Research autopsy programmes in oncology: shared experience from 14 centres across the world.

While there is a great clinical need to understand the biology of metastatic cancer in order to treat it more effectively, research is hampered by limited sample availability. Research autopsy programmes can crucially advance the field through synchronous, extensive, and high-volume sample collection. However, it remains an underused strategy in translational research. Via an extensive questionnaire, we collected information on the study design, enrolment strategy, study conduct, sample and data management, and challenges and opportunities of research autopsy programmes in oncology worldwide. Fourteen programmes participated in this study. Eight programmes operated 24 h/7 days, resulting in a lower median postmortem interval (time between death and start of the autopsy, 4 h) compared with those operating during working hours (9 h). Most programmes (n = 10) succeeded in collecting all samples within a median of 12 h after death. A large number of tumour sites were sampled during each autopsy (median 15.5 per patient). The median number of samples collected per patient was 58, including different processing methods for tumour samples but also non-tumour tissues and liquid biopsies. Unique biological insights derived from these samples included metastatic progression, treatment resistance, disease heterogeneity, tumour dormancy, interactions with the tumour micro-environment, and tumour representation in liquid biopsies. Tumour patient-derived xenograft (PDX) or organoid (PDO) models were additionally established, allowing for drug discovery and treatment sensitivity assays. Apart from the opportunities and achievements, we also present the challenges related with postmortem sample collections and strategies to overcome them, based on the shared experience of these 14 programmes. Through this work, we hope to increase the transparency of postmortem tissue donation, to encourage and aid the creation of new programmes, and to foster collaborations on these unique sample collections. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

WCRC-25: A novel luminal Invasive Lobular Carcinoma cell line model.

Breast cancer is categorized by the molecular and histologic presentation of the tumor, with the major histologic subtypes being No Special Type (NST) and Invasive Lobular Carcinoma (ILC). ILC are characterized by growth in a single file discohesive manner with stromal infiltration attributed to their hallmark pathognomonic loss of E-cadherin ( CDH1 ). Few ILC cell line models are available to researchers. Here we report the successful establishment and characterization of a novel ILC cell line, WCRC-25, from a metastatic pleural effusion from a postmenopausal Caucasian woman with metastatic ILC. WCRC-25 is an ER-negative luminal epithelial ILC cell line with both luminal and Her2-like features. It exhibits anchorage independent growth and haptotactic migration towards Collagen I. Sequencing revealed a CDH1 Q706* truncating mutation, together with mutations in FOXA1, CTCF, BRCA2 and TP53 , which were also seen in a series of metastatic lesions from the patient. Copy number analyses revealed amplification and deletion of genes frequently altered in ILC while optical genome mapping revealed novel structural rearrangements. RNA-seq analysis comparing the primary tumor, metastases and the cell line revealed signatures for cell cycle progression and receptor tyrosine kinase signaling. To assess targetability, we treated WCRC-25 with AZD5363 and Alpelisib confirming WCRC-25 as susceptible to PI3K/AKT signaling inhibition as predicted by our RNA sequencing analysis. In conclusion, we report WCRC-25 as a novel ILC cell line with promise as a valuable research tool to advance our understanding of ILC and its therapeutic vulnerabilities. Financial support: The work was in part supported by a Susan G Komen Leadership Grant to SO (SAC160073) and NCI R01 CA252378 (SO/AVL). AVL and SO are Komen Scholars, Hillman Foundation Fellows and supported by BCRF. This project used the UPMC Hillman Cancer Center and Tissue and Research Pathology/Pitt Biospecimen Core shared resource which is supported in part by award P30CA047904. This research was also supported in part by the University of Pittsburgh Center for Research Computing, RRID:SCR_022735, through the resources provided. Specifically, this work used the HTC cluster, which is supported by NIH award number S10OD028483. Finally, partial support was provided by the Magee-Womens Research Institute and Foundation, The Shear Family Foundation, and The Metastatic Breast Cancer Network.

Static Aerated Composting of African Swine Fever Virus-Infected Swine Carcasses with Rice Hulls and Sawdust.

