Radioisotopic treatment of bone pain from metastatic prostate cancer

Feasibility of 153Sm production using MNSR research reactor through a multi-stage approach

The main objective of this study was to explore the feasibility of producing ¹⁵³Sm radioisotope in miniature neutron source reactors (MNSRs) in Isfahan-Iran. As the first step of this study, the MNSR's geometry was created by using the MCNP6.2 simulation code and afterwards a validity check was performed by comparing the results with the experimental data. Then, by applying values obtained through simulation, the production process was followed up to 20 irradiation cycles using different irradiation and cooling periods (irradiation setups). The results showed that the proposed simulation technique has an acceptable agreement with the experiments (with a difference of nearly 6%). In spite of limitations, such as irradiation time and flux in such reactors, our results showed that by choosing the correct irradiation setup, it is possible to produces ¹⁵³Sm up to 852.26 mCi g^-1 in 20 successive irradiation cycles. However, after the 10th cycle, the production reached 90% of the maximum point. Nevertheless, the continuance of the irradiation process with a new target (by 10 plus 10 discrete irradiation) can double the total activity in comparison with 20 successive irradiation cycles, without any increase in the fuel consumption of the reactor. These findings increase the prospect of a large-scale production of the life-saving ¹⁵³Sm radioisotope in MNSR reactors.

A review of solute encapsulating nanoparticles used as delivery systems with emphasis on branched amphipathic peptide capsules

Various strategies are being developed to improve delivery and increase the biological half-lives of pharmacological agents. To address these issues, drug delivery technologies rely on different nano-sized molecules including: lipid vesicles, viral capsids and nano-particles. Peptides are a constituent of many of these nanomaterials and overcome some limitations associated with lipid-based or viral delivery systems, such as tune-ability, stability, specificity, inflammation, and antigenicity. This review focuses on the evolution of bio-based drug delivery nanomaterials that self-assemble forming vesicles/capsules. While lipid vesicles are preeminent among the structures; peptide-based constructs are emerging, in particular peptide bilayer delimited capsules. The novel biomaterial-Branched Amphiphilic Peptide Capsules (BAPCs) display many desirable properties. These nano-spheres are comprised of two branched peptides-bis(FLIVI)-K-KKKK and bis(FLIVIGSII)-K-KKKK, designed to mimic diacyl-phosphoglycerides in molecular architecture. They undergo supramolecular self-assembly and form solvent-filled, bilayer delineated capsules with sizes ranging from 20 nm to 2 μm depending on annealing temperatures and time. They are able to encapsulate different fluorescent dyes, therapeutic drugs, radionuclides and even small proteins. While sharing many properties with lipid vesicles, the BAPCs are much more robust. They have been analyzed for stability, size, cellular uptake and localization, intra-cellular retention and, bio-distribution both in culture and in vivo.

Clinical development of novel therapeutics for castration-resistant prostate cancer: historic challenges and recent successes

There have been more drugs approved by the US Food and Drug Administration for the treatment of castration-resistant prostate cancer in the past 3 years than in the prior 3 decades, with additional drugs on the verge of approval based on the results of recently reported randomized trials. While an improvement in the understanding of the pathogenesis of castration-resistant prostate cancer has undeniably accelerated the transition of novel approaches from "bench to bedside," the recent successes in the treatment of prostate cancer are also a result of the efforts of clinical investigators to redefine the framework in which drugs for castration-resistant disease are evaluated. This review will explore the shifting paradigm in drug development for castration-resistant prostate cancer over the past several decades, and highlight how new definitions, trial designs, and endpoints have facilitated the emergence of new therapies for this challenging disease.

Palliative und supportive Therapie bei Patienten mit fortgeschrittenem Prostatakarzinom

In patients with advanced prostate cancer, quality of life and prevention of complications come to the fore. Besides handling local complications such as obstruction, hematuria and lymphedema, treatment of bone metastases and their complications is of great importance. Analgesic measures, bisphosphonates, radiation therapy, radionuclide therapy and neurosurgical procedures are available. Spinal cord compression with acute motor and sensory deficiency requires immediate neurosurgical and/or radiation therapy. Tumor anemia should be treated appropriately.

Safety and efficacy of repeat administration of samarium Sm-153 lexidronam to patients with metastatic bone pain

BACKGROUND

Samarium Sm 153 lexidronam (Sm-153) is an effective and well-tolerated treatment for painful bone metastases. The purpose of the analysis was to assess the safety and efficacy of repeated doses of Sm-153 in patients with metastatic bone pain.

METHODS

Data were collected prospectively for 202 patients administered 1.0 mCi/kg of Sm-153. Particular emphasis was placed on analysis of data from 55 patients receiving > or = 2 doses. Pain scores, adverse events, and hematologic parameters were assessed after each dose.

RESULTS

Mild, transient suppression of platelets and white blood cell counts was the most common adverse event after treatment. Nadirs were approximately half of baseline at 4 weeks after dosing with recovery by Week 8 in 90% of patients. Temporary grade 3 thrombocytopenia occurred in 11%, 12%, and 17% of patients after the first, second, and third drug administration, respectively. Grade 3 leukopenia occurred in less than 7% of patients independent of the number of administrations. Significant decreases in pain scores (P < .001) were observed at Week 4 after each of the first 3 doses and maintained at Week 8 after the first 2 doses (P < .003) but not the third. Decreases in pain scores were observed in 70%, 63%, and 80% of patients, respectively, at Week 4 after the first 3 administrations.

CONCLUSIONS

Repeated dosing of 1.0 mCi/kg of Sm-153 was both safe and effective and is a reasonable treatment option in patients whose bone pain responds and then recurs after an initial dose provided that adequate hematologic function is present at the time of drug administration.

Diagnostic and therapeutic use of radioisotopes for bony disease in prostate cancer: Current practice

Nuclear medicine techniques continue to be important non-invasive imaging tools assisting the diagnosis, monitoring and--in some cases--treatment of prostate cancer. Bone scintigraphy was the premier modality to have an extensive role in the staging of prostate cancer and has remained an integral tool for over three decades in the assessment of newly diagnosed disease or in follow-up staging. Therapeutic treatment and palliation of disseminated disease, particularly in the skeleton, has also been successful with several radioisotopes including strontium-89 chloride. Despite advances in nuclear medicine techniques and molecular imaging technology such as positron emission tomography and radioimmunoscintigraphy, bone scintigraphy still remains the gold standard in the assessment of osseous metastatic disease in prostate cancer. Thus, it is important to continually review the modalities that have remained important over time and not just to focus on newer technologies. This article summarizes the current diagnostic and therapeutic use of radioisotopes for bony disease in prostate cancer with particular reference to radionuclide bone scintigraphy and positron emission tomography.

Pharmacological management of metastatic boney pain

Many malignancies metastasise to the skeleton. This often results in a relatively unique pain process, which dramatically affects a patient's quality of life. With one in three members of the population likely to develop cancer at some stage in their lives, the prevalence of bone metastases is high. Despite the large financial investment on therapies for these patients, treatment is still suboptimal. In this article, the various treatments available are reviewed. Opiates and bisphosphonates, the mainstays in current practise, are covered in detail, and evolving therapies that may shape future management are also discussed.