The FDA has granted Fast Track designation to Moderna’s investigational single-dose mRNA-1345 vaccine against the respiratory syncytial virus (RSV) for people over 60 years of age.

mRNA-1345 is a vaccine against RSV encoding for a prefusion F glycoprotein, which elicits a superior neutralizing antibody response compared to the postfusion state, according to the company. RSV is the leading cause of respiratory illness in young children. Older adults (65+) are at high risk for severe RSV infections. mRNA-1345 uses the same lipid nanoparticle (LNP) as Moderna’s authorized COVID-19 vaccine and contains optimized protein and codon sequences.

“We are pursuing an mRNA RSV vaccine to protect the most vulnerable populations – young children and older adults,” said Stéphane Bancel, Chief Executive Officer of Moderna. “We are studying mRNA-1345 in these populations in an ongoing clinical trial and we look forward to sharing data when available. The Fast Track designation for older adults underscores the urgent need for a vaccine against RSV. With our investments in science and manufacturing, we have taken eleven infectious disease vaccines into human clinical trials. We have accelerated research and development of our infectious disease therapeutic area and we will continue to advance our mRNA vaccines into new areas of high unmet need.”

Respiratory syncytial virus is a common respiratory virus that generally causes cold-like symptoms. In the United States and areas with similar climates, RSV infections occur primarily during fall, winter, and spring. Most people recover in a week or two, but RSV can be serious, especially for infants and older adults. RSV is the most common cause of bronchiolitis and pneumonia in children younger than one year of age in the United States and can result in pneumonia and respiratory distress in older adults. According to the U.S. Centers for Disease Control and Prevention, in the United States, RSV leads each year, on average, to approximately 58,000 hospitalizations among children younger than five years old, 177,000 hospitalizations among adults 65 years and older and 14,000 deaths among adults 65 years and older. There is no approved vaccine available today for RSV.

Fast Track is designed to facilitate the development and expedite the review of therapies and vaccines for serious conditions and that fill an unmet medical need. Programs with Fast Track designation may benefit from early and frequent communication with the FDA, in addition to a rolling submission of the marketing application. The Company previously received Fast Track designation for its COVID-19 vaccine candidate, Zika vaccine candidate (mRNA-1893), methylmalonic acidemia (MMA) (mRNA-3704) and propionic acidemia (PA) (mRNA-3927) programs.

The Phase 1 study of mRNA-1345 to evaluate the tolerability and reactogenicity of mRNA-1345 in younger adults, older adults and children is ongoing. All four cohorts of younger adults (ages 18-49 years) are fully enrolled. Dosing in the older adult cohort (ages 65-79 years) is ongoing. The age range of toddlers in this de-escalation Phase 1 study is 12-59 months. The Company shared the first interim analysis of the Phase 1 study of mRNA-1345, through 1-month post-vaccination, of the younger adult cohorts at its annual Vaccines Day on April 14, 2021. Results showed the vaccine candidate generated a geometric mean rise in neutralizing antibodies relative to baseline of at least 11-fold.