Radiosensitizer-Releasing Fiducial 'Nanofiducial': A New Concept in Radiotherapy

PURPOSE/OBJECTIVE(S)

Fiducial is a material used in stereotactic radiotherapy (SRT). Additionally, radiosensitizing nanostructures are an interesting opportunity for improving RT clinical benefits. In this study, it was aimed to combine both technologies by designing and synthesizing a tailor-made 'nanofiducial' functionalized with a radiosensitizing nanoparticle.

MATERIALS/METHODS

AGuIX are sub-5 nm nanoparticles containing gadolinium (Z = 64) having both MRI contrast capability and radiosensitization effects. It was planned to embed the AGuIX nanoparticle in poly(lactic-co-glycolic acid) (PLGA) nanofiber mats. Nanofiber mats were prepared by electrospinning method. Imaging of the nanofiber structure was evaluated using Scanning Electron Microscopy (SEM). Detailed analyzes were carried out for porosity and mechanical strength measurements in addition to DSC and FTIR. EDS micrographs of fiber meshes were taken to show that AGuIX was loaded into nanofiber mats. The amount of AGuIX released from the nanofiber mats in PBS was quantified by inductively coupled plasma mass spectrometry (ICP-MS).

RESULTS

Nanofibers were produced in two different forms, one 'no AguIX' embedded and the other loaded with '5 % AguIX'. The nanofiber formulation was prepared using PLGA poly(lactic-co-glycolic acid) 50:50 polymer with a molecular weight of 38,000-54,000. A mixture of Tethrahydrofuran and Dimethylformamide was used as the polymer solvent. The mixing ratio of THF:DMF was 65:35 and the rate of PLGA was 25%. According to the SEM results, nanofibers were randomly aligned and the release of AGuIX was observed up to 12 hours after fiducial formation in pH 7.4 PBS buffer solution. Nanofiducials computed tomography images were taken and nanofiducials were viewed as hypointense area. Hounsfield Unit values for "no AGuIX" sample and "5% AGuIX containing sample" were as follows: average -62.5(max -16; STD 11.7); -87.2 (max -60; STD 8.7).

CONCLUSION

Radiosensitizing nanostructures are promising for increasing the effectiveness of radiotherapy in cancer treatment, achieving high dose effects at lower doses, and reducing side effects. In this study, a fiducial structure functionalized with an effective radiosensitizing nanoparticle was preliminary tested for local application.

The long-term impact of the Leprosy Post-Exposure Prophylaxis (LPEP) program on leprosy incidence: A modelling study

Background

The Leprosy Post-Exposure Prophylaxis (LPEP) program explored the feasibility and impact of contact tracing and the provision of single dose rifampicin (SDR) to eligible contacts of newly diagnosed leprosy patients in Brazil, India, Indonesia, Myanmar, Nepal, Sri Lanka and Tanzania. As the impact of the programme is difficult to establish in the short term, we apply mathematical modelling to predict its long-term impact on the leprosy incidence.

Methodology

The individual-based model SIMCOLEP was calibrated and validated to the historic leprosy incidence data in the study areas. For each area, we assessed two scenarios: 1) continuation of existing routine activities as in 2014; and 2) routine activities combined with LPEP starting in 2015. The number of contacts per index patient screened varied from 1 to 36 between areas. Projections were made until 2040.

Principal findings

In all areas, the LPEP program increased the number of detected cases in the first year(s) of the programme as compared to the routine programme, followed by a faster reduction afterwards with increasing benefit over time. LPEP could accelerate the reduction of the leprosy incidence by up to six years as compared to the routine programme. The impact of LPEP varied by area due to differences in the number of contacts per index patient included and differences in leprosy epidemiology and routine control programme.

Conclusions

The LPEP program contributes significantly to the reduction of the leprosy incidence and could potentially accelerate the interruption of transmission. It would be advisable to include contact tracing/screening and SDR in routine leprosy programmes.

