Pasteleosa: Sanofi ditches mRNA COVID-19 vaccine amid rivals' success

PARIS, Sept 28 (Reuters) - Sanofi (SASY.PA) is dropping plans for its own mRNA-based COVID-19 vaccine because of the dominant role of the BioNTech-Pfizer (22UAy.DE)(PFE.N) alliance as well as Moderna (MRNA.O) in the fight against the pandemic, the company said on Tuesday.

The move highlights the challenges of competing in particular with pioneer BioNTech (22UAy.DE), which rose from obscurity through its alliance with pharma major Pfizer last year. The pair have delivered close to 1.5 billion doses so far, making them the western world's largest COVID-19 vaccine maker.

French healthcare group Sanofi will instead focus on efforts with British partner GlaxoSmithKline to bring another COVID-19 vaccine candidate to market based on the more conventional protein-based approach, where mass trials are ongoing. read more

The decision to drop clinical development of a shot based on mRNA, or messenger RNA, acquired as part of its takeover of Translate Bio , came despite positive Phase I/II study interim results announced on Tuesday where participants' blood readings showed a strong immune reaction.

But Sanofi said the read-out encouraged it only to pursue the technology as a potential vaccine against influenza and other diseases, giving up on the area of COVID-19 because of the strong market presence of the two approved mRNA shots.

"These results will clearly help inform the path forward for our mRNA development programs," said Jean-Francois Toussaint, global head of research and development at Sanofi Pasteur.

Sanofi's shares gained 1.1% to 83.01 euros by 0850 GMT, outperforming a 0.9% decline in the STOXX Europe 600 Health Care (.SXDP).

"The decision to end RNA looks to be interpreted as positive since they will save development costs and concentrate on other products and ventures," said Ion-Marc Valahu, a fund manager at Geneva-based investment firm Clairinvest.

The company said it started testing an mRNA shot against seasonal influenza in humans in June and will launch follow-on clinical studies next year.

The development of RNA flu shots is already shaping up to be a tight race as drugmakers hope they can more quickly adjust the vaccine to ever-changing strains in circulation.

Pfizer said this week it started testing an mRNA flu vaccine. Moderna has several influenza vaccine candidates in development, including combinations that include a COVID-19 booster. read more

Established influenza vaccine supplier Seqirus, part of Australia's CSL (CSL.AX), for instance, is working on next-generation low-dose RNA flu shots, known as self-amplifying RNA.

Companies including Novavax are working on novel flu shots using new technology beyond mRNA. read more

Sanofi reported 2.5 billion euros ($2.9 billion) in sales from flu vaccines in 2020, the largest of its vaccine business, which recorded total sales of 5.9 billion euros.

The mRNA vaccines trick the human body into producing proteins known as antigens that are found on the surface of the coronavirus that causes COVID-19. That primes the immune system to quell future infections.

Under the more traditional protein-based vaccine approach that Sanofi will now focus on, the antigen is bioengineered in labs and combined with an efficacy booster known as an adjuvant, provided by GSK.

Sanofi executive Thomas Triomphe told journalists in a briefing that the EU and Britain had ordered 75 million doses of this vaccine, banking on future regulatory approval.

German biotech firm CureVac (5CV.DE) earlier this month also acknowledged rivals' dominance when it cancelled some of the contract manufacturing deals for its experimental mRNA COVID-19 vaccine with two prospective partners. read more

CureVac's product is under review by the European Union's drugs regulator with an uncertain outcome after disappointing trial results.