GlaxoSmithKline (GSK) and Medicago have started phase 3 clinical testing of their plant-based adjuvanted COVID-19 vaccine.

The phase 3 study will evaluate two 3.75 micrograms doses of the vaccine candidate, administered 21 days apart.

Initially, it will enrol up to 30,000 participants including healthy adults aged 18 to 65 years old, after which older adults aged 65 years and up and adults with comorbidities will also be included.

In a statement, Medicago said it had received approval from Canadian and US regulatory authorities to proceed with enrolment in the late-stage study based on positive interim phase 2 results.

The phase 2 portion of the clinical development programme is almost completed, with results expected to be made public in April, according to GSK and Medicago.
The vaccine candidate combines Medicago’s recombinant coronavirus virus-like particles (CoVLP) with GSK’s pandemic adjuvant system.

Medicago’s CoVLPs mimic the structure of the SARS-CoV-2 virus that causes COVID-19, which allows them to be recognised and targeted by the immune system.

In addition, adjuvants can be of particular use in a pandemic situation, as the boosted immune response can reduce the amount of antigen required per dose, allowing for more vaccine doses to be manufactured and distributed.

GSK and Medicago signed a deal in July 2020 to develop and evaluate a COVID-19 vaccine candidate combining Medicago’s CoVLPs and GSK’s adjuvant.

Novavax has revealed final efficacy analysis of its COVID-19 vaccine NVX-CoV2373, after reporting interim results from the UK-based phase 3 trial in January.

The final analysis from the trial, which enrolled 15,000 participants, demonstrated a 96.4% vaccine efficacy in mild, moderate and severe disease caused by the original COVID-19 strain.

Against the B.1.1.7 strain, first identified in the UK, NVX-CoV2373 was found to have 86.3% efficacy, reflecting an overall vaccine efficacy of 89.7%.

In participants aged 65 years and older, ten cases of COVID-19 were observed, with 90% of these cases occurring in the placebo group.

Novavax also announced data from a phase 2b trial of NVX-CoV2373 conducted in South Africa.

Analysis of vaccine efficacy among 147 PCR-positive COVID-19 cases demonstrated an overall efficacy of 48.6% against ‘predominantly variant strains’.

According to Novavax, most of the cases circulating during the efficacy analysis were caused by the B.1.351 variant circulating in SA.

Among HIV-negative participants, the efficacy of NVX-CoV2373 was found to be 55.4%, with complete analysis showing that vaccine-induced protection began 14 days after the first dose.

Novavax added that increased efficacy was observed seven days after the second dose.

Pfizer/BioNTech’s COVID-19 vaccine has been found to neutralise the variant discovered in Brazil, according to a laboratory study published in the New England Journal of Medicine.

The study, conducted by scientists from Pfizer and BioNTech alongside researchers from the University of Texas Medical Branch, used blood samples from people who had received the BNT162b2 vaccine.

They then used an engineered version of the virus that carries the same mutations on the spike protein of the P.1 variant, which is currently rapidly spreading in Brazil, to determine the level of neutralisation produced by the Pfizer/BioNTech vaccine.

The results suggested that the vaccine was able to neutralise the P.1 variant, with the levels of neutralisation ‘roughly equivalent’ to the jab’s effect on the original SARS-CoV-2 strain.
Previously, the Pfizer/BioNTech vaccine has been found to neutralise variants discovered in the UK and South Africa.

However, neutralisation of the South Africa variant, or B.1.351-spike virus, was reduced by around two-thirds in BNT162b2-vaccinated blood samples.

The researchers noted that it is difficult to determine the effect this reduction in antibodies will have on the vaccine’s efficacy against the B.1.351 variant.

This is because there is currently no way to determine the level of antibodies required to protect against the virus.

“Ultimately, conclusions about vaccine-mediated protection that are extrapolated from neutralisation or T-cell data must be validated by real-world evidence collected in regions where the SARS-CoV-2 variants are circulating,” commented the researchers.

Sanofi and Translate Bio have announced the launch of a phase 1/2 trial evaluating their mRNA-based COVID-19 vaccine candidate MRT5500.

The randomised, placebo-controlled trial will evaluate the safety, tolerability and immunogenicity of MRT5500 and is expected to enrol 415 healthy adults aged 18 years and older.

Participants taking part in the phase 1/2 trial will receive one dose of MRT5500 or two doses administered 21 days apart. Sanofi and Translate will investigate three different dose levels of the vaccine candidate – 15µg, 45µg or 135µg.

The companies added that preclinical studies are also ongoing and are set to continue over the coming months.

These studies will evaluate if MRT5500 and additional mRNA vaccine candidates can induce neutralising antibodies against emerging SARS-CoV-2 variants.

“Our mRNA vaccine candidate is the result of our expertise in infectious diseases coupled with the innovative technologies of our partner,” said Thomas Triomphe, executive vice president and global head of Sanofi Pasteur.

“Initiating the phase 1/2 trial represents an important step forward in our goal of bringing another effective vaccine to the ongoing fight against the COVID-19 pandemic,” he added.

CHMP will review the combination of bamlanivimab and etesemivab as well as bamlanivimab monotherapy.

The European Medicines Agency (EMA) has announced that its Committee for Medicinal Products for Human Use (CHMP) has launched a rolling review for Eli Lilly’s COVID-19 antibodies bamlanivimab and etesemivab.

The CHMP’s review will assess data on the antibodies used in combination for the treatment of COVID-19, and also will review bamlanivimab monotherapy.

The initiation of the rolling review is based on preliminary results from two studies – one evaluating the combination of the two antibodies and another looking at the use of bamlanivimab alone for the treatment of COVID-19.

In Lilly’s combination study – the phase 3 BLAZE-1 trial – bamlanivimab 2800mg was administered alongside estesevimab 2800mg in high-risk patients who had recently been diagnosed with COVID-19.

The study met its primary endpoint, achieving a significant reduction in COVID-19-related hospitalisations and deaths in high-risk COVID-19 patients.

Across the entire study population of 1,035 patients, there were 11 events in patients receiving Lilly’s antibody combination treatment, while 36 events occurred in the placebo group.

This represented a 70% risk reduction, with no deaths occurring in the bamlanivimab and etesevimab-treated group.

In the US, bamlanivimab received an emergency use authorisation (EUA) from the US Food and Drug Administration (FDA) for the treatment of mild-to-moderate COVID-19 in November 2020.