The US Food and Drug Administration (FDA) has granted fast track designation to mRNA-1345, Moderna’s investigational single-dose messenger RNA (mRNA) vaccine against respiratory syncytial virus (RSV), in adults older than 60 years of age.

“We are pursuing an mRNA RSV vaccine to protect the most vulnerable populations – young children and older adults,” stated 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.”

RSV is a common respiratory virus that generally causes cold-like symptoms which most people recover from in a week or two. However, RSV can be serious, especially for infants and older adults and there is no approved vaccine currently available. RSV is the most common cause of bronchiolitis and pneumonia in children younger than one year of age in the US and can cause pneumonia and respiratory distress in older adults. According to the US Centers for Disease Control and Prevention (CDC), RSV causes, on average, approximately 58,000 hospitalisations in children under five and 177,000 hospitalisations among adults 65 years and older in the US each year. Moreover, the CDC reports RSV causes 14,000 deaths among adults 65 years plus each year.

Fast Track designation is designed to facilitate the development and expedite the review of therapies and vaccines for serious conditions that fill an unmet medical need. Programmes with this title may benefit from early and frequent communication with the FDA, in addition to a rolling submission of the marketing application.

mRNA-1345 is currently under evaluation in an ongoing Phase I study. The trial is assessing the vaccine’s tolerability and reactogenicity in younger adults, older adults and children. All four cohorts of younger adults (ages 18-49 years) are fully enrolled, while dosing in the older adult cohort (ages 65-79 years) is ongoing. The company shared the first interim analysis of the study, through one month post-vaccination, of the younger adult cohorts at its annual Vaccines Day on 14 April 2021. Results showed the vaccine candidate generated at least an 11-fold geometric mean rise in neutralising antibodies relative to baseline.

Moderna also intends to evaluate combinations of mRNA-1345 with its vaccines against other respiratory pathogens in children and separately in older adults.

About mRNA-1345

mRNA-1345 is a vaccine against RSV encoding for a prefusion F glycoprotein. It uses the same lipid nanoparticle (LNP) as the authorised COVID-19 Vaccine Moderna (now Spikevax) and contains optimised protein and codon sequences.