Playing catch-up to Big Pharma, Moderna posts come-from-behind RSV data

The top-line readout from COVID-19 vaccine maker Moderna for a respiratory syncytial virus (RSV) vaccine seems to keep pace with leading competitors GSK and Pfizer as the three gear up for what is expected to be a very tight commercial market.

Moderna reported that its vaccine was 83.7% effective against RSV-associated lower respiratory tract disease (LRTD) as defined by two or more symptoms among trial participants that were at least 60 years old. The phase 3 trial recruited roughly 37,000 adults across 22 countries.

Efficacy in LRTD as defined by three or more symptoms was 82.4%. Moderna says the shot is safe and that most side effects were mild or moderate. The rate of grade 3 or higher local adverse events was 3.2% for treated patients and 1.7% for patients who received placebo. Moderna expects to submit an approval application to global regulators in the first half of 2023 and will present more in-depth data at an upcoming medical conference. 

In an interview with Fierce Biotech, Moderna Senior Vice President of Respiratory Vaccines Francesca Ceddia, M.D., said the company is still accruing severe disease cases. While she cautioned against making comparisons without direct data, Ceddia said Moderna's shot stacks up most comparably to GSK in terms of efficacy against disease defined as two or more symptoms. 

Moderna's data represent just one entry into a race to finally bring an RSV vaccine forward as the virus courses through the U.S. population in concert with COVID-19 and the flu. The company is hoping to bring the shot as its second approved product, but this time things will be a little different. Moderna ascended to the Big Pharma ranks after launching its COVID-19 vaccine amid the pandemic, but the RSV market will be much different than the emergency-use driven COVID-19 market. 

Both GSK and Pfizer have already filed for approval with the FDA to prevent lower respiratory tract disease caused by RSV in people 60 years and older. Both were granted priority reviews, with a decision date slated for May. 

Unlike Pfizer and GSK, Moderna has not received a priority review tag for its RSV shot, although Ceddia says the company plans to use one of the two it has waiting in the wings—one having been purchased and the other earned thanks to the COVID-19 shot. Still, Moderna seems to be weighing all its options to stake a claim in the market.

In October, GSK reported that its shot was 82.6% effective overall but 94.1% effective in patients with severe disease, which was defined in part as having two lower respiratory signs. The shot did have efficacy in LRTD as defined by three or more symptoms. Pfizer, on the other hand, posted 66.7% efficacy against RSV-associated lower respiratory illness defined by two or more symptoms, but that jumped to 85.7% in patients who had lower respiratory illness defined by three or more symptoms.  

All three companies are also eyeing expanding the use of the shots to children, a second sprint that includes French pharma Sanofi. Moderna is currently testing the shot in a phase 1 trial in adolescents while Pfizer ended a maternal trial early in November after it reached one of two co-primary endpoints. Ceddia says Moderna hopes to have data from its phase 1 trial “within the next few months.”

“Our priority now is to make sure that we finalize everything we need to do for the older adults,” she said. 

Editor's note: This story was updated to clarify that Moderna intends to use a priority review voucher on its RSV vaccine and to include editorial on Sanofi's RSV candidate.