The Leprosy Post-Exposure Prophylaxis (LPEP) program explored the feasibility and impact of contact tracing and the provision of SDR to eligible contacts of newly diagnosed leprosy patients in states or districts of Brazil, India, Indonesia, Myanmar, Nepal, Sri Lanka and Tanzania. This study investigated the long-term impact of the LPEP program on the leprosy new case detection rate (NCDR). Our results show that LPEP could reduce the NCDR beyond the impact of the routine leprosy control programme and that many new cases could be prevented. The benefit of LPEP increases gradually over time. LPEP could accelerate the time of reaching predicted NCDR levels of 2040 under routine program by up to six years. Furthermore, we highlighted how the impact varies between countries due to differences in the number of contacts per index patient screened and differences in leprosy epidemiology and national control programme. Generally, including both household contacts and neighbours (> 20 contacts per index patient) would yield the highest impact.

Effects of a School-Based Health Intervention Program in Marginalized Communities of Port Elizabeth, South Africa (the KaziBantu Study): Protocol for a Randomized Controlled Trial

BACKGROUND

The burden of poverty-related infectious diseases remains high in low- and middle-income countries, while noncommunicable diseases (NCDs) are rapidly gaining importance. To address this dual disease burden, the KaziBantu project aims at improving and promoting health literacy as a means for a healthy and active lifestyle. The project implements a school-based health intervention package consisting of physical education, moving-to-music, and specific health and nutrition education lessons from the KaziKidz toolkit. It is complemented by the KaziHealth workplace health intervention program for teachers.

OBJECTIVES

The aim of the KaziBantu project is to assess the effect of a school-based health intervention package on risk factors for NCDs, health behaviors, and psychosocial health in primary school children in disadvantaged communities in Port Elizabeth, South Africa. In addition, we aim to test a workplace health intervention for teachers.

METHODS

A randomized controlled trial (RCT) will be conducted in 8 schools. Approximately 1000 grade 4 to grade 6 school children, aged 9 to 13 years, and approximately 60 teachers will be recruited during a baseline survey in early 2019. For school children, the study is designed as a 36-week, cluster RCT (KaziKidz intervention), whereas for teachers, a 24-week intervention phase (KaziHealth intervention) is planned. The intervention program consists of 3 main components; namely, (1) KaziKidz and KaziHealth teaching material, (2) workshops, and (3) teacher coaches. After randomization, 4 of the 8 schools will receive the education program, whereas the other schools will serve as the control group. Intervention schools will be further randomized to the different combinations of 2 additional intervention components: teacher workshops and teacher coaching.

RESULTS

This study builds on previous experience and will generate new evidence on health intervention responses to NCD risk factors in school settings as a decision tool for future controlled studies that will enable comparisons among marginalized communities between South African and other African settings.

CONCLUSIONS

The KaziKidz teaching material is a holistic educational and instructional tool designed for primary school teachers in low-resource settings, which is in line with South Africa's Curriculum and Assessment Policy Statement. The ready-to-use lessons and assessments within KaziKidz should facilitate the use and implementation of the teaching material. Furthermore, the KaziHealth interventions should empower teachers to take care of their health through knowledge gains regarding disease risk factors, physical activity, fitness, psychosocial health, and nutrition indicators. Teachers as role models will be able to promote better health behaviors and encourage a healthy and active lifestyle for children at school. We conjecture that improved health and well-being increase teachers' productivity with trickle-down effects on the children they teach and train.

TRIAL REGISTRATION

International Standard Randomized Controlled Trial Number (ISRCTN): 18485542; http://www.isrctn.com/ISRCTN18485542.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/14097.

