Synthesis and automated fluorine-18 radiolabeling of new PSMA-617 derivatives with a CuAAC radiosynthetic approach

In the last decade, the development of new radiopharmaceuticals for the imaging and therapy of prostate cancer has been a highly active and important area of research, especially focusing on the prostate-specific membrane antigen (PSMA), an antigen which is upregulated in prostate, as well as in other tumor cells. A large variety of PSMA ligands have been radiolabeled, to date. Among the various derivatives, PSMA-617 resulted to be one of the most interesting in terms of interaction with the antigen and clinical properties, and its lutetium-177 labeled version has recently been approved by regulatory agencies for therapeutic purposes. For this reasons, the radiolabeling with fluorine-18 of a PSMA-617 derivative might be of interest. Beside other methodologies to radiolabel macromolecules with fluorine-18, the “click-chemistry” approach resulted to be very useful, and the copper-catalyzed azide-alkyne cycloaddition (CuAAC) is considered one of most efficient and reliable. This paper proposes the synthesis of a suitable precursor for the radiolabeling with fluorine-18 of a new PSMA-617 derivative. The whole radiosynthetic procedure has been fully automated, and the final product, which proved to be stable in plasma, has been obtained with radiochemical yield and purity suitable for subsequent preclinical studies.     

Effectiveness of the Transoral Endoscopic Vertical Gastroplasty (TOGa?): a Good Balance Between Weight Loss and Complications, if Compared with Gastric Bypass and Biliopancreatic Diversion

Background

The effectiveness of restrictive procedures has been inferior to that of malabsorbitive ones. Recent variants of restrictive procedures, i.e., gastric banding and sleeve gastrectomy, confirm the strive for more efficacious solutions with less complications. We investigated the balance between effectiveness and complications for a new restrictive procedure, a Transoral Endoscopic Vertical Gastroplasty (TOGa?)

Methods

Seventy-nine morbidly obese patients were submitted to one out of three surgical procedures: TOGa? (29 patients), laparoscopic gastric bypass (LRYGBP; 20 patients), and biliopancreatic diversion (BPD; 30 patients). Mean BMI were 41.7 (35.4?C46.6), 44.8 (36.4?C54), and 47.5 (41?C60.3), respectively. All the patients reached a 2-year follow-up.

Results

In TOGa? group BMI, respectively at 12 and 24?months, was 34.5 and 35.5, with 44 and 48.3?% of patients with BMI lower than 35. In LRYGBP group, BMI was 30.7 and 29.2?kg/m², with 80 and 85?% of patients with BMI?<?35. In BPD group, BMI was 30 and 29.6?kg/m², with 100 and 93.3?% of patients with BMI?<?35. In TOGa? group, 59?% of patients with an initial BMI?<?45 reached a BMI?<?35, in comparison to 48?% recorded in the whole group and to 14.3?% in patients with initial BMI????45.

Conclusions

In selected patients, TOGa?, was associated with good results after two years in terms of weight loss, even in comparison with LRYGBP and BPD. Minimal trauma, absence of complications, and short hospital stay justify this procedure for patients with low BMI.     

Lymphocytes genetically modified to express tumor antigens target DCs in vivo and induce antitumor immunity

The exploitation of the physiologic processing and presenting machinery of DCs by in vivo loading of tumor-associated antigens may improve the immunogenic potential and clinical efficacy of DC-based cancer vaccines. Here we show that lymphocytes genetically modified to express self/tumor antigens, acting as antigen carriers, efficiently target DCs in vivo in tumor-bearing mice. The infusion of tyrosinase-related protein 2-transduced (TRP-2-transduced) lymphocytes induced the establishment of protective immunity and long-term memory in tumor-bearing mice. Analysis of the mechanism responsible for the induction of such an immune response allowed us to demonstrate that cross-presentation of the antigen mediated by the CD11c(+)CD8alpha(+) DC subset had occurred. Furthermore, we demonstrated in vivo and in vitro that DCs had undergone activation upon phagocytosis of genetically modified lymphocytes, a process mediated by a cell-to-cell contact mechanism independent of CD40 triggering. Targeting and activation of secondary lymphoid organ-resident DCs endowed antigen-specific T cells with full effector functions, which ultimately increased tumor growth control and animal survival in a therapeutic tumor setting. We conclude that the use of transduced lymphocytes represents an efficient method for the in vivo loading of tumor-associated antigens on DCs.     

Contrast-Enhanced Spectral Mammography and tumor size assessment: a valuable tool for appropriate surgical management of breast lesions

Purpose

To compare the accuracy of Contrast-Enhanced Spectral Mammography (CESM), MG, US, and breast MRI in estimating the size of breast lesions requiring surgery. The postoperative histology size of the lesion was used as the gold standard.

Material and methods

Two hundred thirty-three non-benign lesions in 189 patients were included in the analyses. All the selected patients underwent CESM and at least one other conventional diagnostic exam (US, MG, or MRI). Subsequently, all the patients underwent surgery preceded by cytological/histological examination. The largest diameter of the lesion at imaging was measured by a radiologist with more than 10 years’ experience and then compared with the size of the lesion in the histological sample at the surgery (gold standard).

Results

Among the 233 breast lesions, 196 were evaluated with US, 206 with MG and 160 with MRI. We found no statistically significant differences between size measurements using CESM and MRI compared with the measurements at the surgery (p value 0.63 and 0.51), whereas a significant difference was found for MG and US (p?<?0.001).

Conclusion

CESM is a reliable method for estimating the size of breast lesions: its performance seems superior to US and MG and comparable to MRI.

     

High rate of hematological responses to sorafenib in FLT3‐ITD acute myeloid leukemia relapsed after allogeneic hematopoietic stem cell transplantation

Relapse represents the most significant cause of failure of allogeneic hematopoietic stem cell transplantation (HSCT) for FLT3‐ITD‐positive acute myeloid leukemia (AML), and available therapies are largely unsatisfactory. In this study, we retrospectively collected data on the off‐label use of the tyrosine kinase inhibitor sorafenib, either alone or in association with hypomethylating agents and adoptive immunotherapy, in 13 patients with post‐transplantation FLT3‐ITD‐positive AML relapses. Hematological response was documented in 12 of 13 patients (92%), and five of 13 (38%) achieved complete bone marrow remission. Treatment was overall manageable in the outpatient setting, although all patients experienced significant adverse events, especially severe cytopenias (requiring a donor stem cell boost in five patients) and typical hand‐foot syndrome. None of the patients developed graft‐vs.‐host disease following sorafenib alone, whereas this was frequently observed when this was given in association with donor T‐cell infusions. Six patients are alive and in remission at the last follow‐up, and four could be bridged to a second allogeneic HSCT, configuring a 65 ± 14% overall survival at 100 d from relapse. Taken together, our data suggest that sorafenib might represent a valid treatment option for patients with FLT3‐ITD‐positive post‐transplantation relapses, manageable also in combination with other therapeutic strategies.     

A case of pulmonary thromboembolism in thalassemia intermedia: are these patients at risk for thrombotic events?

We describe a case of pulmonary thromboembolism in a 48-year-old woman with thalassemia intermedia and no other risk factors. Multiple bilateral defects were detected by perfusion lung scan. No sources of emboli were detected, despite extensive evaluation. We suggest that a chronic hypercoagulable state due to multiple coagulation alterations might be a cause of thromboembolic events in thalassemia intermedia patients, even when no other risk factors are present.