Identifying and ensuring the inactivation of the African Swine Fever virus in deadstock is a gap in the swine industry's knowledge and response capabilities. The results of our study demonstrate that ASFv in deadstock was inactivated using static aerated composting as the carcass disposal method. Replicated compost piles with whole market hogs and two different carbon sources were constructed. In-situ bags containing ASFv-infected spleen tissue were placed alongside each of the carcasses and throughout the pile. The bags were extracted at days 0, 1, 3, 7, 14, 28, 56, and 144 for ASFv detection and isolation. Real-time PCR results showed that DNA of ASFv was detected in all samples tested on day 28. The virus concentration identified through virus isolation was found to be below the detection limit by day 3 in rice hulls and by day 7 in sawdust. Given the slope of the decay, near-zero concentration with 99.9% confidence occurred at 5.0 days in rice hulls and at 6.4 days in sawdust. Additionally, the result of virus isolation also showed that the virus in bone marrow samples collected at 28 days was inactivated.

Masibambane-Ladies Chat: Developing an Online Gender-Enhanced PrEP Information-Motivation Workshop for Young South African Women.

This article describes the processes of transforming an in-person group-based intervention to promote uptake of PrEP among young woman in South Africa to an online interactive "workshop" during the COVID-19 pandemic. Beginning in person and continuing virtually, we used a step-by-step participatory approach with multiple stakeholder groups to develop nine activities to increase knowledge about, as well as motivation and intention to take PrEP, and to address gender-based barriers to PrEP. Activities were informed by our theoretical framework and formative work with young women ages 18-25. We demonstrate how we developed a gender-enhanced online PrEP workshop that was interactive, group-based, and in accordance with elements of established successful intervention design; why WhatsApp emerged as the most accessible application for the young women in our workshop; and how an intervention with a hybrid approach-alternating between chat box and live sessions-combined with verbal, written, and emoji-based communication enabled interaction among participants.

Connecting Future Environmental Trends and Assessments of Fish and Wildlife Resources of Concern: A Case Study of Big Pine Key, Florida.

Changes in hydrologic and climatic trends will influence the ecology of Florida, and climate scenarios agree that many areas of Florida are susceptible to sea-level rise impacts. The U.S. Fish and Wildlife Service's Climate Change Action Program focuses on a framework to examine climate change effects on fish, wildlife, plants, and habitats of all three. To follow the program, this study examines how to incorporate current scientific knowledge about regional climate projections in U.S. Fish and Wildlife Service analyses. It provides climate change and sea-level rise projections based on 2017 projections, information on changes in tropical cyclones, temperatures, and precipitation. This study also examines future effects of sea-level rise on existing habitat from saltwater intrusion of the freshwater lens below Big Pine Key. Projections of future sea-water elevations will periodically be reached or exceeded well before 2040 from short-term, stochastic, and extreme events (e.g., king tides and storm surge), and will increasingly inundate the root zone before complete saltwater intrusion. Future trends were connected to 2017 stakeholder-driven conversations about adaptation strategies to develop a suite of actions for creating temporary or permanent freshwater resources. However, beyond 3 ft (0.9 m) of sea-level rise, there are few adaptation options available for the Florida Key deer beyond relocations outside of the Florida Keys. Overall, the approach of connecting future environmental trends to assessments of fish and wildlife resources of concern can be transferred to other situations. Additionally, this approach can be used to update these analyses, such as with the recent 2022 sea-level rise updates by the National Oceanic and Atmospheric Administration, released after this work was conducted.

Hidden heterogeneity: Uncovering patterns of adherence in microbicide trials for HIV prevention.

