By Christy Santhosh and Mariam Sunny
June 18 (Reuters) - The U.S. Food and Drug Administration's advisory panel is set to vote on whether the benefits of Moderna's flu vaccine outweigh its risks in older adults, after regulators reversed course on rejecting the drugmaker's initial application for the shot.
Moderna is seeking a traditional approval for the shot, called mFlusiva, for adults 50 to 64 years old, and an accelerated approval, which requires the company to conduct additional studies to confirm
the vaccine's benefit, for adults 65 and older.
Moderna has agreed to run an additional study and submit more data in adults 65 and older if it gets approval for that age group.
The meeting of the FDA's Vaccine and Related Biological Products Advisory Committee comes after the recent departures of FDA Commissioner Marty Makary and vaccine chief Vinay Prasad.
Makary and Prasad left the agency following a series of controversies over vaccine and rare-disease drug reviews, including Moderna's flu vaccine application. Senior FDA officials had then said Moderna put patients at risk by not giving the preferred higher-dose flu vaccine to patients 65 and over as the control arm in its clinical trial.
Acting Commissioner Kyle Diamantas has since moved to stabilize agency operations and repair relations with the biotech sector after months of upheaval.
In briefing documents published ahead of the meeting, FDA staff reviewers said data demonstrating an immune response to Moderna's flu shot might support effectiveness in adults 65 years and older.
The documents, however, flagged concerns over its effectiveness in immunocompromised people and very frail older adults who were excluded from trials.
Moderna said in its document that its vaccine outperformed standard-dose shots in adults aged 50 to 64, while a separate, smaller study showed it generated a strong immune response compared with a high-dose flu vaccine in adults 65 and older.
"Every year when we approve flu vaccines, we don't have efficacy data. So I think the question will be whether or not they thought that the immunogenicity study was big enough," said Paul Offit, director of the Vaccine Education Center at the Children's Hospital of Philadelphia.
If approved, Moderna's shot would be the first seasonal flu shot in the U.S. made with mRNA technology, a faster vaccine platform than conventional methods. It would compete with flu vaccines from Sanofi, GSK, CSL Seqirus and AstraZeneca.
Unlike traditional flu vaccines, mFlusiva does not rely on chicken eggs for production, helping manufacturers better match the vaccine to circulating flu strains and shorten the time between strain selection and vaccine availability, Moderna said.
The FDA's decision on the vaccine is expected by August 5. Jefferies analyst Andrew Tsai does not expect flu revenue for Moderna until 2027 and sees $750 million of U.S. flu and COVID-flu combo vaccine sales by 2030.
(Reporting by Christy Santhosh and Mariam Sunny in Bengaluru; Editing by Anil D'Silva)