Evaluation of in vitro Assays to Assess the Modulation of Dendritic Cells Functions by Therapeutic Antibodies and Aggregates

Therapeutic antibodies have the potential to induce immunogenicity leading to the development of anti-drug antibodies (ADA) that consequently may result in reduced serum drug concentrations, a loss of efficacy or potential hypersensitivity reactions. Among other factors, aggregated antibodies have been suggested to promote immunogenicity, thus enhancing ADA production. Dendritic cells (DC) are the most efficient antigen-presenting cell population and are crucial for the initiation of T cell responses and the subsequent generation of an adaptive immune response. This work focuses on the development of predictive in vitro assays that can monitor DC maturation, in order to determine whether drug products have direct DC stimulatory capabilities. To this end, four independent laboratories aligned a common protocol to differentiate human monocyte-derived DC (moDC) that were treated with either native or aggregated preparations of infliximab, natalizumab, adalimumab, or rituximab. These drug products were subjected to different forms of physical stress, heat and shear, resulting in aggregation and the formation of subvisible particles. Each partner developed and optimized assays to monitor diverse end-points of moDC maturation: measuring the upregulation of DC activation markers via flow cytometry, analyzing cytokine, and chemokine production via mRNA and protein quantification and identifying cell signaling pathways via quantification of protein phosphorylation. These study results indicated that infliximab, with the highest propensity to form aggregates when heat-stressed, induced a marked activation of moDC as measured by an increase in CD83 and CD86 surface expression, IL-1β, IL-6, IL-8, IL-12, TNFα, CCL3, and CCL4 transcript upregulation and release of respective proteins, and phosphorylation of the intracellular signaling proteins Syk, ERK1/2, and Akt. In contrast, natalizumab, which does not aggregate under these stress conditions, induced no DC activation in any assay system, whereas adalimumab or rituximab aggregates induced only slight parameter variation. Importantly, the data generated in the different assay systems by each partner site correlated and supported the use of these assays to monitor drug-intrinsic propensities to drive maturation of DC. This moDC assay is also a valuable tool as an in vitro model to assess the intracellular mechanisms that drive DC activation by aggregated therapeutic proteins.

The Leprosy Post-Exposure Prophylaxis (LPEP) programme: update and interim analysis

Innovative approaches are required to further enhance leprosy control, reduce the number of people developing leprosy, and curb transmission. Early case detection, contact screening, and chemoprophylaxis currently is the most promising approach to achieve this goal. The Leprosy Post-Exposure Prophylaxis (LPEP) programme generates evidence on the feasibility of integrating contact tracing and single-dose rifampicin (SDR) administration into routine leprosy control activities in different settings. The LPEP programme is implemented within the leprosy control programmes of Brazil, Cambodia, India, Indonesia, Myanmar, Nepal, Sri Lanka and Tanzania. Focus is on three key interventions: tracing the contacts of newly diagnosed leprosy patients; screening the contacts for leprosy; and administering SDR to eligible contacts. Country-specific protocol adaptations refer to contact definition, minimal age for SDR, and staff involved. Central coordination, detailed documentation and rigorous supervision ensure quality evidence. Around 2 years of field work had been completed in seven countries by July 2017. The 5,941 enrolled index patients (89·4% of the registered) identified a total of 123,311 contacts, of which 99·1% were traced and screened. Among them, 406 new leprosy patients were identified (329/100,000), and 10,883 (8·9%) were excluded from SDR for various reasons. Also, 785 contacts (0·7%) refused the prophylactic treatment with SDR. Overall, SDR was administered to 89·0% of the listed contacts. Post-exposure prophylaxis with SDR is safe; can be integrated into the routines of different leprosy control programmes; and is generally well accepted by index patients, their contacts and the health workforce. The programme has also invigorated local leprosy control.

