Therapeutic efficacy and safety results of 177Lu-PSMA therapy in metastatic castration-resistant prostate cancer patients: first experience of a developing South Asian Country.

OBJECTIVE: Metastatic castration resistant-prostate cancer (mCRPC) is deadly condition that remains incurable despite various therapies. Initial studies have shown promising results with Lutetium-177 prostate-specific membrane antigen ( 177 Lu-PSMA) therapy for advanced prostate cancer. However, most of the published efficacy and safety data is retrospective. The purpose of the study was to prospectively evaluate the therapeutic efficacy and safety results of 177 Lu-PSMA therapy in mCRPC patients after 2 cycles. METHODS: Twenty-five patients of mCRPC, treated with standard care treatment were enrolled for 2 cycles of 177 Lu-PSMA therapy. Prostate-specific antigen (PSA), Eastern Cooperative Oncology Group (ECOG) performance status, Visual Analogue Score (VAS) and Analgesic Quantification Scale (AQS) for efficacy and hemoglobin, total leukocyte, platelets and serum creatinine for toxicity were recorded pre and post-therapy. Paired sample t-test was used for statistical analysis. RESULTS: Treated patients with mean PSA level of 157 ng/ml received mean dose of 6.84 GBq of 177 Lu-PSMA. For PSA, partial response (PR) was seen in 11/25 (44%), stable disease (SD) in 8/25 (32%) and progressive disease (PD) in 6/25 (24%) patients. Grade 1 and 2 hemoglobin toxicity was seen in 5/25 (20%) and 6/25 (24%) patients respectively. No patient developed grade 3 or 4 bone marrow toxicities. Grade 1 and 2 nephrotoxicity was seen in 1 patient each. Statistically significant difference was seen in ECOG, VAS and AQS scores ( P  < 0.001). No significant nephrotoxicity was observed ( P  = 0.558). CONCLUSION: Efficacy and safety of 177 Lu-PSMA therapy after 2 cycles have shown significant PSA response and pain palliation in heavily pretreated mCRPC patients.

IAEA Contribution to Nanosized Targeted Radiopharmaceuticals for Drug Delivery.

The rapidly growing interest in the application of nanoscience in the future design of radiopharmaceuticals and the development of nanosized radiopharmaceuticals in the late 2000's, resulted in the creation of a Coordinated Research Project (CRP) by the International Atomic Energy Agency (IAEA) in 2014. This CRP entitled 'Nanosized delivery systems for radiopharmaceuticals' involved a team of expert scientist from various member states. This team of scientists worked on a number of cutting-edge areas of nanoscience with a focus on developing well-defined, highly effective and site-specific delivery systems of radiopharmaceuticals. Specifically, focus areas of various teams of scientists comprised of the development of nanoparticles (NPs) based on metals, polymers, and gels, and their conjugation/encapsulation or decoration with various tumor avid ligands such as peptides, folates, and small molecule phytochemicals. The research and development efforts also comprised of developing optimum radiolabeling methods of various nano vectors using diagnostic and therapeutic radionuclides including Tc-99m, Ga-68, Lu-177 and Au-198. Concerted efforts of teams of scientists within this CRP has resulted in the development of various protocols and guidelines on delivery systems of nanoradiopharmaceuticals, training of numerous graduate students/post-doctoral fellows and publications in peer reviewed journals while establishing numerous productive scientific networks in various participating member states. Some of the innovative nanoconstructs were chosen for further preclinical applications-all aimed at ultimate clinical translation for treating human cancer patients. This review article summarizes outcomes of this major international scientific endeavor.

IAEA contribution to the development of 64Cu radiopharmaceuticals for theranostic applications.

Copper-64 is a very attractive radioisotope with unique nuclear properties that allow using it as both a diagnostic and therapeutic agent, thus providing an almost ideal example of a theranostic radionuclide. A characteristic of Cu-64 stems from the intrinsic biological nature of copper ions that play a fundamental role in a large number of cellular processes. Cu-64 is a radionuclide that reflects the natural biochemical pathways of Cu-64 ions, therefore, can be exploited for the detection and therapy of certain malignancies and metabolic diseases. Beside these applications of Cu-64 ions, this radionuclide can be also used for radiolabelling bifunctional chelators carrying a variety of pharmacophores for targeting different biological substrates. These include peptide-based substrates and immunoconjugates as well as small-molecule bioactive moieties. Fueled by the growing interest of Member States (MS) belonging to the International Atomic Energy Agency (IAEA) community, a dedicated Coordinated Research Project (CRP) was initiated in 2016, which recruited thirteen participating MS from four continents. Research activities and collaborations between the participating countries allowed for collection of an impressive series of results, particularly on the production, preclinical evaluation and, in a few cases, clinical evaluation of various 64Cu-radiopharmaceuticals that may have potential impact on future development of the field. Since this CRP was finalized at the beginning of 2020, this short review summarizes outcomes, outputs and results of this project with the purpose to propagate to other MS and to the whole scientific community, some of the most recent achievements on this novel class of theranostic 64Cu-pharmaceuticals.

