific activity and a high labeling efficiency (>99%). The synthesis does not require a final step of separation or the use of organic solvents.

Prostate cancer is the most common noncutaneous cancer among men, rendering the diagnosis and staging of significant medical and public interest. One of the most interesting developments in the application of nuclear oncology has been the development of novel diagnostic agents that are able to facilitate targeted therapies using the concept of theranostics. This review summarizes the current and emerging molecular imaging techniques for the investigation of patients with prostate cancer with emphasis on the potential of 64Cu-PSMA PET/CT in staging, restaging, and the application of theranostics.

Lu-177-labeled PSMA-617 is a promising new therapeutic agent for radioligand therapy (RLT) of patients with metastatic castration resistant prostate cancer (mCRPC). Initiated by the German Society of Nuclear Medicine, a retrospective multicenter data analysis was started in 2015 to evaluate efficacy and safety of Lu-177-PSMA-617 in a large cohort of patients. Methods: One hundred forty-five patients (median age, 73 y; range, 43-88 y) with mCRPC were treated with Lu-177-PSMA-617 in 12 therapy centers between February 2014 and July 2015 with 1-4 therapy cycles and an activity range of 2-8 GBq per cycle. Toxicity was categorized by the common toxicity criteria for adverse events (version 4.0) on the basis of serial blood tests and the attending physician's report. The primary endpoint for efficacy was biochemical response as defined by a prostate-specific antigen decline 50% from baseline to at least 2 wk after the start of RLT. Results: A total of 248 therapy cycles were performed in 145 patients. Data for biochemical response in 99 patients as well as data for physician-reported and laboratory-based toxicity in 145 and 121 patients, respectively, were available. The median follow-up was 16 wk (range, 2-30 wk). Nineteen patients died during the observation period. Grade 3-4 hematotoxicity occurred in 18 patients: 10%, 4%, and 3% of the patients experienced anemia, thrombocytopenia, and leukopenia, respectively. Xerostomia occurred in 8%. The overall biochemical response rate was 45% after all therapy cycles, whereas 40% of patients already responded after a single cycle. Elevated alkaline phosphatase and the presence of visceral metastases were negative predictors and the total number of therapy cycles positive predictors of biochemical response. Conclusion: The present retrospective multicenter study of Lu-177-PSMA-617 RLT demonstrates favorable safety and high efficacy exceeding those of other third-line systemic therapies in mCRPC patients. Future phase II/III studies are warranted to elucidate the survival benefit of this new therapy in patients with mCRPC.

Substantial molecular and clinical heterogeneity of high-grade neuroendocrine neoplasms (NENs) G3, all of which were previously referred to as neuroendocrine carcinomas, has been observed. Although data are still limited, somatostatin receptor expression in well-differentiated G3 NENs of the pancreas (according to the new WHO 2017 classification) may enable peptide receptor radionuclide therapy for these patients. We report our treatment experience of a G3 NEN patient with discordant Ki-67 proliferation indices (between primary tumor and the metastases), who had a long survival over a span of 10 years with excellent quality of life and no adverse effects after repeated cycles of PRRT.

Ectopic Cushing syndrome secondary to corticotropin releasing hormone (CRH)-secreting tumors or CRH and adrenocorticotropin hormone cosecreting tumors is extremely rare. We report here the case of a 54-year-old man who experienced CRH-secreting pancreatic neuroendocrine tumor causing Cushing syndrome, initially detected by SSTR (somatostatin receptor) scintigraphy, then significantly progressed with multiple liver metastases, demonstrating significantly increased SSTR expression on Ga-DOTATOC PET/CT and a "mismatch" imaging pattern on F-FDG PET/CT. The patient underwent peptide receptor radionuclide therapy with Lu/Y-DOTATOC and demonstrated excellent response to the treatment.

