Sanofi, GSK start Phase I/II study of COVID-19 vaccine candidate

Sanofi and GlaxoSmithKline announced Thursday the start of a Phase I/II study of their experimental adjuvanted COVID-19 vaccine, with plans to move to late-stage trials this year. The companies added that in parallel, they are scaling up manufacturing of the antigen and adjuvant with the target of producing up to one billion doses of the vaccine in 2021.

"Moving this vaccine candidate into clinical development is an important moment," remarked Roger Connor, president of GlaxoSmithKline's vaccines division. Meanwhile, Thomas Triomphe, global head of Sanofi Pasteur, said "we aim to deliver the first results in early December," adding "positive data will enable a prompt start of the pivotal Phase III trial by the end of this year."

While a number of vaccines are already in late-stage development, including ones from AstraZeneca and Moderna, John Shiver, senior vice president of global vaccines R&D at Sanofi, said "I'm not concerned that we're a few months behind some of the other vaccine candidates." Shiver suggested that Sanofi's "experience with very similar viruses" will allow it to gain back time on other development candidates.

"Compelling" preclinical data

Sanofi and GlaxoSmithKline, who announced their vaccine collaboration in April, noted that the Phase I/II study will evaluate the safety, reactogenicity and immunogenicity of the COVID-19 vaccine candidate in 440 healthy adults in the US. The study will include two groups, with Shiver noting that the companies are targeting the enrolment of 140 people aged over 50 to identify a vaccine formulation that is best suited to them. The vaccine pairs GlaxoSmithKline's pandemic adjuvant technology with Sanofi's S-protein COVID-19 antigen, which is based on recombinant DNA technology.

According to the drugmakers, preclinical data has shown that two injections of the adjuvanted recombinant vaccine led to high levels of neutralising antibodies that are comparable to levels in humans who recovered from SARS-CoV-2 infection. Results, which Shiver called "compelling," also demonstrated an "acceptable" reactogenicity profile for the vaccine.

In July, the US government agreed to provide more than $2.1 billion to support further development, manufacturing and delivery of 100 million initial doses of Sanofi and GlaxoSmithKline's vaccine. The government has a further option for the supply of an additional 500 million vaccine doses in the longer term. The companies have also reached an agreement with the UK government for the supply of up to 60 million doses of the vaccine.

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