Efficacy and Safety of a Recombinant Plant-Based Adjuvanted Covid-19 Vaccine.

BACKGROUND: Coronavirus-like particles (CoVLP) that are produced in plants and display the prefusion spike glycoprotein of the original strain of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are combined with an adjuvant (Adjuvant System 03 [AS03]) to form the candidate vaccine. METHODS: In this phase 3, multinational, randomized, placebo-controlled trial conducted at 85 centers, we assigned adults (≥18 years of age) in a 1:1 ratio to receive two intramuscular injections of the CoVLP+AS03 vaccine or placebo 21 days apart. The primary objective of the trial was to determine the efficacy of the CoVLP+AS03 vaccine in preventing symptomatic coronavirus disease 2019 (Covid-19) beginning at least 7 days after the second injection, with the analysis performed after the detection of at least 160 cases. RESULTS: A total of 24,141 volunteers participated in the trial; the median age of the participants was 29 years. Covid-19 was confirmed by polymerase-chain-reaction assay in 165 participants in the intention-to-treat population; all viral samples that could be sequenced contained variants of the original strain. Vaccine efficacy was 69.5% (95% confidence interval [CI], 56.7 to 78.8) against any symptomatic Covid-19 caused by five variants that were identified by sequencing. In a post hoc analysis, vaccine efficacy was 78.8% (95% CI, 55.8 to 90.8) against moderate-to-severe disease and 74.0% (95% CI, 62.1 to 82.5) among the participants who were seronegative at baseline. No severe cases of Covid-19 occurred in the vaccine group, in which the median viral load for breakthrough cases was lower than that in the placebo group by a factor of more than 100. Solicited adverse events were mostly mild or moderate and transient and were more frequent in the vaccine group than in the placebo group; local adverse events occurred in 92.3% and 45.5% of participants, respectively, and systemic adverse events in 87.3% and 65.0%. The incidence of unsolicited adverse events was similar in the two groups up to 21 days after each dose (22.7% and 20.4%) and from day 43 through day 201 (4.2% and 4.0%). CONCLUSIONS: The CoVLP+AS03 vaccine was effective in preventing Covid-19 caused by a spectrum of variants, with efficacy ranging from 69.5% against symptomatic infection to 78.8% against moderate-to-severe disease. (Funded by Medicago; ClinicalTrials.gov number, NCT04636697.).

Phase 1 randomized trial of a plant-derived virus-like particle vaccine for COVID-19.

Several severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines are being deployed, but the global need greatly exceeds the supply, and different formulations might be required for specific populations. Here we report Day 42 interim safety and immunogenicity data from an observer-blinded, dose escalation, randomized controlled study of a virus-like particle vaccine candidate produced in plants that displays the SARS-CoV-2 spike glycoprotein (CoVLP: NCT04450004 ). The co-primary outcomes were the short-term tolerability/safety and immunogenicity of CoVLP formulations assessed by neutralizing antibody (NAb) and cellular responses. Secondary outcomes in this ongoing study include safety and immunogenicity assessments up to 12 months after vaccination. Adults (18-55 years, n = 180) were randomized at two sites in Quebec, Canada, to receive two intramuscular doses of CoVLP (3.75 µg, 7.5 µg, and 15 µg) 21 d apart, alone or adjuvanted with AS03 or CpG1018. All formulations were well tolerated, and adverse events after vaccination were generally mild to moderate, transient and highest in the adjuvanted groups. There was no CoVLP dose effect on serum NAbs, but titers increased significantly with both adjuvants. After the second dose, NAbs in the CoVLP + AS03 groups were more than tenfold higher than titers in Coronavirus 2019 convalescent sera. Both spike protein-specific interferon-γ and interleukin-4 cellular responses were also induced. This pre-specified interim analysis supports further evaluation of the CoVLP vaccine candidate.

Efficacy, immunogenicity, and safety of a plant-derived, quadrivalent, virus-like particle influenza vaccine in adults (18-64 years) and older adults (≥65 years): two multicentre, randomised phase 3 trials.

