Introduction: Fibroblast activation protein (FAP) is overexpressed in several solid tumors and therefore represents an attractive target for radiotheranostic applications. Recent investigations demonstrated rapid and high uptake of small-molecule inhibitors of FAP ( 68 Ga-FAPI-46) for PET imaging. Here, we report our initial experience in terms of feasibility and safety of 90 Y-labelled FAPI-46 ( 90 Y-FAPI-46) for radioligand therapy (RLT) of extensively pretreated patients with solid tumors. Methods: Patients were considered for 90 Y-FAPI-46 therapy in case of (a) exhaustion of all approved therapies based on multidisciplinary tumor board decision and (b) high FAP expression, defined as SUVmax ≥ 10 in more than 50% of all lesions. If tolerated, posttherapeutic 90 Y-FAPI-46 bremsstrahlung scintigraphy was performed to visually confirm systemic distribution and focal tumor uptake, and 90 Y-FAPI-46 PET scans at multiple timepoints were performed to determine absorbed dose. Blood-based dosimetry was used to determine bone-marrow absorbed dose. Adverse Events were graded using CTCAE v.5.0. Results: Nine patients with either metastatic soft tissue or bone sarcoma (N = 6) and pancreatic cancer (N = 3) were treated between June 2020 and March 2021. Patients received a median of 3.8 (IQR 3.25-5.40) GBq for the first cycle and three patients received subsequent cycles with a median of 7.4 (IQR 7.3-7-5) GBq. Post-therapy 90 Y-FAPI-46 bremsstrahlung scintigraphy demonstrated sufficient 90 Y-FAPI-46 uptake in tumor lesions in 7 of 9 patients (78%). Mean absorbed dose was 0.52 Gy/GBq (IQR 0.41-0.65) in kidney, 0.04 Gy/GBq (IQR 0.03-0.06) in bone marrow and below 0.26 Gy/GBq in the lung and liver. Measured tumor lesions received up to 2.28 Gy/GBq (median 1.28Gy/GBq). Hematologic G3/G4 toxicities were noted in four patients (44%), of which

Introduction: Bone and soft tissue sarcomas express fibroblast activation protein (FAP) on tumor cells and associated fibroblast. Therefore, FAP is a promising therapeutic and diagnostic target.Novel radio-labelled FAP-Inhibitors (e.g. 68 Ga-FAPI46) have shown high tumor uptake in positron emission tomography (PET) in sarcoma patients. Here we report endpoints of the FAPI-PET prospective observational trial.Methods: Forty-seven patients with bone or soft tissue sarcomas undergoing clinical 68 Ga-FAPI-PET were eligible for enrollment into the FAPI-PET observational trial. Of these patients, 43 patients also underwent 18 F-Fluordesoxyglucose PET (FDG). The primary study endpoint was the association of 68 Ga-FAPI-PET uptake intensity and histopathological FAP-expression analyzed with Spearman's r correlation. Secondary endpoints were detection rate, positive predictive value (PPV), interreader reproducibility, and change in management. Datasets were interpreted by two blinded readers.Results: Primary endpoint was met and the association between FAPI-PET uptake intensity and histopathological FAP-expression was significant (Spearman's r = 0.43; p = 0.03). By histopathological validation PPV was 1.00 (95% CI, 0.87-1.00) on a per-patient and 0.97 (95% CI, 0.84-1.00) on a per-region basis. In cases with histopathologic validation, 27 of 28 (96%) confirmed patients and 32 of 34 (94%) confirmed regions were PET positive resulting in an SE of 0.96 (95%CI, 0.82-1.00) on a per-patient and 0.94 (95%CI, 0.80-0.99) on a per-region basis. The detection rate on a per-patient basis in FAPI-and FDG-PET was 76.6% and 81.4%, respectively.In 8 (18.6%) patients FAPI-PET resulted in an upstaging compared to FDG-PET. FAPI-PET readers showed substantial to almost perfect agreement for the defined regions (Fleiss kappa: primary κ = 0.78; local nodal κ = 0.54; distant nodal κ = 0.91; lung κ = 0.86; bone κ = 0.69 and other κ = 0.65). Clinical management changed in 13 (30%) patients after FAPI-PET. Conclusion:We confirm an association of tumoral FAPI-PET uptake intensity and histopathological FAP expression in sarcoma patients. Further, using blinded reads and independent histopathological validation we report high PPV and sensitivity of FAPI-PET for sarcoma staging.

Treatment of a defined subset of patients with outpatient intravenous ceftriaxone was safe and effective. Signs of sepsis were the only factor significantly associated with bloodstream infection. This study provides a baseline for future prospective studies assessing the safety of withholding antibiotics in this subset of patients.