BackgroundFor almost a decade, terbium radioisotopes have been explored for their potential theragnostic application in nuclear medicine: Tb-152 and Tb-155 are the radioisotopes identified for PET or SPECT imaging, while Tb-149 and Tb-161 have suitable decay characteristics for alpha- and combined beta(-)/Auger-e(-)-therapy, respectively. In the present study, the application of Tb-152, in combination with PSMA-617 for imaging of prostate-specific membrane antigen (PSMA)-positive prostate cancer, was demonstrated in a preclinical setting and in a patient with metastatic castration-resistant prostate cancer (mCRPC).Results(152)Tb was produced at the ISOLDE facility at CERN/Geneva, Switzerland, by spallation, followed by on-line mass separation. The chemical separation was performed at Paul Scherrer Institute using chromatographic methods, as previously reported. Tb-152 was employed for labeling PSMA-617, and the radioligand was extensively investigated in vitro to demonstrate similar characteristics to its Lu-177-labeled counterpart. Preclinical PET/CT imaging studies performed with mice enabled visualization of PSMA-positive PC-3 PIP tumors, while uptake in PSMA-negative PC-3 flu tumors were absent. Based on these promising preclinical results, Tb-152 was shipped to Zentralklinik Bad Berka, Germany, where it was used for labeling of PSMA-617, enabling PET imaging of a patient with mCRPC. PET/CT scans were performed over a period of 25h post injection (p.i.) of the radioligand (140MBq). The images were of diagnostic quality, particularly those acquired at later time points, and enabled the detection of the same metastatic lesions and of local recurrent tumor as previously detected by Ga-68-PSMA-11 PET/CT acquired 45min p.i.ConclusionsThe results of this study demonstrate the successful preparation and preclinical testing of Tb-152-PSMA-617 and its first application in a patient with mCRPC. This work could pave the way towards clinical application of other Tb radionuclides in the near future, most importantly Tb-161, which has promising decay characteristics for an effective treatment of mCRPC patients.

Patients with metastatic castration-resistant prostate cancer (mCRPC) and visceral (liver or lung) metastases have a poor prognosis and worse outcomes than those with bone disease with or without lymph nodes involvement. The high prostate-specific membrane antigen expression in prostate cancer metastases makes it a promising approach for targeted radionuclide therapy of prostate cancer. Lutetium-177 (Lu)-labeled prostate-specific membrane antigen radioligand therapy (Lu-PRLT) has demonstrated encouraging efficacy in mCRPC. We report here an mCRPC patient with lung, lymph nodes, and extensive bone metastases, who underwent Lu-PRLT and had excellent response to the treatment and complete regression of lung metastases after Lu-PRLT.

Prostate-specific membrane antigen (PSMA) is overexpressed in a majority of prostate cancer cells, which has led to the development of radiolabeled small-molecule inhibitors of PSMA for molecular imaging and targeted radioligand therapy. Lu-labeled PSMA, with therapeutic β-emission and concomitant γ radiation, permits posttherapy imaging for the assessment of biodistribution and uptake in tumors and normal organs, as well as dosimetry. We report a patient with prostate cancer and metastatic lymph nodes-related lower extremity lymphedema, who presented with dermal backflow and soft-tissue uptake in the lower extremity on posttherapeutic whole body scan after intravenous Lu-PSMA treatment.

Somatostatin receptor PET/CT using (68)Ga-labeled somatostatin analogs, is a mainstay for the evaluation of the somatostatin receptor status in neuroendocrine neoplasms. In addition, the assessment of glucose metabolism by (18)F-FDG PET/CT at diagnosis can overcome probable shortcomings of histopathologic grading. This offers a systematic theranostic approach for the management of neuroendocrine neoplasms, that is, patient selection for the appropriate treatment-surgery, somatostatin analogs, peptide receptor radionuclide therapy, targeted therapies like everolimus and sunitinib, or chemotherapy-and also for therapy response monitoring. Novel targets, for example, the chemokine receptor CXCR4 in higher-grade tumors and glucagon like peptide-1 receptor in insulinomas, appear promising for imaging. Scandium-44 and Copper-64, especially on account of their longer half-life (for pretherapeutic dosimetry) and cyclotron production (which favors mass production), might be the potential alternatives to (68)Ga for PET/CT imaging. The future of molecular imaging lies in Radiomics, that is, qualitative and quantitative characterization of tumor phenotypes in correlation with tumor genomics and proteomics, for a personalized cancer management.