BACKGROUND: Interpretation of clinical trial results testing vaginal microbicide gels for HIV prevention depends on participant adherence. Prior to the era of antiretrovirals, microbicide trials collected adherence data via self-report, and trials typically reported trial population adherence as overall averages in primary results manuscripts. This study first sought to determine if different patterns of adherence from three trials of vaginal microbicide gels could be identified, using self-reported data and if so, how those patterns compare across trials. The second objective was to explore which individual-level factors were associated with different adherence patterns. METHODS: Data from the following three clinical trials of vaginal microbicides were used for this study: HIV Prevention Trials Network (HPTN) 035 testing PRO 2000 and Buffergel, the Microbicides Development Programme (MDP) 301 testing PRO 2000, and the Population Council's Carraguard study, testing Carraguard gel. Latent Class Analysis (LCA) was used to identify longitudinal patterns of adherence using self-reported data about gel use. Multinomial multivariable logistic regression was used to estimate relative risk-ratios for factors which were independently associated with different latent adherence trajectories within each trial, and compared across trials. RESULTS: Included in this analysis are 2,282 women from HPTN 035 (age 17-56 years), 6238 women from MDP 301 (age 16-75 years), and 6039 women from Carraguard (age 16-73 years). Using LCA, 3-4 different patterns of gel adherence were identified in each trial; these patterns were similar across the trials. Factors associated with adherence patterns were identified in all trials. Older age was associated with the adherence trajectory that consistently reported gel use in three trials. Participant-reported negative reaction of partners to the gel was associated with trajectories that reported less consistent adherence in two trials. A greater number of baseline-reported sex partners or sex acts was associated with trajectories which reported less consistent adherence in some trials. Trial site location was associated with membership of trajectories in all trials. CONCLUSION: LCA was able to identify patterns of microbicide gel adherence in clinical trials that used self-reported data. Key factors associated with patterns of adherence in this study were participant age, clinical trial site location, and partner reaction to the study gel. These findings, in particular, age and perceived partner reaction to the method, are consistent with results from other clinical trials and programmatic rollout of biomedical HIV prevention methods for women in Africa. This study contributes to the body of evidence that women need more support to navigate power dynamics within their relationships with men so that they can successfully use HIV prevention methods.

ESR1 mutant breast cancers show elevated basal cytokeratins and immune activation.

Estrogen receptor alpha (ER/ESR1) is frequently mutated in endocrine resistant ER-positive (ER+) breast cancer and linked to ligand-independent growth and metastasis. Despite the distinct clinical features of ESR1 mutations, their role in intrinsic subtype switching remains largely unknown. Here we find that ESR1 mutant cells and clinical samples show a significant enrichment of basal subtype markers, and six basal cytokeratins (BCKs) are the most enriched genes. Induction of BCKs is independent of ER binding and instead associated with chromatin reprogramming centered around a progesterone receptor-orchestrated insulated neighborhood. BCK-high ER+ primary breast tumors exhibit a number of enriched immune pathways, shared with ESR1 mutant tumors. S100A8 and S100A9 are among the most induced immune mediators and involve in tumor-stroma paracrine crosstalk inferred by single-cell RNA-seq from metastatic tumors. Collectively, these observations demonstrate that ESR1 mutant tumors gain basal features associated with increased immune activation, encouraging additional studies of immune therapeutic vulnerabilities.

"You tell him that 'baby, I am protecting myself'": Women's agency and constraint around willingness to use pre-exposure prophylaxis in the Masibambane Study.

OBJECTIVES: To explore women's willingness to consider using pre-exposure prophylaxis for HIV prevention in the context of gendered relationship dynamics, in Durban, South Africa. METHODS: As formative research prior to development of a gender-informed intervention to introduce pre-exposure prophylaxis to young, urban, educated women, we conducted six focus-group discussions and eight in-depth interviews with 46 women ages 18-25 years, who were not current pre-exposure prophylaxis users. Women were recruited from clinic and community settings using a criterion-based snowball sampling technique. Qualitative data were coded and analyzed thematically, with a team-based consensus approach for final coding, analytical decisions, and data interpretation. RESULTS: Women clearly understood the benefits of pre-exposure prophylaxis for themselves and their partners, focusing on promoting health and their right to protect themselves from HIV infection. At the same time, and in accordance with findings from other studies, women were realistic about the concerns that would arise among male partners, including disapproval, loss of trust, possible loss of the relationship, and in some instances, the potential for violence, if they were to propose pre-exposure prophylaxis use. To resolve this tension, some women advocated for covert use as the best option for themselves and others argued for disclosure, proposing various approaches to working with partners to adopt pre-exposure prophylaxis. The suggestion that both partners use pre-exposure prophylaxis was made repeatedly. Thus, women sought to avoid discussions of trust or lack of trust and a partner's possible infidelities, choosing instead to focus on preserving or even building a relationship through suggesting pre-exposure prophylaxis use. CONCLUSION: Women offered diverse narratives on agency and constraint in relation to choosing pre-exposure prophylaxis as a future prevention strategy, as well as ways to engage with their male partners about pre-exposure prophylaxis. These findings speak to the need for interventions to bolster women's confidence, sense of empowerment, and their communication and decision-making skills for successful HIV prevention.

Virus viability in spiked swine bone marrow tissue during above-ground burial method and under in vitro conditions.

