FDA Grants Fast Track to Moderna’s mRNA RSV Vaccine for Adults

Moderna recently announced that FDA granted Fast Track designation for its mRNA respiratory syncytial virus (RSV) vaccine, mRNA-1345, for use in adults 60 years of age and older.

FDA Fast Track facilitates the development and expedites the review of therapies and vaccines for serious conditions that fill an unmet medical need.

Moderna recently received this designation for its COVID-19 vaccine candidate, Zika vaccine candidate (mRNA-1893), methylmalonic acidemia (MMA) (mRNA-3704), and propionic acidemia (PA) (mRNA-3927) programs.

“We are pursuing an mRNA RSV vaccine to protect the most vulnerable populations – young children and older adults,” Stéphane Bancel, chief executive officer of Moderna, said in the announcement. 

“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,” Bancel continued. 

mRNA-1345 is an RSV vaccine for a prefusion F glycoprotein, which elicits antibody responses compared to the postfusion state, a Moderna spokesperson explained. 

The Phase 1 study of mRNA-1345 will evaluate the tolerability and reactogenicity of mRNA-1345 in younger adults, older adults, and children. Researchers have fully enrolled all cohorts of younger adults, and dosing in the older adult cohort is ongoing. 

In April, Moderna stated that mRNA-1345 generated a geometric mean rise in neutralizing antibodies relative to baseline at least 11-fold and increased RSV neutralizing antibodies in seropositive younger adults.

The company plans to evaluate the potential combinations of mRNA-1345 with its vaccines against other respiratory pathogens in children and separately in older adults.

Moderna owns worldwide commercial rights to mRNA-1345.

RSV is the most common cause of bronchiolitis and pneumonia in children younger than one year in the US and can result in pneumonia and respiratory distress in older adults. 

The virus leads to nearly 58,000 hospitalizations annually among children younger than five years old, 177,000 hospitalizations among adults 65 years of age and older, and 14,000 deaths among adults 65 years and older, according to CDC. 

Currently, there is no approved RSV vaccine available.        

But top companies, including GSK and AstraZeneca, have developed potential RSV vaccine candidates.

In December 2020, GSK initiated a Phase 3 study investigating the safety and efficacy of its RSV vaccine candidate for maternal immunization. 

The study will enroll 10,000 pregnant women aged 18 to 49 years to uncover if a single dose of GSK’s RSV Maternal unadjuvanted vaccine candidate, GSK3888550A, can prevent RSV-associated lower respiratory tract infections (LRTI) in newborn infants. 

Interim results are expected by the second half of 2022.

And last month, AstraZeneca announced that its long-acting antibody, nirsevimab, was safe and tolerable in infants at high risk of RSV in a Phase 2/3 clinical trial. 

The MEDLEY 2/3 trial evaluated nirsevimab compared to Synagis in infants with chronic lung disease, congenital heart disease, prematurity, or those entering their first RSV season.