BACKGROUND: Seasonal influenza remains a substantial public health threat despite the availability of egg-derived and other vaccines. Plant-based manufacturing might address some of the limitations of current vaccines. We describe two phase 3 efficacy studies of a recombinant quadrivalent virus-like particle (QVLP) influenza vaccine manufactured in plants, one in adults aged 18-64 years (the 18-64 study) and one in older people aged 65 years and older (the 65-plus study). METHODS: We did two randomised, observer-blind, multinational studies in the northern hemisphere in the 2017-18 (the 18-64 study) and 2018-19 (the 65-plus study) influenza seasons. The 18-64 study was done at 73 sites and the 65-plus study was done at 104 sites, both across Asia, Europe, and North America. In the 18-64 study, inclusion criteria were body-mass index less than 40 kg/m2; age 18-64 years at screening visit; and good health. In the 65-plus study, inclusion criteria were body-mass index of maximum 35 kg/m2; aged 65 years or older at screening visit; not living in a rehabilitation centre or care home; and no acute or evolving medical problems. Participants in the 18-64 study were randomly assigned (1:1) to receive either QVLP vaccine (30 µg haemagglutinin per strain) or placebo. Participants in the 65-plus study were randomly assigned (1:1) to receive QVLP vaccine (30 µg haemagglutinin per strain) or quadrivalent inactivated vaccine (QIV; 15 µg haemagglutinin per strain). The primary outcome in the 18-64 study was absolute vaccine efficacy to prevent laboratory-confirmed, respiratory illness caused by antigenically matched influenza strains. The primary outcome in the 65-plus study was relative vaccine efficacy to prevent laboratory-confirmed influenza-like illness caused by any influenza strain. The primary analyses were done in the per-protocol population and safety was assessed in all participants who received the assigned treatment. These studies are registered with ClinicalTrials.gov (18-64 study NCT03301051; 65-plus study NCT03739112). FINDINGS: In the 18-64 study, between Aug 30, 2017, and Jan 15, 2018, 10 160 participants were randomly assigned to receive either QVLP vaccine (5077 participants) or placebo (5083 participants). The per-protocol population consisted of 4814 participants in the QVLP group and 4812 in the placebo group. The study did not meet its primary endpoint of 70% absolute vaccine efficacy for the QVLP vaccine (35·1% [95% CI 17·9 to 48·7]) against respiratory illness caused by matched strains. 55 (1·1%) of 5064 participants in the QVLP group versus 51 (1·0%) of 5072 in the placebo group had a serious adverse event. Four (0·1%) and six [0·1%] participants had severe treatment-related treatment-emergent adverse events. In the 65-plus study, between Sept 18, 2018, and Feb 22, 2019, 12 794 participants were randomly assigned to receive either QVLP vaccine (6396 participants) or QIV (6398 participants). The per-protocol population consisted of 5996 participants in the QVLP group and 6026 in the QIV group. The study met its primary non-inferiority endpoint with a relative vaccine efficacy of the QVLP vaccine for the prevention of influenza-like illness caused by any strain of 8·8% (-16·7 to 28·7). 263 (4·1%) of 6352 participants in the QVLP group versus 266 (4·2%) of 6366 in the QIV group had serious adverse events (one [<0·1%] vs two [<0·1%] were considered treatment-related); one (<0·1%) versus three (<0·1%) participants had severe treatment-related treatment-emergent adverse events. INTERPRETATION: These efficacy studies are the first large-scale studies of any plant-derived human vaccine. Together, they show that the plant-derived QVLP vaccine can provide substantial protection against respiratory illness and influenza-like illness caused by influenza viruses in adults. QVLP vaccine was well tolerated and no major safety signal arose in participants who received QVLP vaccine across the two studies. FUNDING: Medicago.

In vivo effect of insulin to decrease matrix metalloproteinase-2 and -9 activity after arterial injury.

UNLABELLED: In vitro, insulin has both growth-promoting and vasculoprotective effects. In vivo, the effect of insulin is mainly protective. Insulin treatment (3 U/day) decreases smooth muscle cell (SMC) migration and neointimal growth after carotid angioplasty in normal rats maintained at normoglycemia by oral glucose. SMC migration requires limited proteolysis of the extracellular matrix, which is mediated by matrix metalloproteinases (MMPs). In this study, we investigated the effects of normoglycemic hyperinsulinemia on MMP activity after balloon angioplasty. Rats were divided into three groups: (1) control implants and tap water; (2) control implants and oral glucose, and (3) insulin implants (3 U/day) and oral glucose. RESULTS: Gelatin zymography revealed that insulin reduced the gelatinolytic activity of pro-MMP-2 by 46% (p < 0.05), MMP-2 by 44% (p < 0.05) and MMP-9 by 51% (p < 0.05) compared to controls after arterial injury. Insulin also reduced mRNA levels of MMP-2 (p < 0.05) and MMP-9 (p < 0.05) and protein levels of MMP-2 (p < 0.05). In contrast, there were no significant changes in membrane-type 1 MMP protein and tissue inhibitors of MMP activity after insulin treatment. Thus, these results suggest a mechanism by which insulin inhibits SMC migration and supports a vasculoprotective role for insulin in vivo.