The emergence of high consequence animal diseases usually requires managing significant mortality. A desirable aspect of any carcass management method is the ability to contain and inactivate the target pathogen. The above-ground burial (AGB) technique was recently developed and proposed as an alternative carcass management method. Here, we investigate the tenacity of swinepox virus (SwPV), as a surrogate model for African swine fever virus (ASFV) in swine carcasses during the AGB process. For this, SwPV was inoculated intrafemorally in 90 adult swine carcasses, which were subsequently disposed under AGB conditions. Bone marrow samples were recovered periodically throughout 12 months and virus viability was assessed by virus isolation (VI), whereas the presence of SwPV DNA was evaluated by quantitative polymerase chain reaction (qPCR). Additionally, an in vitro study assessed the inactivation rate of SwPV, Senecavirus A (SVA), and bovine viral diarrhoea virus (BVDV). Viral suspensions were mixed with bone marrow material and maintained at 21-23°C for 30 days. Virus viability was assessed by VI and viral titration. In the field study, SwPV remained viable only in 11 (55%) bone marrow samples collected on day 7; only viral DNA (and not infectivity) was detected afterwards. SwPV inactivation was estimated to have occurred by day 11. The in vitro testing revealed a variable tenacity of the studied viruses. The viability period was estimated in 28, 80, and 118 days, respectively, for BVDV, SwPV, and SVA. Overall, these findings indicate that the AGB technique was effective in quickly inactivating SwPV. Additionally, the SwPV inactivation rate is comparable to ASFV under field studies and poses a potential model for preliminary ASFV inactivation studies with reduced biosecurity requirements. Moreover, this study contributes to understanding the inactivation kinetics of viruses under specific conditions, which is critical when designing and applying countermeasures in case of biosecurity breaches in sites managing animal mortality.

The Development and Implementation of an Autopsy/ Tissue Donation for Breast Cancer Research.

There is growing interest in tissue procurement for cancer research through autopsy. Establishing an autopsy/tissue donation programme for breast cancer research within an academic medical centre in the United States requires consideration, planning, multi-departmental collaboration and labour-intensive maintenance. It is the purpose of this paper to outline the necessary considerations in implementing and maintaining a tissue donation and autopsy programme within a breast cancer centre at a comprehensive cancer centre. Considerations of programme planning include: patient engagement, the recruitment of patients and families into the programme, the role and scope of work of the clinical coordinator, regulatory issues and the coordination with both pathology and the research team at time of death and autopsy/tissue donation. All aspects of the tissue donation/rapid autopsy programme development and implementation are discussed and illustrated through case study. An Autopsy/ Tissue Donation for breast cancer research can be successfully developed and implemented.

Biobanking: How Oncology Nurses Can Contribute to Its Use.

Biobanking is one of the most valuable tools in precision medicine. The ability of scientists to sequence tumors, blood, and normal tissue obtained from biorepositories has defined efficacious tumor targeting and a much better understanding of cancer pathology pathways. However, these biorepositories require a great deal of effort to establish and maintain. Oncology nurses are key in helping to bank tissue during routine procedures as well as complex surgeries. Nurses can obtain informed consent from patients and coordinate the banking of samples in a timely manner to ensure sample quality. Oncology nurses play an important role in informing patients of their biobanking options and connecting patients with the appropriate team for their biobanking needs.

What Is the Burden of Heterosexually Acquired HIV Due to HSV-2? Global and Regional Model-Based Estimates of the Proportion and Number of HIV Infections Attributable to HSV-2 Infection.

BACKGROUND: Biological and epidemiological evidence suggest that herpes simplex virus type 2 (HSV-2) elevates HIV acquisition and transmission risks. We improved previous estimates of the contribution of HSV-2 to HIV infections by using a dynamic transmission model. SETTING: World Health Organization regions. METHODS: We developed a mathematical model of HSV-2/HIV transmission among 15- to 49-year-old heterosexual, non-drug-injecting populations, calibrated using region-specific demographic and HSV-2/HIV epidemiological data. We derived global and regional estimates of the contribution of HSV-2 to HIV infection over 10 years [the transmission population-attributable fraction (tPAF)] under 3 additive scenarios, assuming: (1) HSV-2 increases only HIV acquisition risk (conservative); (2) HSV-2 also increases HIV transmission risk (liberal); and (3) HIV or antiretroviral therapy (ART) also modifies HSV-2 transmission risk, and HSV-2 decreases ART effect on HIV transmission risk (fully liberal). RESULTS: Under the conservative scenario, the predicted tPAF was 37.3% (95% uncertainty interval: 33.4%-43.2%), and an estimated 5.6 (4.5-7.0) million incident heterosexual HIV infections were due to HSV-2 globally over 2009-2018. The contribution of HSV-2 to HIV infections was largest for the African region [tPAF = 42.6% (38.0%-51.2%)] and lowest for the European region [tPAF = 11.2% (7.9%-13.8%)]. The tPAF was higher among female sex workers, their clients, and older populations, reflecting their higher HSV-2 prevalence. The tPAF was approximately 50% and 1.3- to 2.4-fold higher for the liberal or fully liberal scenario than the conservative scenario across regions. CONCLUSION: HSV-2 may have contributed to at least 37% of incident HIV infections in the past decade worldwide, and even more in Africa, and may continue to do so despite increased ART access unless future improved HSV-2 control measures, such as vaccines, become available.