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Rationale: Hepatocellular carcinoma (HCC) is the sixth most prevalent cancer and the third most frequent cause of cancer-related death. A growing number of local and systemic therapies are available, and accurate staging is critical for management decisions. We assessed the impact of neovasculature imaging by 68 Ga-Ga-PSMA-11 PET/CT on disease staging, prognostic groups and management of patients with HCC compared to staging with computed tomography (CT).Methods: Forty patients who received imaging with 68 Ga-Ga-PSMA-11 PET/CT for HCC staging between September 2018 and September 2019 were retrospectively included.Management pre-and post-PET scan was assessed by standardized surveys. Presence of HCC was evaluated by three blinded readers on a per-patient and per-region basis for PET/CT (PET criteria) and multi-phase contrast-enhanced CT (CT criteria) in separate sessions. Lesions were validated by follow-up imaging or histopathology, and progression-free survival (PFS) was recorded. Endpoints were detection rate and positive predictive value (PPV) for 68 Ga-Ga-PSMA-11 PET vs. CT, inter-reader reproducibility, and changes in stage, prognostic groups and management plans.Results: Median age was 65 years (range, 37-81), median Child-Pugh score was 5 (range, 5-9). Most patients were treatment naïve (27 of 40, 67.5%). The sensitivity of PET vs. CT to identify liver lesions for patients with lesion validation was 31/32 (97%) for both modalities, while it was 6/6 (100%) vs. 4/6 (67%) for extra-hepatic lesions. PET and CT each had a PPV of 100% at the liver level. PET vs. CT stage was congruent in 30/40 (75%) patients; upstaging was seen in 8/40 patients (20%), while 2/40 (5%) had downstaging by PET. Intended management changed in 19/40 patients (47.5%); 9/19 of these patients were found to have detectable distant metastases (47.4%) and assigned stage 4 disease, the majority of whom were shifted to systemic therapy (8 of 9, 89%).Two patients underwent 177 Lu-Lu-PSMA-617 radioligand therapy. Median PFS was 5.2 months for the entire cohort; 5.3 months for PET M0, and 4.7 months for PET M1 patients, respectively. Conclusion:68 Ga-Ga-PSMA-11 PET demonstrated higher accuracy than CT in the detection of HCC metastases and was associated with management change in about half of the patient cohort.

Aims The aim of this retrospective analysis was to examine the pattern of cardiac 68Ga-fibroblast-activation protein-α inhibitor (FAPI) uptake in patients after acute myocardial infarction (AMI) using PET and to investigate its association with results of coronary angiography. We correlated FAPI uptake with biomarkers of myocardial damage including left ventricular function. Methods and Results A cohort of 10 patients with no history of coronary artery disease underwent PET 18 ± 20.6 days after AMI (ST-segment elevation myocardial infarction [n = 5] and non–ST-segment elevation infarction [n = 5]), respectively. SUVmax, SUVmean, and SUVpeak of localized tracer uptake were calculated; tracer uptake volume was reported as fibroblast activation volume (FAV), with imaging data being correlated with clinical parameters. Focal FAPI uptake was observed in all patients. Average uptake at 10 minutes postinjection was 8.9 ± 4.4 (SUVmax), 7.6 ± 4.0 (SUVpeak), and 5.3 ± 2.8 (SUVmean), respectively. Affected myocardium showed a partial to complete match between tracer uptake and confirmed culprit lesion by coronary angiography in 44.4% and 55.6% of patients, respectively. A strong correlation between FAV and peak creatine kinase level (r = 0.90, P < 0.01) and inverse correlation of FAV with left ventricular function (r = −0.69, P < 0.05) was observed. Conclusions This analysis demonstrates in vivo visualization of fibroblast activation after AMI. The uptake area showed a very good agreement with the affected coronary territory. A strong correlation of the de novo established parameter FAV with left ventricular function and peak creatine kinase was observed. This imaging modality may provide important insights into mechanisms of structural remodeling after AMI at an early stage.

Overall, there is evidence that disease control and quality of life improve significantly after 117Lu PRRT therapy. Clinical trials on this therapy are scarce, and there is a need for further studies to establish proper management guidelines.

Introduction Positron emission tomography (PET) using small ligands of the fibroblast activation protein (FAP) was recently introduced. However, optimal uptake time has not been defined yet. Here, we systematically compare early (~ 10 min p.i.) and late (~ 60 min p.i.) FAPI-46 imaging in patients with various types of cancer. Methods This is a retrospective single-institutional study. Imaging was performed at the Essen University Hospital, Germany. A total of 69 patients who underwent dual time-point imaging for either restaging (n = 52, 75%) or staging (n = 17, 25%) of cancer were included. Patients underwent PET with two acquisitions: early (mean 11 min, SD 4) and late (mean 66 min, SD 9). Mean injected activity was 148 MBq (SD 33). Results In total, 400 lesions were detected in 69 patients. Two of 400 (0.5%) lesions were only seen in early time-point imaging but not in late time-point imaging. On a per-patient level, there was no significant difference between SUVmax of hottest tumor lesions (Wilcoxon: P = 0.73). Organ uptake demonstrated significant early to late decrease in SUVmean (average ∆SUVmean: − 0.48, − 0.14, − 0.27 for gluteus, liver, and mediastinum, respectively; Wilcoxon: P < 0.001). On a per-lesion basis, a slight increase of SUVmax was observed (average ∆SUVmax: + 0.4, Wilcoxon: P = 0.03). Conclusion In conclusion, early (~ 10 min p.i.) versus late (~ 60 min p.i.) FAPI-46 imaging resulted in equivalent lesion uptake and tumor detection. For improved feasibility and scan volume, we implement early FAPI-46 PET in future clinical and research protocols.