Moderna Doses First Patients in Phase 2 Study of mRNA RSV Vaccine

Moderna recently dosed the first participant in the Phase 2/3 study of its mRNA respiratory syncytial virus (RSV) vaccine candidate.

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

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 the CDC.  

In August, FDA granted fast track designation to mRNA-135 for adults 60 years of age and older after the vaccine generated a geometric mean rise in neutralizing antibodies relative to baseline at least 11-fold and increased RSV neutralizing antibodies in seropositive younger adults. 

“We believe that vaccine candidate against RSV can have a positive impact on public health as RSV represents a significant unmet global need,” Stephane Bancel, CEO of Moderna, said in the announcement. 

“We believe that combination vaccines against multiple respiratory pathogens can help ensure that people are fully vaccinated by leading to higher compliance and better uptake, which may result in a longer-term benefit to health care systems and protect people from a broader number of respiratory viruses,” Bancel continued. 

Interim data from a Phase 1 study of mRNA-1345 in older adults showed that neutralizing antibodies were present at baseline in all participants, as expected. 

A single mRNA-1345 vaccination of 50 micrograms, 100 micrograms, or 200 micrograms boosted neutralizing antibody titers against RSV-A by nearly 14-fold and against RSV-B by nearly 10-fold.

Moderna’s mRNA vaccine portfolio includes candidates against respiratory viruses, candidates against tropical viruses, and candidates against latent viruses.

In its respiratory virus vaccine program, in addition to its RSV vaccine candidate, the company is advancing its COVID-19 booster vaccine candidates and a seasonal flu vaccine candidate (mRNA-1010). 

Previously, Moderna recently 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.