Women design their own vaginal microbicide trial: Suggestions on how to improve adherence from former participants of HIV prevention trials.

Low adherence in vaginal microbicide clinical trials for HIV prevention has impeded interpretation of trial results and hindered evaluation of potentially efficacious HIV prevention gels. Understanding the underlying reasons why women join trials and their barriers to product use can support identification of ways to improve adherence and its reporting. Eight focus group discussion workshops were conducted with 46 former microbicide trial participants in Durban, South Africa and Mwanza, Tanzania. Participants provided feedback on why women join trials, the barriers to using study gel and reporting adherence accurately, and how clinical trial design can be improved to support better adherence and its reporting. Women join microbicide trials for a number of important reasons such as healthcare and financial reimbursement. Fear of adverse effects from the investigational product was the most important reason why participants reported not using the gel. The key reason for inaccurate reporting of gel use was fear of removal from the trial. Participants made concrete suggestions for improving microbicide trial design such as applicator use testing and real time feedback, improving education to participants about how trials answer their research questions, and improving transparency and clarity about study procedures. Participants also gave feedback on an innovative trial design with a non-randomised arm. Identifying HIV prevention products for women requires better understanding of the lives of women asked to join these trials, and application of that understanding to microbicide trial design. This study has demonstrated that participants and research teams can work collaboratively to design clinical trials that meet needs of both the research and of participants.

Prevention, Partners, and Power Imbalances: Women's Views on How Male Partners Affected Their Adherence to Vaginal Microbicide Gels During HIV Prevention Trials in Africa.

BACKGROUND: Low adherence has contributed to disappointing results for trials testing vaginal microbicides for HIV prevention. This study engaged former gel trial participants to understand the reasons behind low adherence and seek suggestions on how to improve products and adherence to microbicides. This analysis examines the impact of participant perceptions of male partners on participant adherence and suggestions on how to address those issues. METHODS: Eight focus group discussion workshops were conducted with 46 former microbicide trial participants in South Africa and Tanzania. Participants provided feedback on why women join trials, barriers to using gels and reporting adherence accurately, and how adherence and adherence reporting can be improved. RESULTS: Participants reported that male partners can affect women's ability to use gels. For some, the lubricating effects caused relationship conflicts due to suspicion of male partners about infidelity. Needing to provide sex to partners on demand was a barrier to gel use. Participants suggested a gel formulation which was thicker and less noticeable, and explicit male partner engagement to enhance understanding of the purpose of the gels. CONCLUSIONS: The imbalance of power in intimate relationships affects the ability of women to use microbicides as directed. To improve adherence to HIV prevention methods within trials and for successful rollout of proven HIV prevention methods in populations, it is important that the complicated dynamics of sex and relationships be taken into greater consideration and that women receive targeted support to navigate product use and communication within the context of these gender dynamics.

The WOMAN trial: clinical and contextual factors surrounding the deaths of 483 women following post-partum haemorrhage in developing countries.