Insulin inhibits and oral sucrose increases neointimal growth after arterial injury in rats.

BACKGROUND/AIMS: In our previous studies, rats on insulin treatment (5 U/day) and oral glucose to avoid hypoglycemia had reduced neointimal growth after arterial injury. However, plasma glucose in the insulin-treated rats was lower than normal and the effect of oral glucose remained undetermined. In this study, the effects of normoglycemic hyperinsulinemia and oral glucose or sucrose were investigated in the same model. METHODS: Rats were divided into 6 groups: (1) control implants and tap water; (2) insulin implants (5 U/day) and oral glucose + i.p. glucose to avoid any glucose lowering; (3) insulin implants (4 U/day) and oral glucose; (4) insulin implants (4 U/day) and oral sucrose; (5) control implants and oral glucose, and (6) control implants and oral sucrose. RESULTS: Insulin treatment at both doses reduced neointimal area (p < 0.001) 14 days after injury in rats receiving oral glucose but not in those receiving oral sucrose. Oral glucose, without insulin, had no effect on neointimal formation, whereas oral sucrose increased neointimal growth (p < 0.05). Oral sucrose (p < 0.05) but not oral glucose decreased insulin sensitivity measured with hyperinsulinemic clamps. CONCLUSIONS: (1) Insulin decreases neointimal growth after arterial injury independent of glucose-lowering or oral glucose administration and (2) oral sucrose per se affects neointimal growth.

Insulin increases reendothelialization and inhibits cell migration and neointimal growth after arterial injury.

OBJECTIVE: Insulin has both growth-promoting and protective vascular effects in vitro, however the predominant effect in vivo is unclear. We investigated the effects of insulin in vivo on neointimal growth after arterial injury. METHODS AND RESULTS: Rats were given subcutaneous control (C) or insulin implants (3U/d;I) 3 days before arterial (carotid or aortic) balloon catheter injury. Normoglycemia was maintained by oral glucose and, after surgery, by intraperitoneal glucose infusion (saline in C). Insulin decreased intimal area (P<0.01) but did not change intimal cell proliferation or apoptosis. However, insulin inhibited cell migration into the intima (P<0.01) and increased expression of smooth muscle cell (SMC) differentiation markers (P<0.05). Insulin also increased reendothelialization (P<0.01) and the number of circulating progenitor cells (P<0.05). CONCLUSIONS: These results are the first demonstration that insulin has a protective effect on both SMC and endothelium in vivo, resulting in inhibition of neointimal growth after vessel injury.

Anti-atherogenic effect of insulin in vivo.

Metabolic syndrome is a risk factor for atherosclerosis and restenosis. In metabolic syndrome, insulin resistance coexists with hyperinsulinemia and hyperlipidemia. Hyperlipidemia has growth-promoting effects, whereas insulin has both growth-promoting and growth-inhibitory effects on vascular smooth muscle cells in vitro. The objective of this study was to investigate the effects of hyperlipidemia and hyperinsulinemia on vascular cell growth in vivo after arterial injury. Rats fed a low-fat diet were treated with either subcutaneous blank (LFC) or insulin (LFI) implants. Rats fed a high-fat diet also received blank (HFC) or insulin (HFI) implants. After 3 days, rats received balloon carotid injury, and 14 days later they were sacrificed to measure neointimal area and proliferation. Hyperinsulinemia was present in LFI and HFI and hyperlipidemia was present in HFC and HFI. Neointimal area was higher in HFC (0.153 +/- 0.009 mm(2), p < 0.05) but lower in LFI (0.098 +/- 0.005, p < 0.01) than LFC (0.127 +/- 0.005). In HFI (0.142 +/- 0.008, p < 0.05) neointimal area was not different from HFC or LFC. In conclusion, insulin reduced neointimal growth, but the effect of insulin was diminished by the high-fat diet. Thus, our results demonstrate an anti-atherogenic effect of insulin in vivo and suggest that in metabolic syndrome insulin resistance rather than hyperinsulinemia is the atherogenic risk factor.