GSK, Sanofi eye Q4 approval as COVID jab starts phase 3

GlaxoSmithKline's COVID-19 drive has advanced on two fronts, with the start of phase 3 trials of its Sanofi-partnered vaccine candidate as well as an FDA emergency approval for antibody sotrovimab, developed with Vir Biotech.

GSK and Sanofi think they could be on track for approval of the recombinant protein-based vaccine – delivered with GSK's immune-response boosting adjuvant – before the end of the year.

The phase 3 trial will include one shot targeting the original SARS-CoV-2 virus as well as a second against the B.1.351 variant first identified in South Africa, and will include 35,000 patients from the  US, Asia, Africa, and Latin America.

"Recent scientific evidence shows that antibodies created against the B.1.351 variant may provide broad cross-protection against other more transmissible variants," said GSK and Sanofi in a joint statement.

The primary endpoint of the study is the prevention of symptomatic COVID-19 in SARS-CoV-2 naïve adults, while the study will also gauge the jab's effectiveness at preventing severe COVID-19 disease and asymptomatic infection.

With an eye on countries' emerging plans for booster shots, the two companies will also carry out complementary studies to assess the ability of the vaccine to generate a strong booster response – regardless of the initial vaccine received by an individual.

The start of dosing in the phase 3 trial gets GSK and Sanofi's programme back on track after lacklustre immune response data in older subjects recruited into phase 1/2 trials forced the two partners to reformulate the vaccine component of the shot.

Phase 2 results in 772 subjects with the new version reported earlier this month showed that the vaccine produced "strong" neutralising antibody levels that were comparable to those generated by natural infection with SARS-CoV-2, according to the drugmakers.

The companies also said that manufacturing will begin in the coming weeks "to enable rapid access to the vaccine should it be approved."

Sotrovimab becomes third US COVID antibody option

Meanwhile, the FDA's emergency use authorisation of sotrovimab (VIR-7831) for people aged 12 and over with mild-to-moderate COVID-19 at risk of developing severe symptoms gives the US a third antibody option for the disease after Regeneron's casirivimab/imdevimab and Eli Lilly's bamlanivimab/etesevimab combinations.

Like the other antibodies, GSK and Vir's drug is not authorised for use in patients who are hospitalised due to COVID-19 or require oxygen therapy. A rolling review of sotrovimab is also underway in the EU.

The EUA is based on results from the ongoing COMET-ICE study which found that sotrovimab was able to cut the risk of hospitalisation for more than 24 hours or death by 85% compared to placebo in non-hospitalised patients with COVID-19.

Like the other antibodies, sotrovimab is designed to attach to the spike protein of SARS-CoV-2, limiting the ability of the virus to enter the body's cells. GSK and Vir have also suggested that their antibody is less likely to stimulate resistance as it targets part of the spike protein that rarely mutates.

The FDA said that laboratory testing shows that sotrovimab retains activity against the current circulating variants first reported in the UK, South Africa, Brazil, California, New York and India.

The positive COVID-19 developments could go some way to alleviate pressure on GSK chief executive Emma Walmsley, whose future at the helm has been a matter of debate after activist investor Elliott Management built a stake in the struggling pharma.