BACKGROUND: Post-partum haemorrhage (PPH) is a leading cause of maternal death worldwide. The WOMAN trial assessed the effects of tranexamic acid (TXA) on death and surgical morbidity in women with PPH. The trial recorded 483 maternal deaths. We report the circumstances of the women who died. METHODS: The WOMAN trial recruited 20,060 women with a clinical diagnosis of PPH after a vaginal birth or caesarean section. We randomly allocated women to receive TXA or placebo. When a woman died, we asked participating clinicians to report the cause of death and to provide a short narrative of the events surrounding the death. We collated and edited for clarity the narrative data. RESULTS: Case fatality rates were 3.0% in Africa and 1.7% in Asia. Nearly three quarters of deaths were within 3 h of delivery and 91% of these deaths were from bleeding. Women who delivered outside a participating hospital (12%) were three times more likely to die (OR = 3.12, 95%CI 2.55-3.81) than those who delivered in hospital. Blood was often unavailable due to shortages or because relatives could not afford to buy it. Clinicians highlighted late presentation, maternal anaemia and poor infrastructure as key contributory factors. CONCLUSIONS: Although TXA use reduces bleeding deaths by almost one third, mortality rates similar to those in high income countries will not be achieved without tackling late presentation, maternal anaemia, availability of blood for transfusion and poor infrastructure.

Opportunities in the integration of primary care and public health nursing: Two case exemplars on physical activity and nutrition.

OBJECTIVE: The integration of primary care and public health nursing may provide new opportunities for transforming nursing practice that addresses population health. Effective programs emphasize multilevel approaches that include both downstream (education) and upstream (policy change) actions. The purpose of this article is to identify downstream and upstream nursing actions that integrate public health and primary care practice through two case exemplars concerning disparities in physical activity and nutrition. METHODS: Describe two research case exemplars: (1) a secondary analysis of school physical activity policy for female adolescents in 36 public middle schools and (2) a focus group study of African American adults in a community kitchen program. RESULTS: In exemplar 1, school policies lacked population-based standards and presented structural disadvantages to African American girls who were already obese. In exemplar 2, participants found the community kitchen program to be more effective than the federally funded nutrition program. DISCUSSION: Integrating primary care and public health nursing could improve the tailoring of physical activity and nutrition programs to local populations by following core principles of community engagement, infrastructural sustainability, aligned leadership, and data sharing for population health improvement.

False positive diagnosis of malingering due to the use of multiple effort tests.

OBJECTIVE: Effort indicators are used to determine if neuropsychological test results are valid measures of a patient's cognitive abilities. The use of multiple effort measures is often advocated, but the false positive rate for multiple indicators depends on the number of measures used and the correlation among indicators. This study presents a meta-analysis of correlations among effort measures. False positive rates for multiple correlated indicators are then estimated using Monte Carlo simulations. METHODS: a literature search of published studies identified 22 independent samples in which 407 correlations among 31 effort measures were available in 3564 participants with normal effort. Participants were patients with neurological or psychiatric disorders and healthy volunteers. RESULTS: Meta-analysis showed a mean correlation among effort indicators of 0.31. Monte Carlo simulation based on a 15% false positive rate for individual indicators showed that, when 10 effort indicators are used together, 38% of patients with valid performance will be incorrectly identified as malingering if two failures is the diagnostic standard. Failure on five of 10 measures is required for a false positive rate of 10% or less. If five effort indicators are interpreted, a false positive rate of 19% results when two test failures are assumed to characterize poor effort and failure on three measures is required to maintain 90% specificity. CONCLUSIONS: False positive rates for effort tests increase significantly as the number of indicators that are administered is increased.

Results from tandem Phase 1 studies evaluating the safety, reactogenicity and immunogenicity of the vaccine candidate antigen Plasmodium falciparum FVO merozoite surface protein-1 (MSP1(42)) administered intramuscularly with adjuvant system AS01.

