Safety and Immunogenicity of ChAd63/MVA Pfs25-IMX313 in a Phase I First-in-Human Trial.

BACKGROUND: Transmission blocking vaccines targeting the sexual-stages of the malaria parasite could play a major role to achieve elimination and eradication of malaria. The Plasmodium falciparum Pfs25 protein (Pfs25) is the most clinically advanced candidate sexual-stage antigen. IMX313, a complement inhibitor C4b-binding protein that forms heptamers with the antigen fused to it, improve antibody responses. This is the first time that viral vectors have been used to induce antibodies in humans against an antigen that is expressed only in the mosquito vector. METHODS: Clinical trial looking at safety and immunogenicity of two recombinant viral vectored vaccines encoding Pfs25-IMX313 in healthy malaria-naive adults. Replication-deficient chimpanzee adenovirus serotype 63 (ChAd63) and the attenuated orthopoxvirus modified vaccinia virus Ankara (MVA), encoding Pfs25-IMX313, were delivered by the intramuscular route in a heterologous prime-boost regimen using an 8-week interval. Safety data and samples for immunogenicity assays were taken at various time-points. RESULTS: The reactogenicity of the vaccines was similar to that seen in previous trials using the same viral vectors encoding other antigens. The vaccines were immunogenic and induced both antibody and T cell responses against Pfs25, but significant transmission reducing activity (TRA) was not observed in most volunteers by standard membrane feeding assay. CONCLUSION: Both vaccines were well tolerated and demonstrated a favorable safety profile in malaria-naive adults. However, the transmission reducing activity of the antibodies generated were weak, suggesting the need for an alternative vaccine formulation. TRIAL REGISTRATION: Clinicaltrials.gov NCT02532049

Human vaccination against RH5 induces neutralizing antimalarial antibodies that inhibit RH5 invasion complex interactions.

The development of a highly effective vaccine remains a key strategic goal to aid the control and eventual eradication of Plasmodium falciparum malaria. In recent years, the reticulocyte-binding protein homolog 5 (RH5) has emerged as the most promising blood-stage P. falciparum candidate antigen to date, capable of conferring protection against stringent challenge in Aotus monkeys. We report on the first clinical trial to our knowledge to assess the RH5 antigen - a dose-escalation phase Ia study in 24 healthy, malaria-naive adult volunteers. We utilized established viral vectors, the replication-deficient chimpanzee adenovirus serotype 63 (ChAd63), and the attenuated orthopoxvirus modified vaccinia virus Ankara (MVA), encoding RH5 from the 3D7 clone of P. falciparum. Vaccines were administered i.m. in a heterologous prime-boost regimen using an 8-week interval and were well tolerated. Vaccine-induced anti-RH5 serum antibodies exhibited cross-strain functional growth inhibition activity (GIA) in vitro, targeted linear and conformational epitopes within RH5, and inhibited key interactions within the RH5 invasion complex. This is the first time to our knowledge that substantial RH5-specific responses have been induced by immunization in humans, with levels greatly exceeding the serum antibody responses observed in African adults following years of natural malaria exposure. These data support the progression of RH5-based vaccines to human efficacy testing

Phase I studies: the role of publicly funded academic-healthcare partnerships

Emanuel and colleagues’ meta-analysis found that phase I studies are very safe.1 However, the accompanying editorial mentioned that phase I studies are a “secret realm” and that “most studies are conducted outside academic medical centres at private facilities run by pharmaceutical companies or contract research organisations.”2After a major safety problem at a commercial phase I facility in 2006,3 the UK Medicines and Healthcare products Regulatory Agency (MHRA) introduced an accreditation scheme to enhance phase I safety standards in the UK. There are now four publicly funded phase I accredited clinical research facilities in the UK that have been open to non-commercial facilities since 2013. These include one university-hospital partnership (the Southampton National Institute for Health Research (NIHR) Wellcome Trust Clinical Research Facility) funded by the National Institute for Health Research. This provides an environment for early phase studies within the heart of an acute NHS hospital along with academic input from local university investigators. Phase I studies in patient populations and healthy volunteers are a crucial part of drug development. The UK Department of Health NIHR experimental medicine infrastructure has created a setting that delivers industry and publicly funded phase I trials while allowing recruitment from the entire UK population.<br/

Risk factors for persistent abnormality on chest radiographs at 12-weeks post hospitalisation with PCR confirmed COVID-19

Background: The long-term consequences of COVID-19 remain unclear. There is concern a proportion of patients will progress to develop pulmonary fibrosis. We aimed to assess the temporal change in CXR infiltrates in a cohort of patients following hospitalisation for COVID-19. Methods: We conducted a single-centre prospective cohort study of patients admitted to University Hospital Southampton with confirmed SARS-CoV2 infection between 20th March and 3rd June 2020. Patients were approached for standard-of-care follow-up 12-weeks after hospitalisation. Inpatient and follow-up CXRs were scored by the assessing clinician for extent of pulmonary infiltrates; 0–4 per lung (Nil = 0, &lt; 25% = 1, 25–50% = 2, 51–75% = 3, &gt; 75% = 4). Results: 101 patients with paired CXRs were included. Demographics: 53% male with a median (IQR) age 53.0 (45–63) years and length of stay 9 (5–17.5) days. The median CXR follow-up interval was 82 (77–86) days with median baseline and follow-up CXR scores of 4.0 (3–5) and 0.0 (0–1) respectively. 32% of patients had persistent CXR abnormality at 12-weeks. In multivariate analysis length of stay (LOS), smoking-status and obesity were identified as independent risk factors for persistent CXR abnormality. Serum LDH was significantly higher at baseline and at follow-up in patients with CXR abnormalities compared to those with resolution. A 5-point composite risk score (1-point each; LOS ≥ 15 days, Level 2/3 admission, LDH &gt; 750 U/L, obesity and smoking-status) strongly predicted risk of persistent radiograph abnormality (0.81). Conclusion: Persistent CXR abnormality 12-weeks post COVID-19 was common in this cohort. LOS, obesity, increased serum LDH, and smoking-status were risk factors for radiograph abnormality. These findings require further prospective validation.</p

High level efficacy in humans of a next-generation plasmodium falciparum anti-sporozoite vaccine: R21 in Matrix-M (TM) adjuvant

It remains a global health priority to develop a durable and highly efficacious malaria vaccine. The most advanced malaria vaccine candidate, RTS,S/AS01 has completed Phase III testing in a multicentre study across several African sites and demonstrates low-level (~30%) efficacy against clinical malaria in children aged 5-17 months after a three dose schedule. Efficacy wanes rapidly over time and there remain some safety concerns that require further assessment in the planned pilot deployment trials due to commence in Africa in 2018

High level efficacy in humans of a next-generation plasmodium falciparum anti-sporozoite vaccine: R21 in Matrix-M (TM) adjuvant

It remains a global health priority to develop a durable and highly efficacious malaria vaccine. The most advanced malaria vaccine candidate, RTS,S/AS01 has completed Phase III testing in a multicentre study across several African sites and demonstrates low-level (~30%) efficacy against clinical malaria in children aged 5-17 months after a three dose schedule. Efficacy wanes rapidly over time and there remain some safety concerns that require further assessment in the planned pilot deployment trials due to commence in Africa in 2018