Synthesis and Biodistribution Study of Biocompatible 198Au Nanoparticles by use of Arabinoxylan as Reducing and Stabilizing Agent.

Radioactive gold-198 is a useful diagnostic and therapeutic agent. Gold in the form of nanoparticles possesses even more exciting properties. This work aimed at arabinoxylan-mediated synthesis and biodistribution study of radioactive gold nanoparticles (198AuNPs). The particles were synthesized by mixing suspension of arabinoxylan with H198AuCl4 without use of any additional reducing and stabilizing agents. An aqueous suspension of arabinoxylan was added to a H198AuCl4 solution, which resulted in reduction of Au3+ to 198AuNPs. Biodistribution was studied in vitro and in rabbit. The particles having exceptional stability were readily formed. Highest radioactivity was recorded in spleen after 3 h followed by liver, heart, kidney, and lungs after i.v. administration. After 24 h, the activity was not detectable in the spleen; it accumulated in the liver. However, after oral administration, the activity mainly accumulated in the colon. In serum proteins, the distribution was α1-globulin 6.5%, α2-globulin ~ 2%, ß-globulin ~ 1%, γ-globulin 0.7%, and albumin 0.7% of the administered dose. This indicates a low protein binding implying high bioavailability of the particles. The cytotoxicity study showed that the particles were inactive against HeLa cell line and Agrobacteriumtumefaciens. Highly stable 198AuNPs reported in this work have the potential for targeting the colon. They show affinity for globulins, the property that can be used in the study of the immune system.

Correction to: Synthesis and Biodistribution Study of Biocompatible 198Au Nanoparticles by use of Arabinoxylan as Reducing and Stabilizing Agent.

The original version of this article unfortunately contained a mistake.

Studying the biological feasibility of [99mTc(CO)3]-dextran-cysteine-cysteine-mannose as a potential molecular radiopharmaceutical for sentinel node detection.

OBJECTIVE: The aim of this work was to radiolabel and bioevaluate the technetium-99m labeled dextran dicysteine mannose (DCCM) [(99m)Tc(CO)3]-DCCM for sentinel lymph node detection. METHODS: Dextran dicysteine mannose was radiolabeled using the carbonyl method. Various parameters were studied such as in vitro stability at room temperature up to 5 h, protein binding and partition coefficient. Bioevaluation was performed in a rabbit model by developing images under a gamma camera at various time intervals. Biodistribution was performed in Wistar rat models (n = 3) by dissection and measurement of percent injected dose in various body organs, at 60 and 180 min post-injection intervals. Biodistribution was performed in two different groups of animals: in the first group, the radiolabeled compound was injected at a concentration of 200 µg/ml, thus delivering 10 µg radiolabeled compound at the site of injection; in the second group, the radiolabeled compound was injected at a concentration of 50 µg/ml, delivering 2.5 µg radiolabeled compound at the site of injection. RESULTS: Radiolabeling efficacy was 97.5 ± 1% which remained quite stable till 5 h. Protein binding data show that 71.1 ± 5% drug exhibited binding with blood proteins. Partition coefficient results show that our radiopharmaceutical is quite hydrophilic in nature. It can be inferred from the imaging data that sentinel node can be visualized within 30 min post-injection. Rat dissection data showed that when the radiolabeled compound was injected at a concentration of 50 µg/ml, at 60 min post-injection, ~2.85% of activity was retained in the sentinel node with a significantly less accumulation, e.g., ~0.12%, in the secondary node, which resulted in very high popliteal extraction (PE) value, e.g., ~98%. At 180 min post-injection, 2.46 ± 0.29 % was found to be retained in the sentinel node and PE (99.64 ± 0.23%), thus resulting in almost complete washout from the secondary node (0.05 ± 0.01%). CONCLUSION: The study demonstrates that radiolabeled DCCM might be a successful radiopharmaceutical for sentinel node detection.

Dermatofibrosarcoma protuberans arising in a decorative tattoo.

Dermatofibrosarcoma protuberans (DFSP) is an uncommon, locally aggressive cutaneous tumour of intermediate grade malignancy. A number of reports have linked local trauma of varying aetiology with the later development of DFSP. In addition, a variety of skin disorders and, in rare cases, cutaneous tumours, have been described in association with decorative tattoos. This is often associated with delayed diagnosis. We report the first case of DFSP arising in a tattoo and discuss the available evidence for a causative link between DFSP and local trauma of this nature.