BACKGROUND: The development of an asexual blood stage vaccine against Plasmodium falciparum malaria based on the major merozoite surface protein-1 (MSP1) antigen is founded on the protective efficacy observed in preclinical studies and induction of invasion and growth inhibitory antibody responses. The 42 kDa C-terminus of MSP1 has been developed as the recombinant protein vaccine antigen, and the 3D7 allotype, formulated with the Adjuvant System AS02A, has been evaluated extensively in human clinical trials. In preclinical rabbit studies, the FVO allele of MSP142 has been shown to have improved immunogenicity over the 3D7 allele, in terms of antibody titres as well as growth inhibitory activity of antibodies against both the heterologous 3D7 and homologous FVO parasites. METHODS: Two Phase 1 clinical studies were conducted to examine the safety, reactogenicity and immunogenicity of the FVO allele of MSP142 in the adjuvant system AS01 administered intramuscularly at 0-, 1-, and 2-months: one in the USA and, after evaluation of safety data results, one in Western Kenya. The US study was an open-label, dose escalation study of 10 and 50 µg doses of MSP142 in 26 adults, while the Kenya study, evaluating 30 volunteers, was a double-blind, randomized study of only the 50 µg dose with a rabies vaccine comparator. RESULTS: In these studies it was demonstrated that this vaccine formulation has an acceptable safety profile and is immunogenic in malaria-naïve and malaria-experienced populations. High titres of anti-MSP1 antibodies were induced in both study populations, although there was a limited number of volunteers whose serum demonstrated significant inhibition of blood-stage parasites as measured by growth inhibition assay. In the US volunteers, the antibodies generated exhibited better cross-reactivity to heterologous MSP1 alleles than a MSP1-based vaccine (3D7 allele) previously tested at both study sites. CONCLUSIONS: Given that the primary effector mechanism for blood stage vaccine targets is humoral, the antibody responses demonstrated to this vaccine candidate, both quantitative (total antibody titres) and qualitative (functional antibodies inhibiting parasite growth) warrant further consideration of its application in endemic settings. TRIAL REGISTRATIONS: Clinical Trials NCT00666380.

Prolonged protection provided by a single dose of atovaquone-proguanil for the chemoprophylaxis of Plasmodium falciparum malaria in a human challenge model.

BACKGROUND: We conducted a randomized, placebo-controlled, double-blind trial to establish the efficacy of atovaquone-proguanil to prevent malaria with the goal of simulating weekly dosing in a human Plasmodium falciparum challenge model. METHODS: Thirty volunteers randomly received 1 of the following dose regimens: (1) 250 milligrams of atovaquone and 100 milligrams of proguanil (250/100 milligrams) 1 day prior to infectious mosquito challenge (day -1), (2) 250/100 milligrams on day 4 after challenge, (3) 250/100 milligrams on day -7, (4) 500 milligrams of atovaquone and 200 milligrams of proguanil (500/200 milligrams) on day -7 or, (5) 1000 milligrams of atovaquone and 400 milligrams of proguanil (1000/400 milligrams) on day -7. All regimens included matching placebo such that all volunteers received identical pill numbers. Six volunteers served as open-label infectivity controls. Volunteers underwent mosquito sporozoite challenge with P. falciparum 3D7 strain. Follow-up consisted of serial microscopy and close clinical monitoring for 90 days. RESULTS: Six of 6 infectivity controls developed parasitemia as expected. Two of 5 evaluable volunteers receiving 250/100 milligrams 7 days prior to challenge and 1 of 6 volunteers receiving 1000/400 milligrams 7 days prior to challenge were microscopically diagnosed with malaria. All other volunteers were protected. Atovaquone exposure (area under the curve) during liver stage development was low in 2 of 3 volunteers with prophylactic failure (423 and 199 ng/mL × days compared with a mean for protected volunteers of 1903 ng/mL × days), as was peak concentration (165 and 81 ng/mL compared with a mean of 594 ng/mL in volunteers with prophylactic success). Elimination half-life was short in volunteers with prophylactic failure (2.4, 2.0, and 3.3 days compared with a mean of 4.1 days in volunteers with prophylactic success). CONCLUSIONS: Single-dose atovaquone-proguanil provides effective malaria chemoprophylaxis against P. falciparum challenge at dosing intervals supportive of weekly dosing. Postexposure prophylaxis 4 days after challenge was 100% effective.

Plasmodium falciparum infection during suppressive prophylaxis with mefloquine does not induce an antibody response to merozoite surface protein-1(42).

A sensitive biomarker of malaria infection would obviate the need for placebo control arms in clinical trials of malaria prophylactic drugs. Antibodies to the 42-kDa fragment of merozoite surface protein-1 (MSP1(42)) have been identified as a potential marker of malaria exposure in individuals receiving prophylaxis with mefloquine. We conducted an open-label trial to determine the sensitivity of seroconversion to MSP1(42), defined as a fourfold rise in enzyme-linked immunosorbant assay (ELISA) titer, among 23 malaria naïve volunteers receiving mefloquine prophylaxis and 6 controls after Plasmodium falciparum sporozoite challenge. All members of the control cohort but none of the mefloquine cohort developed patent parasitemia. Four of six controls but zero of the mefloquine cohort seroconverted to MSP1(42). We conclude that malaria infection during suppressive prophylaxis does not induce antibody response to the blood-stage antigen MSP1(42) in a malaria-naïve study population.