The objective of this study was to analyze the safety and efficacy of the 177Lu-labeled DOTAGA-based prostate-specific membrane antigen (PSMA) ligand 177Lu-DOTAGA-(I-y)fk(Sub-KuE) (177Lu-PSMA) in patients with metastatic castration-resistant prostate cancer (mCRPC). Methods: Fifty-six mCRPC patients underwent PSMA radioligand therapy (RLT) with 177Lu-PSMA. 68Ga-PSMA-(N,N9-bis-[2-hydroxy-5-(carboxyethyl)benzyl]ethylenediamine-N,N9-diacetic acid) (68Ga-PSMA) PET/CT was used for patient selection and follow-up after PSMA RLT. Hematologic status, renal function, and serum prostate-specific antigen levels were documented before and after therapy. Dosimetry was performed in 30 patients. Results:177Lu-PSMA demonstrated high absorbed tumor doses (median, 3.3 mGy/MBq) compared with the levels in normal organs. Parotid glands received higher doses (1.3 mGy/MBq) than kidneys (0.8 mGy/MBq). All patients tolerated the therapy without any acute adverse effects. Except for mild reversible xerostomia in 2 patients, no long-term side effects were observed. There was a small but statistically significant reduction in erythrocyte and leukocyte counts; only the reduction in erythrocyte counts decreased slightly below the reference range. No thrombocytopenia occurred. The severity of pain was significantly reduced in 2 of 6 patients (33.3%). A decrease in prostate-specific antigen levels was noted in 45 of 56 patients (80.4%). Of 25 patients monitored for at least 6 mo after 2 or more PSMA RLT cycles, a molecular response evaluation (68Ga-PSMA PET/CT) revealed partial remission in 14, stable disease in 2, and progressive disease in 9 patients. Contrast-enhanced CT revealed partial remission in 5, stable disease in 13, and progressive disease in 7 patients. The median progression-free survival was 13.7 mo, and the median overall survival was not reached during follow-up for 28 mo. Conclusion: PSMA RLT with 177Lu-PSMA is feasible, safe, and effective in end-stage progressive mCRPC with appropriate selection and follow-up of patients by 68Ga-PSMA PET/CT through application of the concept of theranostics.

Purpose To characterise efficacy and safety of (177)Lu-DOTATOC as agent for peptide receptor radiotherapy (PRRT) of advanced neuroendocrine tumours (NET). Patients and methods Fifty-six subjects with metastasized and progressive NET (50% gastroenteral, 26.8% pancreatic, 23.2% other primary sites) treated consecutively with (177)Lu-DOTATOC were analysed retrospectively. Subjects were administered (177)Lu-DOTATOC (mean 2.1 cycles; range 1-4) as 7.0GBq (median) doses at three-monthly intervals. Efficacy was analysed using CT and/or MRI according to RECIST 1.1 criteria and results were stratified for the number of administered cycles and the primary tumour origin. Results In the total NET population (A), median progression-free (PFS) and overall survival (OS) were 17.4 and 34.2 months, respectively, assessed in a follow-up time (mean ± SD) of 16.1 ± 12.4 months. In patients receiving more than one cycle, mean follow-up time was 22.4 ± 11.0 months for all NETs (B) and PFS was 32.0 months for all NETs (B), 34.5 months for GEP-NET (C), and 11.9 months for other NETs (D). Objective response rates (Complete/Partial Responses) were 33.9%, 40.6%, 54.2%, and 0% for A, B, C, and D groups, respectively, while disease control rates in the same were 66.1%, 93.8%, 100%, and 75%. Complete responses (16.1%, 18.8% and 25.0% for groups A, B and C) were high, 78% of which were maintained throughout the follow up. There were no serious adverse events. One case of self-limiting grade 3 myelotoxicity was reported. Although 20% of patients had mild renal insufficiency at baseline, there was no evidence of exacerbated or de novo renal toxicity after treatment. Conclusion (177)Lu-DOTATOC is a novel agent for PRRT with major potential to induce objective tumour responses and sustained disease control in progressive neuroendocrine tumours, even when administered in moderate activities. The observed safety profile suggests a particularly favourable therapeutic index, including in patients with impaired bone marrow or renal function, which reflects a uniquely low uptake of (177)Lu-DOTATOC by normal organs.