Analysis of Pros and Cons in Using [68Ga]Ga-PSMA-11 and [18F]PSMA-1007: Production, Costs, and PET/CT Applications in Patients with Prostate Cancer.

The aim of this work is to compare [68Ga]Ga-PSMA-11 and [18F]PSMA-1007 PET/CT as imaging agents in patients with prostate cancer (PCa). Comparisons were made by evaluating times and costs of the radiolabeling process, imaging features including pharmacokinetics, and impact on patient management. The analysis of advantages and drawbacks of both radioligands might help to make a better choice based on firm data. For [68Ga]Ga-PSMA-11, the radiochemical yield (RCY) using a low starting activity (L, average activity of 596.55 ± 37.97 MBq) was of 80.98 ± 0.05%, while using a high one (H, average activity of 1436.27 ± 68.68 MBq), the RCY was 71.48 ± 0.04%. Thus, increased starting activities of [68Ga]-chloride negatively influenced the RCY. A similar scenario occurred for [18F]PSMA-1007. The rate of detection of PCa lesions by Positron Emission Tomography/Computed Tomography (PET/CT) was similar for both radioligands, while their distribution in normal organs significantly differed. Furthermore, similar patterns of biodistribution were found among [18F]PSMA-1007, [68Ga]Ga-PSMA-11, and [177Lu]Lu-PSMA-617, the most used agent for RLT. Moreover, the analysis of economical aspects for each single batch of production corrected for the number of allowed PET/CT examinations suggested major advantages of [18F]PSMA-1007 compared with [68Ga]Ga-PSMA-11. Data from this study should support the proper choice in the selection of the PSMA PET radioligand to use on the basis of the cases to study.

On site production of [18F]PSMA-1007 using different [18F]fluoride activities: practical, technical and economical impact.

BACKGROUND: Prostate-specific membrane antigen is overexpressed in prostate cancer and it is considered a good target for positron emission tomography/computed tomography imaging of primary cancer and recurrent/metastatic disease, as well as for radioligand therapy. Different PSMA-analogues labeled with [68Ga]gallium have been investigated, showing excellent imaging properties; however, only small amounts can be produced for each radiolabeling. Recently, a [18F]fluoride labeled PSMA-inhibitor, [18F]PSMA-1007, has been introduced, and it has ensured large-scale productions, overcoming this limitation of [68Ga]PSMAs. In this study, PSMA-1007 has been labeled with low (A), medium (B) and high (C) starting activities of [18F]fluoride, in order to verify if radiochemical yield, radiochemical purity and stability of [18F]PSMA-1007 were affected. These parameters have been measured in sixty-five consecutive batches. In addition, the estimation of [18F]PSMA-1007 production costs is provided. RESULTS: The radiochemical yield for low and medium activities of [18F]fluoride was 52%, while for the high one it decreased to 40%. The radiochemical purity was 99% for all three activities. [18F]PSMA-1007 did not show radiolysis up to 8 h after the end of synthesis, confirming that the radiopharmaceutical is stable and suitable to perform diagnostic studies in humans for a long period of time after the end of radiolabeling. Furthermore, radiochemical stability was demonstrated in fetal bovine serum at 4 °C and 37 °C for 120'. CONCLUSIONS: A starting activity of [18F]fluoride of 90 GBq (B) seems to be the best option enabling a final amount of about of 50 GBq of [18F]PSMA-1007, which is promising as it allows to: (a) perform a large number of scans, and/or (b) supply the radiopharmaceutical to any peripheral diagnostic centers in need.

Long-term follow-up study on the role of serum CA-125 as a prognostic factor in 221 newly diagnosed patients with Hodgkin's lymphoma.

The present study has explored the possible value of sCA-125 as a prognostic factor in Hodgkin's lymphoma (HL). From August 1992 to June 2005 sCA-125 was measured at presentation and at the end of the treatments in 221 newly diagnosed adult patients with HL. In this study 90/221 (41%) patients showed a value greater than the standard upper limit of 35 U/ml, and 79/90 (88%) with an abnormal sCA-125 were at an advanced stage of the disease. Patients with elevated sCA-125 showed a significant reduction in complete remission (CR) rate (76%vs. 98%; p < 0.0001). Failure of normalization of sCA-125 during the treatment revealed that CR had not been reached. Furthermore, no traces of the glycoprotein sCA-125 were found in a series of paraffin-embedded samples coming from 15 patients of this study. In addition, soluble CA-125 was not detected in supernatants coming from four different Hodgkin-derived cell lines. The long-term follow-up revealed that the group of patients with sCA-125 lower than 35 U/ml, at diagnosis, had an estimated 92% event free survival (EFS) rate and a 94% overall survival (OS) rate, while the group of patients with sCA-125 greater than 35 U/ml had only a 60% EFS rate (log-rank 33.43, p < 0.0001) and a 70% OS rate (log-rank 23.52, p < 0.0001). Extranodal disease, severe lymphocytopenia and age proved to be the only standard factors that could represent a poor chance to survive. At multivariate analysis, high sCA-125, E sites >1 and age were the only independent factors producing poor outcomes in terms of CR, EFS and OS. Therefore, we believe that sCA-125 is a simple, reliable and reproducible tool, which may improve existing prognostic systems.