A committee of outside experts to the U.S. CDC are set to vote on whether to expand the age group of adults recommended to receive respiratory syncytial virus (RSV) vaccines this year, as GSK (GSK.L) battles rival Pfizer (PFE.N) and new entrant Moderna (MRNA.O) to keep its top position in the market.
Rituparna Das, Moderna's therapeutic head of respiratory vaccines, said the company's mRESVIA shot had 50% efficacy in preventing RSV after 18 months, speaking at the meeting of the Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices on Wednesday. It is a lower number than GSK and Pfizer previously showed in their own clinical trials.
Moderna shares fell around 6% in early trading.
The committee will meet Wednesday through Friday to consider and recommend who should get RSV, influenza, COVID-19 and other vaccines and how strong to make those recommendations.
Although the CDC generally follows the committee's votes, the final decision rests with the agency's director.
Last year, GSK's Arexvy and Pfizer's Abrysvo went head-to-head for adults over the age of 60. GSK won two-thirds of the market, mostly due to its contracts with retail pharmacies, including CVS (CVS.N). Moderna received approval for its shot, mRESVIA, for the same age group last month.
Headed into this autumn, GSK has FDA approval to expand use of its vaccine to adults ages 50 to 59 at increased risk from the illness, making it the first shot endorsed for that age group.
Pfizer said it submitted data for its shot in adults aged 18 to 59 and hopes to get the expanded approval as early as the fourth quarter.
"Getting to that 50- to 59-year-old population early is pretty meaningful," said Guggenheim Partners analyst Evan Wang.
"Not only does it add 10 to 15 million more high-risk individuals to the total pool, it also is significant because ... this could give them an edge as they kind of negotiate with retail pharmacies for contracts," Wang added.
Unlike GSK, Pfizer has started the contracting season with an FDA approval in hand for pregnant women to protect their babies. Last year, it did not receive the maternal approval until late August, after the vaccination campaign had begun.
RSV typically causes cold-like symptoms but is also a leading cause of pneumonia in toddlers and older adults, leading to 177,000 hospitalizations and 14,000 deaths in the United States annually.
Combined revenue for the Pfizer and GSK shots in their first year of availability topped $2.4 billion.
Analysts, on average, expect sales of $1.59 billion for GSK's RSV shot, $1.47 billion for Pfizer's and $370 million this year for Moderna.
Pfizer Chief Executive Albert Bourla has acknowledged that Abrysvo had a "bad launch" last year, and company executives have said they are focused on improving its performance.
Pfizer recently secured a contract to supply close to 5 million doses of its vaccine in the UK over the next two years. Britain-based GSK said it was disappointed not to have been selected.
Protection from the Pfizer and GSK shots has been shown in trials to last at least two RSV seasons. In their clinical trials, GSK's RSV vaccine Arexvy was 78% effective in preventing severe RSV over a second year and Pfizer's was 78% effective through a second RSV season.
Moderna has previously cautioned against comparing its vaccine's efficacy to rivals, noting that the trials were not head-to-head and used different case definitions for RSV disease.
Analysts believe the market will grow from 2023, in part because the companies have been marketing the shots directly to consumers since last year.
"They definitely got the low hanging fruit last year," said Morningstar analyst Damien Conover.
Guggenheim's Wang said he expects the market to be between $2.5 billion and $3 billion this year.