Study protocol for a cluster randomised controlled factorial design trial to assess the effectiveness and feasibility of reactive focal mass drug administration and vector control to reduce malaria transmission in the low endemic setting of Namibia

INTRODUCTION

To interrupt malaria transmission, strategies must target the parasite reservoir in both humans and mosquitos. Testing of community members linked to an index case, termed reactive case detection (RACD), is commonly implemented in low transmission areas, though its impact may be limited by the sensitivity of current diagnostics. Indoor residual spraying (IRS) before malaria season is a cornerstone of vector control efforts. Despite their implementation in Namibia, a country approaching elimination, these methods have been met with recent plateaus in transmission reduction. This study evaluates the effectiveness and feasibility of two new targeted strategies, reactive focal mass drug administration (rfMDA) and reactive focal vector control (RAVC) in Namibia.

METHODS AND ANALYSIS

This is an open-label cluster randomised controlled trial with 2×2 factorial design. The interventions include: rfMDA (presumptive treatment with artemether-lumefantrine (AL)) versus RACD (rapid diagnostic testing and treatment using AL) and RAVC (IRS with Acellic 300CS) versus no RAVC. Factorial design also enables comparison of the combined rfMDA+RAVC intervention to RACD. Participants living in 56 enumeration areas will be randomised to one of four arms: rfMDA, rfMDA+RAVC, RACD or RACD+RAVC. These interventions, triggered by index cases detected at health facilities, will be targeted to individuals residing within 500 m of an index. The primary outcome is cumulative incidence of locally acquired malaria detected at health facilities over 1 year. Secondary outcomes include seroprevalence, infection prevalence, intervention coverage, safety, acceptability, adherence, cost and cost-effectiveness.

ETHICS AND DISSEMINATION

Findings will be reported on clinicaltrials.gov, in peer-reviewed publications and through stakeholder meetings with MoHSS and community leaders in Namibia.

TRIAL REGISTRATION NUMBER

NCT02610400; Pre-results.

A whole blood in vitro cytokine release assay with aqueous monoclonal antibody presentation for the prediction of therapeutic protein induced cytokine release syndrome in humans

The administration of several monoclonal antibodies (mAbs) to humans has been associated with acute adverse events characterized by clinically significant release of cytokines in the blood. The limited predictive value of toxicology species in this field has triggered intensive research to establish human in vitro assays using peripheral blood mononuclear cells or blood to predict cytokine release in humans. A thorough characterization of these assays is required to understand their predictive value for hazard identification and risk assessment in an optimal manner, and to highlight potential limitations of individual assay formats. We have characterized a whole human blood cytokine release assay with only minimal dilution by the test antibodies (95% v/v blood) in aqueous presentation format, an assay which has so far received less attention in the scientific world with respect to the evaluation of its suitability to predict cytokine release in humans. This format was compared with a human PBMC assay with immobilized mAbs presentation already well-characterized by others. Cytokine secretion into plasma or cell culture supernatants after 24h incubation with the test mAbs (anti-CD28 superagonist TGN1412-like material (TGN1412L), another anti-CD28 superagonistic mAb (ANC28.1), a T-cell depleting mAb (Orthoclone™), and a TGN1412 isotype-matched control (Tysabri™) not associated with clinically-relevant cytokine release) was detected by a multiplex assay based on electrochemiluminescent excitation. We provide proof that this whole blood assay is a suitable new method for hazard identification of safety-relevant cytokine release in the clinic based on its ability to detect the typical cytokine signatures found in humans for the tested mAbs and on a markedly lower assay background and cytokine release with the isotype-matched control mAb Tysabri™ - a clear advantage over the PBMC assay. Importantly, quantitative and qualitative differences in the relative cytokine responses to the individual mAbs, in the concentration-response relationships and the prominent cytokine signatures for individual mAbs in the two formats reflect diverging mechanisms of cytokine release and different levels of dependency on high density coating even for two anti-CD28 super-agonistic antibodies. These results clearly show that one generic approach to assessment of cytokine release using in vitro assays is not sufficient, but rather the choice of the method, i.e. applying the whole blood assay or the PBMC assay needs to be well considered depending on the target characteristics and the mechanistic features of the therapeutic mAbs being evaluated.