– “I am afraid I can not fully understand this”
Neither can I. I expect it doesn’t quite make sense. I think “read-out” should read “results”.
As best I can work out, Sanofi were developing three types of vaccines – mRNA vaccines against covid-19, mRNA vaccines against seasonal ‘flu, and an “adjuvanted recombinant protein vaccine” against covid-19.
Of these three, they decided to drop the mRNA vaccine against covid-19, “because of the strong market presence of the two approved mRNA shots” – ie. their Phase I/II results indicate that their mRNA vaccine against covid-19 has no decisive advantage over the existing ones from Pfizer and Moderna, so they’re concentrating their resources on their other two approaches instead.