Sanofi says it's back to the drawing board on mRNA flu vaccines

By Ludwig Burger

(Reuters) - Sanofi said that trials show the currently available mRNA technology behind the most successful COVID-19 shots will not be effective against influenza and it is already working on a next generation of shots.

The French drugmaker, one of the world's largest vaccine makers, said early-stage testing on humans of its experimental influenza shot based on mRNA, or messenger RNA, showed a strong immune response against A strains of the virus but missed the mark on less prevalent B strains.

Both A and B viruses are responsible for seasonal flu epidemics each year and currently available flu shots work against both strains.

Rival Moderna in February unveiled similar trial results for a vaccine candidate called mRNA-1010 and said in April a further candidate was not successful in a trial.

"To succeed in mRNA flu, you need the next generation of mRNA technology, which is exactly what we are working on," Thomas Triomphe, head of vaccines at Sanofi, told Reuters.

Pursuing the current generation any further would amount to "throwing spaghetti on the wall", he added.

The technology upgrade Sanofi is working on would need to show a better immune response against B strains, have better lipid encapsulation of mRNA molecules and longer durability at normal fridge temperatures, he said, without being drawn on when such a candidate might come to market.

Pfizer last year started a large late-stage trial testing an mRNA-based flu vaccine candidate. In collaboration with partner BioNTech, an early-stage study is underway to test a combined mRNA shot against COVID-19 and flu.

Sanofi, which is among the top four global vaccines makers by sales, trailing GSK, Merck & Co and Pfizer, has a broad vaccines offering, including flu, childhood shots and travel vaccines.

The French company's vaccine sales accounted for 7.2 billion euros ($7.85 billion) of 43 billion euros in group sales last year.

A high-dose version of established protein-based influenza vaccines for the elderly, branded as Efluelda or Fluzone, has been a particularly strong sales driver.

At an investor event to showcase its vaccine business, the company reaffirms its goal to have more than 10 billion euros in annual vaccines sales by 2030.

($1 = 0.9169 euros)

(Reporting by Ludwig Burger;Editing by Elaine Hardcastle)